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Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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Early in boot Linux patches memset and memcpy to branch to platform
optimized versions of these routines. The NG4 (Niagra 4) versions are
currently used on all platforms starting from T4. Recently, there were M7
optimized routines added into UEK4 but not into mainline yet. So, even
with M7 optimized routines NG4 are still going to be used on T4, T5, M5,
and M6 processors.
While investigating how to improve initialization time of dentry_hashtable
which is 8G long on M6 ldom with 7T of main memory, I noticed that
memset() does not reset all the memory in this array, after studying the
code, I realized that NG4memset() branches use %icc register instead of
%xcc to check compare, so if value of length is over 32-bit long, which is
true for 8G array, these routines fail to work properly.
The fix is to replace all %icc with %xcc in these routines. (Alternative
is to use %ncc, but this is misleading, as the code already has sparcv9
only instructions, and cannot be compiled on 32-bit).
This is important to fix this bug, because even older T4-4 can have 2T of
memory, and there are large memory proportional data structures in kernel
which can be larger than 4G in size. The failing of memset() is silent
and corruption is hard to detect.
Link: http://lkml.kernel.org/r/1488432825-92126-2-git-send-email-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Babu Moger <babu.moger@oracle.com>
Cc: Babu Moger <babu.moger@amd.com>
Cc: David Miller <davem@davemloft.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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The single caller passes a string to delta_ipc_open, which copies with a
fixed size larger than the string. So it copies some random data after
the original string the ro segment.
If the string was at the end of a page it may fault.
Just copy the string with a normal strcpy after clearing the field.
Found by a LTO build (which errors out)
because the compiler inlines the functions and can resolve
the string sizes and triggers the compile time checks in memcpy.
In function `memcpy',
inlined from `delta_ipc_open.constprop' at linux/drivers/media/platform/sti/delta/delta-ipc.c:178:0,
inlined from `delta_mjpeg_ipc_open' at linux/drivers/media/platform/sti/delta/delta-mjpeg-dec.c:227:0,
inlined from `delta_mjpeg_decode' at linux/drivers/media/platform/sti/delta/delta-mjpeg-dec.c:403:0:
/home/andi/lsrc/linux/include/linux/string.h:337:0: error: call to `__read_overflow2' declared with attribute error: detected read beyond size of object passed as 2nd parameter
__read_overflow2();
Link: http://lkml.kernel.org/r/20171222001212.1850-1-andi@firstfloor.org
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Hugues FRUCHET <hugues.fruchet@st.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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For kexec_file loading, if kexec_buf.top_down is 'true', the memory which
is used to load kernel/initrd/purgatory is supposed to be allocated from
top to down. This is also consistent with the old kexec loading
interface.
However, the current arch_kexec_walk_mem() doesn't do like this. It
ignores checking kexec_buf.top_down, but calls walk_system_ram_res()
directly to go through all resources of System RAM, to try to find a
memory region which can contain the specific kexec buffer, then calls
locate_mem_hole_callback() to allocate memory in that found memory region
from top to down. This is not right.
Here add checking if kexec_buf.top_down is 'true' in
arch_kexec_walk_mem(), if yes, call the newly added
walk_system_ram_res_rev() to find memory region from top to down to load
kernel.
The problem is the current kexec file loading has different behaviour with
the old kexec loading. In kexec loading, user space kexec_tools utility
does most of job, it searches in /proc/iomem to try to find a memory
region from top to down to load kernel. Therefore with the kexec loading,
x86_64 bzImage kernel are all loaded at top of System RAM. However, the
kexec file loading just searches for available memory region in iomem
resource from bottom to top, then try to allocate from top to down in that
region. E.g on my testing system with 2G memory as below, the kexec
loading will put kernel near 0x000000013fffffff, while kexec file loading
will put kernel near 0x000000003ffddfff. There's no bug reported yet,
just we need consider it when take care of the kexec collaboration with
other kernel components like kaslr/hotplug etc, and also the
consistentency between the different kexec interface.
