From: Pavel Begunkov asml.silence@gmail.com
mainline inclusion from mainline-5.5-rc3 commit 7c504e65206a4379ff38fe41d21b32b6c2c3e53e category: feature bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=27 CVE: NA ---------------------------
There is no reliable way to submit and wait in a single syscall, as io_submit_sqes() may under-consume sqes (in case of an early error). Then it will wait for not-yet-submitted requests, deadlocking the user in most cases.
Don't wait/poll if can't submit all sqes
Signed-off-by: Pavel Begunkov asml.silence@gmail.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: yangerkun yangerkun@huawei.com Reviewed-by: zhangyi (F) yi.zhang@huawei.com Signed-off-by: Cheng Jian cj.chengjian@huawei.com --- fs/io_uring.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/fs/io_uring.c b/fs/io_uring.c index 61b468153815..e0b372819d8e 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -5135,6 +5135,9 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, submitted = io_submit_sqes(ctx, to_submit, f.file, fd, &cur_mm, false); mutex_unlock(&ctx->uring_lock); + + if (submitted != to_submit) + goto out; } if (flags & IORING_ENTER_GETEVENTS) { unsigned nr_events = 0; @@ -5148,6 +5151,7 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, } }
+out: percpu_ref_put(&ctx->refs); out_fput: fdput(f);