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* hugetlbfs: remove unneeded return value of hugetlb_vmtruncate()Miaohe Lin2021-02-241-5/+2
| | | | | | | | | | | | | The function hugetlb_vmtruncate() is guaranteed to always success since commit 7aa91e104028 ("hugetlb: allow extending ftruncate on hugetlbfs"). So we should remove the unneeded return value which is always 0. Link: https://lkml.kernel.org/r/20210208084637.47789-1-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlbfs: fix some comment typosMiaohe Lin2021-02-241-4/+4
| | | | | | | | | | | Fix typos reserv to reserve, minimim to minimum. No functional change intended. Link: https://lkml.kernel.org/r/20210130092351.28072-1-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlbfs: correct some obsolete comments about inode i_mutexMiaohe Lin2021-02-241-2/+2
| | | | | | | | | | | | Since commit 9902af79c01a ("parallel lookups: actual switch to rwsem"), i_mutex of inode is converted to i_rwsem. So replace i_mutex with i_rwsem to make comments up to date. Link: https://lkml.kernel.org/r/20210127093111.36672-1-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlbfs: make hugepage size conversion more readableMiaohe Lin2021-02-241-2/+2
| | | | | | | | | | | | The calculation 1U << (h->order + PAGE_SHIFT - 10) is actually equal to (PAGE_SHIFT << (h->order)) >> 10. So we can make it more readable by replace it with huge_page_size(h) >> 10. Link: https://lkml.kernel.org/r/20210122083141.24548-1-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlbfs: remove meaningless variable avoid_reserveMiaohe Lin2021-02-241-3/+9
| | | | | | | | | | | | | | The variable avoid_reserve is meaningless because we never changed its value and just passed it to alloc_huge_page(). So remove it to make code more clear that in hugetlbfs_fallocate, we never avoid reserve when alloc hugepage yet. Also add a comment offered by Mike Kravetz to explain this. Link: https://lkml.kernel.org/r/20210120071508.9078-1-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlbfs: correct obsolete function name in hugetlbfs_read_iter()Miaohe Lin2021-02-241-1/+1
| | | | | | | | | | | | | | Since commit 36e789144267 ("kill do_generic_mapping_read"), the function do_generic_mapping_read() is renamed to do_generic_file_read(). And then commit 47c27bc46946 ("fs: pass iocb to do_generic_file_read") renamed it to generic_file_buffered_read(). So replace do_generic_mapping_read() with generic_file_buffered_read() to keep comment uptodate. Link: https://lkml.kernel.org/r/20210118063210.47118-1-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlbfs: use helper macro default_hstate in init_hugetlbfs_fsMiaohe Lin2021-02-241-1/+1
| | | | | | | | | | | | | Since commit e5ff215941d5 ("hugetlb: multiple hstates for multiple page sizes"), we can use macro default_hstate to get the struct hstate which we use by default. But init_hugetlbfs_fs() forgot to use it. Link: https://lkml.kernel.org/r/20210116091827.20982-1-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlbfs: remove useless BUG_ON(!inode) in hugetlbfs_setattr()Miaohe Lin2021-02-241-2/+0
| | | | | | | | | | | | When we reach here with inode = NULL, we should have crashed as inode has already been dereferenced via hstate_inode. So this BUG_ON(!inode) does not take effect and should be removed. Link: https://lkml.kernel.org/r/20210118110700.52506-1-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlbfs: remove special hugetlbfs_set_page_dirty()Mike Kravetz2021-02-241-12/+1
| | | | | | | | | | | | | | | | | | | | Matthew Wilcox noticed that hugetlbfs_set_page_dirty always returns 0. Instead, it should return 1 or 0 depending on the previous state of the dirty bit. In addition, the call to compound_head is redundant as it is also performed in calling routine set_page_dirty. Replace the hugetlbfs specific routine hugetlbfs_set_page_dirty with __set_page_dirty_no_writeback as it addresses both of these issues. Link: https://lkml.kernel.org/r/20201221192542.15732-2-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Suggested-by: Matthew Wilcox <willy@infradead.org> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: David Hildenbrand <david@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/hugetlb: change hugetlb_reserve_pages() to type boolMike Kravetz2021-02-241-2/+2
| | | | | | | | | | | | | | | | | | | | | While reviewing a bug in hugetlb_reserve_pages, it was noticed that all callers ignore the return value. Any failure is considered an ENOMEM error by the callers. Change the function to be of type bool. The function will return true if the reservation was successful, false otherwise. Callers currently assume a zero return code indicates success. Change the callers to look for true to indicate success. No functional change, only code cleanup. Link: https://lkml.kernel.org/r/20201221192542.15732-1-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlb: convert page_huge_active() HPageMigratable flagMike Kravetz2021-02-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use the new hugetlb page specific flag HPageMigratable to replace the page_huge_active interfaces. By it's name, page_huge_active implied that a huge page was on the active list. However, that is not really what code checking the flag wanted to know. It really wanted to determine if the huge page could be migrated. This happens when the page is actually added to the page cache and/or task page table. This is the reasoning behind the name change. The VM_BUG_ON_PAGE() calls in the *_huge_active() interfaces are not really necessary as we KNOW the page is a hugetlb page. Therefore, they are removed. The routine page_huge_active checked for PageHeadHuge before testing the active bit. This is unnecessary in the case where we hold a reference or lock and know it is a hugetlb head page. page_huge_active is also called without holding a reference or lock (scan_movable_pages), and can race with code freeing the page. The extra check in page_huge_active shortened the race window, but did not prevent the race. Offline code calling scan_movable_pages already deals with these races, so removing the check is acceptable. Add comment to racy code. [songmuchun@bytedance.com: remove set_page_huge_active() declaration from include/linux/hugetlb.h] Link: https://lkml.kernel.org/r/CAMZfGtUda+KoAZscU0718TN61cSFwp4zy=y2oZ=+6Z2TAZZwng@mail.gmail.com Link: https://lkml.kernel.org/r/20210122195231.324857-3-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: David Hildenbrand <david@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlb: use page.private for hugetlb specific page flagsMike Kravetz2021-02-241-9/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "create