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Message-Id: <20211214051955.3569843-1-eric.dumazet@gmail.com>
Date: Mon, 13 Dec 2021 21:19:55 -0800
From: Eric Dumazet <eric.dumazet@...il.com>
To: "David S . Miller" <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>
Cc: netdev <netdev@...r.kernel.org>,
Eric Dumazet <edumazet@...gle.com>,
Eric Dumazet <eric.dumazet@...il.com>,
syzbot <syzkaller@...glegroups.com>
Subject: [PATCH net-next] net: linkwatch: be more careful about dev->linkwatch_dev_tracker
From: Eric Dumazet <edumazet@...gle.com>
Apparently a concurrent linkwatch_add_event() could
run while we are in __linkwatch_run_queue().
We need to free dev->linkwatch_dev_tracker tracker
under lweventlist_lock protection to avoid this race.
syzbot report:
[ 77.935949][ T3661] reference already released.
[ 77.941015][ T3661] allocated in:
[ 77.944482][ T3661] linkwatch_fire_event+0x202/0x260
[ 77.950318][ T3661] netif_carrier_on+0x9c/0x100
[ 77.955120][ T3661] __ieee80211_sta_join_ibss+0xc52/0x1590
[ 77.960888][ T3661] ieee80211_sta_create_ibss.cold+0xd2/0x11f
[ 77.966908][ T3661] ieee80211_ibss_work.cold+0x30e/0x60f
[ 77.972483][ T3661] ieee80211_iface_work+0xb70/0xd00
[ 77.977715][ T3661] process_one_work+0x9ac/0x1680
[ 77.982671][ T3661] worker_thread+0x652/0x11c0
[ 77.987371][ T3661] kthread+0x405/0x4f0
[ 77.991465][ T3661] ret_from_fork+0x1f/0x30
[ 77.995895][ T3661] freed in:
[ 77.999006][ T3661] linkwatch_do_dev+0x96/0x160
[ 78.004014][ T3661] __linkwatch_run_queue+0x233/0x6a0
[ 78.009496][ T3661] linkwatch_event+0x4a/0x60
[ 78.014099][ T3661] process_one_work+0x9ac/0x1680
[ 78.019034][ T3661] worker_thread+0x652/0x11c0
[ 78.023719][ T3661] kthread+0x405/0x4f0
[ 78.027810][ T3661] ret_from_fork+0x1f/0x30
[ 78.042541][ T3661] ------------[ cut here ]------------
[ 78.048253][ T3661] WARNING: CPU: 0 PID: 3661 at lib/ref_tracker.c:120 ref_tracker_free.cold+0x110/0x14e
[ 78.062364][ T3661] Modules linked in:
[ 78.066424][ T3661] CPU: 0 PID: 3661 Comm: kworker/0:5 Not tainted 5.16.0-rc4-next-20211210-syzkaller #0
[ 78.076075][ T3661] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[ 78.090648][ T3661] Workqueue: events linkwatch_event
[ 78.095890][ T3661] RIP: 0010:ref_tracker_free.cold+0x110/0x14e
[ 78.102191][ T3661] Code: ea 03 48 c1 e0 2a 0f b6 04 02 84 c0 74 04 3c 03 7e 4c 8b 7b 18 e8 6b 54 e9 fa e8 26 4d 57 f8 4c 89 ee 48 89 ef e8 fb 33 36 00 <0f> 0b 41 bd ea ff ff ff e9 bd 60 e9 fa 4c 89 f7 e8 16 45 a2 f8 e9
[ 78.127211][ T3661] RSP: 0018:ffffc90002b5fb18 EFLAGS: 00010246
[ 78.133684][ T3661] RAX: 0000000000000000 RBX: ffff88807467f700 RCX: 0000000000000000
[ 78.141928][ T3661] RDX: 0000000000000001 RSI: 0000000000000001 RDI: 0000000000000001
[ 78.150087][ T3661] RBP: ffff888057e105b8 R08: 0000000000000001 R09: ffffffff8ffa1967
[ 78.158211][ T3661] R10: 0000000000000001 R11: 0000000000000000 R12: 1ffff9200056bf65
[ 78.166204][ T3661] R13: 0000000000000292 R14: ffff88807467f718 R15: 00000000c0e0008c
[ 78.174321][ T3661] FS: 0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
