syzbot


divide error in netfs_submit_writethrough

Status: upstream: reported C repro on 2024/04/05 02:43
Subsystems: netfs
[Documentation on labels]
Reported-by: syzbot+f3a09670f3d2a55b89b2@syzkaller.appspotmail.com
First crash: 50d, last: 9d06h
Discussions (2)
Title Replies (including bot) Last reply
[syzbot] [netfs?] divide error in netfs_submit_writethrough 0 (2) 2024/04/23 10:29
Re: [syzbot] [netfs?] divide error in netfs_submit_writethrough 1 (1) 2024/04/07 10:47

Sample crash report:
divide error: 0000 [#1] PREEMPT SMP KASAN NOPTI
CPU: 3 PID: 5183 Comm: syz-executor293 Not tainted 6.9.0-rc5-syzkaller-00025-ga2c63a3f3d68 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:netfs_submit_writethrough+0x201/0x280 fs/netfs/output.c:427
Code: fc ff df 48 89 fa 48 c1 ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 1a 8b 8b 0c 01 00 00 48 89 e8 31 d2 <48> f7 f1 48 89 c5 48 0f af e9 e9 1d ff ff ff e8 9b a3 b8 ff eb df
RSP: 0018:ffffc90003477760 EFLAGS: 00010246
RAX: 0000000000001000 RBX: ffff88802d072c00 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff82304719 RDI: ffff88802d072d0c
RBP: 0000000000001000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000003 R12: 0000000000000000
R13: ffff8880324e05e0 R14: ffff88802d072d20 R15: 0000000000000000
FS:  0000555585aef480(0000) GS:ffff88806b500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc516dc998 CR3: 0000000029bf4000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 netfs_advance_writethrough+0x13f/0x170 fs/netfs/output.c:449
 netfs_perform_write+0x1b9f/0x26b0 fs/netfs/buffered_write.c:385
 netfs_buffered_write_iter_locked+0x213/0x2c0 fs/netfs/buffered_write.c:454
 netfs_file_write_iter+0x1e0/0x470 fs/netfs/buffered_write.c:493
 v9fs_file_write_iter+0xa1/0x100 fs/9p/vfs_file.c:407
 call_write_iter include/linux/fs.h:2110 [inline]
 do_iter_readv_writev+0x504/0x780 fs/read_write.c:741
 vfs_writev+0x36f/0xdb0 fs/read_write.c:971
 do_pwritev+0x1b2/0x260 fs/read_write.c:1072
 __do_sys_pwritev2 fs/read_write.c:1131 [inline]
 __se_sys_pwritev2 fs/read_write.c:1122 [inline]
 __x64_sys_pwritev2+0xef/0x160 fs/read_write.c:1122
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x260 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fecc4c95b59
Code: 48 83 c4 28 c3 e8 67 17 00 00 0f 1f 80 00 00 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff380e4b18 EFLAGS: 00000216 ORIG_RAX: 0000000000000148
RAX: ffffffffffffffda RBX: 00007fff380e4b30 RCX: 00007fecc4c95b59
RDX: 0000000000000001 RSI: 0000000020000240 RDI: 0000000000000003
RBP: 00007fff380e4b38 R08: 0000000000000000 R09: 0000000000000015
R10: 0000000000000000 R11: 0000000000000216 R12: 0000000000000000
R13: 00007fff380e4d98 R14: 0000000000000001 R15: 0000000000000001
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:netfs_submit_writethrough+0x201/0x280 fs/netfs/output.c:427
Code: fc ff df 48 89 fa 48 c1 ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 1a 8b 8b 0c 01 00 00 48 89 e8 31 d2 <48> f7 f1 48 89 c5 48 0f af e9 e9 1d ff ff ff e8 9b a3 b8 ff eb df
RSP: 0018:ffffc90003477760 EFLAGS: 00010246
RAX: 0000000000001000 RBX: ffff88802d072c00 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff82304719 RDI: ffff88802d072d0c
RBP: 0000000000001000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000003 R12: 0000000000000000
R13: ffff8880324e05e0 R14: ffff88802d072d20 R15: 0000000000000000
FS:  0000555585aef480(0000) GS:ffff88806b500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc516dc998 CR3: 0000000029bf4000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	df 48 89             	fisttps -0x77(%rax)
   3:	fa                   	cli
   4:	48 c1 ea 03          	shr    $0x3,%rdx
   8:	0f b6 14 02          	movzbl (%rdx,%rax,1),%edx
   c:	48 89 f8             	mov    %rdi,%rax
   f:	83 e0 07             	and    $0x7,%eax
  12:	83 c0 03             	add    $0x3,%eax
  15:	38 d0                	cmp    %dl,%al
  17:	7c 04                	jl     0x1d
  19:	84 d2                	test   %dl,%dl
  1b:	75 1a                	jne    0x37
  1d:	8b 8b 0c 01 00 00    	mov    0x10c(%rbx),%ecx
  23:	48 89 e8             	mov    %rbp,%rax
  26:	31 d2                	xor    %edx,%edx
* 28:	48 f7 f1             	div    %rcx <-- trapping instruction
  2b:	48 89 c5             	mov    %rax,%rbp
  2e:	48 0f af e9          	imul   %rcx,%rbp
  32:	e9 1d ff ff ff       	jmp    0xffffff54
  37:	e8 9b a3 b8 ff       	call   0xffb8a3d7
  3c:	eb df                	jmp    0x1d

Crashes (17):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/04/23 10:28 upstream a2c63a3f3d68 21339d7b .config console log report syz C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream divide error in netfs_submit_writethrough
2024/05/11 20:15 upstream cf87f46fd34d 9026e142 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream divide error in netfs_submit_writethrough
2024/05/01 10:07 upstream 18daea77cca6 3ba885bc .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream divide error in netfs_submit_writethrough
2024/04/23 10:15 upstream a2c63a3f3d68 21339d7b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream divide error in netfs_submit_writethrough
2024/05/12 14:39 upstream cf87f46fd34d 9026e142 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 divide error in netfs_submit_writethrough
2024/05/10 05:53 upstream 448b3fe5a0ea de979bc2 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 divide error in netfs_submit_writethrough
2024/05/06 03:04 upstream b9158815de52 610f2a54 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 divide error in netfs_submit_writethrough
2024/05/02 00:42 upstream 0106679839f7 3ba885bc .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 divide error in netfs_submit_writethrough
2024/05/02 00:34 upstream 0106679839f7 3ba885bc .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 divide error in netfs_submit_writethrough
2024/04/28 18:32 upstream 2c8159388952 07b455f9 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 divide error in netfs_submit_writethrough
2024/04/27 21:40 upstream 5eb4573ea63d 07b455f9 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 divide error in netfs_submit_writethrough
2024/04/27 16:10 upstream 5eb4573ea63d 07b455f9 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 divide error in netfs_submit_writethrough
2024/04/25 11:25 upstream e88c4cfcb7b8 8bdc0f22 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 divide error in netfs_submit_writethrough
2024/04/23 14:58 upstream 71b1543c83d6 21339d7b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 divide error in netfs_submit_writethrough
2024/04/21 16:41 upstream 977b1ef51866 af24b050 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 divide error in netfs_submit_writethrough
2024/04/14 06:02 upstream fa4022cb7361 c8349e48 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 divide error in netfs_submit_writethrough
2024/04/01 02:38 upstream 39cd87c4eb2b 6baf5069 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 divide error in netfs_submit_writethrough
* Struck through repros no longer work on HEAD.