hugetlb flags to consolidate state", v3. While discussing a series of hugetlb fixes in [1], it became evident that the hugetlb specific page state information is stored in a somewhat haphazard manner. Code dealing with state information would be easier to read, understand and maintain if this information was stored in a consistent manner. This series uses page.private of the hugetlb head page for storing a set of hugetlb specific page flags. Routines are priovided for test, set and clear of the flags. [1] https://lore.kernel.org/r/20210106084739.63318-1-songmuchun@bytedance.com This patch (of 4): As hugetlbfs evolved, state information about hugetlb pages was added. One 'convenient' way of doing this was to use available fields in tail pages. Over time, it has become difficult to know the meaning or contents of fields simply by looking at a small bit of code. Sometimes, the naming is just confusing. For example: The PagePrivate flag indicates a huge page reservation was consumed and needs to be restored if an error is encountered and the page is freed before it is instantiated. The page.private field contains the pointer to a subpool if the page is associated with one. In an effort to make the code more readable, use page.private to contain hugetlb specific page flags. These flags will have test, set and clear functions similar to those used for 'normal' page flags. More importantly, an enum of flag values will be created with names that actually reflect their purpose. In this patch, - Create infrastructure for hugetlb specific page flag functions - Move subpool pointer to page[1].private to make way for flags Create routines with meaningful names to modify subpool field - Use new HPageRestoreReserve flag instead of PagePrivate Conversion of other state information will happen in subsequent patches. Link: https://lkml.kernel.org/r/20210122195231.324857-1-mike.kravetz@oracle.com Link: https://lkml.kernel.org/r/20210122195231.324857-2-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: David Hildenbrand <david@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge tag 'idmapped-mounts-v5.12' of ↵Linus Torvalds2021-02-231-14/+21
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux Pull idmapped mounts from Christian Brauner: "This introduces idmapped mounts which has been in the making for some time. Simply put, different mounts can expose the same file or directory with different ownership. This initial implementation comes with ports for fat, ext4 and with Christoph's port for xfs with more filesystems being actively worked on by independent people and maintainers. Idmapping mounts handle a wide range of long standing use-cases. Here are just a few: - Idmapped mounts make it possible to easily share files between multiple users or multiple machines especially in complex scenarios. For example, idmapped mounts will be used in the implementation of portable home directories in systemd-homed.service(8) where they allow users to move their home directory to an external storage device and use it on multiple computers where they are assigned different uids and gids. This effectively makes it possible to assign random uids and gids at login time. - It is possible to share files from the host with unprivileged containers without having to change ownership permanently through chown(2). - It is possible to idmap a container's rootfs and without having to mangle every file. For example, Chromebooks use it to share the user's Download folder with their unprivileged containers in their Linux subsystem. - It is possible to share files between containers with non-overlapping idmappings. - Filesystem that lack a proper concept of ownership such as fat can use idmapped mounts to implement discretionary access (DAC) permission checking. - They allow users to efficiently changing ownership on a per-mount basis without having to (recursively) chown(2) all files. In contrast to chown (2) changing ownership of large sets of files is instantenous with idmapped mounts. This is especially useful when ownership of a whole root filesystem of a virtual machine or container is changed. With idmapped mounts a single syscall mount_setattr syscall will be sufficient to change the ownership of all files. - Idmapped mounts always take the current ownership into account as idmappings specify what a given uid or gid is supposed to be mapped to. This contrasts with the chown(2) syscall which cannot by itself take the current ownership of the files it changes into account. It simply changes the ownership to the specified uid and gid. This is especially problematic when recursively chown(2)ing a large set of files which is commong with the aforementioned portable home directory and container and vm scenario. - Idmapped mounts allow to change ownership locally, restricting it to specific mounts, and temporarily as the ownership changes only apply as long as the mount exists. Several userspace projects have either already put up patches and pull-requests for this feature or will do so should you decide to pull this: - systemd: In a wide variety of scenarios but especially right away in their implementation of portable home directories. https://systemd.io/HOME_DIRECTORY/ - container runtimes: containerd, runC, LXD:To share data between host and unprivileged containers, unprivileged and privileged containers, etc. The pull request for idmapped mounts support in containerd, the default Kubernetes runtime is already up for quite a while now: https://github.com/containerd/containerd/pull/4734 - The virtio-fs developers and several users have expressed interest in using this feature with virtual machines once virtio-fs is ported. - ChromeOS: Sharing host-directories with unprivileged containers. I've tightly synced with all those projects and all of those listed here have also expressed their need/desire for this feature on the mailing list. For more info on how people use this there's a bunch of talks about this too. Here's just two recent ones: https://www.cncf.io/wp-content/uploads/2020/12/Rootless-Containers-in-Gitpod.pdf https://fosdem.org/2021/schedule/event/containers_idmap/ This comes with an extensive xfstests suite covering both ext4 and xfs: https://git.kernel.org/brauner/xfstests-dev/h/idmapped_mounts It covers truncation, creation, opening, xattrs, vfscaps, setid execution, setgid inheritance and more both with idmapped and non-idmapped mounts. It already helped to discover an unrelated xfs setgid inheritance bug which has since been fixed in mainline. It will be sent for inclusion with the xfstests project should you decide to merge this. In order to support per-mount idmappings