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 E7A4469954; Wed, 21 Feb 2024 13:12:16 +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=1708521137; cv=none; b=sKkSjRqpwws7UsJ3rRwImKJ6Bc9fDJY6dQBX3bpQZC3knIKtFfZZ1SLzH31f3VEfLCAeHRMkSW6cP73i9mIcehmQih4l1Ajc3dDCQ/gGOlKRt8CIhTnuiOQM4hZ4nrRrdJsf3vvUBabN42/G+Twde/ceX216j7TH/YD6eGsNmLs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708521137; c=relaxed/simple; bh=lrDgqVVjxri6rVUhCnbEmiLuOwB3LrtQiMLWlu/QaJE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=eyQAk6/k5Uc+EGiN3REhBelpE+zwu6f1dsbpjjXBSnyyK+U68iGK+c4bsYO4/c1D6bi1XKYyLxisVfK/Tl9oXs9xKrMSBEV/u5d8jRw8n+kx61m9p/Z8Tdz8ZiIfKfoK0tRrS9Mb4sjOKusX/qutSfVJ5ogAR2C6Y+yoVyUshfk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ZuMNU2Br; 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="ZuMNU2Br" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 08A2EC433C7; Wed, 21 Feb 2024 13:12:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1708521136; bh=lrDgqVVjxri6rVUhCnbEmiLuOwB3LrtQiMLWlu/QaJE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZuMNU2BrepB5OXtpH0r46B3z+WP8JA13f4ZpoMQ6n5H6AMR3YIeB2GdFM10GWdbz8 kqAmnC5P+9iLGv2B0SxlDIBZg9Lq97QLgnbTFmRCnCrMlrrtKJov12WszgpAUvrunt SpP1nppwDVPYdV9kgZi7F/JacIwlXic6+XaJaIUw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zhengchao Shao , Paolo Abeni , Sasha Levin Subject: [PATCH 4.19 031/202] netlink: fix potential sleeping issue in mqueue_flush_file Date: Wed, 21 Feb 2024 14:05:32 +0100 Message-ID: <20240221125932.786503356@linuxfoundation.org> X-Mailer: git-send-email 2.43.2 In-Reply-To: <20240221125931.742034354@linuxfoundation.org> References: <20240221125931.742034354@linuxfoundation.org> User-Agent: quilt/0.67 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 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zhengchao Shao [ Upstream commit 234ec0b6034b16869d45128b8cd2dc6ffe596f04 ] I analyze the potential sleeping issue of the following processes: Thread A Thread B ... netlink_create //ref = 1 do_mq_notify ... sock = netlink_getsockbyfilp ... //ref = 2 info->notify_sock = sock; ... ... netlink_sendmsg ... skb = netlink_alloc_large_skb //skb->head is vmalloced ... netlink_unicast ... sk = netlink_getsockbyportid //ref = 3 ... netlink_sendskb ... __netlink_sendskb ... skb_queue_tail //put skb to sk_receive_queue ... sock_put //ref = 2 ... ... ... netlink_release ... deferred_put_nlk_sk //ref = 1 mqueue_flush_file spin_lock remove_notification netlink_sendskb sock_put //ref = 0 sk_free ... __sk_destruct netlink_sock_destruct skb_queue_purge //get skb from sk_receive_queue ... __skb_queue_purge_reason kfree_skb_reason __kfree_skb ... skb_release_all skb_release_head_state netlink_skb_destructor vfree(skb->head) //sleeping while holding spinlock In netlink_sendmsg, if the memory pointed to by skb->head is allocated by vmalloc, and is put to sk_receive_queue queue, also the skb is not freed. When the mqueue executes flush, the sleeping bug will occur. Use vfree_atomic instead of vfree in netlink_skb_destructor to solve the issue. Fixes: c05cdb1b864f ("netlink: allow large data transfers from user-space") Signed-off-by: Zhengchao Shao Link: https://lore.kernel.org/r/20240122011807.2110357-1-shaozhengchao@huawei.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- net/netlink/af_netlink.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index e91489b3274c..72936d154c96 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -374,7 +374,7 @@ static void netlink_skb_destructor(struct sk_buff *skb) if (is_vmalloc_addr(skb->head)) { if (!skb->cloned || !atomic_dec_return(&(skb_shinfo(skb)->dataref))) - vfree(skb->head); + vfree_atomic(skb->head); skb->head = NULL; } -- 2.43.0