[Mar23 15:13] Linux version 4.16.0-rc3+ (bhe@localhost.localdomain) (gcc version
[ +0.000000] Command line: BOOT_IMAGE=/vmlinuz-4.16.0-rc3+ root=UUID=be8f8e3a-9
[ +0.000000] x86/fpu: x87 FPU will use FXSAVE
[ +0.000000] e820: BIOS-provided physical RAM map:
[ +0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable
[ +0.000000] BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved
[ +0.000000] BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
[ +0.000000] BIOS-e820: [mem 0x0000000000100000-0x000000003ffddfff] usable
[ +0.000000] BIOS-e820: [mem 0x000000003ffde000-0x000000003fffffff] reserved
[ +0.000000] BIOS-e820: [mem 0x00000000feffc000-0x00000000feffffff] reserved
[ +0.000000] BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved
[ +0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000013fffffff] usable
I searched on internet and found the original patches posted for adding
bzImage 64 support into the old kexec loading, which is located in user
space kexec_tools utility made by Yinghai, and Vivek and hpa reviewed
patches. Still I didn't found out why kernel has to be put at top of
system RAM. I guess low memory are reserved for system usage mostly,
putting kexec kernel at top is safer and no need to exclude those
resereved regions by system or firmware which we may not find out all of
them, but not very sure about it.
Link: http://lkml.kernel.org/r/20180322033722.9279-3-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Philipp Rudo <prudo@linux.vnet.ibm.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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This function, being a variant of walk_system_ram_res() introduced in
commit 8c86e70acead ("resource: provide new functions to walk through
resources"), walks through a list of all the resources of System RAM in
reversed order, i.e., from higher to lower.
It will be used in kexec_file code.
Link: http://lkml.kernel.org/r/20180322033722.9279-2-bhe@redhat.com
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Philipp Rudo <prudo@linux.vnet.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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If the test_printf module is loaded before the crng is initialized, the
plain 'p' tests will fail because the printed address will not be hashed
and the buffer will contain '(ptrval)' instead.
This patch adds a call to wait_for_random_bytes() before plain 'p' tests
to make sure the crng is initialized.
Link: http://lkml.kernel.org/r/20180604113708.11554-1-thierry.escande@linaro.org
Signed-off-by: Thierry Escande <thierry.escande@linaro.org>
Acked-by: Tobin C. Harding <me@tobin.cc>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David Miller <davem@davemloft.net>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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Add a more complicated test for memory.low hierarchical behavior. It
creates the following hierarchy:
A memory.low = 50M
B memory.low = 50M
C memory.low = 50M
D memory.low = 50M memory.(swap.)max = 200M
E memory.low = 50M
/ \
F' F memory.low = 50M
G memory.low = 50M
H memory.low = 50M
I memory.low = 50M
J memory.low = 50M
K memory.low = 50M, memory.usage = 50M
First, it creates local memory pressure by charging pagecache to F' and
checks that K's memory.low actually works (usage ~= 50M). The it sets C's
memory.low to 0 and repeats the test to check that K's memory.low is not
working anymore, despite that memory.low is disabled above the cgroup with
memory pressure (D).
Link: http://lkml.kernel.org/r/20180522133106.24306-1-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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There are two cases when effective memory guarantee calculation is
mistakenly skipped:
1) If memcg is a child of the root cgroup, and the root cgroup is not
root_mem_cgroup (in other words, if the reclaim is targeted).
Top-level memory cgroups are handled specially in
mem_cgroup_protected(), because the root memory cgroup doesn't have
memory guarantee and can't limit its children guarantees. So, all
effective guarantee calculation is skipped. But in case of targeted
reclaim things are different: cgroups, which parent exceeded its memory
limit aren't special.
2) If memcg has no charged memory (memory usage is 0). In this case
mem_cgroup_protected() always returns MEMCG_PROT_NONE, which is correct
and prevents to generate fake memory low events for empty cgroups. But
skipping memory emin/elow calculation is wrong: if there is no global
memory pressure there might be no good chance again, so we can end up
with effective guarantees set to 0 without any reason.
