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 D17FB22083 for ; Mon, 20 Oct 2025 03:15:11 +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=1760930111; cv=none; b=MDfPboEf+q39Aa187CS3j6BOsgzsD46XGjyTZHZb4XK6R+7z9GN0MQHSNar8yHNOgwNLLFpx+8//OECoVsWbQq4V90PcOZD7c3SX3ecEfHe/Qrd4MTbytB6bPSDMxszBtok3liNS3OQIfd3SvMDoAUkzdEo0JGTxThWJTSKqRT0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760930111; c=relaxed/simple; bh=DS5T/YJJqo09OtEnG6ykFTxHXdt6Ff1HpV3fqDw6Glc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=OTY5AVGK34u22zKP/3YiOqttg6hZFVUZ0jKaEEDEXNEuDHnOWZ4kvXv9ri/MRJNtSR6kepNprZS/tR7k+zEcdKz3iTwm0LgURD4/fwhwERZjv4cO8fTe9vmxcBUffvy7TRE67G95EDXLQeR6T0yN+CH5jXDZIOCCqdI3dqgw7s4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=qc1++FI9; 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="qc1++FI9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 95AA1C4CEF9; Mon, 20 Oct 2025 03:15:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1760930111; bh=DS5T/YJJqo09OtEnG6ykFTxHXdt6Ff1HpV3fqDw6Glc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=qc1++FI9IBh+tvY+jd1eUi3HWm5bUvLJ9W+QMPKMZjAy9AhCPQ6sMginPPTxbQnnX h1wg2I9JtyDhKKKguPFqZbPi2swTXbzfPjowgGNCpixvcN27cgC9A9KrgYT3BlFK6W t4S97pQ78PSYjvv0kg7sqIr7KTVq3z+bJkK7SznRGVTCdUPCLYaJMXeDIHwJljGg38 jfBNTXVSHRtQcwkMnp9a2UHWWByu4JOSJsUJVb1DU9uWVTRLfj8xxd6kAggV5Ln8z+ Hf6UqGrG++pItdN6E+LPwXspK7azEUV7kbO9mcIVf/cBtss4julq3v2bMGP9GGlPlo VouCaHLmdgJUw== Message-ID: <54ad259c-b29f-4444-8d3c-1ec37abc628d@kernel.org> Date: Mon, 20 Oct 2025 03:15:08 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [BUG] f2fs: divide error in f2fs_all_cluster_page_ready on v6.17 To: "Bai, Shuangpeng" , "jaegeuk@kernel.org" Cc: "linux-f2fs-devel@lists.sourceforge.net" , "linux-kernel@vger.kernel.org" , "syzkaller@googlegroups.com" References: <44D8F7B3-68AD-425F-9915-65D27591F93F@psu.edu> Content-Language: en-US From: Chao Yu In-Reply-To: <44D8F7B3-68AD-425F-9915-65D27591F93F@psu.edu> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Hi Bai, On 10/12/25 23:49, Bai, Shuangpeng wrote: > Hi Kernel Maintainers, > > Our tool found a new kernel bug "divide error in f2fs_all_cluster_page_ready". Please see the details below. > > Kernel commit: 6.17 > Kernel config: attachment > Reproducer: attachment > > The reproducer triggers the crash reliably in ~500 seconds on a QEMU x86_64 VM. > > I’m happy to test debug patches or provide additional information. Finally, I can reproduce this bug, thanks for your help. :) I have figured out a fix below, could you please help to test it? https://lore.kernel.org/linux-f2fs-devel/20251020023453.329467-1-chao@kernel.org Thanks, > > > Oops: divide error: 0000 [#1] SMP KASAN PTI > CPU: 0 UID: 0 PID: 11441 Comm: syz.0.46 Not tainted 6.17.0 #1 PREEMPT(full) > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 > RIP: 0010:f2fs_all_cluster_page_ready+0x106/0x550 fs/f2fs/compress.c:857 > Code: 00 8b 4d 00 48 89 d8 48 c1 e8 20 74 19 48 89 d8 31 d2 48 f7 f1 48 89 d5 eb 14 48 89 5c 24 10 e8 40 a4 6d fd eb 2d 89 d8 31 d2 f1 89 d5 31 ff 48 89 ee e8 0c a9 6d fd 48 85 ed 74 0c e8 22 a4 > RSP: 0018:ffffc90006616e60 EFLAGS: 00010246 > RAX: 0000000000000003 RBX: 0000000000000003 RCX: 0000000000000000 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 > RBP: ffffc90006617270 