The patch titled
Subject: s/epoll: robustify irq safety with lockdep_assert_irqs_enabled()
has been added to the -mm tree. Its filename is
fs-epoll-robustify-irq-safety-with-lockdep_assert_irqs_enabled.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/fs-epoll-robustify-irq-safety-with-lockdep_assert_irqs_enabled.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/fs-epoll-robustify-irq-safety-with-lockdep_assert_irqs_enabled.patch
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------------------------------------------------------
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.
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>
---
fs/eventpoll.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
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 +670,9 @@ static __poll_t ep_scan_ready_list(struc
struct epitem *epi, *nepi;
LIST_HEAD(txlist);
+ /* must not be called with irqs off */
+ lockdep_assert_irqs_enabled();
+
/*
* We need to lock this because we could be hit by
* eventpoll_release_file() and epoll_ctl().
@@ -764,6 +767,9 @@ static int ep_remove(struct eventpoll *e
{
struct file *file = epi->ffd.file;
+ /* must not be called with irqs off */
+ lockdep_assert_irqs_enabled();
+
/*
* Removes poll wait queue hooks.
*/
@@ -1412,6 +1418,9 @@ static int ep_insert(struct eventpoll *e
struct epitem *epi;
struct ep_pqueue epq;
+ /* must not be called with irqs off */
+ lockdep_assert_irqs_enabled();
+
user_watches = atomic_long_read(&ep->user->epoll_watches);
if (unlikely(user_watches >= max_user_watches))
return -ENOSPC;
@@ -1540,6 +1549,9 @@ static int ep_modify(struct eventpoll *e
int pwake = 0;
poll_table pt;
+ /* must not be called with irqs off */
+ lockdep_assert_irqs_enabled();
+
init_poll_funcptr(&pt, NULL);
/*
_
Patches currently in -mm which might be from dave@xxxxxxxxxxxx are
ipc-sem-prevent-queuestatus-tearing-in-semop.patch
fs-epoll-loosen-irq-safety-in-ep_scan_ready_list.patch
fs-epoll-loosen-irq-safety-in-epoll_insert-and-epoll_remove.patch
fs-epoll-robustify-irq-safety-with-lockdep_assert_irqs_enabled.patch
ipc-drop-ipc_lock.patch
lib-rhashtable-simplify-bucket_table_alloc.patch
lib-rhashtable-guarantee-initial-hashtable-allocation.patch
ipc-get-rid-of-ids-tables_initialized-hack.patch
ipc-simplify-ipc-initialization.patch
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