In commit 0a65bc27bd64 ("eventpoll: Set epoll timeout if it's in the
future"), a bug was introduced causing the loop in ep_poll to hang under
certain circumstances.
When the timeout is non-NULL and ep_schedule_timeout returns false, the
flag timed_out was not set to true. This causes a hang.
Adjust the logic and set timed_out, if needed, fixing the original code.
Reported-by: Christian Brauner <brauner@xxxxxxxxxx>
Closes: https://lore.kernel.org/linux-fsdevel/20250426-haben-redeverbot-0b58878ac722@brauner/
Reported-by: Mike Pagano <mpagano@xxxxxxxxxx>
Closes: https://bugs.gentoo.org/954806
Reported-by: Carlos Llamas <cmllamas@xxxxxxxxxx>
Closes: https://lore.kernel.org/linux-fsdevel/aBAB_4gQ6O_haAjp@xxxxxxxxxx/
Fixes: 0a65bc27bd64 ("eventpoll: Set epoll timeout if it's in the future")
Tested-by: Carlos Llamas <cmllamas@xxxxxxxxxx>
Signed-off-by: Joe Damato <jdamato@xxxxxxxxxx>
---
fs/eventpoll.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 4bc264b854c4..1a5d1147f082 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -2111,7 +2111,9 @@ static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events,
write_unlock_irq(&ep->lock);
- if (!eavail && ep_schedule_timeout(to))
+ if (!ep_schedule_timeout(to))
+ timed_out = 1;
+ else if (!eavail)
timed_out = !schedule_hrtimeout_range(to, slack,
HRTIMER_MODE_ABS);
__set_current_state(TASK_RUNNING);
base-commit: f520bed25d17bb31c2d2d72b0a785b593a4e3179
--
2.43.0
