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  1. 03 5月, 2018 6 次提交
  3. 20 3月, 2018 1 次提交
  5. 15 3月, 2018 2 次提交
    • T
      fs/aio: Use RCU accessors for kioctx_table->table[] · d0264c01
      由 Tejun Heo 提交于 
      While converting ioctx index from a list to a table, db446a08
("aio: convert the ioctx list to table lookup v3") missed tagging
kioctx_table->table[] as an array of RCU pointers and using the
appropriate RCU accessors.  This introduces a small window in the
lookup path where init and access may race.

Mark kioctx_table->table[] with __rcu and use the approriate RCU
accessors when using the field.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NJann Horn <jannh@google.com>
Fixes: db446a08 ("aio: convert the ioctx list to table lookup v3")
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: stable@vger.kernel.org # v3.12+
      d0264c01
    • T
      fs/aio: Add explicit RCU grace period when freeing kioctx · a6d7cff4
      由 Tejun Heo 提交于 
      While fixing refcounting, e34ecee2 ("aio: Fix a trinity splat")
incorrectly removed explicit RCU grace period before freeing kioctx.
The intention seems to be depending on the internal RCU grace periods
of percpu_ref; however, percpu_ref uses a different flavor of RCU,
sched-RCU.  This can lead to kioctx being freed while RCU read
protected dereferences are still in progress.

Fix it by updating free_ioctx() to go through call_rcu() explicitly.

v2: Comment added to explain double bouncing.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NJann Horn <jannh@google.com>
Fixes: e34ecee2 ("aio: Fix a trinity splat")
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: stable@vger.kernel.org # v3.13+
      a6d7cff4
  7. 25 10月, 2017 1 次提交
    • M
      locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns... · 6aa7de05
      由 Mark Rutland 提交于 
      locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns to READ_ONCE()/WRITE_ONCE()

Please do not apply this to mainline directly, instead please re-run the
coccinelle script shown below and apply its output.

For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
preference to ACCESS_ONCE(), and new code is expected to use one of the
former. So far, there's been no reason to change most existing uses of
ACCESS_ONCE(), as these aren't harmful, and changing them results in
churn.

However, for some features, the read/write distinction is critical to
correct operation. To distinguish these cases, separate read/write
accessors must be used. This patch migrates (most) remaining
ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following
coccinelle script:

----
// Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and
// WRITE_ONCE()

// $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch

virtual patch

@ depends on patch @
expression E1, E2;
@@

- ACCESS_ONCE(E1) = E2
+ WRITE_ONCE(E1, E2)

@ depends on patch @
expression E;
@@

- ACCESS_ONCE(E)
+ READ_ONCE(E)
----
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davem@davemloft.net
Cc: linux-arch@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: shuah@kernel.org
Cc: snitzer@redhat.com
Cc: thor.thayer@linux.intel.com
Cc: tj@kernel.org
Cc: viro@zeniv.linux.org.uk
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
      6aa7de05
  9. 20 9月, 2017 1 次提交
  11. 09 9月, 2017 1 次提交
    • J
      mm/migrate: new migrate mode MIGRATE_SYNC_NO_COPY · 2916ecc0
      由 Jérôme Glisse 提交于 
      Introduce a new migration mode that allow to offload the copy to a device
DMA engine.  This changes the workflow of migration and not all
address_space migratepage callback can support this.

This is intended to be use by migrate_vma() which itself is use for thing
like HMM (see include/linux/hmm.h).

No additional per-filesystem migratepage testing is needed.  I disables
MIGRATE_SYNC_NO_COPY in all problematic migratepage() callback and i
added comment in those to explain why (part of this patch).  The commit
message is unclear it should say that any callback that wish to support
this new mode need to be aware of the difference in the migration flow
from other mode.

Some of these callbacks do extra locking while copying (aio, zsmalloc,
balloon, ...) and for DMA to be effective you want to copy multiple
pages in one DMA operations.  But in the problematic case you can not
easily hold the extra lock accross multiple call to this callback.

Usual flow is:

For each page {
 1 - lock page
 2 - call migratepage() callback
 3 - (extra locking in some migratepage() callback)
 4 - migrate page state (freeze refcount, update page cache, buffer
     head, ...)
 5 - copy page
 6 - (unlock any extra lock of migratepage() callback)
 7 - return from migratepage() callback
 8 - unlock page
}

The new mode MIGRATE_SYNC_NO_COPY:
 1 - lock multiple pages
For each page {
 2 - call migratepage() callback
 3 - abort in all problematic migratepage() callback
 4 - migrate page state (freeze refcount, update page cache, buffer
     head, ...)
} // finished all calls to migratepage() callback
 5 - DMA copy multiple pages
 6 - unlock all the pages

To support MIGRATE_SYNC_NO_COPY in the problematic case we would need a
new callback migratepages() (for instance) that deals with multiple
pages in one transaction.

Because the problematic cases are not important for current usage I did
not wanted to complexify this patchset even more for no good reason.

