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authorSteven Rostedt <srostedt@redhat.com>2009-03-10 17:16:35 -0400
committerSteven Rostedt <srostedt@redhat.com>2009-03-10 17:16:35 -0400
commit80370cb758e7ca2692cd9fb5e413d970b1f4b2b2 (patch)
tree2c1451f4a374d8b7a515fe39b4bb24bb6a323db9 /kernel
parentef18012b248b47ec9a12c3a83ca5e99782d39c5d (diff)
tracing: use raw spinlocks for trace_vprintk
Impact: prevent locking up by lockdep tracer The lockdep tracer uses trace_vprintk and thus trace_vprintk can not call back into lockdep without locking up. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 8c6a902db40a..4c97947650ae 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1176,7 +1176,8 @@ void trace_graph_return(struct ftrace_graph_ret *trace)
*/
int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args)
{
- static DEFINE_SPINLOCK(trace_buf_lock);
+ static raw_spinlock_t trace_buf_lock =
+ (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
static u32 trace_buf[TRACE_BUF_SIZE];
struct ring_buffer_event *event;
@@ -1201,7 +1202,9 @@ int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args)
if (unlikely(atomic_read(&data->disabled)))
goto out;
- spin_lock_irqsave(&trace_buf_lock, flags);
+ /* Lockdep uses trace_printk for lock tracing */
+ local_irq_save(flags);
+ __raw_spin_lock(&trace_buf_lock);
len = vbin_printf(trace_buf, TRACE_BUF_SIZE, fmt, args);
if (len > TRACE_BUF_SIZE || len < 0)
@@ -1220,7 +1223,8 @@ int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args)
ring_buffer_unlock_commit(tr->buffer, event);
out_unlock:
- spin_unlock_irqrestore(&trace_buf_lock, flags);
+ __raw_spin_unlock(&trace_buf_lock);
+ local_irq_restore(flags);
out:
ftrace_preempt_enable(resched);