R08: ffffffff84552d26 R09: 0000000000000000 > R10: ffff888155ad2000 R11: ffffffff81d2aa26 R12: 0000000000000001 > R13: dffffc0000000000 R14: 0000000000000010 R15: ffffc90006617260 > FS: 00007f8bac5b5640(0000) GS:ffff888220f02000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 000056508a326000 CR3: 0000000117bec000 CR4: 00000000000006f0 > Call Trace: > > f2fs_write_cache_pages fs/f2fs/data.c:3078 [inline] > __f2fs_write_data_pages fs/f2fs/data.c:3290 [inline] > f2fs_write_data_pages+0x1c19/0x3600 fs/f2fs/data.c:3317 > do_writepages+0x38e/0x640 mm/page-writeback.c:2634 > filemap_fdatawrite_wbc mm/filemap.c:386 [inline] > __filemap_fdatawrite_range mm/filemap.c:419 [inline] > file_write_and_wait_range+0x2ba/0x3e0 mm/filemap.c:794 > f2fs_do_sync_file+0x6e6/0x1b00 fs/f2fs/file.c:294 > generic_write_sync include/linux/fs.h:3043 [inline] > f2fs_file_write_iter+0x76e/0x2700 fs/f2fs/file.c:5259 > new_sync_write fs/read_write.c:593 [inline] > vfs_write+0x7e9/0xe00 fs/read_write.c:686 > ksys_write+0x19d/0x2d0 fs/read_write.c:738 > do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] > do_syscall_64+0xf7/0x470 arch/x86/entry/syscall_64.c:94 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > RIP: 0033:0x7f8bab7ae49d > Code: 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007f8bac5b4f98 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 > RAX: ffffffffffffffda RBX: 00007f8baba26180 RCX: 00007f8bab7ae49d > RDX: 000000000000ffbd RSI: 0000200000000240 RDI: 0000000000000007 > RBP: 00007f8bab848268 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 > R13: 00007f8baba26218 R14: 00007f8baba26180 R15: 00007f8bac595000 > > Modules linked in: > ---[ end trace 0000000000000000 ]--- > RIP: 0010:f2fs_all_cluster_page_ready+0x106/0x550 fs/f2fs/compress.c:857 > Code: 00 8b 4d 00 48 89 d8 48 c1 e8 20 74 19 48 89 d8 31 d2 48 f7 f1 48 89 d5 eb 14 48 89 5c 24 10 e8 40 a4 6d fd eb 2d 89 d8 31 d2 f1 89 d5 31 ff 48 89 ee e8 0c a9 6d fd 48 85 ed 74 0c e8 22 a4 > RSP: 0018:ffffc90006616e60 EFLAGS: 00010246 > RAX: 0000000000000003 RBX: 0000000000000003 RCX: 0000000000000000 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 > RBP: ffffc90006617270 R08: ffffffff84552d26 R09: 0000000000000000 > R10: ffff888155ad2000 R11: ffffffff81d2aa26 R12: 0000000000000001 > R13: dffffc0000000000 R14: 0000000000000010 R15: ffffc90006617260 > FS: 00007f8bac5b5640(0000) GS:ffff888220f02000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 000056508a326000 CR3: 0000000117bec000 CR4: 00000000000006f0 > ---------------- > Code disassembly (best guess): > 0: 00 8b 4d 00 48 89 add %cl,-0x76b7ffb3(%rbx) > 6: d8 48 c1 fmuls -0x3f(%rax) > 9: e8 20 74 19 48 call 0x4819742e > e: 89 d8 mov %ebx,%eax > 10: 31 d2 xor %edx,%edx > 12: 48 f7 f1 div %rcx > 15: 48 89 d5 mov %rdx,%rbp > 18: eb 14 jmp 0x2e > 1a: 48 89 5c 24 10 mov %rbx,0x10(%rsp) > 1f: e8 40 a4 6d fd call 0xfd6da464 > 24: eb 2d jmp 0x53 > 26: 89 d8 mov %ebx,%eax > 28: 31 d2 xor %edx,%edx > * 2a: f7 f1 div %ecx <-- trapping instruction > 2c: 89 d5 mov %edx,%ebp > 2e: 31 ff xor %edi,%edi > 30: 48 89 ee mov %rbp,%rsi > 33: e8 0c a9 6d fd call 0xfd6da944 > 38: 48 85 ed test %rbp,%rbp > 3b: 74 0c je 0x49 > 3d: e8 .byte 0xe8 > 3e: 22 .byte 0x22 > 3f: a4 movsb %ds:(%rsi),%es:(%rdi) > > Best, > Shuangpeng >