From b874d4aae58b92144ec2c8fa5dc0a27c98388fcc Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 12 Mar 2024 15:58:41 -0600 Subject: [PATCH] block: limit block time caching to in_task() context We should not have any callers of this from non-task context, but Jakub ran [1] into one from blk-iocost. Rather than risk running into others, or future ones, just limit blk_time_get_ns() to when it is called from a task. Any other usage is invalid. [1] https://lore.kernel.org/lkml/CAHk-=wiOaBLqarS2uFhM1YdwOvCX4CZaWkeyNDY1zONpbYw2ig@mail.gmail.com/ Fixes: da4c8c3d0975 ("block: cache current nsec time in struct blk_plug") Reported-by: Jakub Kicinski Signed-off-by: Jens Axboe --- block/blk.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/blk.h b/block/blk.h index a19b7b42e650..5cac4e29ae17 100644 --- a/block/blk.h +++ b/block/blk.h @@ -534,7 +534,7 @@ static inline u64 blk_time_get_ns(void) { struct blk_plug *plug = current->plug; - if (!plug) + if (!plug || !in_task()) return ktime_get_ns(); /*