vfsmounts are marked with user namespaces. The idmapping of the user namespace will be used to map the ids of vfs objects when they are accessed through that mount. By default all vfsmounts are marked with the initial user namespace. The initial user namespace is used to indicate that a mount is not idmapped. All operations behave as before and this is verified in the testsuite. Based on prior discussions we want to attach the whole user namespace and not just a dedicated idmapping struct. This allows us to reuse all the helpers that already exist for dealing with idmappings instead of introducing a whole new range of helpers. In addition, if we decide in the future that we are confident enough to enable unprivileged users to setup idmapped mounts the permission checking can take into account whether the caller is privileged in the user namespace the mount is currently marked with. The user namespace the mount will be marked with can be specified by passing a file descriptor refering to the user namespace as an argument to the new mount_setattr() syscall together with the new MOUNT_ATTR_IDMAP flag. The system call follows the openat2() pattern of extensibility. The following conditions must be met in order to create an idmapped mount: - The caller must currently have the CAP_SYS_ADMIN capability in the user namespace the underlying filesystem has been mounted in. - The underlying filesystem must support idmapped mounts. - The mount must not already be idmapped. This also implies that the idmapping of a mount cannot be altered once it has been idmapped. - The mount must be a detached/anonymous mount, i.e. it must have been created by calling open_tree() with the OPEN_TREE_CLONE flag and it must not already have been visible in the filesystem. The last two points guarantee easier semantics for userspace and the kernel and make the implementation significantly simpler. By default vfsmounts are marked with the initial user namespace and no behavioral or performance changes are observed. The manpage with a detailed description can be found here: https://git.kernel.org/brauner/man-pages/c/1d7b902e2875a1ff342e036a9f866a995640aea8 In order to support idmapped mounts, filesystems need to be changed and mark themselves with the FS_ALLOW_IDMAP flag in fs_flags. The patches to convert individual filesystem are not very large or complicated overall as can be seen from the included fat, ext4, and xfs ports. Patches for other filesystems are actively worked on and will be sent out separately. The xfstestsuite can be used to verify that port has been done correctly. The mount_setattr() syscall is motivated independent of the idmapped mounts patches and it's been around since July 2019. One of the most valuable features of the new mount api is the ability to perform mounts based on file descriptors only. Together with the lookup restrictions available in the openat2() RESOLVE_* flag namespace which we added in v5.6 this is the first time we are close to hardened and race-free (e.g. symlinks) mounting and path resolution. While userspace has started porting to the new mount api to mount proper filesystems and create new bind-mounts it is currently not possible to change mount options of an already existing bind mount in the new mount api since the mount_setattr() syscall is missing. With the addition of the mount_setattr() syscall we remove this last restriction and userspace can now fully port to the new mount api, covering every use-case the old mount api could. We also add the crucial ability to recursively change mount options for a whole mount tree, both removing and adding mount options at the same time. This syscall has been requested multiple times by various people and projects. There is a simple tool available at https://github.com/brauner/mount-idmapped that allows to create idmapped mounts so people can play with this patch series. I'll add support for the regular mount binary should you decide to pull this in the following weeks: Here's an example to a simple idmapped mount of another user's home directory: u1001@f2-vm:/$ sudo ./mount --idmap both:1000:1001:1 /home/ubuntu/ /mnt u1001@f2-vm:/$ ls -al /home/ubuntu/ total 28 drwxr-xr-x 2 ubuntu ubuntu 4096 Oct 28 22:07 . drwxr-xr-x 4 root root 4096 Oct 28 04:00 .. -rw------- 1 ubuntu ubuntu 3154 Oct 28 22:12 .bash_history -rw-r--r-- 1 ubuntu ubuntu 220 Feb 25 2020 .bash_logout -rw-r--r-- 1 ubuntu ubuntu 3771 Feb 25 2020 .bashrc -rw-r--r-- 1 ubuntu ubuntu 807 Feb 25 2020 .profile -rw-r--r-- 1 ubuntu ubuntu 0 Oct 16 16:11 .sudo_as_admin_successful -rw------- 1 ubuntu ubuntu 1144 Oct 28 00:43 .viminfo u1001@f2-vm:/$ ls -al /mnt/ total 28 drwxr-xr-x 2 u1001 u1001 4096 Oct 28 22:07 . drwxr-xr-x 29 root root 4096 Oct 28 22:01 .. -rw------- 1 u1001 u1001 3154 Oct 28 22:12 .bash_history -rw-r--r-- 1 u1001 u1001 220 Feb 25 2020 .bash_logout -rw-r--r-- 1 u1001 u1001 3771 Feb 25 2020 .bashrc -rw-r--r-- 1 u1001 u1001 807 Feb 25 2020 .profile -rw-r--r-- 1 u1001 u1001 0 Oct 16 16:11 .sudo_as_admin_successful -rw------- 1 u1001 u1001 1144 Oct 28 00:43 .viminfo u1001@f2-vm:/$ touch /mnt/my-file u1001@f2-vm:/$ setfacl -m u:1001:rwx /mnt/my-file u1001@f2-vm:/$ sudo setcap -n 1001 cap_net_raw+ep /mnt/my-file u1001@f2-vm:/$ ls -al /mnt/my-file -rw-rwxr--+ 1 u1001 u1001 0 Oct 28 22:14 /mnt/my-file u1001@f2-vm:/$ ls -al /home/ubuntu/my-file -rw-rwxr--+ 1 ubuntu ubuntu 0 Oct 28 22:14 /home/ubuntu/my-file u1001@f2-vm:/$ getfacl /mnt/my-file getfacl: Removing leading '/' from absolute path names # file: mnt/my-file # owner: u1001 # group: u1001 user::rw- user:u1001:rwx group::rw- mask::rwx other::r-- u1001@f2-vm:/$ getfacl /home/ubuntu/my-file getfacl: Removing leading '/' from absolute path names # file: home/ubuntu/my-file # owner: ubuntu # group: ubuntu user::rw- user:ubuntu:rwx group::rw- mask::rwx other::r--" * tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: (41 commits) xfs: remove the possibly unused mp variable in xfs_file_compat_ioctl xfs: support idmapped mounts ext4: support idmapped mounts fat: handle idmapped mounts tests: add mount_setattr() selftests fs: introduce MOUNT_ATTR_IDMAP fs: add mount_setattr() fs: add attr_flags_to_mnt_flags helper fs: split out functions to hold writers namespace: only take read lock in do_reconfigure_mnt() mount: make {lock,unlock}_mount_hash() static namespace: take lock_mount_hash() directly when changing flags nfs: do not export idmapped mounts overlayfs: do not mount on top of idmapped mounts ecryptfs: do not mount on top of idmapped mounts ima: handle idmapped mounts apparmor: handle idmapped mounts fs: make helpers idmap mount aware exec: handle idmapped mounts would_dump: handle idmapped mounts ...
