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 190241EFE31; Sun, 24 Mar 2024 22:57:26 +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=1711321047; cv=none; b=kXLLnwpPqfGYKf3uTivv15lmFw9LYi935NU08qx5gCMWZlB1BdOMU5ZjRwdZ/lgdLNpgg8DCFVUOgG2pMrgHHEdjKFl1RxITZVLWleZ6gHLYVn2jQXx++5es53hOLmRcDzbfdqMjbka6ZqLMNU4gijMULbl0QG/EDGkC66W6ZCQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711321047; c=relaxed/simple; bh=Ob+u0v7iJbF2fdhov1SjWGCt8FchSjZcmIy7w6TcGok=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=jTCz1nBvwkHjh4YA1dq+w89ZEZ+DQf2sEIpWD/1s9Y+ufZAXG1h/YZsbKe8obG+rQ2EuExspce6mtgEV9ApoXspvxjPrV6kC1Jx38bcAWyY9M9wA9Rhvz3cutJhlXjydSeZQnDN0Sg/msIFwWInpOD4CeGbWbLhqxG5Lmt1t4dU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=tBjldkNA; 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="tBjldkNA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DE0ECC433F1; Sun, 24 Mar 2024 22:57:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711321046; bh=Ob+u0v7iJbF2fdhov1SjWGCt8FchSjZcmIy7w6TcGok=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tBjldkNAMlUt7dGQz1DXDnEQHgu8sTPhriHfTLNS6OcMlSotw80Xrk6cvqYryQFCj uqmoYiWBIg2aNyepyW9C2bUUdOh3v7/rJT8yTdo4eOHMreNmBXgARCBlOwzlqERTYA QdzS6UJM+BF4/lpu7R1eIHz5PVo8EPXyPdKhwCmTM8A8bE12F95RPS2V5nrPNk9CVX majdktyIZRPZirhJdPia3RkW+CD8r39qPCQHF9gi5pNLI7L+zW3CH5P0gRV+5+gNm+ B5P0rUgXnTwJtrqn+7dwEZR+gBc10qF8xQdunRuwkJxF8f2Zl2pd8e7QZydw0G58YQ Y9bzU5dbqGxVQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Josef Bacik , Jeff Layton , Trond Myklebust , Sasha Levin Subject: [PATCH 6.7 609/713] nfs: fix panic when nfs4_ff_layout_prepare_ds() fails Date: Sun, 24 Mar 2024 18:45:35 -0400 Message-ID: <20240324224720.1345309-610-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240324224720.1345309-1-sashal@kernel.org> References: <20240324224720.1345309-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: Josef Bacik [ Upstream commit 719fcafe07c12646691bd62d7f8d94d657fa0766 ] We've been seeing the following panic in production BUG: kernel NULL pointer dereference, address: 0000000000000065 PGD 2f485f067 P4D 2f485f067 PUD 2cc5d8067 PMD 0 RIP: 0010:ff_layout_cancel_io+0x3a/0x90 [nfs_layout_flexfiles] Call Trace: ? __die+0x78/0xc0 ? page_fault_oops+0x286/0x380 ? __rpc_execute+0x2c3/0x470 [sunrpc] ? rpc_new_task+0x42/0x1c0 [sunrpc] ? exc_page_fault+0x5d/0x110 ? asm_exc_page_fault+0x22/0x30 ? ff_layout_free_layoutreturn+0x110/0x110 [nfs_layout_flexfiles] ? ff_layout_cancel_io+0x3a/0x90 [nfs_layout_flexfiles] ? ff_layout_cancel_io+0x6f/0x90 [nfs_layout_flexfiles] pnfs_mark_matching_lsegs_return+0x1b0/0x360 [nfsv4] pnfs_error_mark_layout_for_return+0x9e/0x110 [nfsv4] ? ff_layout_send_layouterror+0x50/0x160 [nfs_layout_flexfiles] nfs4_ff_layout_prepare_ds+0x11f/0x290 [nfs_layout_flexfiles] ff_layout_pg_init_write+0xf0/0x1f0 [nfs_layout_flexfiles] __nfs_pageio_add_request+0x154/0x6c0 [nfs] nfs_pageio_add_request+0x26b/0x380 [nfs] nfs_do_writepage+0x111/0x1e0 [nfs] nfs_writepages_callback+0xf/0x30 [nfs] write_cache_pages+0x17f/0x380 ? nfs_pageio_init_write+0x50/0x50 [nfs] ? nfs_writepages+0x6d/0x210 [nfs] ? nfs_writepages+0x6d/0x210 [nfs] nfs_writepages+0x125/0x210 [nfs] do_writepages+0x67/0x220 ? generic_perform_write+0x14b/0x210 filemap_fdatawrite_wbc+0x5b/0x80 file_write_and_wait_range+0x6d/0xc0 nfs_file_fsync+0x81/0x170 [nfs] ? nfs_file_mmap+0x60/0x60 [nfs] __x64_sys_fsync+0x53/0x90 do_syscall_64+0x3d/0x90 entry_SYSCALL_64_after_hwframe+0x46/0xb0 Inspecting the core with drgn I was able to pull this >>> prog.crashed_thread().stack_trace()[0] #0 at 0xffffffffa079657a (ff_layout_cancel_io+0x3a/0x84) in ff_layout_cancel_io at fs/nfs/flexfilelayout/flexfilelayout.c:2021:27 >>> prog.crashed_thread().stack_trace()[0]['idx'] (u32)1 >>> prog.crashed_thread().stack_trace()[0]['flseg'].mirror_array[1].mirror_ds (struct nfs4_ff_layout_ds *)0xffffffffffffffed This is clear from the stack trace, we call nfs4_ff_layout_prepare_ds() which could error out initializing the mirror_ds, and then we go to clean it all up and our check is only for if (!mirror->mirror_ds). This is inconsistent with the rest of the users of mirror_ds, which have if (IS_ERR_OR_NULL(mirror_ds)) to keep from tripping over this exact scenario. Fix this up in ff_layout_cancel_io() to make sure we don't panic when we get an error. I also spot checked all the other instances of checking mirror_ds and we appear to be doing the correct checks everywhere, only unconditionally dereferencing mirror_ds when we know it would be valid. Signed-off-by: Josef Bacik Fixes: b739a5bd9d9f ("NFSv4/flexfiles: Cancel I/O if the layout is recalled or revoked") Reviewed-by: Jeff Layton Signed-off-by: Trond Myklebust Signed-off-by: Sasha Levin --- fs/nfs/flexfilelayout/flexfilelayout.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c index ef817a0475ffa..3e724cb7ef01d 100644 --- a/fs/nfs/flexfilelayout/flexfilelayout.c +++ b/fs/nfs/flexfilelayout/flexfilelayout.c @@ -2016,7 +2016,7 @@ static void ff_layout_cancel_io(struct pnfs_layout_segment *lseg) for (idx = 0; idx < flseg->mirror_array_cnt; idx++) { mirror = flseg->mirror_array[idx]; mirror_ds = mirror->mirror_ds; - if (!mirror_ds) + if (IS_ERR_OR_NULL(mirror_ds)) continue; ds = mirror->mirror_ds->ds; if (!ds) -- 2.43.0