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* Merge commit 'v2.6.36-rc7' into perf/coreIngo Molnar2010-10-081-0/+4
|\ | | | | | | | | | | | | | | | | Conflicts: arch/x86/kernel/module.c Merge reason: Resolve the conflict, pick up fixes. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * modules: Fix module_bug_list list corruption raceLinus Torvalds2010-10-051-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With all the recent module loading cleanups, we've minimized the code that sits under module_mutex, fixing various deadlocks and making it possible to do most of the module loading in parallel. However, that whole conversion totally missed the rather obscure code that adds a new module to the list for BUG() handling. That code was doubly obscure because (a) the code itself lives in lib/bugs.c (for dubious reasons) and (b) it gets called from the architecture-specific "module_finalize()" rather than from generic code. Calling it from arch-specific code makes no sense what-so-ever to begin with, and is now actively wrong since that code isn't protected by the module loading lock any more. So this commit moves the "module_bug_{finalize,cleanup}()" calls away from the arch-specific code, and into the generic code - and in the process protects it with the module_mutex so that the list operations are now safe. Future fixups: - move the module list handling code into kernel/module.c where it belongs. - get rid of 'module_bug_list' and just use the regular list of modules (called 'modules' - imagine that) that we already create and maintain for other reasons. Reported-and-tested-by: Thomas Gleixner <tglx@linutronix.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Adrian Bunk <bunk@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | jump label: Base patch for jump labelJason Baron2010-09-221-0/+6
|/ | | | | | | | | | | | | | | | | base patch to implement 'jump labeling'. Based on a new 'asm goto' inline assembly gcc mechanism, we can now branch to labels from an 'asm goto' statment. This allows us to create a 'no-op' fastpath, which can subsequently be patched with a jump to the slowpath code. This is useful for code which might be rarely used, but which we'd like to be able to call, if needed. Tracepoints are the current usecase that these are being implemented for. Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Jason Baron <jbaron@redhat.com> LKML-Reference: <ee8b3595967989fdaf84e698dc7447d315ce972a.1284733808.git.jbaron@redhat.com> [ cleaned up some formating ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* module: cleanup comments, remove noinlineRusty Russell2010-08-051-4/+8
| | | | | | | | | | On my (32-bit x86) machine, sys_init_module() uses 124 bytes of stack once load_module() is inlined. This effectively reverts ffb4ba76 which inlined it due to stack pressure. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: group post-relocation functions into post_relocation()Rusty Russell2010-08-051-24/+32
| | | | | | | | | | | | This simply hoists more code out of load_module; we also put the identification of the extable and dynamic debug table in with the others in find_module_sections(). We move the taint check to the actual add/remove of the dynamic debug info: this is certain (find_module_sections is too early). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Yehuda Sadeh <yehuda@hq.newdream.net>
* module: move module args strndup_user to just before useRusty Russell2010-08-051-15/+13
| | | | | | | Instead of copying and allocating the args and storing it in load_info, we can just allocate them right before we need them. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: pass load_info into other functionsRusty Russell2010-08-051-215/+157
| | | | | | | Pass the struct load_info into all the other functions in module loading. This neatens things and makes them more consistent. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: fix sysfs cleanup for !CONFIG_SYSFSRusty Russell2010-08-051-7/+6
| | | | | | | | | | | Restore the stub module_remove_modinfo_attrs, remove the now-unused !CONFIG_SYSFS module_sysfs_init. Also, rename mod_kobject_remove() to mod_sysfs_teardown() as it is the logical counterpart to mod_sysfs_setup now. Reported-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: sysfs cleanupRusty Russell2010-08-051-43/+34
| | | | | | | | | We change the sysfs functions to take struct load_info, and call them all in mod_sysfs_setup(). We also clean up the #ifdefs a little. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: layout_and_allocateRusty Russell2010-08-051-99/+125
