On 04/01/2021 15:57, Greg Kroah-Hartman wrote:
From: Pavel Begunkov asml.silence@gmail.com
commit b1b6b5a30dce872f500dc43f067cba8e7f86fc7d upstream.
For cancelling io_uring requests it needs either to be able to run currently enqueued task_works or having it shut down by that moment. Otherwise io_uring_cancel_files() may be waiting for requests that won't ever complete.
Greg, can you drop it from stable for now? I'll backport it later when related problems are sorted.
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.
Cc: stable@vger.kernel.org # 5.5+ Signed-off-by: Pavel Begunkov asml.silence@gmail.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
fs/file.c | 2 -- kernel/exit.c | 2 ++ 2 files changed, 2 insertions(+), 2 deletions(-)
--- 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; @@ -453,7 +452,6 @@ void exit_files(struct task_struct *tsk) struct files_struct * files = tsk->files; if (files) {
io_uring_files_cancel(files);--- 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> @@ -762,6 +763,7 @@ 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 */