[ 78.183310][ T3661] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 78.190156][ T3661] CR2: 000000c000208800 CR3: 000000007f7b5000 CR4: 00000000003506f0
[ 78.198235][ T3661] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 78.206214][ T3661] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 78.214328][ T3661] Call Trace:
[ 78.217679][ T3661] <TASK>
[ 78.220621][ T3661] ? __sanitizer_cov_trace_const_cmp4+0x1c/0x70
[ 78.226981][ T3661] ? nlmsg_notify+0xbe/0x280
[ 78.231607][ T3661] ? ref_tracker_dir_exit+0x330/0x330
[ 78.237654][ T3661] ? linkwatch_do_dev+0x96/0x160
[ 78.242628][ T3661] ? __linkwatch_run_queue+0x233/0x6a0
[ 78.248170][ T3661] ? linkwatch_event+0x4a/0x60
[ 78.252946][ T3661] ? process_one_work+0x9ac/0x1680
[ 78.258136][ T3661] ? worker_thread+0x853/0x11c0
[ 78.263020][ T3661] ? kthread+0x405/0x4f0
[ 78.267905][ T3661] ? ret_from_fork+0x1f/0x30
[ 78.272670][ T3661] ? netdev_state_change+0xa1/0x130
[ 78.278019][ T3661] ? netdev_exit+0xd0/0xd0
[ 78.282466][ T3661] ? dev_activate+0x420/0xa60
[ 78.287261][ T3661] linkwatch_do_dev+0x96/0x160
[ 78.292043][ T3661] __linkwatch_run_queue+0x233/0x6a0
[ 78.297505][ T3661] ? linkwatch_do_dev+0x160/0x160
[ 78.302561][ T3661] linkwatch_event+0x4a/0x60
[ 78.307225][ T3661] process_one_work+0x9ac/0x1680
[ 78.312292][ T3661] ? pwq_dec_nr_in_flight+0x2a0/0x2a0
[ 78.317757][ T3661] ? rwlock_bug.part.0+0x90/0x90
[ 78.322726][ T3661] ? _raw_spin_lock_irq+0x41/0x50
[ 78.327844][ T3661] worker_thread+0x853/0x11c0
[ 78.332543][ T3661] ? process_one_work+0x1680/0x1680
[ 78.338500][ T3661] kthread+0x405/0x4f0
[ 78.342610][ T3661] ? set_kthread_struct+0x130/0x130
Fixes: 63f13937cbe9 ("net: linkwatch: add net device refcount tracker")
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Reported-by: syzbot <syzkaller@...glegroups.com>
---
net/core/link_watch.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/net/core/link_watch.c b/net/core/link_watch.c
index d7d089963b1da4142a0863715382aa81241625eb..b0f5344d1185be66d05cd1dc50cffc5ccfe883ef 100644
--- a/net/core/link_watch.c
+++ b/net/core/link_watch.c
@@ -166,7 +166,10 @@ static void linkwatch_do_dev(struct net_device *dev)
netdev_state_change(dev);
}
- dev_put_track(dev, &dev->linkwatch_dev_tracker);
+ /* Note: our callers are responsible for
+ * calling netdev_tracker_free().
+ */
+ dev_put(dev);
}
static void __linkwatch_run_queue(int urgent_only)
@@ -209,6 +212,10 @@ static void __linkwatch_run_queue(int urgent_only)
list_add_tail(&dev->link_watch_list, &lweventlist);
continue;
}
+ /* We must free netdev tracker under
+ * the spinlock protection.
+ */
+ netdev_tracker_free(dev, &dev->linkwatch_dev_tracker);
spin_unlock_irq(&lweventlist_lock);
linkwatch_do_dev(dev);
do_dev--;
@@ -232,6 +239,10 @@ void linkwatch_forget_dev(struct net_device *dev)
if (!list_empty(&dev->link_watch_list)) {
list_del_init(&dev->link_watch_list);
clean = 1;
+ /* We must release netdev tracker under
+ * the spinlock protection.
+ */
+ netdev_tracker_free(dev, &dev->linkwatch_dev_tracker);
}
spin_unlock_irqrestore(&lweventlist_lock, flags);
if (clean)
--
2.34.1.173.g76aa8bc2d0-goog
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