On March 5, 2020 04:51:51 Ming Lei <tom.leiming@xxxxxxxxx> wrote:
On Tue, Mar 3, 2020 at 8:37 PM Cengiz Can <cengiz@xxxxxxxxxx> wrote:Added a reassignment into the NULL check block to fix the issue. Fixes: c780e86dd48 ("blktrace: Protect q->blk_trace with RCU") Signed-off-by: Cengiz Can <cengiz@xxxxxxxxxx> --- kernel/trace/blktrace.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index 4560878f0bac..29ea88f10b87 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c@@ -1896,8 +1896,10 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,} ret = 0; - if (bt == NULL) + if (bt == NULL) { ret = blk_trace_setup_queue(q, bdev); + bt = q->blk_trace;I'd suggest to use the following line for avoiding RCU warning: bt = rcu_dereference_protected(q->blk_trace, lockdep_is_held(&q->blk_trace_mutex)); Otherwise, the patch looks fine for me:
Thank you. Please kindly see v2.
Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx> Thanks, Ming Lei