| | | | | | | | | | | | | | | | layout_and_allocate() does everything up to and including the final struct module placement inside the allocated module memory. We have to store the symbol layout information in our struct load_info though. This avoids the nasty code we had before where 'mod' pointed first to the version inside the temporary allocation containing the entire file, then later was moved to point to the real struct module: now the main code only ever sees the final module address. (Includes fix for the Tony Luck-found Linus-diagnosed failure path error). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: fix crash in get_ksymbol() when oopsing in module initRusty Russell2010-08-051-1/+2
| | | | | | | | | | | | | | | | | | Andrew had the sole pleasure of tickling this bug in linux-next; when we set up "info->strtab" it's pointing into the temporary copy of the module. For most uses that is fine, but kallsyms keeps a pointer around during module load (inside mod->strtab). If we oops for some reason inside a module's init function, kallsyms will use the mod->strtab pointer into the now-freed temporary module copy. (Later oopses work fine: after init we overwrite mod->strtab to point to a compacted core-only strtab). Reported-by: Andrew "Grumpy" Morton <akpm@linux-foundation.org> Signed-off-by: Rusty "Buggy" Russell <rusty@rustcorp.com.au> Tested-by: Andrew "Happy" Morton <akpm@linux-foundation.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: kallsyms functions take struct load_infoRusty Russell2010-08-051-39/+29
| | | | | | Simple refactor causes us to lift struct definition to top of file. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: refactor out section header rewriting: FIX modversionsRusty Russell2010-08-051-6/+6
| | | | | | | We can't do the find_sec after removing the SHF_ALLOC flags; it won't find the sections. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: refactor out section header rewritingRusty Russell2010-08-051-25/+45
| | | | | | | | | Put all the "rewrite and check section headers" in one place. This adds another iteration over the sections, but it's far clearer. We iterate once for every find_section() so we already iterate over many times. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: add load_infoLinus Torvalds2010-08-051-103/+125
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Btw, here's a patch that _looks_ large, but it really pretty trivial, and sets things up so that it would be way easier to split off pieces of the module loading. The reason it looks large is that it creates a "module_info" structure that contains all the module state that we're building up while loading, instead of having individual variables for all the indices etc. So the patch ends up being large, because every "symindex" access instead becomes "info.index.sym" etc. That may be a few characters longer, but it then means that we can just pass a pointer to that "info" structure around. and let all the pieces fill it in very naturally. As an example of that, the patch also moves the initialization of all those convenience variables into a "setup_module_info()" function. And at this point it really does become very natural to start to peel off some of the error labels and move them into the helper functions - now the "truncated" case is gone, and is handled inside that setup function instead. So maybe you don't like this approach, and it does make the variable accesses a bit longer, but I don't think unreadably so. And the patch really does look big and scary, but there really should be absolutely no semantic changes - most of it was a trivial and mindless rename. In fact, it was so mindless that I on purpose kept the existing helper functions looking like this: - err = check_modinfo(mod, sechdrs, infoindex, versindex); + err = check_modinfo(mod, info.sechdrs, info.index.info, info.index.vers); rather than changing them to just take the "info" pointer. IOW, a second phase (if you think the approach is ok) would change that calling convention to just do err = check_modinfo(mod, &info); (and same for "layout_sections()", "layout_symtabs()" etc.) Similarly, while right now it makes things _look_ bigger, with things like this: versindex = find_sec(hdr, sechdrs, secstrings, "__versions"); becoming info->index.vers = find_sec(info->hdr, info->sechdrs, info->secstrings, "__versions"); in the new "setup_module_info()" function, that's again just a result of it being a search-and-replace patch. By using the 'info' pointer, we could just change the 'find_sec()' interface so that it ends up being info->index.vers = find_sec(info, "__versions"); instead, and then we'd actually have a shorter and more readable line. So for a lot of those mindless variable name expansions there's would be room for separate cleanups. I didn't move quite everything in there - if we do this to layout_symtabs, for example, we'd want to move the percpu, symoffs, stroffs, *strmap variables to be fields in that module_info structure too. But that's a much smaller patch, I moved just the really core stuff that is currently being set up and used in various parts. But even in this rough form, it removes close to 70 lines from that function (but adds 22 lines overall, of course - the structure definition, the helper function declarations and call-sites etc etc). