dect
/
linux-2.6
Archived
13
0
Fork 0
Code Releases Activity

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>
This commit is contained in:
Steven Rostedt 2009-03-10 17:16:35 -04:00
parent ef18012b24
commit 80370cb758
1 changed files with 7 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
kernel/trace/trace.c
View File

@ -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);