Link: http://lkml.kernel.org/r/20180522132528.23769-2-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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Explicitly propagate effective memory min/low values down by the tree.
If there is the global memory pressure, it's not really necessary.
Effective memory guarantees will be propagated automatically as we
traverse memory cgroup tree in the reclaim path.
But if there is no global memory pressure, effective memory protection
still matters for local (memcg-scoped) memory pressure. So, we have to
update effective limits in the subtree, if a user changes memory.min and
memory.low values.
Link: http://lkml.kernel.org/r/20180522132528.23769-1-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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Hexagon arch does not seem to have subscribed to _HAVE_COLOR_ZERO_PAGE
framework. Hence zero_page_mask variable is not needed.
Link: http://lkml.kernel.org/r/20180517061105.30447-1-khandual@linux.vnet.ibm.com
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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Fix printk format warning in hexagon/kernel/setup.c:
../arch/hexagon/kernel/setup.c: In function 'setup_arch':
../arch/hexagon/kernel/setup.c:69:2: warning: format '%x' expects argument of type 'unsigned int', but argument 2 has type 'long unsigned int' [-Wformat]
where:
extern unsigned long __phys_offset;
#define PHYS_OFFSET __phys_offset
Link: http://lkml.kernel.org/r/adce8db5-4b01-dc10-7fbb-6a64e0787eb5@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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fix it for droppage of memcg-replace-mm-owner-with-mm-memcg.patch
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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e27be240df53 ("mm: memcg: make sure memory.events is uptodate when waking
pollers") converted most of memcg event counters to per-memcg atomics,
which made them less confusing for a user. The "oom_kill" counter
remained untouched, so now it behaves differently than other counters
(including "oom"). This adds nothing but confusion.
Let's fix this by adding the MEMCG_OOM_KILL event, and follow the
MEMCG_OOM approach. This also removes a hack from count_memcg_event_mm(),
introduced earlier specially for the OOM_KILL counter.
Link: http://lkml.kernel.org/r/20180508124637.29984-1-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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With PHYS_ADDR_MAX there is now a type safe variant for all bits set.
Make use of it.
Patch created using a semantic patch as follows:
// <smpl>
@@
typedef phys_addr_t;
@@
-(phys_addr_t)ULLONG_MAX
+PHYS_ADDR_MAX
// </smpl>
Link: http://lkml.kernel.org/r/20180419214204.19322-1-stefan@agner.ch
Signed-off-by: Stefan Agner <stefan@agner.ch>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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mm/*.c files use symbolic and octal styles for permissions.
Using octal and not symbolic permissions is preferred by many as more
readable.
https://lkml.org/lkml/2016/8/2/1945
Prefer the direct use of octal for permissions.
Done using
$ scripts/checkpatch.pl -f --types=SYMBOLIC_PERMS --fix-inplace mm/*.c
and some typing.
Before: $ git grep -P -w "0[0-7]{3,3}" mm | wc -l
44
After: $ git grep -P -w "0[0-7]{3,3}" mm | wc -l
86
Miscellanea:
o Whitespace neatening around these conversions.
Link: http://lkml.kernel.org/r/2e032ef111eebcd4c5952bae86763b541d373469.1522102887.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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Use new return type vm_fault_t for fault handler. For now, this is just
documenting that the function returns a VM_FAULT value rather than an
errno. Once all instances are converted, vm_fault_t will become a
distinct type.
Commit 1c8f422059ae ("mm: change return type to vm_fault_t")
Link: http://lkml.kernel.org/r/20180425043413.GA21467@jordon-HP-15-Notebook-PC
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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Both smatch and coverity are reporting potential issues with spectre
variant 1 with the 'semnum' index within the sma->sems array, ie:
ipc/sem.c:388 sem_lock() warn: potential spectre issue 'sma->sems'
ipc/sem.c:641 perform_atomic_semop_slow() warn: potential spectre issue 'sma->sems'
ipc/sem.c:721 perform_atomic_semop() warn: potential spectre issue 'sma->sems'
Avoid any possible speculation by using array_index_nospec() thus ensuring
the semnum value is bounded to [0, sma->sem_nsems). With the exception of
sem_lock() all of these are slowpaths.
