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  1. 07 May, 2012 2 commits
    • Josh Cartwright's avatar
      jffs2: Fix lock acquisition order bug in gc path · 226bb7df
      Josh Cartwright authored 
      The locking policy is such that the erase_complete_block spinlock is
nested within the alloc_sem mutex.  This fixes a case in which the
acquisition order was erroneously reversed.  This issue was caught by
the following lockdep splat:

   =======================================================
   [ INFO: possible circular locking dependency detected ]
   3.0.5 #1
   -------------------------------------------------------
   jffs2_gcd_mtd6/299 is trying to acquire lock:
    (&c->alloc_sem){+.+.+.}, at: [<c01f7714>] jffs2_garbage_collect_pass+0x314/0x890

   but task is already holding lock:
    (&(&c->erase_completion_lock)->rlock){+.+...}, at: [<c01f7708>] jffs2_garbage_collect_pass+0x308/0x890

   which lock already depends on the new lock.

   the existing dependency chain (in reverse order) is:

   -> #1 (&(&c->erase_completion_lock)->rlock){+.+...}:
          [<c008bec4>] validate_chain+0xe6c/0x10bc
          [<c008c660>] __lock_acquire+0x54c/0xba4
          [<c008d240>] lock_acquire+0xa4/0x114
          [<c046780c>] _raw_spin_lock+0x3c/0x4c
          [<c01f744c>] jffs2_garbage_collect_pass+0x4c/0x890
          [<c01f937c>] jffs2_garbage_collect_thread+0x1b4/0x1cc
          [<c0071a68>] kthread+0x98/0xa0
          [<c000f264>] kernel_thread_exit+0x0/0x8

   -> #0 (&c->alloc_sem){+.+.+.}:
          [<c008ad2c>] print_circular_bug+0x70/0x2c4
          [<c008c08c>] validate_chain+0x1034/0x10bc
          [<c008c660>] __lock_acquire+0x54c/0xba4
          [<c008d240>] lock_acquire+0xa4/0x114
          [<c0466628>] mutex_lock_nested+0x74/0x33c
          [<c01f7714>] jffs2_garbage_collect_pass+0x314/0x890
          [<c01f937c>] jffs2_garbage_collect_thread+0x1b4/0x1cc
          [<c0071a68>] kthread+0x98/0xa0
          [<c000f264>] kernel_thread_exit+0x0/0x8

   other info that might help us debug this:

    Possible unsafe locking scenario:

          CPU0                    CPU1
          ----                    ----
     lock(&(&c->erase_completion_lock)->rlock);
                                  lock(&c->alloc_sem);
                                  lock(&(&c->erase_completion_lock)->rlock);
     lock(&c->alloc_sem);

    *** DEADLOCK ***

   1 lock held by jffs2_gcd_mtd6/299:
    #0:  (&(&c->erase_completion_lock)->rlock){+.+...}, at: [<c01f7708>] jffs2_garbage_collect_pass+0x308/0x890

   stack backtrace:
   [<c00155dc>] (unwind_backtrace+0x0/0x100) from [<c0463dc0>] (dump_stack+0x20/0x24)
   [<c0463dc0>] (dump_stack+0x20/0x24) from [<c008ae84>] (print_circular_bug+0x1c8/0x2c4)
   [<c008ae84>] (print_circular_bug+0x1c8/0x2c4) from [<c008c08c>] (validate_chain+0x1034/0x10bc)
   [<c008c08c>] (validate_chain+0x1034/0x10bc) from [<c008c660>] (__lock_acquire+0x54c/0xba4)
   [<c008c660>] (__lock_acquire+0x54c/0xba4) from [<c008d240>] (lock_acquire+0xa4/0x114)
   [<c008d240>] (lock_acquire+0xa4/0x114) from [<c0466628>] (mutex_lock_nested+0x74/0x33c)
   [<c0466628>] (mutex_lock_nested+0x74/0x33c) from [<c01f7714>] (jffs2_garbage_collect_pass+0x314/0x890)
   [<c01f7714>] (jffs2_garbage_collect_pass+0x314/0x890) from [<c01f937c>] (jffs2_garbage_collect_thread+0x1b4/0x1cc)
   [<c01f937c>] (jffs2_garbage_collect_thread+0x1b4/0x1cc) from [<c0071a68>] (kthread+0x98/0xa0)
   [<c0071a68>] (kthread+0x98/0xa0) from [<c000f264>] (kernel_thread_exit+0x0/0x8)

This was introduce in '81cfc9f1 jffs2: Fix serious write stall due to erase'.

Cc: stable@kernel.org [2.6.37+]
Signed-off-by: default avatarJosh Cartwright <joshc@linux.com>
Signed-off-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
      226bb7df
    • Will Newton's avatar
      mtd: fix oops in dataflash driver · 7a84477c
      Will Newton authored 
      I'm seeing an oops in mtd_dataflash.c with Linux 3.3. What appears to
be happening is that otp_select_filemode calls mtd_read_fact_prot_reg
with -1 for offset and length and a NULL buffer to test if OTP
operations are supported. This finds its way down to otp_read in
mtd_dataflash.c and causes an oops when memcpying the returned data
into the NULL buf.

None of the checks in otp_read catches the negative length and offset.
Changing the length of the dummy read to 0 prevents the oops.

Cc: stable@kernel.org [3.3+]
Signed-off-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
      7a84477c
  3. 21 Apr, 2012 23 commits
  5. 20 Apr, 2012 14 commits
  7. 19 Apr, 2012 1 commit
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