Link: http://lkml.kernel.org/r/20170817000548.32038-14-jglisse@redhat.comSigned-off-by: NJérôme Glisse <jglisse@redhat.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Evgeny Baskakov <ebaskakov@nvidia.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mark Hairgrove <mhairgrove@nvidia.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Sherry Cheung <SCheung@nvidia.com>
Cc: Subhash Gutti <sgutti@nvidia.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      2916ecc0
  13. 08 9月, 2017 1 次提交
  15. 05 9月, 2017 1 次提交
  17. 28 6月, 2017 1 次提交
  19. 20 6月, 2017 2 次提交
  21. 02 3月, 2017 1 次提交
  23. 25 2月, 2017 1 次提交
  25. 20 2月, 2017 1 次提交
  27. 15 1月, 2017 1 次提交
    • S
      aio: fix lock dep warning · a12f1ae6
      由 Shaohua Li 提交于 
      lockdep reports a warnning. file_start_write/file_end_write only
acquire/release the lock for regular files. So checking the files in aio
side too.

[  453.532141] ------------[ cut here ]------------
[  453.533011] WARNING: CPU: 1 PID: 1298 at ../kernel/locking/lockdep.c:3514 lock_release+0x434/0x670
[  453.533011] DEBUG_LOCKS_WARN_ON(depth <= 0)
[  453.533011] Modules linked in:
[  453.533011] CPU: 1 PID: 1298 Comm: fio Not tainted 4.9.0+ #964
[  453.533011] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.0-1.fc24 04/01/2014
[  453.533011]  ffff8803a24b7a70 ffffffff8196cffb ffff8803a24b7ae8 0000000000000000
[  453.533011]  ffff8803a24b7ab8 ffffffff81091ee1 ffff8803a5dba700 00000dba00000008
[  453.533011]  ffffed0074496f59 ffff8803a5dbaf54 ffff8803ae0f8488 fffffffffffffdef
[  453.533011] Call Trace:
[  453.533011]  [<ffffffff8196cffb>] dump_stack+0x67/0x9c
[  453.533011]  [<ffffffff81091ee1>] __warn+0x111/0x130
[  453.533011]  [<ffffffff81091f97>] warn_slowpath_fmt+0x97/0xb0
[  453.533011]  [<ffffffff81091f00>] ? __warn+0x130/0x130
[  453.533011]  [<ffffffff8191b789>] ? blk_finish_plug+0x29/0x60
[  453.533011]  [<ffffffff811205d4>] lock_release+0x434/0x670
[  453.533011]  [<ffffffff8198af94>] ? import_single_range+0xd4/0x110
[  453.533011]  [<ffffffff81322195>] ? rw_verify_area+0x65/0x140
[  453.533011]  [<ffffffff813aa696>] ? aio_write+0x1f6/0x280
[  453.533011]  [<ffffffff813aa6c9>] aio_write+0x229/0x280
[  453.533011]  [<ffffffff813aa4a0>] ? aio_complete+0x640/0x640
[  453.533011]  [<ffffffff8111df20>] ? debug_check_no_locks_freed+0x1a0/0x1a0
[  453.533011]  [<ffffffff8114793a>] ? debug_lockdep_rcu_enabled.part.2+0x1a/0x30
[  453.533011]  [<ffffffff81147985>] ? debug_lockdep_rcu_enabled+0x35/0x40
[  453.533011]  [<ffffffff812a92be>] ? __might_fault+0x7e/0xf0
[  453.533011]  [<ffffffff813ac9bc>] do_io_submit+0x94c/0xb10
[  453.533011]  [<ffffffff813ac2ae>] ? do_io_submit+0x23e/0xb10
[  453.533011]  [<ffffffff813ac070>] ? SyS_io_destroy+0x270/0x270
[  453.533011]  [<ffffffff8111d7b3>] ? mark_held_locks+0x23/0xc0
[  453.533011]  [<ffffffff8100201a>] ? trace_hardirqs_on_thunk+0x1a/0x1c
[  453.533011]  [<ffffffff813acb90>] SyS_io_submit+0x10/0x20
[  453.533011]  [<ffffffff824f96aa>] entry_SYSCALL_64_fastpath+0x18/0xad
[  453.533011]  [<ffffffff81119190>] ? trace_hardirqs_off_caller+0xc0/0x110
[  453.533011] ---[ end trace b2fbe664d1cc0082 ]---

Cc: Dmitry Monakhov <dmonakhov@openvz.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NShaohua Li <shli@fb.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      a12f1ae6
  29. 26 12月, 2016 1 次提交
    • T
      ktime: Get rid of the union · 2456e855
      由 Thomas Gleixner 提交于 
      ktime is a union because the initial implementation stored the time in
scalar nanoseconds on 64 bit machine and in a endianess optimized timespec
variant for 32bit machines. The Y2038 cleanup removed the timespec variant
and switched everything to scalar nanoseconds. The union remained, but
become completely pointless.