Link: http://lkml.kernel.org/r/20180423171131.njs4rfm2yzyeg6do@linux-n805
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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Reorder Kconfig entries, so that menuconfig displays proper indentation.
Link: http://lkml.kernel.org/r/alpine.LRH.2.02.1804251601160.30569@file01.intranet.prod.int.rdu2.redhat.com
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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KCOV is code coverage collection facility used, in particular, by
syzkaller system call fuzzer. There is some interest in using syzkaller
on arm devices. So port KCOV to arm.
On implementation level this merely declares that KCOV is supported and
disables instrumentation of 3 special cases. Reasons for disabling are
commented in code.
Tested with qemu-system-arm/vexpress-a15.
Link: http://lkml.kernel.org/r/20180511143248.112484-1-dvyukov@google.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Abbott Liu <liuwenliang@huawei.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Koguchi Takuo <takuo.koguchi.sw@hitachi.com>
Cc: <syzkaller@googlegroups.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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During a context switch, we first switch_mm() to the next task's mm, then
switch_to() that new task. This means that vmalloc'd regions which had
previously been faulted in can transiently disappear in the context of the
prev task.
Functions instrumented by KCOV may try to access a vmalloc'd kcov_area
during this window, and as the fault handling code is instrumented, this
results in a recursive fault.
We must avoid accessing any kcov_area during this window. We can do so
with a new flag in kcov_mode, set prior to switching the mm, and cleared
once the new task is live. Since task_struct::kcov_mode isn't always a
specific enum kcov_mode value, this is made an unsigned int.
The manipulation is hidden behind kcov_{prepare,finish}_switch() helpers,
which are empty for !CONFIG_KCOV kernels.
The code uses macros because I can't use static inline functions without a
circular include dependency between <linux/sched.h> and <linux/kcov.h>,
since the definition of task_struct uses things defined in <linux/kcov.h>
Link: http://lkml.kernel.org/r/20180504135535.53744-4-mark.rutland@arm.com
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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fancier code comment from Mark
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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add comment explaining kcov_fault_in_area()
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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code cleanup
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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On many architectures the vmalloc area is lazily faulted in upon first
access. This is problematic for KCOV, as __sanitizer_cov_trace_pc
accesses the (vmalloc'd) kcov_area, and fault handling code may be
instrumented. If an access to kcov_area faults, this will result in
mutual recursion through the fault handling code and
__sanitizer_cov_trace_pc(), eventually leading to stack corruption and/or
overflow.
We can avoid this by faulting in the kcov_area before
__sanitizer_cov_trace_pc() is permitted to access it. Once it has been
faulted in, it will remain present in the process page tables, and will
not fault again.
Link: http://lkml.kernel.org/r/20180504135535.53744-3-mark.rutland@arm.com
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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Patch series "kcov: fix unexpected faults".
These patches fix a few issues where KCOV code could trigger recursive
faults, discovered while debugging a patch enabling KCOV for arch/arm:
* On CONFIG_PREEMPT kernels, there's a small race window where
__sanitizer_cov_trace_pc() can see a bogus kcov_area.
* Lazy faulting of the vmalloc area can cause mutual recursion between
fault handling code and __sanitizer_cov_trace_pc().
* During the context switch, switching the mm can cause the kcov_area to
be transiently unmapped.
These are prerequisites for enabling KCOV on arm, but the issues
themsevles are generic -- we just happen to avoid them by chance rather
than design on x86-64 and arm64.
This patch (of 3):
For kernels built with CONFIG_PREEMPT, some C code may execute before or
after the interrupt handler, while the hardirq count is zero. In these
cases, in_task() can return true.