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: reduce stack usage for each_symbol()Linus Torvalds2010-08-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | And now that I'm looking at that call-chain (to see if it would make sense to use some other more specific lock - doesn't look like it: all the readers are using RCU and this is the only writer), I also give you this trivial one-liner. It changes each_symbol() to not put that constant array on the stack, resulting in changing movq $C.388.31095, %rsi #, tmp85 subq $376, %rsp #, movq %rdi, %rbx # fn, fn leaq -208(%rbp), %rdi #, tmp84 movq %rbx, %rdx # fn, rep movsl xorl %esi, %esi # leaq -208(%rbp), %rdi #, tmp87 movq %r12, %rcx # data, call each_symbol_in_section.clone.0 # into xorl %esi, %esi # subq $216, %rsp #, movq %rdi, %rbx # fn, fn movq $arr.31078, %rdi #, call each_symbol_in_section.clone.0 # which is not so much about being obviously shorter and simpler because we don't unnecessarily copy that constant array around onto the stack, but also about having a much smaller stack footprint (376 vs 216 bytes - see the update of 'rsp'). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: refactor load_module part 5Rusty Russell2010-08-051-76/+106
| | | | | | | | | | 1) Extract out the relocation loop into apply_relocations 2) Extract license and version checks into check_module_license_and_versions 3) Extract icache flushing into flush_module_icache 4) Move __obsparm warning into find_module_sections 5) Move license setting into check_modinfo. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: refactor load_module part 4Rusty Russell2010-08-051-17/+15
| | | | | | | | | | | Allocate references inside module_unload_init(), clean up inside module_unload_free(). This version fixed to do allocation before __this_cpu_write, thanks to bug reports from linux-next from Dave Young <hidave.darkstar@gmail.com> and Stephen Rothwell <sfr@canb.auug.org.au>. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: refactor load_module part 3Rusty Russell2010-08-051-47/+75
| | | | | | | Extract out the allocation and copying in from userspace, and the first set of modinfo checks. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: refactor load_module part 2Linus Torvalds2010-08-051-57/+72
| | | | | | | | | | Here's a second one. It's slightly less trivial - since we now have error cases - and equally untested so it may well be totally broken. But it also cleans up a bit more, and avoids one of the goto targets, because the "move_module()" helper now does both allocations or none. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: refactor load_moduleLinus Torvalds2010-08-051-61/+69
| | | | | | | | | | I'd start from the trivial stuff. There's a fair amount of straight-line code that just makes the function hard to read just because you have to page up and down so far. Some of it is trivial to just create a helper function for. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: module_unload_init() cleanupEric Dumazet2010-08-051-6/+0
| | | | | | | | No need to clear mod->refptr in module_unload_init(), since alloc_percpu() already clears allocated chunks. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (removed unused var)
* dynamic debug: move ddebug_remove_module() down into free_module()Jason Baron2010-07-271-1/+3
| | | | | | | | | | | | | | | | | | | The command echo "file ec.c +p" >/sys/kernel/debug/dynamic_debug/control causes an oops. Move the call to ddebug_remove_module() down into free_module(). In this way it should be called from all error paths. Currently, we are missing the remove if the module init routine fails. Signed-off-by: Jason Baron <jbaron@redhat.com> Reported-by: Thomas Renninger <trenn@suse.de> Tested-by: Thomas Renninger <trenn@suse.de> Cc: <stable@kernel.org> [2.6.32+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* module: initialize module dynamic debug laterYehuda Sadeh2010-07-041-8/+15