Get rid of the union and just keep ktime_t as simple typedef of type s64.

The conversion was done with coccinelle and some manual mopping up.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
      2456e855
  31. 25 12月, 2016 1 次提交
  33. 23 12月, 2016 1 次提交
    • A
      move aio compat to fs/aio.c · c00d2c7e
      由 Al Viro 提交于 
      ... and fix the minor buglet in compat io_submit() - native one
kills ioctx as cleanup when put_user() fails.  Get rid of
bogus compat_... in !CONFIG_AIO case, while we are at it - they
should simply fail with ENOSYS, same as for native counterparts.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      c00d2c7e
  35. 05 12月, 2016 1 次提交
  37. 31 10月, 2016 4 次提交
  39. 28 9月, 2016 1 次提交
  41. 16 9月, 2016 1 次提交
    • J
      aio: mark AIO pseudo-fs noexec · 22f6b4d3
      由 Jann Horn 提交于 
      This ensures that do_mmap() won't implicitly make AIO memory mappings
executable if the READ_IMPLIES_EXEC personality flag is set.  Such
behavior is problematic because the security_mmap_file LSM hook doesn't
catch this case, potentially permitting an attacker to bypass a W^X
policy enforced by SELinux.

I have tested the patch on my machine.

To test the behavior, compile and run this:

    #define _GNU_SOURCE
    #include <unistd.h>
    #include <sys/personality.h>
    #include <linux/aio_abi.h>
    #include <err.h>
    #include <stdlib.h>
    #include <stdio.h>
    #include <sys/syscall.h>

    int main(void) {
        personality(READ_IMPLIES_EXEC);
        aio_context_t ctx = 0;
        if (syscall(__NR_io_setup, 1, &ctx))
            err(1, "io_setup");

        char cmd[1000];
        sprintf(cmd, "cat /proc/%d/maps | grep -F '/[aio]'",
            (int)getpid());
        system(cmd);
        return 0;
    }

In the output, "rw-s" is good, "rwxs" is bad.
Signed-off-by: NJann Horn <jann@thejh.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      22f6b4d3
  43. 24 5月, 2016 1 次提交
  45. 04 4月, 2016 1 次提交
  47. 05 9月, 2015 1 次提交
  49. 16 4月, 2015 1 次提交
    • J
      aio: fix serial draining in exit_aio() · dc48e56d
      由 Jens Axboe 提交于 
      exit_aio() currently serializes killing io contexts. Each context
killing ends up having to do percpu_ref_kill(), which in turns has
to wait for an RCU grace period. This can take a long time, depending
on the number of contexts. And there's no point in doing them serially,
when we could be waiting for all of them in one fell swoop.

This patches makes my fio thread offload test case exit 0.2s instead
of almost 6s.
Reviewed-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NJens Axboe <axboe@fb.com>
      dc48e56d
  51. 12 4月, 2015 5 次提交
    • A
      mirror O_APPEND and O_DIRECT into iocb->ki_flags · 2ba48ce5
      由 Al Viro 提交于 
      ... avoiding write_iter/fcntl races.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      2ba48ce5
    • A
      ->aio_read and ->aio_write removed · 84363182
      由 Al Viro 提交于 
      no remaining users
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      84363182
    • A
      aio_run_iocb(): kill dead check · 47e39362
      由 Al Viro 提交于 
      We check if ->ki_pos is positive.  However, by that point we have
already done rw_verify_area(), which would have rejected such
unless the file had been one of /dev/mem, /dev/kmem and /proc/kcore.
All of which do not have vectored rw methods, so we would've bailed
out even earlier.

This check had been introduced before rw_verify_area() had been added there
- in fact, it was a subset of checks done on sync paths by rw_verify_area()
(back then the /dev/mem exception didn't exist at all).  The rest of checks
(mandatory locking, etc.) hadn't been added until later.  Unfortunately,
by the time the call of rw_verify_area() got added, the /dev/mem exception
had already appeared, so it wasn't obvious that the older explicit check
downstream had become dead code.  It *is* a dead code, though, since the few
files for which the exception applies do not have ->aio_{read,write}() or
->{read,write}_iter() and for them we won't reach that check anyway.

What's more, even if we ever introduce vectored methods for /dev/mem
and friends, they'll have to cope with negative positions anyway, since
readv(2) and writev(2) are using the same checks as read(2) and write(2) -
i.e. rw_verify_area().

Let's bury it.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      47e39362
    • A
      ioctx_alloc(): remove pointless check · 08397acd
      由 Al Viro 提交于 
      Way, way back kiocb used to be picked from arrays, so ioctx_alloc()
checked for multiplication overflow when calculating the size of
such array.  By the time fs/aio.c went into the tree (in 2002) they
were already allocated one-by-one by kmem_cache_alloc(), so that
check had already become pointless.  Let's bury it...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      08397acd
    • A
      aio_setup_vectored_rw(): switch to {compat_,}import_iovec() · 32a56afa
      由 Al Viro 提交于 
      Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      32a56afa