On 11/13/2014 07:07 PM, Steven Rostedt wrote: > > Jens (Cc'd) maintains the blktrace. He can take this if he wants. > > -- Steve > > > On Mon, 10 Nov 2014 11:40:49 +0100 > Arianna Avanzini <[email protected]> wrote: > >> Currently, blktrace can be started/stopped via its ioctl-based interface >> (used by the userspace blktrace tool) or via its ftrace interface. The >> function blk_trace_remove_queue(), called each time an "enable" tunable >> of the ftrace interface transitions to zero, removes the trace from the >> running list, even if no function from the sysfs interface adds it to >> such a list. This leads to a null pointer dereference. >> This commit changes the blk_trace_remove_queue() function so that it >> does not remove the blk_trace from the running list. >> >> v2: >> - Now the patch removes the invocation of list_del() instead of >> adding an useless if branch, as suggested by Namhyung Kim. >> >> Signed-off-by: Arianna Avanzini <[email protected]> >> --- >> kernel/trace/blktrace.c | 3 --- >> 1 file changed, 3 deletions(-) >> >> diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c >> index c1bd4ad..bd05fd2 100644 >> --- a/kernel/trace/blktrace.c >> +++ b/kernel/trace/blktrace.c >> @@ -1493,9 +1493,6 @@ static int blk_trace_remove_queue(struct request_queue >> *q) >> if (atomic_dec_and_test(&blk_probes_ref)) >> blk_unregister_tracepoints(); >> >> - spin_lock_irq(&running_trace_lock); >> - list_del(&bt->running_list); >> - spin_unlock_irq(&running_trace_lock); >> blk_trace_free(bt); >> return 0;
Applied, thanks! -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
