Commit bea493a031fe3337f4fe5479e8e865513828ea76

Authored by Peter Zijlstra
Committed by Linus Torvalds
1 parent 91b943ee4a

[PATCH] rt-mutex: fixup rt-mutex debug code

BUG: warning at kernel/rtmutex-debug.c:125/rt_mutex_debug_task_free() (Not tainted)
 [<c04051e3>] show_trace_log_lvl+0x58/0x16a
 [<c04057f0>] show_trace+0xd/0x10
 [<c0405900>] dump_stack+0x19/0x1b
 [<c043f03d>] rt_mutex_debug_task_free+0x35/0x6a
 [<c04224c0>] free_task+0x15/0x24
 [<c042378c>] copy_process+0x12bd/0x1324
 [<c0423835>] do_fork+0x42/0x113
 [<c04021dd>] sys_fork+0x19/0x1b
 [<c0403fb7>] syscall_call+0x7/0xb

In copy_process(), dup_task_struct() also duplicates the ->pi_lock,
->pi_waiters and ->pi_blocked_on members.  rt_mutex_debug_task_free()
called from free_task() validates these members.  However free_task() can
be invoked before these members are reset for the new task.

Move the initialization code before the first bail that can hit free_task().

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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

... ... @@ -984,6 +984,8 @@
984 984 if (!p)
985 985 goto fork_out;
986 986  
  987 + rt_mutex_init_task(p);
  988 +
987 989 #ifdef CONFIG_TRACE_IRQFLAGS
988 990 DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled);
989 991 DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled);
... ... @@ -1087,8 +1089,6 @@
1087 1089 p->curr_chain_key = 0;
1088 1090 p->lockdep_recursion = 0;
1089 1091 #endif
1090   -
1091   - rt_mutex_init_task(p);
1092 1092  
1093 1093 #ifdef CONFIG_DEBUG_MUTEXES
1094 1094 p->blocked_on = NULL; /* not blocked yet */