| | | | | | | | | | | | | We should initialize the module dynamic debug datastructures only after determining that the module is not loaded yet. This fixes a bug that introduced in 2.6.35-rc2, where when a trying to load a module twice, we also load it's dynamic printing data twice which causes all sorts of nasty issues. Also handle the dynamic debug cleanup later on failure. Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (removed a #ifdef) Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* module: fix bne2 "gave up waiting for init of module libcrc32c"Rusty Russell2010-06-051-32/+59
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Problem: it's hard to avoid an init routine stumbling over a request_module these days. And it's not clear it's always a bad idea: for example, a module like kvm with dynamic dependencies on kvm-intel or kvm-amd would be neater if it could simply request_module the right one. In this particular case, it's libcrc32c: libcrc32c_mod_init crypto_alloc_shash crypto_alloc_tfm crypto_find_alg crypto_alg_mod_lookup crypto_larval_lookup request_module If another module is waiting inside resolve_symbol() for libcrc32c to finish initializing (ie. bne2 depends on libcrc32c) then it does so holding the module lock, and our request_module() can't make progress until that is released. Waiting inside resolve_symbol() without the lock isn't all that hard: we just need to pass the -EBUSY up the call chain so we can sleep where we don't hold the lock. Error reporting is a bit trickier: we need to copy the name of the unfinished module before releasing the lock. Other notes: 1) This also fixes a theoretical issue where a weak dependency would allow symbol version mismatches to be ignored. 2) We rename use_module to ref_module to make life easier for the only external user (the out-of-tree ksplice patches). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Tim Abbot <tabbott@ksplice.com> Tested-by: Brandon Philips <bphilips@suse.de>
* module: verify_export_symbols under the lockRusty Russell2010-06-051-16/+10
| | | | | | | | | | | | | It disabled preempt so it was "safe", but nothing stops another module slipping in before this module is added to the global list now we don't hold the lock the whole time. So we check this just after we check for duplicate modules, and just before we put the module in the global list. (find_symbol finds symbols in coming and going modules, too). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: move find_module check to endLinus Torvalds2010-06-051-5/+7
| | | | | | | | | | | | | | | | | | | I think Rusty may have made the lock a bit _too_ finegrained there, and didn't add it to some places that needed it. It looks, for example, like PATCH 1/2 actually drops the lock in places where it's needed ("find_module()" is documented to need it, but now load_module() didn't hold it at all when it did the find_module()). Rather than adding a new "module_loading" list, I think we should be able to just use the existing "modules" list, and just fix up the locking a bit. In fact, maybe we could just move the "look up existing module" a bit later - optimistically assuming that the module doesn't exist, and then just undoing the work if it turns out that we were wrong, just before adding ourselves to the list. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: make locking more fine-grained.Rusty Russell2010-06-051-23/+42
| | | | | | | | | | | | | | | Kay Sievers <kay.sievers@vrfy.org> reports that we still have some contention over module loading which is slowing boot. Linus also disliked a previous "drop lock and regrab" patch to fix the bne2 "gave up waiting for init of module libcrc32c" message. This is more ambitious: we only grab the lock where we need it. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Brandon Philips <brandon@ifup.org> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Linus Torvalds <torvalds@linux-foundation.org>
* module: Make module sysfs functions private.Rusty Russell2010-06-051-4/+25
| | | | | | | | | | | These were placed in the header in ef665c1a06 to get the various SYSFS/MODULE config combintations to compile. That may have been necessary then, but it's not now. These functions are all local to module.c. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Randy Dunlap <randy.dunlap@oracle.com>
* module: move sysfs exposure to end of load_moduleRusty Russell2010-06-051-11/+36
| | | | | | | | | | | This means a little extra work, but is more logical: we don't put anything in sysfs until we're about to put the module into the global list an parse its parameters. This also gives us a logical place to put duplicate module detection in the next patch. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: fix kdb's illicit use of struct module_use.Rusty Russell2010-06-051-10/+1
