From: Jens Axboe <axboe@xxxxxxxxx> commit 228339662b398a59b3560cd571deb8b25b253c7e upstream. If an application calls io_uring_enter(2) with a timespec passed in, convert that timespec to ktime_t rather than jiffies. The latter does not provide the granularity the application may expect, and may in fact provided different granularity on different systems, depending on what the HZ value is configured at. Turn the timespec into an absolute ktime_t, and use that with schedule_hrtimeout() instead. Link: https://github.com/axboe/liburing/issues/531 Cc: stable@xxxxxxxxxxxxxxx Reported-by: Bob Chen <chenbo.chen@xxxxxxxxxxxxxxx> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/io_uring.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -7590,7 +7590,7 @@ static int io_run_task_work_sig(void) /* when returns >0, the caller should retry */ static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx, struct io_wait_queue *iowq, - signed long *timeout) + ktime_t timeout) { int ret; @@ -7602,8 +7602,9 @@ static inline int io_cqring_wait_schedul if (test_bit(0, &ctx->check_cq_overflow)) return 1; - *timeout = schedule_timeout(*timeout); - return !*timeout ? -ETIME : 1; + if (!schedule_hrtimeout(&timeout, HRTIMER_MODE_ABS)) + return -ETIME; + return 1; } /* @@ -7616,7 +7617,7 @@ static int io_cqring_wait(struct io_ring { struct io_wait_queue iowq; struct io_rings *rings = ctx->rings; - signed long timeout = MAX_SCHEDULE_TIMEOUT; + ktime_t timeout = KTIME_MAX; int ret; do { @@ -7632,7 +7633,7 @@ static int io_cqring_wait(struct io_ring if (get_timespec64(&ts, uts)) return -EFAULT; - timeout = timespec64_to_jiffies(&ts); + timeout = ktime_add_ns(timespec64_to_ktime(ts), ktime_get_ns()); } if (sig) { @@ -7664,7 +7665,7 @@ static int io_cqring_wait(struct io_ring } prepare_to_wait_exclusive(&ctx->cq_wait, &iowq.wq, TASK_INTERRUPTIBLE); - ret = io_cqring_wait_schedule(ctx, &iowq, &timeout); + ret = io_cqring_wait_schedule(ctx, &iowq, timeout); finish_wait(&ctx->cq_wait, &iowq.wq); cond_resched(); } while (ret > 0);
