- 10 Sep, 2015 40 commits
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Frederic Weisbecker authored
There seem to be quite some confusions on the comments, likely due to changes that came after them. Now since it's very non obvious why we have 3 levels of asynchronous code to implement usermodehelpers, it's important to comment in detail the reason of this layout. Signed-off-by:
Frederic Weisbecker <fweisbec@gmail.com> Cc: Rik van Riel <riel@redhat.com> Reviewed-by:
Oleg Nesterov <oleg@redhat.com> Cc: Christoph Lameter <cl@linux.com> Cc: Tejun Heo <tj@kernel.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Frederic Weisbecker authored
Khelper is affine to all CPUs. Now since it creates the call_usermodehelper_exec_[a]sync() kernel threads, those inherit the wide affinity. As such explicitly forcing a wide affinity from those kernel threads is like a no-op. Just remove it. It's needless and it breaks CPU isolation users who rely on workqueue affinity tuning. Signed-off-by:
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Frederic Weisbecker authored
This patchset does a bunch of cleanups and converts khelper to use system unbound workqueues. The 3 first patches should be uncontroversial. The last 2 patches are debatable. Kmod creates kernel threads that perform userspace jobs and we want those to have a large affinity in order not to contend busy CPUs. This is (partly) why we use khelper which has a wide affinity that the kernel threads it create can inherit from. Now khelper is a dedicated workqueue that has singlethread properties which we aren't interested in. Hence those two debatable changes: _ We would like to use generic workqueues. System unbound workqueues are a very good candidate but they are not wide affine, only node affine. Now probably a node is enough to perform many parallel kmod jobs. _ We would like to remove the wait_for_helper kernel thread (UMH_WAIT_PROC handler) to use the workqueue. It means that if the workqueue blocks, and no other worker can take pending kmod request, we can be screwed. Now if we have 512 threads, this should be enough. This patch (of 5): Underscores on function names aren't much verbose to explain the purpose of a function. And kmod has interesting such flavours. Lets rename the following functions: * __call_usermodehelper -> call_usermodehelper_exec_work * ____call_usermodehelper -> call_usermodehelper_exec_async * wait_for_helper -> call_usermodehelper_exec_sync Signed-off-by:
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NeilBrown authored
If request_module() successfully runs modprobe, but modprobe exits with a non-zero status, then the return value from request_module() will be that (positive) error status. So the return from request_module can be: negative errno zero for success positive exit code. Signed-off-by:
NeilBrown <neilb@suse.com> Cc: Goldwyn Rodrigues <rgoldwyn@suse.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Tejun Heo <tj@kernel.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by:
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Hin-Tak Leung authored
Fix B-tree corruption when a new record is inserted at position 0 in the node in hfs_brec_insert(). This is an identical change to the corresponding hfs b-tree code to Sergei Antonov's "hfsplus: fix B-tree corruption after insertion at position 0", to keep similar code paths in the hfs and hfsplus drivers in sync, where appropriate. Signed-off-by:
Hin-Tak Leung <htl10@users.sourceforge.net> Cc: Sergei Antonov <saproj@gmail.com> Cc: Joe Perches <joe@perches.com> Reviewed-by:
Vyacheslav Dubeyko <slava@dubeyko.com> Cc: Anton Altaparmakov <anton@tuxera.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: <stable@vger.kernel.org> Signed-off-by:
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Hin-Tak Leung authored
Pages looked up by __hfs_bnode_create() (called by hfs_bnode_create() and hfs_bnode_find() for finding or creating pages corresponding to an inode) are immediately kmap()'ed and used (both read and write) and kunmap()'ed, and should not be page_cache_release()'ed until hfs_bnode_free(). This patch fixes a problem I first saw in July 2012: merely running "du" on a large hfsplus-mounted directory a few times on a reasonably loaded system would get the hfsplus driver all confused and complaining about B-tree inconsistencies, and generates a "BUG: Bad page state". Most recently, I can generate this problem on up-to-date Fedora 22 with shipped kernel 4.0.5, by running "du /" (="/" + "/home" + "/mnt" + other smaller mounts) and "du /mnt" simultaneously on two windows, where /mnt is a lightly-used QEMU VM image of the full Mac OS X 10.9: $ df -i / /home /mnt Filesystem Inodes IUsed IFree IUse% Mounted on /dev/mapper/fedora-root 3276800 551665 2725135 17% / /dev/mapper/fedora-home 52879360 716221 52163139 2% /home /dev/nbd0p2 4294967295 1387818 4293579477 1% /mnt After applying the patch, I was able to run "du /" (60+ times) and "du /mnt" (150+ times) continuously and simultaneously for 6+ hours. There are many reports of the hfsplus driver getting confused under load and generating "BUG: Bad page state" or other similar issues over the years. [1] The unpatched code [2] has always been wrong since it entered the kernel tree. The only reason why it gets away with it is that the kmap/memcpy/kunmap follow very quickly after the page_cache_release() so the kernel has not had a chance to reuse the memory for something else, most of the time. The current RW driver appears to have followed the design and development of the earlier read-only hfsplus driver [3], where-by version 0.1 (Dec 2001) had a B-tree node-centric approach to read_cache_page()/page_cache_release() per bnode_get()/bnode_put(), migrating towards version 0.2 (June 2002) of caching and releasing pages per inode extents. When the current RW code first entered the kernel [2] in 2005, there was an REF_PAGES conditional (and "//" commented out code) to switch between B-node centric paging to inode-centric paging. There was a mistake with the direction of one of the REF_PAGES conditionals in __hfs_bnode_create(). In a subsequent "remove debug code" commit [4], the read_cache_page()/page_cache_release() per bnode_get()/bnode_put() were removed, but a page_cache_release() was mistakenly left in (propagating the "REF_PAGES <-> !REF_PAGE" mistake), and the commented-out page_cache_release() in bnode_release() (which should be spanned by !REF_PAGES) was never enabled. References: [1]: Michael Fox, Apr 2013 http://www.spinics.net/lists/linux-fsdevel/msg63807.html ("hfsplus volume suddenly inaccessable after 'hfs: recoff %d too large'") Sasha Levin, Feb 2015 http://lkml.org/lkml/2015/2/20/85 ("use after free") https://bugs.launchpad.net/ubuntu/+source/linux/+bug/740814 https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1027887 https://bugzilla.kernel.org/show_bug.cgi?id=42342 https://bugzilla.kernel.org/show_bug.cgi?id=63841 https://bugzilla.kernel.org/show_bug.cgi?id=78761 [2]: http://git.kernel.org/cgit/linux/kernel/git/tglx/history.git/commit/\ fs/hfs/bnode.c?id=d1081202 commit d1081202 Author: Andrew Morton <akpm@osdl.org> Date: Wed Feb 25 16:17:36 2004 -0800 [PATCH] HFS rewrite http://git.kernel.org/cgit/linux/kernel/git/tglx/history.git/commit/\ fs/hfsplus/bnode.c?id=91556682 commit 91556682 Author: Andrew Morton <akpm@osdl.org> Date: Wed Feb 25 16:17:48 2004 -0800 [PATCH] HFS+ support [3]: http://sourceforge.net/projects/linux-hfsplus/ http://sourceforge.net/projects/linux-hfsplus/files/Linux%202.4.x%20patch/hfsplus%200.1/ http://sourceforge.net/projects/linux-hfsplus/files/Linux%202.4.x%20patch/hfsplus%200.2/ http://linux-hfsplus.cvs.sourceforge.net/viewvc/linux-hfsplus/linux/\ fs/hfsplus/bnode.c?r1=1.4&r2=1.5 Date: Thu Jun 6 09:45:14 2002 +0000 Use buffer cache instead of page cache in bnode.c. Cache inode extents. [4]: http://git.kernel.org/cgit/linux/kernel/git/\ stable/linux-stable.git/commit/?id=a5e3985f commit a5e3985f Author: Roman Zippel <zippel@linux-m68k.org> Date: Tue Sep 6 15:18:47 2005 -0700 [PATCH] hfs: remove debug code Signed-off-by:
Sergei Antonov <saproj@gmail.com> Reviewed-by:
Anton Altaparmakov <anton@tuxera.com> Reported-by:
Sasha Levin <sasha.levin@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Vyacheslav Dubeyko <slava@dubeyko.com> Cc: Sougata Santra <sougata@tuxera.com> Cc: <stable@vger.kernel.org> Signed-off-by:
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Jan Harkes authored
Dan Carpenter discovered a buffer overflow in the Coda file system readlink code. A userspace file system daemon can return a 4096 byte result which then triggers a one byte write past the allocated readlink result buffer. This does not trigger with an unmodified Coda implementation because Coda has a 1024 byte limit for symbolic links, however other userspace file systems using the Coda kernel module could be affected. Although this is an obvious overflow, I don't think this has to be handled as too sensitive from a security perspective because the overflow is on the Coda userspace daemon side which already needs root to open Coda's kernel device and to mount the file system before we get to the point that links can be read. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by:
Jan Harkes <jaharkes@cs.cmu.edu> Reported-by:
Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by:
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Joe Perches authored
"CONST <comparison> variable" checks like: if (NULL != foo) and while (0 < bar(...)) where a constant (or what appears to be a constant like an upper case identifier) is on the left of a comparison are generally preferred to be written using the constant on the right side like: if (foo != NULL) and while (bar(...) > 0) Add a test for this. Add a --fix option too, but only do it when the code is immediately surrounded by parentheses to avoid misfixing things like "(0 < bar() + constant)" Signed-off-by:Joe Perches <joe@perches.com> Cc: Nicolas Morey Chaisemartin <nmorey@kalray.eu> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by:
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Joe Perches authored
commit 61031952 ("arch, x86: pmem api for ensuring durability of persistent memory updates") added a new __pmem annotation for sparse verification. Add __pmem to the $Sparse variable so checkpatch can appropriately ignore uses of this attribute too. Signed-off-by:
Ross Zwisler <ross.zwisler@linux.intel.com> Acked-by:
Andy Whitcroft <apw@canonical.com> Signed-off-by:
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Eddie Kovsky authored
Using checkpatch.pl with Perl 5.22.0 generates the following warning: Unescaped left brace in regex is deprecated, passed through in regex; This patch fixes the warnings by escaping occurrences of the left brace inside the regular expression. Signed-off-by:Eddie Kovsky <ewk@edkovsky.org> Cc: Joe Perches <joe@perches.com> Signed-off-by:
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Joe Perches authored
Fixes: and Link: lines may exceed 75 chars in the commit log. So too can stack dump and dmesg lines and lines that seem like filenames. And Fixes: lines don't need to have a "commit" prefix before the commit id. Add exceptions for these types of lines. Signed-off-by:
Paul Bolle <pebolle@tiscali.nl> Signed-off-by:
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Joe Perches authored
Using 0x%d is wrong. Emit a message when it happens. Miscellanea: Improve the %Lu warning to match formats like %16Lu. Signed-off-by:
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Joe Perches authored
Making --strict the default for staging may help some people submit patches without obvious defects. Signed-off-by:
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Joe Perches authored
Some of the block comment tests that are used only for networking are appropriate for all patches. For example, these styles are not encouraged: /* block comment without introductory * */ and /* * block comment with line terminating */ Remove the networking specific test and add comments. There are some infrequent false positives where code is lazily commented out using /* and */ rather than using #if 0/#endif blocks like: /* case foo: case bar: */ case baz: Signed-off-by:
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Joe Perches authored
commit 34d8815f ("checkpatch: add --showfile to allow input via pipe to show filenames") broke the --emacs with --file option. Fix it. Signed-off-by:
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Joe Perches authored
Sergey Senozhatsky has modified several destroy functions that can now be called with NULL values. - kmem_cache_destroy() - mempool_destroy() - dma_pool_destroy() Update checkpatch to warn when those functions are preceded by an if. Update checkpatch to --fix all the calls too only when the code style form is using leading tabs. from: if (foo) <func>(foo); to: <func>(foo); Signed-off-by:
Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: David Rientjes <rientjes@google.com> Cc: Julia Lawall <julia.lawall@lip6.fr> Signed-off-by:
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Joe Perches authored
Some really long declaration macros exist. For instance; DEFINE_DMA_BUF_EXPORT_INFO(exp_info); and DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(name, description) Increase the limit from 2 words to 6 after DECLARE/DEFINE uses. Signed-off-by:
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Joe Perches authored
Many lines exist like if (foo) bar; where the tabbed indentation of the branch is not one more than the "if" line above it. checkpatch should emit a warning on those lines. Miscellenea: o Remove comments from branch blocks o Skip blank lines in block Signed-off-by:
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Joe Perches authored
Using BUG/BUG_ON crashes the kernel and is just unfriendly. Enable code that emits a warning on BUG/BUG_ON use. Make the code emit the message at WARNING level when scanning a patch and at CHECK level when scanning files so that script users don't feel an obligation to fix code that might be above their pay grade. Signed-off-by:
Geert Uytterhoeven <geert@linux-m68k.org> Tested-by:
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Joe Perches authored
Commit IDs should have commit descriptions too. Warn when a 12 to 40 byte SHA-1 is used in commit logs. Signed-off-by:
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Wang Long authored
In kmalloc_oob_krealloc_less, I think it is better to test the size2 boundary. If we do not call krealloc, the access of position size1 will still cause out-of-bounds and access of position size2 does not. After call krealloc, the access of position size2 cause out-of-bounds. So using size2 is more correct. Signed-off-by:
Wang Long <long.wanglong@huawei.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Signed-off-by:
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Wang Long authored
Signed-off-by:
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Kees Cook authored