| | | | | | | | | Linus changed the structure, and luckily this didn't compile any more. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Martin Hicks <mort@sgi.com>
* module: Make the 'usage' lists be two-wayLinus Torvalds2010-06-051-31/+48
| | | | | | | | | | | | | | | | | | | | | | When adding a module that depends on another one, we used to create a one-way list of "modules_which_use_me", so that module unloading could see who needs a module. It's actually quite simple to make that list go both ways: so that we not only can see "who uses me", but also see a list of modules that are "used by me". In fact, we always wanted that list in "module_unload_free()": when we unload a module, we want to also release all the other modules that are used by that module. But because we didn't have that list, we used to first iterate over all modules, and then iterate over each "used by me" list of that module. By making the list two-way, we simplify module_unload_free(), and it allows for some trivial fixes later too. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (cleaned & rebased)
* Merge branch 'for-35' of git://repo.or.cz/linux-kbuildLinus Torvalds2010-06-011-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 'for-35' of git://repo.or.cz/linux-kbuild: (81 commits) kbuild: Revert part of e8d400a to resolve a conflict kbuild: Fix checking of scm-identifier variable gconfig: add support to show hidden options that have prompts menuconfig: add support to show hidden options which have prompts gconfig: remove show_debug option gconfig: remove dbg_print_ptype() and dbg_print_stype() kconfig: fix zconfdump() kconfig: some small fixes add random binaries to .gitignore kbuild: Include gen_initramfs_list.sh and the file list in the .d file kconfig: recalc symbol value before showing search results .gitignore: ignore *.lzo files headerdep: perlcritic warning scripts/Makefile.lib: Align the output of LZO kbuild: Generate modules.builtin in make modules_install Revert "kbuild: specify absolute paths for cscope" kbuild: Do not unnecessarily regenerate modules.builtin headers_install: use local file handles headers_check: fix perl warnings export_report: fix perl warnings ...
| * Rename .data[.percpu][.XXX] to .data[..percpu][..XXX].Denys Vlasenko2010-03-031-1/+1
| | | | | | | | | | Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
* | module: fix reference to mod->percpu after freeing module.Rusty Russell2010-05-311-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rafael sees a sometimes crash at precpu_modfree from kernel/module.c; it only occurred with another (since-reverted) patch, but that patch simply changed timing to uncover this bug, it was otherwise unrelated. The comment about the mod being freed is self-explanatory, but neither Tejun nor I read it. This bug was introduced in 259354deaa, after it had previously been fixed in 6e2b75740b. How embarrassing. Reported-by: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Embarrassingly-Acked-by: Tejun Heo <tj@kernel.org> Cc: Masami Hiramatsu <mhiramat@redhat.com> Tested-by: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Revert "module: drop the lock while waiting for module to complete ↵Linus Torvalds2010-05-251-37/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | initialization." This reverts commit 480b02df3aa9f07d1c7df0cd8be7a5ca73893455, since Rafael reports that it causes occasional kernel paging request faults in load_module(). Dropping the module lock and re-taking it deep in the call-chain is definitely not the right thing to do. That just turns the mutex from a lock into a "random non-locking data structure" that doesn't actually protect what it's supposed to protect. Requested-and-tested-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Brandon Philips <brandon@ifup.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | module: remove duplicate declaration of __ksymtab_gpl_futureWenji Huang2010-05-251-2/+0
| | | | | | | | | | | | | | | | Minor cleanup on duplicate __{start/stop}__ksymtab_gpl_future. Signed-off-by: Wenji Huang <wenji.huang@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Merge branch 'modules' of ↵Linus Torvalds2010-05-211-22/+37
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus * 'modules' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus: module: drop the lock while waiting for module to complete initialization. MODULE_DEVICE_TABLE(isapnp, ...) does nothing hisax_fcpcipnp: fix broken isapnp device table. isapnp: move definitions to mod_devicetable.h so file2alias can reach them.
