[PATCH] fix up lockdep trace in fs/exec.c

Dave Jones · Linus Torvalds · commit 513627d7fec6 · 2006-08-27T11:01:32.000-07:00
This fixes the locking error noticed by lockdep:

  =============================================
  [ INFO: possible recursive locking detected ]
  ---------------------------------------------
  init/1 is trying to acquire lock:
   (&amp;sighand-&gt;siglock){....}, at: [&lt;c047a78a&gt;] flush_old_exec+0x3ae/0x859

  but task is already holding lock:
   (&amp;sighand-&gt;siglock){....}, at: [&lt;c047a77a&gt;] flush_old_exec+0x39e/0x859

  other info that might help us debug this:
  2 locks held by init/1:
   #0:  (tasklist_lock){..--}, at: [&lt;c047a76a&gt;] flush_old_exec+0x38e/0x859
   #1:  (&amp;sighand-&gt;siglock){....}, at: [&lt;c047a77a&gt;] flush_old_exec+0x39e/0x859

  stack backtrace:
   [&lt;c04051e1&gt;] show_trace_log_lvl+0x54/0xfd
   [&lt;c040579d&gt;] show_trace+0xd/0x10
   [&lt;c04058b6&gt;] dump_stack+0x19/0x1b
   [&lt;c043b33a&gt;] __lock_acquire+0x773/0x997
   [&lt;c043bacf&gt;] lock_acquire+0x4b/0x6c
   [&lt;c060630b&gt;] _spin_lock+0x19/0x28
   [&lt;c047a78a&gt;] flush_old_exec+0x3ae/0x859
   [&lt;c0498053&gt;] load_elf_binary+0x4aa/0x1628
   [&lt;c0479cab&gt;] search_binary_handler+0xa7/0x24e
   [&lt;c047b577&gt;] do_execve+0x15b/0x1f9
   [&lt;c04022b4&gt;] sys_execve+0x29/0x4d
   [&lt;c0403faf&gt;] syscall_call+0x7/0xb

Signed-off-by: Arjan van de Ven &lt;arjan@infradead.org&gt;
Signed-off-by: Dave Jones &lt;davej@redhat.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@osdl.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@osdl.org&gt;
diff --git a/fs/exec.c b/fs/exec.c
@@ -751,7 +751,7 @@ static int de_thread(struct task_struct *tsk)
 
 		write_lock_irq(&tasklist_lock);
 		spin_lock(&oldsighand->siglock);
-		spin_lock(&newsighand->siglock);
+		spin_lock_nested(&newsighand->siglock, SINGLE_DEPTH_NESTING);
 
 		rcu_assign_pointer(current->sighand, newsighand);
 		recalc_sigpending();
