On 14/01/2021 15:50, Marcelo Diop-Gonzalez wrote:
> This patch tries to fix a problem with IORING_OP_TIMEOUT events
> not being flushed if they should already have expired. The test below
> hangs before this change (unless you run with $ ./a.out ~/somefile 1):
How sending it as a liburing test?
BTW, there was a test before triggering this issue but was shut off
with "return 0" at some point, but that's not for sure.
>
> #include <fcntl.h>
> #include <stdio.h>
> #include <stdlib.h>
> #include <string.h>
> #include <unistd.h>
>
> #include <liburing.h>
>
> int main(int argc, char **argv) {
> if (argc < 2)
> return 1;
>
> int fd = open(argv[1], O_RDONLY);
> if (fd < 0) {
> perror("open");
> return 1;
> }
>
> struct io_uring ring;
> io_uring_queue_init(4, &ring, 0);
>
> struct io_uring_sqe *sqe = io_uring_get_sqe(&ring);
>
> struct __kernel_timespec ts = { .tv_sec = 9999999 };
> io_uring_prep_timeout(sqe, &ts, 1, 0);
> sqe->user_data = 123;
> int ret = io_uring_submit(&ring);
> if (ret < 0) {
> fprintf(stderr, "submit(timeout_sqe): %d\n", ret);
> return 1;
> }
>
> int n = 2;
> if (argc > 2)
> n = atoi(argv[2]);
>
> char buf;
> for (int i = 0; i < n; i++) {
> sqe = io_uring_get_sqe(&ring);
> if (!sqe) {
> fprintf(stderr, "too many\n");
> exit(1);
> }
> io_uring_prep_read(sqe, fd, &buf, 1, 0);
> }
> ret = io_uring_submit(&ring);
> if (ret < 0) {
> fprintf(stderr, "submit(read_sqe): %d\n", ret);
> exit(1);
> }
>
> struct io_uring_cqe *cqe;
> for (int i = 0; i < n+1; i++) {
> struct io_uring_cqe *cqe;
> int ret = io_uring_wait_cqe(&ring, &cqe);
> if (ret < 0) {
> fprintf(stderr, "wait_cqe(): %d\n", ret);
> return 1;
> }
> if (cqe->user_data == 123)
> printf("timeout found\n");
> io_uring_cqe_seen(&ring, cqe);
> }
> }
>
> v3: Add ->last_flush member to handle more overflow issues
> v2: Properly handle u32 overflow issues
>
> Marcelo Diop-Gonzalez (1):
> io_uring: flush timeouts that should already have expired
>
> fs/io_uring.c | 29 +++++++++++++++++++++++++----
> 1 file changed, 25 insertions(+), 4 deletions(-)
>
--
Pavel Begunkov
