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Commit 92e64178 authored by Davidlohr Bueso's avatar Davidlohr Bueso Committed by Linus Torvalds
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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@linux-foundation.org: remove too-obvious comments]
Link: http://lkml.kernel.org/r/20180721183127.3busfa335zlcjeox@linux-r8p5


Signed-off-by: default avatarDavidlohr Bueso <dbueso@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 304b18b8

fs/eventpoll.c

+8 −0
Original line number Diff line number Diff line
@@ -670,6 +670,8 @@ static __poll_t ep_scan_ready_list(struct eventpoll *ep, 
	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 *ep, struct epitem *epi) 
{

	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 *ep, const struct epoll_event *event, 
	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 *ep, struct epitem *epi, 
	int pwake = 0;

	poll_table pt;



	lockdep_assert_irqs_enabled();



	init_poll_funcptr(&pt, NULL);



	/*