summaryrefslogtreecommitdiff
path: root/include/linux/timer.h
diff options
context:
space:
mode:
authorEric Dumazet <edumazet@google.com>2019-11-07 11:37:38 -0800
committerPaul E. McKenney <paulmck@kernel.org>2020-02-20 15:58:22 -0800
commit90c018942c2babab73814648b37808fc3bf2ed1a (patch)
tree699ef5fe2639ff3d5c171c53b80aa58ba53552e5 /include/linux/timer.h
parent3ca3b0e2cbe0050d1777a22b7fc13cad620eb2ba (diff)
timer: Use hlist_unhashed_lockless() in timer_pending()
The timer_pending() function is mostly used in lockless contexts, so Without proper annotations, KCSAN might detect a data-race [1]. Using hlist_unhashed_lockless() instead of hand-coding it seems appropriate (as suggested by Paul E. McKenney). [1] BUG: KCSAN: data-race in del_timer / detach_if_pending write to 0xffff88808697d870 of 8 bytes by task 10 on cpu 0: __hlist_del include/linux/list.h:764 [inline] detach_timer kernel/time/timer.c:815 [inline] detach_if_pending+0xcd/0x2d0 kernel/time/timer.c:832 try_to_del_timer_sync+0x60/0xb0 kernel/time/timer.c:1226 del_timer_sync+0x6b/0xa0 kernel/time/timer.c:1365 schedule_timeout+0x2d2/0x6e0 kernel/time/timer.c:1896 rcu_gp_fqs_loop+0x37c/0x580 kernel/rcu/tree.c:1639 rcu_gp_kthread+0x143/0x230 kernel/rcu/tree.c:1799 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352 read to 0xffff88808697d870 of 8 bytes by task 12060 on cpu 1: del_timer+0x3b/0xb0 kernel/time/timer.c:1198 sk_stop_timer+0x25/0x60 net/core/sock.c:2845 inet_csk_clear_xmit_timers+0x69/0xa0 net/ipv4/inet_connection_sock.c:523 tcp_clear_xmit_timers include/net/tcp.h:606 [inline] tcp_v4_destroy_sock+0xa3/0x3f0 net/ipv4/tcp_ipv4.c:2096 inet_csk_destroy_sock+0xf4/0x250 net/ipv4/inet_connection_sock.c:836 tcp_close+0x6f3/0x970 net/ipv4/tcp.c:2497 inet_release+0x86/0x100 net/ipv4/af_inet.c:427 __sock_release+0x85/0x160 net/socket.c:590 sock_close+0x24/0x30 net/socket.c:1268 __fput+0x1e1/0x520 fs/file_table.c:280 ____fput+0x1f/0x30 fs/file_table.c:313 task_work_run+0xf6/0x130 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x2b4/0x2c0 arch/x86/entry/common.c:163 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 12060 Comm: syz-executor.5 Not tainted 5.4.0-rc3+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> [ paulmck: Pulled in Eric's later amendments. ] Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'include/linux/timer.h')
-rw-r--r--include/linux/timer.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/timer.h b/include/linux/timer.h
index 1e6650ed066d..0dc19a8c39c9 100644
--- a/include/linux/timer.h
+++ b/include/linux/timer.h
@@ -164,7 +164,7 @@ static inline void destroy_timer_on_stack(struct timer_list *timer) { }
*/
static inline int timer_pending(const struct timer_list * timer)
{
- return timer->entry.pprev != NULL;
+ return !hlist_unhashed_lockless(&timer->entry);
}
extern void add_timer_on(struct timer_list *timer, int cpu);