Commit 1ff5683043196b9ad628a5de6bf8eeca52ee8bfd

Authored by Ingo Molnar
Committed by Linus Torvalds
1 parent dc1829a4c3

[PATCH] lockdep: fix static keys in module-allocated percpu areas

lockdep got confused by certain locks in modules:

 INFO: trying to register non-static key.
 the code is fine but needs lockdep annotation.
 turning off the locking correctness validator.

 Call Trace:
  [<ffffffff8026f40d>] dump_trace+0xaa/0x3f2
  [<ffffffff8026f78f>] show_trace+0x3a/0x60
  [<ffffffff8026f9d1>] dump_stack+0x15/0x17
  [<ffffffff802abfe8>] __lock_acquire+0x724/0x9bb
  [<ffffffff802ac52b>] lock_acquire+0x4d/0x67
  [<ffffffff80267139>] rt_spin_lock+0x3d/0x41
  [<ffffffff8839ed3f>] :ip_conntrack:__ip_ct_refresh_acct+0x131/0x174
  [<ffffffff883a1334>] :ip_conntrack:udp_packet+0xbf/0xcf
  [<ffffffff8839f9af>] :ip_conntrack:ip_conntrack_in+0x394/0x4a7
  [<ffffffff8023551f>] nf_iterate+0x41/0x7f
  [<ffffffff8025946a>] nf_hook_slow+0x64/0xd5
  [<ffffffff802369a2>] ip_rcv+0x24e/0x506
  [...]

Steven Rostedt found the bug: static_obj() check did not take
PERCPU_ENOUGH_ROOM into account, so in-module DEFINE_PER_CPU-area locks
were triggering this message.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Showing 1 changed file with 2 additions and 1 deletions Side-by-side Diff

... ... @@ -1081,7 +1081,8 @@
1081 1081 */
1082 1082 for_each_possible_cpu(i) {
1083 1083 start = (unsigned long) &__per_cpu_start + per_cpu_offset(i);
1084   - end = (unsigned long) &__per_cpu_end + per_cpu_offset(i);
  1084 + end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM
  1085 + + per_cpu_offset(i);
1085 1086  
1086 1087 if ((addr >= start) && (addr < end))
1087 1088 return 1;