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 56B83DDBE for ; Mon, 17 Feb 2025 16:10:04 +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=1739808605; cv=none; b=X50v0W/e83qWZoCFfkMnUWEgRvEJ6ZWePcmQwr815jN2kPhQX3laQ8RffASo5RzWoDqVOHIP7B22M7RyH4NAV+k8MNZVgsFXWIRxHtQmWDGTEbfKSFOKNy1IvdHvfbAVCmJSRkQbndDlJ4ikuHq3Bg2VmGLMgcyoPVZOWgjMgCk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739808605; c=relaxed/simple; bh=fxMtjqq2y522EKxJTwIX5041g1t62k1/SxcaP2TOTo4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=stjbUNPIQjzmWqaSkuAPZ+EX55EDO+ziiTTvBSHez7J2r2IERl2YoJ28d9YA+Nwucq5z7fiBVPT5Y65EO6A01+FG9SZxvqDmzogFx8CTZ6djPPenxy5HpeyupV/0aVto7tgKHsq9r4StBGo8eJnOwGab9RLINiF9WeqPWenFOMk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=U/yCHTC2; 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="U/yCHTC2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B4FC2C4CED1; Mon, 17 Feb 2025 16:10:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1739808604; bh=fxMtjqq2y522EKxJTwIX5041g1t62k1/SxcaP2TOTo4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=U/yCHTC22CTimrFYu6HKGe++xewZP9jU0BcSEB5vauEsEUM+irae37d+65En64U3P peccNTSg34qm5w3v7k+eQScE4sjp5XO5jbFOMFZiBp2TAWV9Xp/1GmFTI7DNkKjNZT Ux7Ud1LGKakbho4PC/xk1RqIinV1h6h0kddyvDsG9IFUtnGV669QCK02aABXffxloI 8sgKqxrcOINwv/xZbqLrxWi+jegoXNOoeFErgkSiRV7U2HUZJyR3h3iZXFeyIjUDbk VZq7QJg6yJ4pGHVxTb+rnthhYMDRdPqI30bfpXqvDstXiPnm3rXy0nJLg4RZqesTMh JWayDnNVRDH5Q== Date: Mon, 17 Feb 2025 16:10:01 +0000 From: Simon Horman To: Nick Child Cc: netdev@vger.kernel.org, haren@linux.ibm.com, ricklind@us.ibm.com, nick.child@ibm.com Subject: Re: [PATCH net] ibmvnic: Don't reference skb after sending to VIOS Message-ID: <20250217161001.GN1615191@kernel.org> References: <20250214155233.235559-1-nnac123@linux.ibm.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250214155233.235559-1-nnac123@linux.ibm.com> On Fri, Feb 14, 2025 at 09:52:33AM -0600, Nick Child wrote: > Previously, after successfully flushing the xmit buffer to VIOS, > the tx_bytes stat was incremented by the length of the skb. > > It is invalid to access the skb memory after sending the buffer to > the VIOS because, at any point after sending, the VIOS can trigger > an interrupt to free this memory. A race between reading skb->len > and freeing the skb is possible (especially during LPM) and will > result in use-after-free: > ================================================================== > BUG: KASAN: slab-use-after-free in ibmvnic_xmit+0x75c/0x1808 [ibmvnic] > Read of size 4 at addr c00000024eb48a70 by task hxecom/14495 > <...> > Call Trace: > [c000000118f66cf0] [c0000000018cba6c] dump_stack_lvl+0x84/0xe8 (unreliable) > [c000000118f66d20] [c0000000006f0080] print_report+0x1a8/0x7f0 > [c000000118f66df0] [c0000000006f08f0] kasan_report+0x128/0x1f8 > [c000000118f66f00] [c0000000006f2868] __asan_load4+0xac/0xe0 > [c000000118f66f20] [c0080000046eac84] ibmvnic_xmit+0x75c/0x1808 [ibmvnic] > [c000000118f67340] [c0000000014be168] dev_hard_start_xmit+0x150/0x358 > <...> > Freed by task 0: > kasan_save_stack+0x34/0x68 > kasan_save_track+0x2c/0x50 > kasan_save_free_info+0x64/0x108 > __kasan_mempool_poison_object+0x148/0x2d4 > napi_skb_cache_put+0x5c/0x194 > net_tx_action+0x154/0x5b8 > handle_softirqs+0x20c/0x60c > do_softirq_own_stack+0x6c/0x88 > <...> > The buggy address belongs to the object at c00000024eb48a00 which > belongs to the cache skbuff_head_cache of size 224 > ================================================================== > > Fixes: 032c5e82847a ("Driver for IBM System i/p VNIC protocol") > Signed-off-by: Nick Child Reviewed-by: Simon Horman