| * | module: drop the lock while waiting for module to complete initialization.Rusty Russell2010-05-191-22/+37
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This fixes "gave up waiting for init of module libcrc32c." which happened at boot time due to multiple parallel module loads. The problem was a deadlock: we wait for a module to finish initializing, but we keep the module_lock mutex so it can't complete. In particular, this could reasonably happen if a module does a request_module() in its initialization routine. So we change use_module() to return an errno rather than a bool, and if it's -EBUSY we drop the lock and wait in the caller, then reaquire the lock. Reported-by: Brandon Philips <brandon@ifup.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Tested-by: Brandon Philips <brandon@ifup.org>
* | | Merge branch 'kdb-merge' of ↵Linus Torvalds2010-05-211-0/+4
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb * 'kdb-merge' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb: (25 commits) kdb,debug_core: Allow the debug core to receive a panic notification MAINTAINERS: update kgdb, kdb, and debug_core info debug_core,kdb: Allow the debug core to process a recursive debug entry printk,kdb: capture printk() when in kdb shell kgdboc,kdb: Allow kdb to work on a non open console port kgdb: Add the ability to schedule a breakpoint via a tasklet mips,kgdb: kdb low level trap catch and stack trace powerpc,kgdb: Introduce low level trap catching x86,kgdb: Add low level debug hook kgdb: remove post_primary_code references kgdb,docs: Update the kgdb docs to include kdb kgdboc,keyboard: Keyboard driver for kdb with kgdb kgdb: gdb "monitor" -> kdb passthrough sparc,sunzilog: Add console polling support for sunzilog serial driver sh,sh-sci: Use NO_POLL_CHAR in the SCIF polled console code kgdb,8250,pl011: Return immediately from console poll kgdb: core changes to support kdb kdb: core for kgdb back end (2 of 2) kdb: core for kgdb back end (1 of 2) kgdb,blackfin: Add in kgdb_arch_set_pc for blackfin ...
| * | | kdb: core for kgdb back end (2 of 2)Jason Wessel2010-05-201-0/+4
| |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch contains the hooks and instrumentation into kernel which live outside the kernel/debug directory, which the kdb core will call to run commands like lsmod, dmesg, bt etc... CC: linux-arch@vger.kernel.org Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Martin Hicks <mort@sgi.com>
* | | sysfs: add struct file* to bin_attr callbacksChris Wright2010-05-211-1/+1
|/ / | | | | | | | | | | | | | | | | This allows bin_attr->read,write,mmap callbacks to check file specific data (such as inode owner) as part of any privilege validation. Signed-off-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* | Merge branch 'sched-core-for-linus' of ↵Linus Torvalds2010-05-181-12/+2
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (49 commits) stop_machine: Move local variable closer to the usage site in cpu_stop_cpu_callback() sched, wait: Use wrapper functions sched: Remove a stale comment ondemand: Make the iowait-is-busy time a sysfs tunable ondemand: Solve a big performance issue by counting IOWAIT time as busy sched: Intoduce get_cpu_iowait_time_us() sched: Eliminate the ts->idle_lastupdate field sched: Fold updating of the last_update_time_info into update_ts_time_stats() sched: Update the idle statistics in get_cpu_idle_time_us() sched: Introduce a function to update the idle statistics sched: Add a comment to get_cpu_idle_time_us() cpu_stop: add dummy implementation for UP sched: Remove rq argument to the tracepoints rcu: need barrier() in UP synchronize_sched_expedited() sched: correctly place paranioa memory barriers in synchronize_sched_expedited() sched: kill paranoia check in synchronize_sched_expedited() sched: replace migration_thread with cpu_stop stop_machine: reimplement using cpu_stop cpu_stop: implement stop_cpu[s]() sched: Fix select_idle_sibling() logic in select_task_rq_fair() ...
