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 3E8CB180043; Tue, 9 Jul 2024 16:24:43 +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=1720542283; cv=none; b=Usy2n7EKGLAqdjgd+tOttDrD2HDJNl5ECurxInjG3xmSM9eqSSLx/8MstZImbK+L8hTb2d4SRAsbwMyN+aNQMmNUPpxi6ICv7CWkBK/HlD4AT7cXO9yeR3znyP3o5JiNradG/2Sk0OgHU9RxPlFTlGn6IHkuiQ/gUTufEYn7BlE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720542283; c=relaxed/simple; bh=7lRbEQCqQpMupPQ3Pa0KTmdnCD+aCGyVQE+QHBlxQ7c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CK0p1e4zBa+jchGhmFZVUPhRjESIs0If6ygL+4NGgEn8F2sEwF6JPPnOinaPdmHxFfLcjBCVD2a8KYH2lnQSkBMiqZHnUmt2hE6i429fz6IcRnzigSeGDwO4RZ6K7hUo0Uh4F0v49EtjTN2POYtLUQ0r96vFhFACFqckTb3NdEQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=pTzHYYcY; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="pTzHYYcY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AC171C3277B; Tue, 9 Jul 2024 16:24:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720542283; bh=7lRbEQCqQpMupPQ3Pa0KTmdnCD+aCGyVQE+QHBlxQ7c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pTzHYYcYW4IvhVVA06cYBtDd845D/RjRnAHwKWIHi5LbZuQo1L6GAVyl50Z95gPKb na8uGCjEhw70+xDpcVJbim/QZ9y6vvffHzmSVuH/RdY14d6ApiqsndjBkji8x5es8k QO2CN3l//NOYWM3DIKUk+q3yIKez3dDDhHSyEwMN8ebVB9arKwvj6+vIQzkS/CBfJZ b4zkPq9bztSptL2apFKBz28wcraRY8qNu01mQMP8d8rntR0ccZn4QnSt23eWu8Cf3b gi0k10LLtJGmqPuYHVj17riULLF3yGmo2MCLoYpkc9uQlpa2s6NPgNCPSjPcjTc3bD /hF/OI7B+6Lgw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Nick Child , Paolo Abeni , Sasha Levin , mpe@ellerman.id.au, haren@linux.ibm.com, ricklind@linux.ibm.com, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 6.1 21/27] ibmvnic: Add tx check to prevent skb leak Date: Tue, 9 Jul 2024 12:23:35 -0400 Message-ID: <20240709162401.31946-21-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240709162401.31946-1-sashal@kernel.org> References: <20240709162401.31946-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.1.97 Content-Transfer-Encoding: 8bit From: Nick Child [ Upstream commit 0983d288caf984de0202c66641577b739caad561 ] Below is a summary of how the driver stores a reference to an skb during transmit: tx_buff[free_map[consumer_index]]->skb = new_skb; free_map[consumer_index] = IBMVNIC_INVALID_MAP; consumer_index ++; Where variable data looks like this: free_map == [4, IBMVNIC_INVALID_MAP, IBMVNIC_INVALID_MAP, 0, 3] consumer_index^ tx_buff == [skb=null, skb=, skb=, skb=null, skb=null] The driver has checks to ensure that free_map[consumer_index] pointed to a valid index but there was no check to ensure that this index pointed to an unused/null skb address. So, if, by some chance, our free_map and tx_buff lists become out of sync then we were previously risking an skb memory leak. This could then cause tcp congestion control to stop sending packets, eventually leading to ETIMEDOUT. Therefore, add a conditional to ensure that the skb address is null. If not then warn the user (because this is still a bug that should be patched) and free the old pointer to prevent memleak/tcp problems. Signed-off-by: Nick Child Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- drivers/net/ethernet/ibm/ibmvnic.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c index 157be4e9be4b7..977116a1b3158 100644 --- a/drivers/net/ethernet/ibm/ibmvnic.c +++ b/drivers/net/ethernet/ibm/ibmvnic.c @@ -2288,6 +2288,18 @@ static netdev_tx_t ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev) (tx_pool->consumer_index + 1) % tx_pool->num_buffers; tx_buff = &tx_pool->tx_buff[bufidx]; + + /* Sanity checks on our free map to make sure it points to an index + * that is not being occupied by another skb. If skb memory is + * not freed then we see congestion control kick in and halt tx. + */ + if (unlikely(tx_buff->skb)) { + dev_warn_ratelimited(dev, "TX free map points to untracked skb (%s %d idx=%d)\n", + skb_is_gso(skb) ? "tso_pool" : "tx_pool", + queue_num, bufidx); + dev_kfree_skb_any(tx_buff->skb); + } + tx_buff->skb = skb; tx_buff->index = bufidx; tx_buff->pool_index = queue_num; -- 2.43.0