| * fs: make helpers idmap mount awareChristian Brauner2021-01-241-11/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Extend some inode methods with an additional user namespace argument. A filesystem that is aware of idmapped mounts will receive the user namespace the mount has been marked with. This can be used for additional permission checking and also to enable filesystems to translate between uids and gids if they need to. We have implemented all relevant helpers in earlier patches. As requested we simply extend the exisiting inode method instead of introducing new ones. This is a little more code churn but it's mostly mechanical and doesnt't leave us with additional inode methods. Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
| * attr: handle idmapped mountsChristian Brauner2021-01-241-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When file attributes are changed most filesystems rely on the setattr_prepare(), setattr_copy(), and notify_change() helpers for initialization and permission checking. Let them handle idmapped mounts. If the inode is accessed through an idmapped mount map it into the mount's user namespace. Afterwards the checks are identical to non-idmapped mounts. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Helpers that perform checks on the ia_uid and ia_gid fields in struct iattr assume that ia_uid and ia_gid are intended values and have already been mapped correctly at the userspace-kernelspace boundary as we already do today. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
| * inode: make init and permission helpers idmapped mount awareChristian Brauner2021-01-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The inode_owner_or_capable() helper determines whether the caller is the owner of the inode or is capable with respect to that inode. Allow it to handle idmapped mounts. If the inode is accessed through an idmapped mount it according to the mount's user namespace. Afterwards the checks are identical to non-idmapped mounts. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Similarly, allow the inode_init_owner() helper to handle idmapped mounts. It initializes a new inode on idmapped mounts by mapping the fsuid and fsgid of the caller from the mount's user namespace. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-7-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
* | mm: hugetlbfs: fix cannot migrate the fallocated HugeTLB pageMuchun Song2021-02-051-1/+2
|/ | | | | | | | | | | | | | | | | | | | | | If a new hugetlb page is allocated during fallocate it will not be marked as active (set_page_huge_active) which will result in a later isolate_huge_page failure when the page migration code would like to move that page. Such a failure would be unexpected and wrong. Only export set_page_huge_active, just leave clear_page_huge_active as static. Because there are no external users. Link: https://lkml.kernel.org/r/20210115124942.46403-3-songmuchun@bytedance.com Fixes: 70c3547e36f5 (hugetlbfs: add hugetlbfs_fallocate()) Signed-off-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: David Hildenbrand <david@redhat.com> Cc: Yang Shi <shy828301@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlbfs: prevent filesystem stacking of hugetlbfsMike Kravetz2020-08-121-0/+6
| | | | | | | | | | | | | | | | | | | | | syzbot found issues with having hugetlbfs on a union/overlay as reported in [1]. Due to the limitations (no write) and special functionality of hugetlbfs, it does not work well in filesystem stacking. There are no know use cases for hugetlbfs stacking. Rather than making modifications to get hugetlbfs working in such environments, simply prevent stacking. [1] https://lore.kernel.org/linux-mm/000000000000b4684e05a2968ca6@google.com/ Reported-by: syzbot+d6ec23007e951dadf3de@syzkaller.appspotmail.com Suggested-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Miklos Szeredi <mszeredi@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Matthew Wilcox <willy@infradead.org> Cc: Colin Walters <walters@verbum.org> Link: http://lkml.kernel.org/r/80f869aa-810d-ef6c-8888-b46cee135907@oracle.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: remove unnecessary wrapper function do_mmap_pgoff()Peter Collingbourne2020-08-071-1/+1
| | | | | | | | | | | | | | | | | | | | | The current split between do_mmap() and do_mmap_pgoff() was introduced in commit 1fcfd8db7f82 ("mm, mpx: add "vm_flags_t vm_flags" arg to do_mmap_pgoff()") to support MPX. The wrapper function do_mmap_pgoff() always passed 0 as the value of the vm_flags argument to do_mmap(). However, MPX support has subsequently been removed from the kernel and there were no more direct callers of do_mmap(); all calls were going via do_mmap_pgoff(). Simplify the code by removing do_mmap_pgoff() and changing all callers to directly call do_mmap(), which now no longer takes a vm_flags argument. Signed-off-by: Peter Collingbourne <pcc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: David Hildenbrand <david@redhat.com> Link: http://lkml.kernel.org/r/20200727194109.1371462-1-pcc@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mmap locking API: convert mmap_sem API commentsMichel Lespinasse2020-06-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | Convert comments that reference old mmap_sem APIs to reference corresponding new mmap locking APIs instead. Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Davidlohr Bueso <dbueso@suse.de> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-12-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlbfs: get unmapped area below TASK_UNMAPPED_BASE for hugetlbfsShijie Hu2020-06-031-8/+59
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In a 32-bit program, running on arm64 architecture. When the address space below mmap base is completely exhausted, shmat() for huge pages will return ENOMEM, but shmat() for normal pages can still success on no-legacy mode. This seems not fair. For normal pages, the calling trace of get_unmapped_area() is: => mm->get_unmapped_area() if on legacy mode, => arch_get_unmapped_area() => vm_unmapped_area() if on no-legacy mode, => arch_get_unmapped_area_topdown() => vm_unmapped_area() For huge pages, the calling trace of get_unmapped_area() is: => file->f_op->get_unmapped_area() => hugetlb_get_unmapped_area() => vm_unmapped_area() To solve this issue, we only need to make hugetlb_get_unmapped_area() take the same way as mm->get_unmapped_area(). Add *bottomup() and *topdown() for hugetlbfs, and check current mm->get_unmapped_area() to decide which one to use. If mm->get_unmapped_area is equal to arch_get_unmapped_area_topdown(), hugetlb_get_unmapped_area() calls topdown routine, otherwise calls bottomup routine. Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Shijie Hu <hushijie3@huawei.com> Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Will Deacon <will@kernel.org> Cc: Xiaoming Ni <nixiaoming@huawei.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: yangerkun <yangerkun@huawei.com> Cc: ChenGang <cg.chen@huawei.com> Cc: Chen Jie <chenjie6@huawei.com> Link: http://lkml.kernel.org/r/20200518065338.113664-1-hushijie3@huawei.