| * | stop_machine: reimplement using cpu_stopTejun Heo2010-05-061-12/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reimplement stop_machine using cpu_stop. As cpu stoppers are guaranteed to be available for all online cpus, stop_machine_create/destroy() are no longer necessary and removed. With resource management and synchronization handled by cpu_stop, the new implementation is much simpler. Asking the cpu_stop to execute the stop_cpu() state machine on all online cpus with cpu hotplug disabled is enough. stop_machine itself doesn't need to manage any global resources anymore, so all per-instance information is rolled into struct stop_machine_data and the mutex and all static data variables are removed. The previous implementation created and destroyed RT workqueues as necessary which made stop_machine() calls highly expensive on very large machines. According to Dimitri Sivanich, preventing the dynamic creation/destruction makes booting faster more than twice on very large machines. cpu_stop resources are preallocated for all online cpus and should have the same effect. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Dimitri Sivanich <sivanich@sgi.com>
* | | Merge branch 'linus' into tracing/coreIngo Molnar2010-04-081-38/+99
|\ \ \ | |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: include/linux/module.h kernel/module.c Semantic conflict: include/trace/events/module.h Merge reason: Resolve the conflict with upstream commit 5fbfb18 ("Fix up possibly racy module refcounting") Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | Fix up possibly racy module refcountingNick Piggin2010-04-051-8/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Module refcounting is implemented with a per-cpu counter for speed. However there is a race when tallying the counter where a reference may be taken by one CPU and released by another. Reference count summation may then see the decrement without having seen the previous increment, leading to lower than expected count. A module which never has its actual reference drop below 1 may return a reference count of 0 due to this race. Module removal generally runs under stop_machine, which prevents this race causing bugs due to removal of in-use modules. However there are other real bugs in module.c code and driver code (module_refcount is exported) where the callers do not run under stop_machine. Fix this by maintaining running per-cpu counters for the number of module refcount increments and the number of refcount decrements. The increments are tallied after the decrements, so any decrement seen will always have its corresponding increment counted. The final refcount is the difference of the total increments and decrements, preventing a low-refcount from being returned. Signed-off-by: Nick Piggin <npiggin@suse.de> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | percpu, module: implement and use is_kernel/module_percpu_address()Tejun Heo2010-03-291-0/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | lockdep has custom code to check whether a pointer belongs to static percpu area which is somewhat broken. Implement proper is_kernel/module_percpu_address() and replace the custom code. On UP, percpu variables are regular static variables and can't be distinguished from them. Always return %false on UP. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Ingo Molnar <mingo@redhat.com>
| * | module: encapsulate percpu handling better and record percpu_sizeTejun Heo2010-03-291-31/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Better encapsulate module static percpu area handling so that code outsidef of CONFIG_SMP ifdef doesn't deal with mod->percpu directly and add mod->percpu_size and record percpu_size in it. Both percpu fields are compiled out on UP. While at it, mark mod->percpu w/ __percpu. This is to prepare for is_module_percpu_address(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Rusty Russell <rusty@rustcorp.com.au>
* | | tracing: Fix compile error in module tracepoints when MODULE_UNLOAD not setSteven Rostedt2010-03-311-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If modules are configured in the build but unloading of modules is not, then the refcnt is not defined. Place the get/put module tracepoints under CONFIG_MODULE_UNLOAD since it references this field in the module structure. As a side-effect, this patch also reduces the code when MODULE_UNLOAD is not set, because these unused tracepoints are not created. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | | tracing: Remove side effect from module tracepoints that caused a GPFLi Zefan2010-03-311-2/+1
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove the @refcnt argument, because it has side-effects, and arguments with side-effects are not skipped by the jump over disabled instrumentation and are executed even when the tracepoint is disabled. This was also causing a GPF as found by Randy Dunlap: Subject: 2.6.33 GP fault only when built with tracing LKML-Reference: <4BA2B69D.3000309@oracle.com> Note, the current 2.6.34-rc has a fix for the actual cause of the GPF, but this fixes one of its triggers. Tested-by: Randy Dunlap <randy.dunlap@oracle.com> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <4BA97FA7.6040406@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>