A task can be interrupted in the middle of a KCOV_DISABLE ioctl while it
resets the task's kcov data via kcov_task_init(). Instrumented code
executed during this period will call __sanitizer_cov_trace_pc(), and as
in_task() returns true, will inspect t->kcov_mode before trying to write
to t->kcov_area.
In kcov_init_task() we update t->kcov_{mode,area,size} with plain stores,
which may be re-ordered, torn, etc. Thus __sanitizer_cov_trace_pc() may
see bogus values for any of these fields, and may attempt to write to
memory which is not mapped.
Let's avoid this by using WRITE_ONCE() to set t->kcov_mode, with a
barrier() to ensure this is ordered before we clear t->kov_{area,size}.
This ensures that any code execute while kcov_init_task() is preempted
will either see valid values for t->kcov_{area,size}, or will see that
t->kcov_mode is KCOV_MODE_DISABLED, and bail out without touching
t->kcov_area.
Link: http://lkml.kernel.org/r/20180504135535.53744-2-mark.rutland@arm.com
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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Use new return type vm_fault_t for fault handler. For now, this is just
documenting that the function returns a VM_FAULT value rather than an
errno. Once all instances are converted, vm_fault_t will become a
distinct type.
commit 1c8f422059ae ("mm: change return type to vm_fault_t")
Link: http://lkml.kernel.org/r/20180510140335.GA25363@jordon-HP-15-Notebook-PC
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Eric Biggers <ebiggers@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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syzbot is reporting too large memory allocation at bfs_fill_super() [1].
Since file system image is corrupted such that bfs_sb->s_start == 0,
bfs_fill_super() is trying to allocate 8MB of continuous memory. Fix this
by adding a sanity check on bfs_sb->s_start, __GFP_NOWARN and printf().
[1] https://syzkaller.appspot.com/bug?id=16a87c236b951351374a84c8a32f40edbc034e96
Link: http://lkml.kernel.org/r/1525862104-3407-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzbot+71c6b5d68e91149fc8a4@syzkaller.appspotmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Tigran Aivazian <aivazian.tigran@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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- use DRY for easier to read stripe updates (ndesaulniers)
- add const to unchanging variable (ndesaulniers)
- update references with message-id URLs
- add Reviewed-by
Link: http://lkml.kernel.org/r/20180418163546.GA45794@beast
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: Boaz Harrosh <ooo@electrozaur.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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On the quest to remove all VLAs from the kernel[1] this adjusts several
cases where allocation is made after an array of structures that points
back into the allocation. The allocations are changed to perform explicit
calculations instead of using a Variable Length Array in a structure.
Additionally, this lets Clang compile this code now, since Clang does not
support VLAIS[2].
[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com
[2] https://lkml.kernel.org/r/CA+55aFy6h1c3_rP_bXFedsTXzwW+9Q9MfJaW7GUmMBrAp-fJ9A@mail.gmail.com
Link: http://lkml.kernel.org/r/20180327203904.GA1151@beast
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: Boaz Harrosh <ooo@electrozaur.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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Nobody ever tried to self destruct by unmapping whole address space at once:
munmap((void *)0, (1ULL << 47) - 4096);
Doing this produces 2 warnings for zero-length vmalloc allocations:
a.out[1353]: segfault at 7f80bcc4b757 ip 00007f80bcc4b757 sp 00007fff683939b8 error 14
a.out: vmalloc: allocation failure: 0 bytes, mode:0xcc0(GFP_KERNEL), nodemask=(null)
...
a.out: vmalloc: allocation failure: 0 bytes, mode:0xcc0(GFP_KERNEL), nodemask=(null)
...
Fix is to switch to kvmalloc().
Steps to reproduce:
// vsyscall=none
#include <sys/mman.h>
#include <sys/resource.h>
int main(void)
{
setrlimit(RLIMIT_CORE, &(struct rlimit){RLIM_INFINITY, RLIM_INFINITY});
munmap((void *)0, (1ULL << 47) - 4096);
return 0;
}
Link: http://lkml.kernel.org/r/20180410180353.GA2515@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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If file size and FAT cluster chain is not matched (corrupted image), we
can hit BUG_ON(!phys) in __fat_get_block().
