All coming events are stored in FIFO order and this is also should be applicable to ->ovflist, which originally is stack, i.e. LIFO.
Thus to keep correct FIFO order ->ovflist should reversed by adding elements to the head of the read list but not to the tail. Signed-off-by: Roman Penyaev <[email protected]> Cc: Davidlohr Bueso <[email protected]> Cc: Jason Baron <[email protected]> Cc: Al Viro <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: [email protected] Cc: [email protected] --- fs/eventpoll.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 2329f96469e2..3627c2e07149 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -722,7 +722,11 @@ static __poll_t ep_scan_ready_list(struct eventpoll *ep, * contain them, and the list_splice() below takes care of them. */ if (!ep_is_linked(epi)) { - list_add_tail(&epi->rdllink, &ep->rdllist); + /* + * ->ovflist is LIFO, so we have to reverse it in order + * to keep in FIFO. + */ + list_add(&epi->rdllink, &ep->rdllist); ep_pm_stay_awake(epi); } } -- 2.19.1