To further clarify the purpose of the "esc" argument, rename it to "only" to reflect that it is a limit, not a list of additional characters to escape. Signed-off-by:
Kees Cook <keescook@chromium.org> Suggested-by:
Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by:
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Kees Cook authored
The esc argument is used to reduce which characters will be escaped. For example, using " " with ESCAPE_SPACE will not produce any escaped spaces. Signed-off-by:
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Linus Walleij authored
print_hex_dump_debug() is likely supposed to be analogous to pr_debug() or dev_dbg() & friends. Currently it will adhere to dynamic debug, but will not stub out prints if CONFIG_DEBUG is not set. Let's make it do the right thing, because I am tired of having my dmesg buffer full of hex dumps on production systems. Signed-off-by:
Linus Walleij <linus.walleij@linaro.org> Signed-off-by:
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Pan Xinhui authored
In __bitmap_parselist we can accept whitespaces on head or tail during every parsing procedure. If input has valid ranges, there is no reason to reject the user. For example, bitmap_parselist(" 1-3, 5, ", &mask, nmaskbits). After separating the string, we get " 1-3", " 5", and " ". It's possible and reasonable to accept such string as long as the parsing result is correct. Signed-off-by:Pan Xinhui <xinhuix.pan@intel.com> Cc: Yury Norov <yury.norov@gmail.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by:
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Pan Xinhui authored
If string end with '-', for exapmle, bitmap_parselist("1,0-",&mask, nmaskbits), It is not in a valid pattern, so add a check after loop. Return -EINVAL on such condition. Signed-off-by: -
Pan Xinhui authored
We can avoid in-loop incrementation of ndigits. Save current totaldigits to ndigits before loop, and check ndigits against totaldigits after the loop. Signed-off-by:
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Alexey Dobriyan authored
Convert from manual allocation/copy_from_user/... to kstrto*() family which were designed for exactly that. One case can not be converted to kstrto*_from_user() to make code even more simpler because of whitespace stripping, oh well... Signed-off-by:
Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by:
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Alexey Dobriyan authored
strtol(3) et al accept "-0", so should we. Signed-off-by:
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Joe Perches authored
Anil's email address bounces and he hasn't had a signoff in over 5 years. Signed-off-by:
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Jason A. Donenfeld authored
The other two implementations of pr_debug_ratelimited include pr_fmt, along with every other pr_* function. But pr_debug_ratelimited forgot to add it with the CONFIG_DYNAMIC_DEBUG implementation. This patch unifies the behavior. Signed-off-by:
Jason A. Donenfeld <Jason@zx2c4.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by:
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Joe Perches authored
Commit e0e81739 ("CRED: Add some configurable debugging [try #6]") added the kdebug mechanism to this file back in 2009. The kdebug macro calls no_printk which always evaluates arguments. Most of the kdebug uses have an unnecessary call of atomic_read(&cred->usage) Make the kdebug macro do nothing by defining it with do { if (0) no_printk(...); } while (0) when not enabled. $ size kernel/cred.o* (defconfig x86-64) text data bss dec hex filename 2748 336 8 3092 c14 kernel/cred.o.new 2788 336 8 3132 c3c kernel/cred.o.old Miscellanea: o Neaten the #define kdebug macros while there Signed-off-by:
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Wei Yongjun authored
Signed-off-by:
Wei Yongjun <yongjun_wei@trendmicro.com.cn> Acked-by:
Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by:
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Vasily Kulikov authored
Signed-off-by:
Vasily Kulikov <segoon@openwall.com> Cc: Solar Designer <solar@openwall.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by:
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Vasily Kulikov authored
Poison pointer values should be small enough to find a room in non-mmap'able/hardly-mmap'able space. E.g. on x86 "poison pointer space" is located starting from 0x0. Given unprivileged users cannot mmap anything below mmap_min_addr, it should be safe to use poison pointers lower than mmap_min_addr. The current poison pointer values of LIST_POISON{1,2} might be too big for mmap_min_addr values equal or less than 1 MB (common case, e.g. Ubuntu uses only 0x10000). There is little point to use such a big value given the "poison pointer space" below 1 MB is not yet exhausted. Changing it to a smaller value solves the problem for small mmap_min_addr setups. The values are suggested by Solar Designer: http://www.openwall.com/lists/oss-security/2015/05/02/6Signed-off-by: -
