diff options
| author | Eric Dumazet <edumazet@google.com> | 2026-06-22 11:01:08 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-06-23 14:40:33 -0700 |
| commit | d09a78a2a469e4fab75108325efb813c49520809 (patch) | |
| tree | 57efa6330bd1ff15345a056edbe843740a74c7b9 /net | |
| parent | e82d8cc4321c373dc46e741cd2dfdaa7921fddb7 (diff) | |
| download | ath-d09a78a2a469e4fab75108325efb813c49520809.tar.gz | |
net: do not acquire dev->tx_global_lock in netdev_watchdog_up()
Marek Szyprowski reported a deadlock during system resume when virtio_net
driver is used.
The deadlock occurs because netif_device_attach() is called while holding
dev->tx_global_lock (via netif_tx_lock_bh() in virtnet_restore_up()).
netif_device_attach() calls __netdev_watchdog_up(), which now also tries
to acquire dev->tx_global_lock to synchronize with dev_watchdog().
This recursive lock acquisition results in a deadlock.
Fix this by removing the tx_global_lock acquisition from netdev_watchdog_up().
The critical state (watchdog_timer and watchdog_ref_held) is already
protected by dev->watchdog_lock, which was introduced in the blamed commit.
Fixes: 8eed5519e496 ("net: watchdog: fix refcount tracking races")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Closes: https://lore.kernel.org/netdev/a443376e-5187-4268-93b3-58047ef113a8@samsung.com/
Signed-off-by: Eric Dumazet <edumazet@google.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260622110108.69541-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/sched/sch_generic.c | 7 |
1 files changed, 2 insertions, 5 deletions
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 3f1c510df850d..ef2b4bf515641 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -594,9 +594,8 @@ void netdev_watchdog_up(struct net_device *dev) return; if (dev->watchdog_timeo <= 0) dev->watchdog_timeo = 5*HZ; - spin_lock_bh(&dev->tx_global_lock); - spin_lock(&dev->watchdog_lock); + spin_lock_bh(&dev->watchdog_lock); if (!mod_timer(&dev->watchdog_timer, round_jiffies(jiffies + dev->watchdog_timeo))) { if (!dev->watchdog_ref_held) { @@ -605,9 +604,7 @@ void netdev_watchdog_up(struct net_device *dev) dev->watchdog_ref_held = true; } } - spin_unlock(&dev->watchdog_lock); - - spin_unlock_bh(&dev->tx_global_lock); + spin_unlock_bh(&dev->watchdog_lock); } EXPORT_SYMBOL_GPL(netdev_watchdog_up); |