From: syzbot <syzbot+b320a4d5f65a61dbbf89@syzkaller.appspotmail.com>
To: fabf@skynet.be, joern@barelysecure.org, joern@lazybastard.org,
linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org,
miquel.raynal@bootlin.com, richard@nod.at,
stable@vger.kernel.org, syzkaller-bugs@googlegroups.com,
vigneshr@ti.com, xiaopei01@kylinos.cn
Subject: Re: [syzbot] [mtd?] divide error in block2mtd_setup2
Date: Tue, 11 Aug 2026 10:15:38 -0700 [thread overview]
Message-ID: <6a7b58ba.ac361c09.22ff0a.0045.GAE@google.com> (raw)
In-Reply-To: <6a791c94.01d0871a.3a0d52.009b.GAE@google.com>
syzbot has found a reproducer for the following issue on:
HEAD commit: f5bbbfec59b4 Merge tag 'probes-fixes-v7.2-rc7' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13a31079580000
kernel config: https://syzkaller.appspot.com/x/.config?x=c44651ea7dd2f307
dashboard link: https://syzkaller.appspot.com/bug?extid=b320a4d5f65a61dbbf89
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16b76149580000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b320a4d5f65a61dbbf89@syzkaller.appspotmail.com
Oops: divide error: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 6029 Comm: syz-executor518 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:add_device drivers/mtd/devices/block2mtd.c:296 [inline]
RIP: 0010:block2mtd_setup2.isra.0+0x3c8/0xc70 drivers/mtd/devices/block2mtd.c:459
Code: 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 2b 08 00 00 48 8b 6d 08 31 ff 48 89 e8 48 c1 e0 09 48 99 <49> f7 ff 48 89 d6 48 89 54 24 10 e8 98 d5 4d fb 48 8b 54 24 10 48
RSP: 0018:ffffc90004ccf9f0 EFLAGS: 00010206
RAX: 0000000000100000 RBX: 1ffff92000999f41 RCX: ffffffff86bc9838
RDX: 0000000000000000 RSI: ffffffff86bc984a RDI: 0000000000000000
RBP: 0000000000000800 R08: 0000000000000005 R09: 000000000000001f
R10: 0000000000000007 R11: 0000000000000000 R12: ffffc90004ccfaa8
R13: 0000000000000000 R14: ffff8880254fe000 R15: 0000000000000000
FS: 000055558148e400(0000) GS:ffff8880d5dec000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055a8208cda78 CR3: 000000003ad58000 CR4: 0000000000352ef0
Call Trace:
<TASK>
block2mtd_setup+0xbd/0xd0 drivers/mtd/devices/block2mtd.c:476
param_attr_store+0x199/0x300 kernel/params.c:589
module_attr_store+0x58/0x80 kernel/params.c:904
sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145
kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x6ac/0x1050 fs/read_write.c:687
ksys_write+0x12a/0x250 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0b39a14737
Code: 48 89 fa 4c 89 df e8 98 1d 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffdcc22a9a0 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000055558148e400 RCX: 00007f0b39a14737
RDX: 000000000000000c RSI: 00007ffdcc22aa50 RDI: 0000000000000004
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffdcc22aa50
R13: 00007ffdcc22aa10 R14: 00007ffdcc22a9f0 R15: 0000000000000002
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:add_device drivers/mtd/devices/block2mtd.c:296 [inline]
RIP: 0010:block2mtd_setup2.isra.0+0x3c8/0xc70 drivers/mtd/devices/block2mtd.c:459
Code: 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 2b 08 00 00 48 8b 6d 08 31 ff 48 89 e8 48 c1 e0 09 48 99 <49> f7 ff 48 89 d6 48 89 54 24 10 e8 98 d5 4d fb 48 8b 54 24 10 48
RSP: 0018:ffffc90004ccf9f0 EFLAGS: 00010206
RAX: 0000000000100000 RBX: 1ffff92000999f41 RCX: ffffffff86bc9838
RDX: 0000000000000000 RSI: ffffffff86bc984a RDI: 0000000000000000
RBP: 0000000000000800 R08: 0000000000000005 R09: 000000000000001f
R10: 0000000000000007 R11: 0000000000000000 R12: ffffc90004ccfaa8
R13: 0000000000000000 R14: ffff8880254fe000 R15: 0000000000000000
FS: 000055558148e400(0000) GS:ffff8880d5dec000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055a8208cda78 CR3: 000000003ad58000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
0: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
7: fc ff df
a: 48 89 fa mov %rdi,%rdx
d: 48 c1 ea 03 shr $0x3,%rdx
11: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1)
15: 0f 85 2b 08 00 00 jne 0x846
1b: 48 8b 6d 08 mov 0x8(%rbp),%rbp
1f: 31 ff xor %edi,%edi
21: 48 89 e8 mov %rbp,%rax
24: 48 c1 e0 09 shl $0x9,%rax
28: 48 99 cqto
* 2a: 49 f7 ff idiv %r15 <-- trapping instruction
2d: 48 89 d6 mov %rdx,%rsi
30: 48 89 54 24 10 mov %rdx,0x10(%rsp)
35: e8 98 d5 4d fb call 0xfb4dd5d2
3a: 48 8b 54 24 10 mov 0x10(%rsp),%rdx
3f: 48 rex.W
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
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prev parent reply other threads:[~2026-08-11 17:15 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-10 0:34 [syzbot] [mtd?] divide error in block2mtd_setup2 syzbot
2026-08-10 2:03 ` Jörn Engel
2026-08-10 9:17 ` Pei Xiao
2026-08-10 12:40 ` Miquel Raynal
2026-08-11 3:02 ` Pei Xiao
2026-08-11 18:19 ` Jörn Engel
2026-08-12 1:45 ` Pei Xiao
2026-08-12 2:51 ` Jörn Engel
2026-08-10 16:27 ` Jörn Engel
2026-08-11 1:21 ` Pei Xiao
2026-08-10 9:12 ` [PATCH] mtd: block2mtd: Fix divide error when erase_size is zero Pei Xiao
2026-08-11 17:15 ` syzbot [this message]
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