| Message ID | 20240805085821.1616528-1-edumazet@google.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 3e7917c0cdad835a5121520fc5686d954b7a61ab |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] net: linkwatch: use system_unbound_wq | expand |
From: Eric Dumazet <edumazet@google.com> Date: Mon, 5 Aug 2024 08:58:21 +0000 > linkwatch_event() grabs possibly very contended RTNL mutex. > > system_wq is not suitable for such work. > > Inspired by many noisy syzbot reports. > > 3 locks held by kworker/0:7/5266: > #0: ffff888015480948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3206 [inline] > #0: ffff888015480948 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3312 > #1: ffffc90003f6fd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3207 [inline] > , at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3312 > #2: ffffffff8fa6f208 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:276 > > Reported-by: syzbot <syzkaller@googlegroups.com> > Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") > Signed-off-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> > --- > net/core/link_watch.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/net/core/link_watch.c b/net/core/link_watch.c > index 8ec35194bfcb8574f53a9fd28f0cb2ebfe9a3f2e..ab150641142aa1545c71fc5d3b11db33c70cf437 100644 > --- a/net/core/link_watch.c > +++ b/net/core/link_watch.c > @@ -148,9 +148,9 @@ static void linkwatch_schedule_work(int urgent) > * override the existing timer. > */ > if (test_bit(LW_URGENT, &linkwatch_flags)) > - mod_delayed_work(system_wq, &linkwatch_work, 0); > + mod_delayed_work(system_unbound_wq, &linkwatch_work, 0); > else > - schedule_delayed_work(&linkwatch_work, delay); > + queue_delayed_work(system_unbound_wq, &linkwatch_work, delay); > } > > > -- > 2.46.0.rc2.264.g509ed76dc8-goog
Hello: This patch was applied to netdev/net.git (main) by Jakub Kicinski <kuba@kernel.org>: On Mon, 5 Aug 2024 08:58:21 +0000 you wrote: > linkwatch_event() grabs possibly very contended RTNL mutex. > > system_wq is not suitable for such work. > > Inspired by many noisy syzbot reports. > > 3 locks held by kworker/0:7/5266: > #0: ffff888015480948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3206 [inline] > #0: ffff888015480948 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3312 > #1: ffffc90003f6fd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3207 [inline] > , at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3312 > #2: ffffffff8fa6f208 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:276 > > [...] Here is the summary with links: - [net] net: linkwatch: use system_unbound_wq https://git.kernel.org/netdev/net/c/3e7917c0cdad You are awesome, thank you!
diff --git a/net/core/link_watch.c b/net/core/link_watch.c index 8ec35194bfcb8574f53a9fd28f0cb2ebfe9a3f2e..ab150641142aa1545c71fc5d3b11db33c70cf437 100644 --- a/net/core/link_watch.c +++ b/net/core/link_watch.c @@ -148,9 +148,9 @@ static void linkwatch_schedule_work(int urgent) * override the existing timer. */ if (test_bit(LW_URGENT, &linkwatch_flags)) - mod_delayed_work(system_wq, &linkwatch_work, 0); + mod_delayed_work(system_unbound_wq, &linkwatch_work, 0); else - schedule_delayed_work(&linkwatch_work, delay); + queue_delayed_work(system_unbound_wq, &linkwatch_work, delay); }
linkwatch_event() grabs possibly very contended RTNL mutex. system_wq is not suitable for such work. Inspired by many noisy syzbot reports. 3 locks held by kworker/0:7/5266: #0: ffff888015480948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3206 [inline] #0: ffff888015480948 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3312 #1: ffffc90003f6fd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3207 [inline] , at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3312 #2: ffffffff8fa6f208 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:276 Reported-by: syzbot <syzkaller@googlegroups.com> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet <edumazet@google.com> --- net/core/link_watch.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)