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlbfs: Use i_mmap_rwsem to address page fault/truncate raceMike Kravetz2020-04-021-8/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | hugetlbfs page faults can race with truncate and hole punch operations. Current code in the page fault path attempts to handle this by 'backing out' operations if we encounter the race. One obvious omission in the current code is removing a page newly added to the page cache. This is pretty straight forward to address, but there is a more subtle and difficult issue of backing out hugetlb reservations. To handle this correctly, the 'reservation state' before page allocation needs to be noted so that it can be properly backed out. There are four distinct possibilities for reservation state: shared/reserved, shared/no-resv, private/reserved and private/no-resv. Backing out a reservation may require memory allocation which could fail so that needs to be taken into account as well. Instead of writing the required complicated code for this rare occurrence, just eliminate the race. i_mmap_rwsem is now held in read mode for the duration of page fault processing. Hold i_mmap_rwsem in write mode when modifying i_size. In this way, truncation can not proceed when page faults are being processed. In addition, i_size will not change during fault processing so a single check can be made to ensure faults are not beyond (proposed) end of file. Faults can still race with hole punch, but that race is handled by existing code and the use of hugetlb_fault_mutex. With this modification, checks for races with truncation in the page fault path can be simplified and removed. remove_inode_hugepages no longer needs to take hugetlb_fault_mutex in the case of truncation. Comments are expanded to explain reasoning behind locking. Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hugh Dickins <hughd@google.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Prakash Sangappa <prakash.sangappa@oracle.com> Link: http://lkml.kernel.org/r/20200316205756.146666-3-mike.kravetz@oracle.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronizationMike Kravetz2020-04-021-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "hugetlbfs: use i_mmap_rwsem for more synchronization", v2. While discussing the issue with huge_pte_offset [1], I remembered that there were more outstanding hugetlb races. These issues are: 1) For shared pmds, huge PTE pointers returned by huge_pte_alloc can become invalid via a call to huge_pmd_unshare by another thread. 2) hugetlbfs page faults can race with truncation causing invalid global reserve counts and state. A previous attempt was made to use i_mmap_rwsem in this manner as described at [2]. However, those patches were reverted starting with [3] due to locking issues. To effectively use i_mmap_rwsem to address the above issues it needs to be held (in read mode) during page fault processing. However, during fault processing we need to lock the page we will be adding. Lock ordering requires we take page lock before i_mmap_rwsem. Waiting until after taking the page lock is too late in the fault process for the synchronization we want to do. To address this lock ordering issue, the following patches change the lock ordering for hugetlb pages. This is not too invasive as hugetlbfs processing is done separate from core mm in many places. However, I don't really like this idea. Much ugliness is contained in the new routine hugetlb_page_mapping_lock_write() of patch 1. The only other way I can think of to address these issues is by catching all the races. After catching a race, cleanup, backout, retry ... etc, as needed. This can get really ugly, especially for huge page reservations. At one time, I started writing some of the reservation backout code for page faults and it got so ugly and complicated I went down the path of adding synchronization to avoid the races. Any other suggestions would be welcome. [1] https://lore.kernel.org/linux-mm/1582342427-230392-1-git-send-email-longpeng2@huawei.com/ [2] https://lore.kernel.org/linux-mm/20181222223013.22193-1-mike.kravetz@oracle.com/ [3] https://lore.kernel.org/linux-mm/20190103235452.29335-1-mike.kravetz@oracle.com [4] https://lore.kernel.org/linux-mm/1584028670.7365.182.camel@lca.pw/ [5] https://lore.kernel.org/lkml/20200312183142.108df9ac@canb.auug.org.au/ This patch (of 2): While looking at BUGs associated with invalid huge page map counts, it was discovered and observed that a huge pte pointer could become 'invalid' and point to another task's page table. Consider the following: A task takes a page fault on a shared hugetlbfs file and calls huge_pte_alloc to get a ptep. Suppose the returned ptep points to a shared pmd. Now, another task truncates the hugetlbfs file. As part of truncation, it unmaps everyone who has the file mapped. If the range being truncated is covered by a shared pmd, huge_pmd_unshare will be called. For all but the last user of the shared pmd, huge_pmd_unshare will clear the pud pointing to the pmd. If the task in the middle of the page fault is not the last user, the ptep returned by huge_pte_alloc now points to another task's page table or worse. This leads to bad things such as incorrect page map/reference counts or invalid memory references. To fix, expand the use of i_mmap_rwsem as follows: - i_mmap_rwsem is held in read mode whenever huge_pmd_share is called. huge_pmd_share is only called via huge_pte_alloc, so callers of huge_pte_alloc take i_mmap_rwsem before calling. In addition, callers of huge_pte_alloc continue to hold the semaphore until finished with the ptep. - i_mmap_rwsem is held in write mode whenever huge_pmd_unshare is called. One problem with this scheme is that it requires taking i_mmap_rwsem before taking the page lock during page faults. This is not the order specified in the rest of mm code. Handling of hugetlbfs pages is mostly isolated today. Therefore, we use this alternative locking order for PageHuge() pages. mapping->i_mmap_rwsem hugetlb_fault_mutex (hugetlbfs specific page fault mutex) page->flags PG_locked (lock_page) To help with lock ordering issues, hugetlb_page_mapping_lock_write() is introduced to write lock the i_mmap_rwsem associated with a page. In most cases it is easy to get address_space via vma->vm_file->f_mapping. However, in the case of migration or memory errors for anon pages we do not have an associated vma. A new routine _get_hugetlb_page_mapping() will use anon_vma to get address_space in these cases. Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Prakash Sangappa <prakash.sangappa@oracle.com> Link: http://lkml.kernel.org/r/20200316205756.146666-2-mike.kravetz@oracle.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlbfs: switch to use of invalfc()Al Viro2020-02-071-1/+1
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs_parse: fold fs_parameter_desc/fs_parameter_specAl Viro2020-02-071-7/+3
| | | | | | The former contains nothing but a pointer to an array of the latter... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs_parser: remove fs_parameter_description name fieldEric Sandeen2020-02-071-1/+0
| | | | | | | | Unused now. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* mm/hugetlbfs: fix for_each_hstate() loop in init_hugetlbfs_fs()Jan Stancek2020-01-031-1/+3
| | | | | | | | | | | | | | LTP memfd_create04 started failing for some huge page sizes after v5.4-10135-gc3bfc5dd73c6. The problem is the check introduced to for_each_hstate() loop that should skip default_hstate_idx. Since it doesn't update 'i' counter, all subsequent huge page sizes are skipped as well. Fixes: 8fc312b32b25 ("mm/hugetlbfs: fix error handling when setting up mounts") Signed-off-by: Jan Stancek <jstancek@redhat.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlb: remove unused hstate in hugetlb_fault_mutex_hash()Wei Yang2019-12-011-2/+2
| | | | | | | | | | | | | | | | | | | | | The first parameter hstate in function hugetlb_fault_mutex_hash() is not used anymore. This patch removes it. [akpm@linux-foundation.org: various build fixes] [cai@lca.pw: fix a GCC compilation warning] Link: http://lkml.kernel.org/r/1570544108-32331-1-git-send-email-cai@lca.pw Link: http://lkml.kernel.org/r/20191005003302.785-1-richardw.yang@linux.intel.com Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> Signed-off-by: Qian Cai <cai@lca.pw> Suggested-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Hugh Dickins <hughd@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlbfs: add O_TMPFILE supportPiotr Sarna2019-12-011-4/+24
