diff options
| author | Peter Zijlstra <[email protected]> | 2015-04-15 17:11:57 +0200 |
|---|---|---|
| committer | Ingo Molnar <[email protected]> | 2015-04-17 09:42:14 +0200 |
| commit | d7bc3197b41e0a1af6677e83f8736e93a1575ce0 (patch) | |
| tree | 8b9dbb106e7c287182b3812c0469a1fea8e46c95 /net/unix/garbage.c | |
| parent | 6a16dda86ebbcfe690c753c3fb469b4f9ad5a5ef (diff) | |
lockdep: Make print_lock() robust against concurrent release
During sysrq's show-held-locks command it is possible that
hlock_class() returns NULL for a given lock. The result is then (after
the warning):
|BUG: unable to handle kernel NULL pointer dereference at 0000001c
|IP: [<c1088145>] get_usage_chars+0x5/0x100
|Call Trace:
| [<c1088263>] print_lock_name+0x23/0x60
| [<c1576b57>] print_lock+0x5d/0x7e
| [<c1088314>] lockdep_print_held_locks+0x74/0xe0
| [<c1088652>] debug_show_all_locks+0x132/0x1b0
| [<c1315c48>] sysrq_handle_showlocks+0x8/0x10
This *might* happen because the thread on the other CPU drops the lock
after we are looking ->lockdep_depth and ->held_locks points no longer
to a lock that is held.
The fix here is to simply ignore it and continue.
Reported-by: Andreas Messerschmid <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Sebastian Andrzej Siewior <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Diffstat (limited to 'net/unix/garbage.c')
0 files changed, 0 insertions, 0 deletions