1. 06 May, 2015 37 commits
  2. 29 Apr, 2015 3 commits
    • Greg Kroah-Hartman's avatar
      Linux 3.10.76 · 89bf6007
      Greg Kroah-Hartman authored
      89bf6007
    • Ben Hutchings's avatar
      dcache: Fix locking bugs in backported "deal with deadlock in d_walk()" · c190d250
      Ben Hutchings authored
      commit 20defcec upstream in 3.2-stable
      
      Steven Rostedt reported:
      > Porting -rt to the latest 3.2 stable tree I triggered this bug:
      >
      > =====================================
      > [ BUG: bad unlock balance detected! ]
      > -------------------------------------
      > rm/1638 is trying to release lock (rcu_read_lock) at:
      > [<c04fde6c>] rcu_read_unlock+0x0/0x23
      > but there are no more locks to release!
      >
      > other info that might help us debug this:
      > 2 locks held by rm/1638:
      >  #0:  (&sb->s_type->i_mutex_key#9/1){+.+.+.}, at: [<c04f93eb>] do_rmdir+0x5f/0xd2
      >  #1:  (&sb->s_type->i_mutex_key#9){+.+.+.}, at: [<c04f9329>] vfs_rmdir+0x49/0xac
      >
      > stack backtrace:
      > Pid: 1638, comm: rm Not tainted 3.2.66-test-rt96+ #2
      > Call Trace:
      >  [<c083f390>] ? printk+0x1d/0x1f
      >  [<c0463cdf>] print_unlock_inbalance_bug+0xc3/0xcd
      >  [<c04653a8>] lock_release_non_nested+0x98/0x1ec
      >  [<c046228d>] ? trace_hardirqs_off_caller+0x18/0x90
      >  [<c0456f1c>] ? local_clock+0x2d/0x50
      >  [<c04fde6c>] ? d_hash+0x2f/0x2f
      >  [<c04fde6c>] ? d_hash+0x2f/0x2f
      >  [<c046568e>] lock_release+0x192/0x1ad
      >  [<c04fde83>] rcu_read_unlock+0x17/0x23
      >  [<c04ff344>] shrink_dcache_parent+0x227/0x270
      >  [<c04f9348>] vfs_rmdir+0x68/0xac
      >  [<c04f9424>] do_rmdir+0x98/0xd2
      >  [<c04f03ad>] ? fput+0x1a3/0x1ab
      >  [<c084dd42>] ? sysenter_exit+0xf/0x1a
      >  [<c0465b58>] ? trace_hardirqs_on_caller+0x118/0x149
      >  [<c04fa3e0>] sys_unlinkat+0x2b/0x35
      >  [<c084dd13>] sysenter_do_call+0x12/0x12
      >
      >
      >
      >
      > There's a path to calling rcu_read_unlock() without calling
      > rcu_read_lock() in have_submounts().
      >
      > 	goto positive;
      >
      > positive:
      > 	if (!locked && read_seqretry(&rename_lock, seq))
      > 		goto rename_retry;
      >
      > rename_retry:
      > 	rcu_read_unlock();
      >
      > in the above path, rcu_read_lock() is never done before calling
      > rcu_read_unlock();
      
      I reviewed locking contexts in all three functions that I changed when
      backporting "deal with deadlock in d_walk()".  It's actually worse
      than this:
      
      - We don't hold this_parent->d_lock at the 'positive' label in
        have_submounts(), but it is unlocked after 'rename_retry'.
      - There is an rcu_read_unlock() after the 'out' label in
        select_parent(), but it's not held at the 'goto out'.
      
      Fix all three lock imbalances.
      Reported-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
      Tested-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      c190d250
    • Guenter Roeck's avatar
      arc: mm: Fix build failure · 9e505ae7
      Guenter Roeck authored
      commit e262eb93 upstream.
      
      Fix misspelled define.
      
      Fixes: 33692f27 ("vm: add VM_FAULT_SIGSEGV handling support")
      Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      9e505ae7