1. 19 Oct, 2011 2 commits
    • Tejun Heo's avatar
      block: make gendisk hold a reference to its queue · 523e1d39
      Tejun Heo authored
      The following command sequence triggers an oops.
      
      # mount /dev/sdb1 /mnt
      # echo 1 > /sys/class/scsi_device/0\:0\:1\:0/device/delete
      # umount /mnt
      
       general protection fault: 0000 [#1] PREEMPT SMP
       CPU 2
       Modules linked in:
      
       Pid: 791, comm: umount Not tainted 3.1.0-rc3-work+ #8 Bochs Bochs
       RIP: 0010:[<ffffffff810d0879>]  [<ffffffff810d0879>] __lock_acquire+0x389/0x1d60
      ...
       Call Trace:
        [<ffffffff810d2845>] lock_acquire+0x95/0x140
        [<ffffffff81aed87b>] _raw_spin_lock+0x3b/0x50
        [<ffffffff811573bc>] bdi_lock_two+0x5c/0x70
        [<ffffffff811c2f6c>] bdev_inode_switch_bdi+0x4c/0xf0
        [<ffffffff811c3fcb>] __blkdev_put+0x11b/0x1d0
        [<ffffffff811c4010>] __blkdev_put+0x160/0x1d0
        [<ffffffff811c40df>] blkdev_put+0x5f/0x190
        [<ffffffff8118f18d>] kill_block_super+0x4d/0x80
        [<ffffffff8118f4a5>] deactivate_locked_super+0x45/0x70
        [<ffffffff8119003a>] deactivate_super+0x4a/0x70
        [<ffffffff811ac4ad>] mntput_no_expire+0xed/0x130
        [<ffffffff811acf2e>] sys_umount+0x7e/0x3a0
        [<ffffffff81aeeeab>] system_call_fastpath+0x16/0x1b
      
      This is because bdev holds on to disk but disk doesn't pin the
      associated queue.  If a SCSI device is removed while the device is
      still open, the sdev puts the base reference to the queue on release.
      When the bdev is finally released, the associated queue is already
      gone along with the bdi and bdev_inode_switch_bdi() ends up
      dereferencing already freed bdi.
      
      Even if it were not for this bug, disk not holding onto the associated
      queue is very unusual and error-prone.
      
      Fix it by making add_disk() take an extra reference to its queue and
      put it on disk_release() and ensuring that disk and its fops owner are
      put in that order after all accesses to the disk and queue are
      complete.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Cc: stable@kernel.org
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      523e1d39
    • Jens Axboe's avatar
      Merge branch 'v3.1-rc10' into for-3.2/core · 5c04b426
      Jens Axboe authored
      Conflicts:
      	block/blk-core.c
      	include/linux/blkdev.h
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      5c04b426
  2. 18 Oct, 2011 1 commit
  3. 17 Oct, 2011 1 commit
    • Linus Torvalds's avatar
      Avoid using variable-length arrays in kernel/sys.c · a84a79e4
      Linus Torvalds authored
      The size is always valid, but variable-length arrays generate worse code
      for no good reason (unless the function happens to be inlined and the
      compiler sees the length for the simple constant it is).
      
      Also, there seems to be some code generation problem on POWER, where
      Henrik Bakken reports that register r28 can get corrupted under some
      subtle circumstances (interrupt happening at the wrong time?).  That all
      indicates some seriously broken compiler issues, but since variable
      length arrays are bad regardless, there's little point in trying to
      chase it down.
      
      "Just don't do that, then".
      Reported-by: default avatarHenrik Grindal Bakken <henribak@cisco.com>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: stable@kernel.org
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      a84a79e4
  4. 16 Oct, 2011 1 commit
  5. 15 Oct, 2011 3 commits
  6. 14 Oct, 2011 6 commits
  7. 13 Oct, 2011 7 commits
  8. 11 Oct, 2011 5 commits
  9. 10 Oct, 2011 11 commits
  10. 08 Oct, 2011 2 commits
  11. 07 Oct, 2011 1 commit