From nobody Fri Dec 19 09:01:13 2025 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 806F82D47F4 for ; Thu, 9 Oct 2025 09:10:18 +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=1760001018; cv=none; b=TilUZ0FMn+BnaqUhicq59vNFmx5yw22eMC4w4u6LPGMXOLiTaczy6Hp2LjA/BvHIOqKuOlipS9nBONfoAwhfGc9jzJHTN75Twh1chtNVbyDK0RktXEv6dNVNMFGngsJ7TcdlQs1cGPHSgl8FD6F7p3j6kIMBz9BTHBpBpnoOxUM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760001018; c=relaxed/simple; bh=cQmyOA1kdsDXT6q0amBPUls1NNiXk6QdOgjeKYuRvB0=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=ptFUzDPnNGi9axs1vqfyFJrS4KW5FoUZag5lGI+ftkkq+R7OG44SNhPUbnzuwwbvnbjf6XiZ7gCTd81Q6TTJre0YzmNeRTqzvy8x/6qaMRMWGQ3iO1YCUSBoMzdDmQ+loSoG/FyCZ8o0rKMQUx0RlGkP4jYQX6HCQksd39SQYfU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=D/JRXv8I; 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="D/JRXv8I" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C5A42C4CEF9; Thu, 9 Oct 2025 09:10:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1760001018; bh=cQmyOA1kdsDXT6q0amBPUls1NNiXk6QdOgjeKYuRvB0=; h=From:To:Cc:Subject:Date:From; b=D/JRXv8I6v9O04pRy64kW+PaTp1lVj8R3x4mwsrA7lzrzjEDHfjUjhwSuSoUBMKiM z9KgsCvzwbJ/CoWpN6fDcrF0DaUPwwdO2+F9v+NTolaj6t5mNuL4v2l6gv94w8rFuc cefaoPU4J16ywJ3VWWoN29V9awNcsoB8GudrUKemKbNjCBg1zqjZj7IISbEes85hiI B3hhOBeshcMMaV87IjAsy0Hx3KTq8XJdm/+Y0KnREFgmMrIrRCDPrfxJiZTNozeM45 nWjXQnECJ0xk8EAS/LYT8ZZow6M/Lul5fXD9gv634wI9lX4NxywfqCxtEv/I6C6sIE Ov9Ipq7CH9q0w== From: Chao Yu To: jaegeuk@kernel.org Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Chao Yu , syzbot+24124df3170c3638b35f@syzkaller.appspotmail.com Subject: [PATCH] f2fs: fix to avoid updating zero-sized extent in extent cache Date: Thu, 9 Oct 2025 16:52:30 +0800 Message-Id: <20251009085230.17146-1-chao@kernel.org> X-Mailer: git-send-email 2.40.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" As syzbot reported: F2FS-fs (loop0): __update_extent_tree_range: extent len is zero, type: 0, e= xtent [0, 0, 0], age [0, 0] Reported-by: syzbot+24124df3170c3638b35f@syzkaller.appspotmail.com ------------[ cut here ]------------ kernel BUG at fs/f2fs/extent_cache.c:678! Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI CPU: 0 UID: 0 PID: 5336 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16= .3-2~bpo12+1 04/01/2014 RIP: 0010:__update_extent_tree_range+0x13bc/0x1500 fs/f2fs/extent_cache.c:6= 78 Call Trace: f2fs_update_read_extent_cache_range+0x192/0x3e0 fs/f2fs/extent_cache.c:1085 f2fs_do_zero_range fs/f2fs/file.c:1657 [inline] f2fs_zero_range+0x10c1/0x1580 fs/f2fs/file.c:1737 f2fs_fallocate+0x583/0x990 fs/f2fs/file.c:2030 vfs_fallocate+0x669/0x7e0 fs/open.c:342 ioctl_preallocate fs/ioctl.c:289 [inline] file_ioctl+0x611/0x780 fs/ioctl.c:-1 do_vfs_ioctl+0xb33/0x1430 fs/ioctl.c:576 __do_sys_ioctl fs/ioctl.c:595 [inline] __se_sys_ioctl+0x82/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f07bc58eec9 In error path of f2fs_zero_range(), it may add a zero-sized extent into extent cache, it should be avoided. Fixes: 6e9619499f53 ("f2fs: support in batch fzero in dnode page") Reported-by: syzbot+24124df3170c3638b35f@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-f2fs-devel/68e5d698.050a0220.256323.0= 032.GAE@google.com Signed-off-by: Chao Yu --- fs/f2fs/file.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index ffa045b39c01..c045e38e60ee 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -1654,8 +1654,11 @@ static int f2fs_do_zero_range(struct dnode_of_data *= dn, pgoff_t start, f2fs_set_data_blkaddr(dn, NEW_ADDR); } =20 - f2fs_update_read_extent_cache_range(dn, start, 0, index - start); - f2fs_update_age_extent_cache_range(dn, start, index - start); + if (index > start) { + f2fs_update_read_extent_cache_range(dn, start, 0, + index - start); + f2fs_update_age_extent_cache_range(dn, start, index - start); + } =20 return ret; } --=20 2.40.1