So, use fat_fs_error() instead.
Link: http://lkml.kernel.org/r/874lilcu67.fsf@mail.parknet.co.jp
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Reported-by: Anatoly Trosinenko <anatoly.trosinenko@gmail.com>
Tested-by: Anatoly Trosinenko <anatoly.trosinenko@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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A struct with a bool member can have different sizes on various
architectures because neither bool size nor alignment is standardized.
So emit a message on the use of bool in structs only in .h files and not
.c files.
There is the real possibility that this test could have a false positive
when a bool is declared as an automatic, so limit the test to .h files
where the only false positive is for declarations in static inline
functions.
Link: http://lkml.kernel.org/r/95477c93db187bab6da8a8ba7c57836868446179.camel@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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proc_pident_instantiate() no longer takes the inode*
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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Code is structured like this:
for ( ... p < last; p++) {
if (memcmp == 0)
break;
}
if (p >= last)
ERROR
OK
gcc doesn't see that if if lookup succeeds than post loop branch will
never be taken and skip it.
Link: http://lkml.kernel.org/r/20180423213954.GD9043@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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When pfn_valid(pfn) returns false, pfn should be aligned with
pageblock_nr_pages other than MAX_ORDER_NR_PAGES in init_pages_in_zone,
because the skipped 2M may be valid pfn, as a result, early allocated
count will not be accurate.
Link: http://lkml.kernel.org/r/1468938136-24228-1-git-send-email-zhongjiang@huawei.com
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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Currently, init_pages_in_zone() walks the zone in pageblock_nr_pages
steps. MAX_ORDER_NR_PAGES is possible to have holes when
CONFIG_HOLES_IN_ZONE is set. it is likely to be different between
MAX_ORDER_NR_PAGES and pageblock_nr_pages. if we skip the size of
MAX_ORDER_NR_PAGES, it will result in the second 2M memroy leak.
Meanwhile, the change will make the code consistent. because the entire
function is based on the pageblock_nr_pages steps.
Link: http://lkml.kernel.org/r/1512395284-13588-1-git-send-email-zhongjiang@huawei.com
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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We don't want to expose page before it's properly setup. During page
setup, we may call page_add_new_anon_rmap() which uses non- atomic bit op.
If page is exposed before it's done, we could overwrite page flags that
are set by get_user_pages_fast() or its callers. Here is a non-fatal
scenario (there might be other fatal problems that I didn't look into):
CPU 1 CPU1
set_pte_at() get_user_pages_fast()
page_add_new_anon_rmap() gup_pte_range()
__SetPageSwapBacked() SetPageReferenced()
Fix the problem by delaying set_pte_at() until page is ready.
I didn't observe the race directly. But I did get few crashes when
trying to access mem_cgroup of pages returned by get_user_pages_fast().
Those page were charged and they showed valid mem_cgroup in kdumps.
So this led me to think the problem came from premature set_pte_at().
I think the fact that nobody complained about this problem is because
the race only happens when using ksm+swap, and it might not cause any
fatal problem even so. Nevertheless, it's nice to have set_pte_at()
done consistently after rmap is added and page is charged.
Link: http://lkml.kernel.org/r/20180108225632.16332-1-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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The "strictlimit" feature was introduced to enforce per-bdi dirty limits
for FUSE which sets bdi max_ratio to 1% by default:
http://article.gmane.org/gmane.linux.kernel.mm/105809
However the feature can be useful for other relatively slow or untrusted
BDIs like USB flash drives and DVD+RW. The patch adds a knob to enable
the feature:
echo 1 > /sys/class/bdi/X:Y/strictlimit
Being enabled, the feature enforces bdi max_ratio limit even if global
(10%) dirty limit is not reached. Of course, the effect is not visible
until /sys/class/bdi/X:Y/max_ratio is decreased to some reasonable value.
