From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 9C61A352060; Tue, 26 Aug 2025 14:35:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756218905; cv=none; b=tReXi4lZXTkbSL6q4glAHXr/PGywFsD879FLOVMJXGscwZ6AGv0V4eS7O1vN7QfrHK/PZJIg1ZtulagPXv28wFoDOYHX6HtDwM0sEneFHTLWBlbV+p4pGo9AQlbaBfACi3djtef+DY6FndY0P4tnOHNU7NnnSY/wMIvPgxfZsY4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756218905; c=relaxed/simple; bh=Wy4VdjflSxxJvdE7cnx6PNcosV1qz0W2u08db/Xqk3c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kTaHr3zRS15yEeG6bMbf+KEuDuVnOBbzwidOqpEET/7WWlb92lJAnk6z4sVXp9Jaos0U4vBl1Ps5mVijSz8KQLhKJK9oju8ca4Re9brG0LvISS0JT7DiPD6siBZJMDNZGu/xfXsj1MXah+gcsS76gJbsEUeBF5jRY7qIsdkOEiQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=d1l18RKX; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="d1l18RKX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DA3ACC4CEF1; Tue, 26 Aug 2025 14:35:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756218905; bh=Wy4VdjflSxxJvdE7cnx6PNcosV1qz0W2u08db/Xqk3c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=d1l18RKX2jUDxT0Ll12w+MDvj9ZSUN+G1860FHjAm4bp9T2+wsEpoXKN7agTg8mUl dOW7WF74lFOvJz3ZW3sH06HhZNqHVZT5uzWpzFUakuV/9SiM6Zhl1PwZCCmSKekx77 SNTtmL3yElQfNV1SActsK8YK+UmL2+q7qSBgDUK0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Quang Le , Willem de Bruijn , Jakub Kicinski Subject: [PATCH 5.4 151/403] net/packet: fix a race in packet_set_ring() and packet_notifier() Date: Tue, 26 Aug 2025 13:07:57 +0200 Message-ID: <20250826110911.047635612@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250826110905.607690791@linuxfoundation.org> References: <20250826110905.607690791@linuxfoundation.org> User-Agent: quilt/0.68 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 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Quang Le commit 01d3c8417b9c1b884a8a981a3b886da556512f36 upstream. When packet_set_ring() releases po->bind_lock, another thread can run packet_notifier() and process an NETDEV_UP event. This race and the fix are both similar to that of commit 15fe076edea7 ("net/packet: fix a race in packet_bind() and packet_notifier()"). There too the packet_notifier NETDEV_UP event managed to run while a po->bind_lock critical section had to be temporarily released. And the fix was similarly to temporarily set po->num to zero to keep the socket unhooked until the lock is retaken. The po->bind_lock in packet_set_ring and packet_notifier precede the introduction of git history. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Quang Le Signed-off-by: Willem de Bruijn Link: https://patch.msgid.link/20250801175423.2970334-1-willemdebruijn.kernel@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/packet/af_packet.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -4504,10 +4504,10 @@ static int packet_set_ring(struct sock * spin_lock(&po->bind_lock); was_running = po->running; num = po->num; - if (was_running) { - WRITE_ONCE(po->num, 0); + WRITE_ONCE(po->num, 0); + if (was_running) __unregister_prot_hook(sk, false); - } + spin_unlock(&po->bind_lock); synchronize_net(); @@ -4539,10 +4539,10 @@ static int packet_set_ring(struct sock * mutex_unlock(&po->pg_vec_lock); spin_lock(&po->bind_lock); - if (was_running) { - WRITE_ONCE(po->num, num); + WRITE_ONCE(po->num, num); + if (was_running) register_prot_hook(sk); - } + spin_unlock(&po->bind_lock); if (pg_vec && (po->tp_version > TPACKET_V2)) { /* Because we don't support block-based V3 on tx-ring */