| | | | | | | | | | | | | | | | | | | | | | | With hugetlbfs, a common pattern for mapping anonymous huge pages is to create a temporary file first. Currently libraries like libhugetlbfs and seastar create these with a standard mkstemp+unlink trick, but it would be more robust to be able to simply pass the O_TMPFILE flag to open(). O_TMPFILE is already supported by several file systems like ext4 and xfs. The implementation simply uses the existi= ng d_tmpfile utility function to instantiate the dcache entry for the file. Tested manually by successfully creating a temporary file by opening it with (O_TMPFILE|O_RDWR) on mounted hugetlbfs and successfully mapping 2M huge pages with it. Without the patch, trying to open a file with O_TMPFILE results in -ENOSUP. Link: http://lkml.kernel.org/r/bc9383eff6e1374d79f3a92257ae829ba1e6ae60.1573285189.git.p.sarna@tlen.pl Signed-off-by: Piotr Sarna <p.sarna@tlen.pl> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/hugetlbfs: fix error handling when setting up mountsMike Kravetz2019-12-011-9/+22
| | | | | | | | | | | | | | | | | | | | | | | It is assumed that the hugetlbfs_vfsmount[] array will contain either a valid vfsmount pointer or NULL for each hstate after initialization. Changes made while converting to use fs_context broke this assumption. While fixing the hugetlbfs_vfsmount issue, it was discovered that init_hugetlbfs_fs never did correctly clean up when encountering a vfs mount error. It was found during code inspection. A small memory allocation failure would be the most likely cause of taking a error path with the bug. This is unlikely to happen as this is early init code. Link: http://lkml.kernel.org/r/94b6244d-2c24-e269-b12c-e3ba694b242d@oracle.com Reported-by: Chengguang Xu <cgxu519@mykernel.net> Fixes: 32021982a324 ("hugetlbfs: Convert to fs_context") Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlbfs: hugetlb_fault_mutex_hash() cleanupMike Kravetz2019-12-011-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | A new clang diagnostic (-Wsizeof-array-div) warns about the calculation to determine the number of u32's in an array of unsigned longs. Suppress warning by adding parentheses. While looking at the above issue, noticed that the 'address' parameter to hugetlb_fault_mutex_hash is no longer used. So, remove it from the definition and all callers. No functional change. Link: http://lkml.kernel.org/r/20190919011847.18400-1-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Davidlohr Bueso <dbueso@suse.de> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Ilie Halip <ilie.halip@gmail.com> Cc: David Bolvansky <david.bolvansky@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'work.mount0' of ↵Linus Torvalds2019-07-191-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs mount updates from Al Viro: "The first part of mount updates. Convert filesystems to use the new mount API" * 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits) mnt_init(): call shmem_init() unconditionally constify ksys_mount() string arguments don't bother with registering rootfs init_rootfs(): don't bother with init_ramfs_fs() vfs: Convert smackfs to use the new mount API vfs: Convert selinuxfs to use the new mount API vfs: Convert securityfs to use the new mount API vfs: Convert apparmorfs to use the new mount API vfs: Convert openpromfs to use the new mount API vfs: Convert xenfs to use the new mount API vfs: Convert gadgetfs to use the new mount API vfs: Convert oprofilefs to use the new mount API vfs: Convert ibmasmfs to use the new mount API vfs: Convert qib_fs/ipathfs to use the new mount API vfs: Convert efivarfs to use the new mount API vfs: Convert configfs to use the new mount API vfs: Convert binfmt_misc to use the new mount API convenience helper: get_tree_single() convenience helper get_tree_nodev() vfs: Kill sget_userns() ...
| * convenience helper get_tree_nodev()Al Viro2019-07-041-1/+1
| | | | | | | | | | | | counterpart of mount_nodev(). Switch hugetlb and pseudo to it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | treewide: Add SPDX license identifier - Makefile/KconfigThomas Gleixner2019-05-211-0/+1
|/ | | | | | | | | | | | | | Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* hugetlbfs: always use address space in inode for resv_map pointerMike Kravetz2019-05-141-2/+9
| | | | | | | | | | | | | | | | | | | | | | | | Continuing discussion about 58b6e5e8f1ad ("hugetlbfs: fix memory leak for resv_map") brought up the issue that inode->i_mapping may not point to the address space embedded within the inode at inode eviction time. The hugetlbfs truncate routine handles this by explicitly using inode->i_data. However, code cleaning up the resv_map will still use the address space pointed to by inode->i_mapping. Luckily, private_data is NULL for address spaces in all such cases today but, there is no guarantee this will continue. Change all hugetlbfs code getting a resv_map pointer to explicitly get it from the address space embedded within the inode. In addition, add more comments in the code to indicate why this is being done. Link: http://lkml.kernel.org/r/20190419204435.16984-1-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reported-by: Yufen Yu <yuyufen@huawei.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlb: use same fault hash key for shared and private mappingsMike Kravetz2019-05-141-5/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | hugetlb uses a fault mutex hash table to prevent page faults of the same pages concurrently. The key for shared and private mappings is different. Shared keys off address_space and file index. Private keys off mm and virtual address. Consider a private mappings of a populated hugetlbfs file. A fault will map the page from the file and if needed do a COW to map a writable page. Hugetlbfs hole punch uses the fault mutex to prevent mappings of file pages. It uses the address_space file index key. However, private mappings will use a different key and could race with this code to map the file page. This causes problems (BUG) for the page cache remove code as it expects the page to be unmapped. A sample stack is: page dumped because: VM_BUG_ON_PAGE(page_mapped(page)) kernel BUG at mm/filemap.c:169! ... RIP: 0010:unaccount_page_cache_page+0x1b8/0x200 ... Call Trace: __delete_from_page_cache+0x39/0x220 delete_from_page_cache+0x45/0x70 remove_inode_hugepages+0x13c/0x380 ? __add_to_page_cache_locked+0x162/0x380 hugetlbfs_fallocate+0x403/0x540 ? _cond_resched+0x15/0x30 ? __inode_security_revalidate+0x5d/0x70 ? selinux_file_permission+0x100/0x130 vfs_fallocate+0x13f/0x270 ksys_fallocate+0x3c/0x80 __x64_sys_fallocate+0x1a/0x20 do_syscall_64+0x5b/0x180 entry_SYSCALL_64_after_hwframe+0x44/0xa9 There seems to be another potential COW issue/race with this approach of different private and shared keys as noted in commit 8382d914ebf7 ("mm, hugetlb: improve page-fault scalability"). Since every hugetlb mapping (even anon and private) is actually a file mapping, just use the address_space index key for all mappings. This results in potentially more hash collisions. However, this should not be the common case. Link: http://lkml.kernel.org/r/20190328234704.27083-3-mike.kravetz@oracle.com Link: http://lkml.kernel.org/r/20190412165235.t4sscoujczfhuiyt@linux-r8p5 Fixes: b5cec28d36f5 ("hugetlbfs: truncate_hugepages() takes a range of pages") Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reviewed-by: Davidlohr Bueso <dbueso@suse.de> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlb: make use of ->free_inode()Al Viro2019-05-011-3/+2
