From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3E9C23BBFC7; Sat, 17 Oct 2026 16:47:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792255651; cv=none; b=ODVJ50Kat2vA3MbAIDAJY1SpHSg+GtAQzKl912b3TA1syyctmvQhUAca+MUPaAtFb+/WANDUuVoKMvnCBes6fLOf0iTzrx5XzISTsYFlGZPeQGZe4FQ13FyNkgP48t824YiZQBPtQ5SQWgRfEAVH34EvNGxiiYl9cf+CoDhS32I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792255651; c=relaxed/simple; bh=CECMdUD4hW2Ct/ioV/e86V4/txM43Xl7RLVACSy2cJ0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=aNUCCdZdl3OOqTzJzeMbUZQlpb1JfZDiOixIAsFXWDEWXWWGjHq7toP+C1eNGA9n9blT2gfCSPjhNOmNa37fAPqNZO6cQeV7RsZmVkePxVRk7963bWPzcqrDRaccIUOkmji2jtQMAGYBIE33mgGBP3a1OdRx6Dj6VPhizNgFsx4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=mFS0/oHj; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="mFS0/oHj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B6E91F000C4; Sat, 17 Oct 2026 16:47:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792255650; bh=AVnK8Vf6lOnxvzCWgb61I9yuDy+tftEdn7e2z478o1c=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=mFS0/oHjsycINgMCHRm+ACC3LLIEK27bhj+DCmJkFHCNFAb8AtwUv5/9/Z3swkax6 jcHvwHjzxeXtsCj+qYqssq77t6NzrAEtdpGR0JDU8JML0ve5Ni16Vin+PdFDIlaOfs Pfg9LC6RfHnHlowDdKUAbywgp/Ai6qCfIfM9FA6c= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Marek Szyprowski , Eric Dumazet , Simon Horman , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.12 847/869] net: do not acquire dev->tx_global_lock in netdev_watchdog_up() Date: Sat, 17 Oct 2026 18:01:28 +0200 Message-ID: <20261017160058.581365431@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160036.979869304@linuxfoundation.org> References: <20261017160036.979869304@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit d09a78a2a469e4fab75108325efb813c49520809 ] 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 Closes: https://lore.kernel.org/netdev/a443376e-5187-4268-93b3-58047ef113a8@samsung.com/ Signed-off-by: Eric Dumazet Tested-by: Marek Szyprowski Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260622110108.69541-1-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/sched/sch_generic.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 7ec650ff9daae..681e0ab6019fb 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -568,9 +568,8 @@ 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) { @@ -579,9 +578,7 @@ 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); -- 2.53.0