From: Davidlohr Bueso <dave@xxxxxxxxxxxx> Subject: s/epoll: robustify irq safety with lockdep_assert_irqs_enabled() Sprinkle lockdep_assert_irqs_enabled() checks in the functions that do not save and restore interrupts when dealing with the ep->wq.lock. These are ep_scan_ready_list() and those called by epoll_ctl(): ep_insert, ep_modify and ep_remove. [akpm@xxxxxxxxxxxxxxxxxxxx: remove too-obvious comments] Link: http://lkml.kernel.org/r/20180721183127.3busfa335zlcjeox@linux-r8p5 Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- diff -puN fs/eventpoll.c~fs-epoll-robustify-irq-safety-with-lockdep_assert_irqs_enabled fs/eventpoll.c --- a/fs/eventpoll.c~fs-epoll-robustify-irq-safety-with-lockdep_assert_irqs_enabled +++ a/fs/eventpoll.c @@ -670,6 +670,8 @@ static __poll_t ep_scan_ready_list(struc struct epitem *epi, *nepi; LIST_HEAD(txlist); + lockdep_assert_irqs_enabled(); + /* * We need to lock this because we could be hit by * eventpoll_release_file() and epoll_ctl(). @@ -764,6 +766,8 @@ static int ep_remove(struct eventpoll *e { struct file *file = epi->ffd.file; + lockdep_assert_irqs_enabled(); + /* * Removes poll wait queue hooks. */ @@ -1412,6 +1416,8 @@ static int ep_insert(struct eventpoll *e struct epitem *epi; struct ep_pqueue epq; + lockdep_assert_irqs_enabled(); + user_watches = atomic_long_read(&ep->user->epoll_watches); if (unlikely(user_watches >= max_user_watches)) return -ENOSPC; @@ -1540,6 +1546,8 @@ static int ep_modify(struct eventpoll *e int pwake = 0; poll_table pt; + lockdep_assert_irqs_enabled(); + init_poll_funcptr(&pt, NULL); /* _