| | | | | | | | moving synchronous parts of ->destroy_inode() to ->evict_inode() is not possible here - they are balancing the stuff done in ->alloc_inode(), not the things acquired while using it or sanity checks. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* hugetlbfs: fix memory leak for resv_mapMike Kravetz2019-04-051-6/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | When mknod is used to create a block special file in hugetlbfs, it will allocate an inode and kmalloc a 'struct resv_map' via resv_map_alloc(). inode->i_mapping->private_data will point the newly allocated resv_map. However, when the device special file is opened bd_acquire() will set inode->i_mapping to bd_inode->i_mapping. Thus the pointer to the allocated resv_map is lost and the structure is leaked. Programs to reproduce: mount -t hugetlbfs nodev hugetlbfs mknod hugetlbfs/dev b 0 0 exec 30<> hugetlbfs/dev umount hugetlbfs/ resv_map structures are only needed for inodes which can have associated page allocations. To fix the leak, only allocate resv_map for those inodes which could possibly be associated with page allocations. Link: http://lkml.kernel.org/r/20190401213101.16476-1-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reported-by: Yufen Yu <yuyufen@huawei.com> Suggested-by: Yufen Yu <yuyufen@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'work.mount' of ↵Linus Torvalds2019-03-121-158/+200
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs mount infrastructure updates from Al Viro: "The rest of core infrastructure; no new syscalls in that pile, but the old parts are switched to new infrastructure. At that point conversions of individual filesystems can happen independently; some are done here (afs, cgroup, procfs, etc.), there's also a large series outside of that pile dealing with NFS (quite a bit of option-parsing stuff is getting used there - it's one of the most convoluted filesystems in terms of mount-related logics), but NFS bits are the next cycle fodder. It got seriously simplified since the last cycle; documentation is probably the weakest bit at the moment - I considered dropping the commit introducing Documentation/filesystems/mount_api.txt (cutting the size increase by quarter ;-), but decided that it would be better to fix it up after -rc1 instead. That pile allows to do followup work in independent branches, which should make life much easier for the next cycle. fs/super.c size increase is unpleasant; there's a followup series that allows to shrink it considerably, but I decided to leave that until the next cycle" * 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (41 commits) afs: Use fs_context to pass parameters over automount afs: Add fs_context support vfs: Add some logging to the core users of the fs_context log vfs: Implement logging through fs_context vfs: Provide documentation for new mount API vfs: Remove kern_mount_data() hugetlbfs: Convert to fs_context cpuset: Use fs_context kernfs, sysfs, cgroup, intel_rdt: Support fs_context cgroup: store a reference to cgroup_ns into cgroup_fs_context cgroup1_get_tree(): separate "get cgroup_root to use" into a separate helper cgroup_do_mount(): massage calling conventions cgroup: stash cgroup_root reference into cgroup_fs_context cgroup2: switch to option-by-option parsing cgroup1: switch to option-by-option parsing cgroup: take options parsing into ->parse_monolithic() cgroup: fold cgroup1_mount() into cgroup1_get_tree() cgroup: start switching to fs_context ipc: Convert mqueue fs to fs_context proc: Add fs_context support to procfs ...
| * hugetlbfs: Convert to fs_contextDavid Howells2019-02-281-158/+200
| | | | | | | | | | | | | | Convert the hugetlbfs to use the fs_context during mount. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | mm/memfd: add an F_SEAL_FUTURE_WRITE seal to memfdJoel Fernandes (Google)2019-03-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Android uses ashmem for sharing memory regions. We are looking forward to migrating all usecases of ashmem to memfd so that we can possibly remove the ashmem driver in the future from staging while also benefiting from using memfd and contributing to it. Note staging drivers are also not ABI and generally can be removed at anytime. One of the main usecases Android has is the ability to create a region and mmap it as writeable, then add protection against making any "future" writes while keeping the existing already mmap'ed writeable-region active. This allows us to implement a usecase where receivers of the shared memory buffer can get a read-only view, while the sender continues to write to the buffer. See CursorWindow documentation in Android for more details: https://developer.android.com/reference/android/database/CursorWindow This usecase cannot be implemented with the existing F_SEAL_WRITE seal. To support the usecase, this patch adds a new F_SEAL_FUTURE_WRITE seal which prevents any future mmap and write syscalls from succeeding while keeping the existing mmap active. A better way to do F_SEAL_FUTURE_WRITE seal was discussed [1] last week where we don't need to modify core VFS structures to get the same behavior of the seal. This solves several side-effects pointed by Andy. self-tests are provided in later patch to verify the expected semantics. [1] https://lore.kernel.org/lkml/20181111173650.GA256781@google.com/ Thanks a lot to Andy for suggestions to improve code. Link: http://lkml.kernel.org/r/20190112203816.85534-2-joel@joelfernandes.org Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Acked-by: John Stultz <john.stultz@linaro.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Jann Horn <jannh@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andy Lutomirski <luto@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: J. Bruce Fields <bfields@fieldses.org> Cc: Jeff Layton <jlayton@kernel.org> Cc: Marc-Andr Lureau <marcandre.lureau@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | hugetlbfs: fix races and page leaks during migrationMike Kravetz2019-03-011-0/+12
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | hugetlb pages should only be migrated if they are 'active'. The routines set/clear_page_huge_active() modify the active state of hugetlb pages. When a new hugetlb page is allocated at fault time, set_page_huge_active is called before the page is locked. Therefore, another thread could race and migrate the page while it is being added to page table by the fault code. This race is somewhat hard to trigger, but can be seen by strategically adding udelay to simulate worst case scheduling behavior. Depending on 'how' the code races, various BUG()s could be triggered. To address this issue, simply delay the set_page_huge_active call until after the page is successfully added to the page table. Hugetlb pages can also be leaked at migration time if the pages are associated with a file in an explicitly mounted hugetlbfs filesystem. For example, consider a two node system with 4GB worth of huge pages available. A program mmaps a 2G file in a hugetlbfs filesystem. It then migrates the pages associated with the file from one node to another. When the program exits, huge page counts are as follows: node0 1024 free_hugepages 1024 nr_hugepages node1 0 free_hugepages 1024 nr_hugepages Filesystem Size Used Avail Use% Mounted on nodev 4.0G 2.0G 2.0G 50% /var/opt/hugepool That is as expected. 