Jan said:
: In principle I have nothing against this and the usecase sounds reasonable
: (in fact I believe the lack of a feature like this is one of reasons why
: desktop automounters usually mount USB devices with 'sync' mount option).
: So feel free to add:
Signed-off-by: Maxim Patlasov <MPatlasov@parallels.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: "Artem S. Tashkinov" <t.artem@lycos.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Jan Kara <jack@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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List groupoom in cgroup features list (exported via
/sys/kernel/cgroup/features), which can be used by a userspace apps (most
likely, systemd) to get an idea which cgroup features are supported by
kernel.
Link: http://lkml.kernel.org/r/20171130152824.1591-8-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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tweak text, fix typo
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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David Rientjes has pointed out that the current way how the root memcg is
accounted for the cgroup aware OOM killer is undocumented. Unlike regular
cgroups there is no accounting going on in the root memcg (mostly for
performance reasons). Therefore we are suming up oom_badness of its
tasks. This might result in an over accounting because of the
oom_score_adj setting. Document this for now.
Link: http://lkml.kernel.org/r/20180130122011.GB21609@dhcp22.suse.cz
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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Add a note that cgroup-aware OOM logic is disabled by default
and describe how to enable it.
Link: http://lkml.kernel.org/r/20171201170149.GB27436@castle.DHCP.thefacebook.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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Document the cgroup-aware OOM killer.
Link: http://lkml.kernel.org/r/20171130152824.1591-7-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: David Rientjes <rientjes@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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Add a "groupoom" cgroup v2 mount option to enable the cgroup-aware OOM
killer. If not set, the OOM selection is performed in a "traditional"
per-process way.
The behavior can be changed dynamically by remounting the cgroupfs.
Link: http://lkml.kernel.org/r/20171130152824.1591-6-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: David Rientjes <rientjes@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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Cgroup-aware OOM killer depends on cgroup mount option and is turned off
by default, despite the user interface (memory.oom_group file) is always
present. As it might be confusing to a user, let's return -ENOTSUPP on an
attempt to access to memory.oom_group if groupoom is not enabled globally.
Example:
$ cd /sys/fs/cgroup/user.slice/
$ cat memory.oom_group
cat: memory.oom_group: Unknown error 524
$ echo 1 > memory.oom_group
-bash: echo: write error: Unknown error 524
$ mount -o remount,groupoom /sys/fs/cgroup
$ echo 1 > memory.oom_group
$ cat memory.oom_group
1
Link: http://lkml.kernel.org/r/20171201170004.GA27436@castle.DHCP.thefacebook.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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The cgroup-aware OOM killer treats leaf memory cgroups as memory
consumption entities and performs the victim selection by comparing them
based on their memory footprint. Then it kills the biggest task inside
the selected memory cgroup.
But there are workloads, which are not tolerant to a such behavior.
Killing a random task may leave the workload in a broken state.
To solve this problem, memory.oom_group knob is introduced. It will
define, whether a memory group should be treated as an indivisible memory
consumer, compared by total memory consumption with other memory consumers
(leaf memory cgroups and other memory cgroups with memory.oom_group set),
and whether all belonging tasks should be killed if the cgroup is
selected.
If set on memcg A, it means that in case of system-wide OOM or memcg-wide
OOM scoped to A or any ancestor cgroup, all tasks, belonging to the
sub-tree of A will be killed. If OOM event is scoped to a descendant
cgroup (A/B, for example), only tasks in that cgroup can be affected. OOM
killer will never touch any tasks outside of the scope of the OOM event.
Also, tasks with oom_score_adj set to -1000 will not be killed because
this has been a long established way to protect a particular process from
seeing an unexpected SIGKILL from the OOM killer. Ignoring this user
defined configuration might lead to data corruptions or other misbehavior.
The default value is 0.
Link: http://lkml.kernel.org/r/20171130152824.1591-5-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: David Rientjes <rientjes@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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attampt to repair mm-oom-cgroup-aware-oom-killer.patch for
memcg-replace-mm-owner-with-mm-memcg.patch
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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two tweaks ariseing from merge fixups, per Roman
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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