Waiman Long authored
The proc_subdir_lock spinlock is used to allow only one task to make change to the proc directory structure as well as looking up information in it. However, the information lookup part can actually be entered by more than one task as the pde_get() and pde_put() reference count update calls in the critical sections are atomic increment and decrement respectively and so are safe with concurrent updates. The x86 architecture has already used qrwlock which is fair and other architectures like ARM are in the process of switching to qrwlock. So unfairness shouldn't be a concern in that conversion. This patch changed the proc_subdir_lock to a rwlock in order to enable concurrent lookup. The following functions were modified to take a write lock: - proc_register() - remove_proc_entry() - remove_proc_subtree() The following functions were modified to take a read lock: - xlate_proc_name() - proc_lookup_de() - proc_readdir_de() A parallel /proc filesystem search with the "find" command (1000 threads) was run on a 4-socket Haswell-EX box (144 threads). Before the patch, the parallel search took about 39s. After the patch, the parallel find took only 25s, a saving of about 14s. The micro-benchmark that I used was artificial, but it was used to reproduce an exit hanging problem that I saw in real application. In fact, only allow one task to do a lookup seems too limiting to me. Signed-off-by:
Waiman Long <Waiman.Long@hp.com> Acked-by:
"Eric W. Biederman" <ebiederm@xmission.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Scott J Norton <scott.norton@hp.com> Cc: Douglas Hatch <doug.hatch@hp.com> Signed-off-by:
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Calvin Owens authored
Currently, /proc/<pid>/map_files/ is restricted to CAP_SYS_ADMIN, and is only exposed if CONFIG_CHECKPOINT_RESTORE is set. Each mapped file region gets a symlink in /proc/<pid>/map_files/ corresponding to the virtual address range at which it is mapped. The symlinks work like the symlinks in /proc/<pid>/fd/, so you can follow them to the backing file even if that backing file has been unlinked. Currently, files which are mapped, unlinked, and closed are impossible to stat() from userspace. Exposing /proc/<pid>/map_files/ closes this functionality "hole". Not being able to stat() such files makes noticing and explicitly accounting for the space they use on the filesystem impossible. You can work around this by summing up the space used by every file in the filesystem and subtracting that total from what statfs() tells you, but that obviously isn't great, and it becomes unworkable once your filesystem becomes large enough. This patch moves map_files/ out from behind CONFIG_CHECKPOINT_RESTORE, and adjusts the permissions enforced on it as follows: * proc_map_files_lookup() * proc_map_files_readdir() * map_files_d_revalidate() Remove the CAP_SYS_ADMIN restriction, leaving only the current restriction requiring PTRACE_MODE_READ. The information made available to userspace by these three functions is already available in /proc/PID/maps with MODE_READ, so I don't see any reason to limit them any further (see below for more detail). * proc_map_files_follow_link() This stub has been added, and requires that the user have CAP_SYS_ADMIN in order to follow the links in map_files/, since there was concern on LKML both about the potential for bypassing permissions on ancestor directories in the path to files pointed to, and about what happens with more exotic memory mappings created by some drivers (ie dma-buf). In older versions of this patch, I changed every permission check in the four functions above to enforce MODE_ATTACH instead of MODE_READ. This was an oversight on my part, and after revisiting the discussion it seems that nobody was concerned about anything outside of what is made possible by ->follow_link(). So in this version, I've left the checks for PTRACE_MODE_READ as-is. [akpm@linux-foundation.org: catch up with concurrent proc_pid_follow_link() changes] Signed-off-by:
Calvin Owens <calvinowens@fb.com> Reviewed-by:
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Vladimir Davydov authored
Reading/writing a /proc/kpage* file may take long on machines with a lot of RAM installed. Signed-off-by:
Vladimir Davydov <vdavydov@parallels.com> Suggested-by:
Andres Lagar-Cavilla <andreslc@google.com> Reviewed-by:
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Vladimir Davydov authored
As noted by Minchan, a benefit of reading idle flag from /proc/kpageflags is that one can easily filter dirty and/or unevictable pages while estimating the size of unused memory. Note that idle flag read from /proc/kpageflags may be stale in case the page was accessed via a PTE, because it would be too costly to iterate over all page mappings on each /proc/kpageflags read to provide an up-to-date value. To make sure the flag is up-to-date one has to read /sys/kernel/mm/page_idle/bitmap first. Signed-off-by:
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