On March 5, 2020 04:51:51 Ming Lei tom.leiming@gmail.com wrote:
On Tue, Mar 3, 2020 at 8:37 PM Cengiz Can cengiz@kernel.wtf 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@kernel.wtf
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@redhat.com
Thanks, Ming Lei