2G of huge pages are taken from the free_hugepages counts, and 2G is the size of the file in the explicitly mounted filesystem. If the file is then removed, the counts become: node0 1024 free_hugepages 1024 nr_hugepages node1 1024 free_hugepages 1024 nr_hugepages Filesystem Size Used Avail Use% Mounted on nodev 4.0G 2.0G 2.0G 50% /var/opt/hugepool Note that the filesystem still shows 2G of pages used, while there actually are no huge pages in use. The only way to 'fix' the filesystem accounting is to unmount the filesystem If a hugetlb page is associated with an explicitly mounted filesystem, this information in contained in the page_private field. At migration time, this information is not preserved. To fix, simply transfer page_private from old to new page at migration time if necessary. There is a related race with removing a huge page from a file and migration. When a huge page is removed from the pagecache, the page_mapping() field is cleared, yet page_private remains set until the page is actually freed by free_huge_page(). A page could be migrated while in this state. However, since page_mapping() is not set the hugetlbfs specific routine to transfer page_private is not called and we leak the page count in the filesystem. To fix that, check for this condition before migrating a huge page. If the condition is detected, return EBUSY for the page. Link: http://lkml.kernel.org/r/74510272-7319-7372-9ea6-ec914734c179@oracle.com Link: http://lkml.kernel.org/r/20190212221400.3512-1-mike.kravetz@oracle.com Fixes: bcc54222309c ("mm: hugetlb: introduce page_huge_active") Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: <stable@vger.kernel.org> [mike.kravetz@oracle.com: v2] Link: http://lkml.kernel.org/r/7534d322-d782-8ac6-1c8d-a8dc380eb3ab@oracle.com [mike.kravetz@oracle.com: update comment and changelog] Link: http://lkml.kernel.org/r/420bcfd6-158b-38e4-98da-26d0cd85bd01@oracle.com Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlbfs: revert "Use i_mmap_rwsem to fix page fault/truncate race"Mike Kravetz2019-01-081-28/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts c86aa7bbfd5568ba8a82d3635d8f7b8a8e06fe54 The reverted commit caused ABBA deadlocks when file migration raced with file eviction for specific hugetlbfs files. This was discovered with a modified version of the LTP move_pages12 test. The purpose of the reverted patch was to close a long existing race between hugetlbfs file truncation and page faults. After more analysis of the patch and impacted code, it was determined that i_mmap_rwsem can not be used for all required synchronization. Therefore, revert this patch while working an another approach to the underlying issue. Link: http://lkml.kernel.org/r/20190103235452.29335-1-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reported-by: Jan Stancek <jstancek@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Prakash Sangappa <prakash.sangappa@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlbfs: Use i_mmap_rwsem to fix page fault/truncate raceMike Kravetz2018-12-281-33/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | hugetlbfs page faults can race with truncate and hole punch operations. Current code in the page fault path attempts to handle this by 'backing out' operations if we encounter the race. One obvious omission in the current code is removing a page newly added to the page cache. This is pretty straight forward to address, but there is a more subtle and difficult issue of backing out hugetlb reservations. To handle this correctly, the 'reservation state' before page allocation needs to be noted so that it can be properly backed out. There are four distinct possibilities for reservation state: shared/reserved, shared/no-resv, private/reserved and private/no-resv. Backing out a reservation may require memory allocation which could fail so that needs to be taken into account as well. Instead of writing the required complicated code for this rare occurrence, just eliminate the race. i_mmap_rwsem is now held in read mode for the duration of page fault processing. Hold i_mmap_rwsem longer in truncation and hold punch code to cover the call to remove_inode_hugepages. With this modification, code in remove_inode_hugepages checking for races becomes 'dead' as it can not longer happen. Remove the dead code and expand comments to explain reasoning. Similarly, checks for races with truncation in the page fault path can be simplified and removed. [mike.kravetz@oracle.com: incorporat suggestions from Kirill] Link: http://lkml.kernel.org/r/20181222223013.22193-3-mike.kravetz@oracle.com Link: http://lkml.kernel.org/r/20181218223557.5202-3-mike.kravetz@oracle.com Fixes: ebed4bfc8da8 ("hugetlb: fix absurd HugePages_Rsvd") Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Prakash Sangappa <prakash.sangappa@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: zero out the vma in vma_init()Andrew Morton2018-08-221-2/+0
| | | | | | | | | | | | | | Rather than in vm_area_alloc(). To ensure that the various oddball stack-based vmas are in a good state. Some of the callers were zeroing them out, others were not. Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'work.open3' of ↵Linus Torvalds2018-08-131-38/+16
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs open-related updates from Al Viro: - "do we need fput() or put_filp()" rules are gone - it's always fput() now. We keep track of that state where it belongs - in ->f_mode. - int *opened mess killed - in finish_open(), in ->atomic_open() instances and in fs/namei.c code around do_last()/lookup_open()/atomic_open(). - alloc_file() wrappers with saner calling conventions are introduced (alloc_file_clone() and alloc_file_pseudo()); callers converted, with much simplification. - while we are at it, saner calling conventions for path_init() and link_path_walk(), simplifying things inside fs/namei.c (both on open-related paths and elsewhere). * 'work.open3' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (40 commits) few more cleanups of link_path_walk() callers allow link_path_walk() to take ERR_PTR() make path_init() unconditionally paired with terminate_walk() document alloc_file() changes make alloc_file() static do_shmat(): grab shp->shm_file earlier, switch to alloc_file_clone() new helper: alloc_file_clone() create_pipe_files(): switch the first allocation to alloc_file_pseudo() anon_inode_getfile(): switch to alloc_file_pseudo() hugetlb_file_setup(): switch to alloc_file_pseudo() ocxlflash_getfile(): switch to alloc_file_pseudo() cxl_getfile(): switch to alloc_file_pseudo() ... and switch shmem_file_setup() to alloc_file_pseudo() __shmem_file_setup(): reorder allocations new wrapper: alloc_file_pseudo() kill FILE_{CREATED,OPENED} switch atomic_open() and lookup_open() to returning 0 in all success cases document ->atomic_open() changes ->atomic_open(): return 0 in all success cases get rid of 'opened' in path_openat() and the helpers downstream ...
| * hugetlb_file_setup(): switch to alloc_file_pseudo()Al Viro2018-07-121-37/+16
| | | | | | | | | | Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * alloc_file(): switch to passing O_... flags instead of FMODE_... modeAl Viro2018-07-121-2/+1
| | | | | | | | | | | | | | ... so that it could set both ->f_flags and ->f_mode, without callers having to set ->f_flags manually. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | mm: use vma_init() to initialize VMAs on stack and data segmentsKirill A. Shutemov2018-07-261-0/+2
|/ | | | | | | | | | | | | | | | Make sure to initialize all VMAs properly, not only those which come from vm_area_cachep. Link: http://lkml.kernel.org/r/20180724121139.62570-3-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlbfs: fix bug in pgoff overflow checkingMike Kravetz2018-04-051-3/+7
| | | | | | | | | | | | | | | | | | | | | | | | | This is a fix for a regression in 32 bit kernels caused by an invalid check for pgoff overflow in hugetlbfs mmap setup. The check incorrectly specified that the size of a loff_t was the same as the size of a long. The regression prevents mapping hugetlbfs files at offsets greater than 4GB on 32 bit kernels. On 32 bit kernels conversion from a page based unsigned long can not overflow a loff_t byte offset. Therefore, skip this check if sizeof(unsigned long) != sizeof(loff_t). Link: http://lkml.kernel.org/r/20180330145402.5053-1-mike.kravetz@oracle.com Fixes: 63489f8e8211 ("hugetlbfs: check for pgoff value overflow") Reported-by: Dan Rue <dan.rue@linaro.org> Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Tested-by: Anders Roxell <anders.roxell@linaro.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Yisheng Xie <xieyisheng1@huawei.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Nic Losby <blurbdust@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>