On 30/12/2020 21:34, Pavel Begunkov wrote:
For cancelling io_uring requests it needs either to be able to run currently enqueued task_wokrs or having it shut down by that moment. Otherwise io_uring_cancel_files() may be waiting for requests that won't ever complete.
Go with the first way and do cancellations before setting PF_EXITING and so before putting the task_work infrastructure into a transition state where task_work_run() would better not be called.
It won't do in the end, because after cancellation we don't have files NULLed yet and SQPOLL task may use find and use them. I guess can't be dropped because of rc, I'll think whether to revert or somehow shut sqpoll.
Cc: stable@vger.kernel.org # 5.5+ Signed-off-by: Pavel Begunkov asml.silence@gmail.com
fs/file.c | 2 -- kernel/exit.c | 2 ++ 2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/file.c b/fs/file.c index c0b60961c672..dab120b71e44 100644 --- a/fs/file.c +++ b/fs/file.c @@ -21,7 +21,6 @@ #include <linux/rcupdate.h> #include <linux/close_range.h> #include <net/sock.h> -#include <linux/io_uring.h> unsigned int sysctl_nr_open __read_mostly = 1024*1024; unsigned int sysctl_nr_open_min = BITS_PER_LONG; @@ -428,7 +427,6 @@ void exit_files(struct task_struct *tsk) struct files_struct * files = tsk->files; if (files) {
io_uring_files_cancel(files);diff --git a/kernel/exit.c b/kernel/exit.c index 3594291a8542..04029e35e69a 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -63,6 +63,7 @@ #include <linux/random.h> #include <linux/rcuwait.h> #include <linux/compat.h> +#include <linux/io_uring.h> #include <linux/uaccess.h> #include <asm/unistd.h> @@ -776,6 +777,7 @@ void __noreturn do_exit(long code) schedule(); }
- io_uring_files_cancel(tsk->files); exit_signals(tsk); /* sets PF_EXITING */
/* sync mm's RSS info before statistics gathering */