diff options
| author | Steven Rostedt <srostedt@redhat.com> | 2009-03-10 17:16:35 -0400 |
|---|---|---|
| committer | Steven Rostedt <srostedt@redhat.com> | 2009-03-10 17:16:35 -0400 |
| commit | 80370cb758e7ca2692cd9fb5e413d970b1f4b2b2 (patch) | |
| tree | 2c1451f4a374d8b7a515fe39b4bb24bb6a323db9 | |
| parent | ef18012b248b47ec9a12c3a83ca5e99782d39c5d (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>
| -rw-r--r-- | 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 8c6a902db40..4c97947650a 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); |