Commit-ID: 80370cb758e7ca2692cd9fb5e413d970b1f4b2b2
Gitweb: http://git.kernel.org/tip/80370cb758e7ca2692cd9fb5e413d970b1f4b2b2
Author: "Steven Rostedt" <srostedt@xxxxxxxxxx>
AuthorDate: Tue, 10 Mar 2009 17:16:35 -0400
Commit: Steven Rostedt <srostedt@xxxxxxxxxx>
CommitDate: Tue, 10 Mar 2009 17:16:35 -0400
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@xxxxxxxxxx>
---
kernel/trace/trace.c | 10 +++++++---
1 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 8c6a902..4c97947 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);
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|