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authorPeter Zijlstra <peterz@infradead.org>2011-12-08 14:34:13 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2011-12-09 07:50:28 -0800
commit09dc3cf93f7d16fdd37a0ad8486faebb5e2769ec (patch)
tree4db1b0103db218d0d0aa26a26232c3674dd18622
parentc193c82f054195aa352ccbef91afc28446e5a30e (diff)
printk: avoid double lock acquire
Commit 4f2a8d3cf5e ("printk: Fix console_sem vs logbuf_lock unlock race") introduced another silly bug where we would want to acquire an already held lock. Avoid this. Reported-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--kernel/printk.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/printk.c b/kernel/printk.c
index 1455a0d4eedd..7982a0a841ea 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -1293,10 +1293,11 @@ again:
raw_spin_lock(&logbuf_lock);
if (con_start != log_end)
retry = 1;
+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+
if (retry && console_trylock())
goto again;
- raw_spin_unlock_irqrestore(&logbuf_lock, flags);
if (wake_klogd)
wake_up_klogd();
}