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 96C991384B9; Sun, 28 Jul 2024 15:45:14 +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=1722181514; cv=none; b=kaqUGnE/sOm25qyTMJpV8M+Ak0wnG0bhCB7n2STZi2p6KyIwSWiluf7wKJFS0aZOT4V/dFHmd8ycAsGW4hp3aEq0Xzdm9EnV7JfcFM1lEANqQdZbQWs6TZQzXaLjISUuOFnWEeZKilyrx60V+P0gu/jX/qM7zlnPNjdtPn8rWhk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722181514; c=relaxed/simple; bh=gFqPNGNUGY7dUOwVXLM8vPLTwR+/uGY6zrxrriAOGAk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=EiWm+22tkLnvWzWqVQfHMumILLjQ4suL/OIDMq4z7PHApf/QPaxDps3OH7r+EvmfSBN+MylAm5TVAWoxQ63leKmGObWoifZDfUSHfF5ZX5AdrNHEKDb6hzweG+HSVwhdFWsfC7WuNX6dkqFcAAK83SGuFAFCsEmsKJ2R8gAy37s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=n8P7tb9S; 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="n8P7tb9S" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 18BA8C4AF0A; Sun, 28 Jul 2024 15:45:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722181514; bh=gFqPNGNUGY7dUOwVXLM8vPLTwR+/uGY6zrxrriAOGAk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=n8P7tb9SaZfw/2+u8cFXvEWz/UDoGh2tiwl/LDWbI9rjJktGIufLUjssiYV6jx0jk YQI9cVjqjCgm3B2xeQpcX4WWBQePqFTHNUnjyboKwBAF9l3PE10xTdloQvRuiNj7sk JTx6Bjc7c0ToYqfwbyxX4Dnu9RFG9fJiyy0aFaaWL8koDHJatEf2O0T1NOfbAEniS4 /HAaRO0n8VnaNpW4DSTudiYr9Y39RCMcoLU3sVGJpqzV6Hkas1JpPKmnZ7BLjE2O2Y dSIubsQ4iB0U8rEnoesp7SAnHtJlO4QTXlDJVfsprcltaowjmYnvCwgolMP0hU/eER mS+rz+SYTUeaA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: =?UTF-8?q?Wojciech=20G=C5=82adysz?= , syzbot+18df508cf00a0598d9a6@syzkaller.appspotmail.com, Theodore Ts'o , Sasha Levin , viro@zeniv.linux.org.uk, brauner@kernel.org, adilger.kernel@dilger.ca, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org Subject: [PATCH AUTOSEL 6.10 33/34] ext4: sanity check for NULL pointer after ext4_force_shutdown Date: Sun, 28 Jul 2024 11:40:57 -0400 Message-ID: <20240728154230.2046786-33-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240728154230.2046786-1-sashal@kernel.org> References: <20240728154230.2046786-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.10.2 Content-Transfer-Encoding: 8bit From: Wojciech Gładysz [ Upstream commit 83f4414b8f84249d538905825b088ff3ae555652 ] Test case: 2 threads write short inline data to a file. In ext4_page_mkwrite the resulting inline data is converted. Handling ext4_grp_locked_error with description "block bitmap and bg descriptor inconsistent: X vs Y free clusters" calls ext4_force_shutdown. The conversion clears EXT4_STATE_MAY_INLINE_DATA but fails for ext4_destroy_inline_data_nolock and ext4_mark_iloc_dirty due to ext4_forced_shutdown. The restoration of inline data fails for the same reason not setting EXT4_STATE_MAY_INLINE_DATA. Without the flag set a regular process path in ext4_da_write_end follows trying to dereference page folio private pointer that has not been set. The fix calls early return with -EIO error shall the pointer to private be NULL. Sample crash report: Unable to handle kernel paging request at virtual address dfff800000000004 KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027] Mem abort info: ESR = 0x0000000096000005 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x05: level 1 translation fault Data abort info: ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000 CM = 0, WnR = 0, TnD = 0, TagAccess = 0 GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [dfff800000000004] address between user and kernel address ranges Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP Modules linked in: CPU: 1 PID: 20274 Comm: syz-executor185 Not tainted 6.9.0-rc7-syzkaller-gfda5695d692c #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : __block_commit_write+0x64/0x2b0 fs/buffer.c:2167 lr : __block_commit_write+0x3c/0x2b0 fs/buffer.c:2160 sp : ffff8000a1957600 x29: ffff8000a1957610 x28: dfff800000000000 x27: ffff0000e30e34b0 x26: 0000000000000000 x25: dfff800000000000 x24: dfff800000000000 x23: fffffdffc397c9e0 x22: 0000000000000020 x21: 0000000000000020 x20: 0000000000000040 x19: fffffdffc397c9c0 x18: 1fffe000367bd196 x17: ffff80008eead000 x16: ffff80008ae89e3c x15: 00000000200000c0 x14: 1fffe0001cbe4e04 x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000001 x10: 0000000000ff0100 x9 : 0000000000000000 x8 : 0000000000000004 x7 : 0000000000000000 x6 : 0000000000000000 x5 : fffffdffc397c9c0 x4 : 0000000000000020 x3 : 0000000000000020 x2 : 0000000000000040 x1 : 0000000000000020 x0 : fffffdffc397c9c0 Call trace: __block_commit_write+0x64/0x2b0 fs/buffer.c:2167 block_write_end+0xb4/0x104 fs/buffer.c:2253 ext4_da_do_write_end fs/ext4/inode.c:2955 [inline] ext4_da_write_end+0x2c4/0xa40 fs/ext4/inode.c:3028 generic_perform_write+0x394/0x588 mm/filemap.c:3985 ext4_buffered_write_iter+0x2c0/0x4ec fs/ext4/file.c:299 ext4_file_write_iter+0x188/0x1780 call_write_iter include/linux/fs.h:2110 [inline] new_sync_write fs/read_write.c:497 [inline] vfs_write+0x968/0xc3c fs/read_write.c:590 ksys_write+0x15c/0x26c fs/read_write.c:643 __do_sys_write fs/read_write.c:655 [inline] __se_sys_write fs/read_write.c:652 [inline] __arm64_sys_write+0x7c/0x90 fs/read_write.c:652 __invoke_syscall arch/arm64/kernel/syscall.c:34 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:48 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:133 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:152 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598 Code: 97f85911 f94002da 91008356 d343fec8 (38796908) ---[ end trace 0000000000000000 ]--- ---------------- Code disassembly (best guess): 0: 97f85911 bl 0xffffffffffe16444 4: f94002da ldr x26, [x22] 8: 91008356 add x22, x26, #0x20 c: d343fec8 lsr x8, x22, #3 * 10: 38796908 ldrb w8, [x8, x25] <-- trapping instruction Reported-by: syzbot+18df508cf00a0598d9a6@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=18df508cf00a0598d9a6 Link: https://lore.kernel.org/all/000000000000f19a1406109eb5c5@google.com/T/ Signed-off-by: Wojciech Gładysz Link: https://patch.msgid.link/20240703070112.10235-1-wojciech.gladysz@infogain.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin --- fs/buffer.c | 2 ++ fs/ext4/inode.c | 5 +++++ 2 files changed, 7 insertions(+) diff --git a/fs/buffer.c b/fs/buffer.c index 8c19e705b9c33..645f0387dfe1d 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -2187,6 +2187,8 @@ static void __block_commit_write(struct folio *folio, size_t from, size_t to) struct buffer_head *bh, *head; bh = head = folio_buffers(folio); + if (!bh) + return; blocksize = bh->b_size; block_start = 0; diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 4bae9ccf5fe01..f14e77c4a6de8 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -2945,6 +2945,11 @@ static int ext4_da_do_write_end(struct address_space *mapping, bool disksize_changed = false; loff_t new_i_size; + if (unlikely(!folio_buffers(folio))) { + folio_unlock(folio); + folio_put(folio); + return -EIO; + } /* * block_write_end() will mark the inode as dirty with I_DIRTY_PAGES * flag, which all that's needed to trigger page writeback. -- 2.43.0