* [syzbot] [nilfs?] general protection fault in nilfs_mdt_save_to_shadow_map
@ 2026-03-17 3:14 syzbot
2026-03-17 8:09 ` Edward Adam Davis
0 siblings, 1 reply; 9+ messages in thread
From: syzbot @ 2026-03-17 3:14 UTC (permalink / raw)
To: konishi.ryusuke, linux-kernel, linux-nilfs, slava, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: b84a0ebe421c Add linux-next specific files for 20260313
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=115098ba580000
kernel config: https://syzkaller.appspot.com/x/.config?x=d079c776411aaf59
dashboard link: https://syzkaller.appspot.com/bug?extid=4b4093b1f24ad789bf37
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15e844da580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11775d52580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ed9cdd5f6ba1/disk-b84a0ebe.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/856b866a24e9/vmlinux-b84a0ebe.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b1d5ecff5545/bzImage-b84a0ebe.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/66467c518306/mount_0.gz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4b4093b1f24ad789bf37@syzkaller.appspotmail.com
loop0: detected capacity change from 0 to 4096
NILFS (loop0): invalid segment: Checksum error in segment payload
NILFS (loop0): trying rollback from an earlier position
NILFS (loop0): recovery complete
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
CPU: 0 UID: 0 PID: 6003 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:nilfs_mdt_save_to_shadow_map+0x141/0x1c0 fs/nilfs2/mdt.c:559
Code: 3f 4c 8d 63 d8 4c 89 e0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 e7 e8 2e 0b 83 fe 4d 8b 24 24 49 83 c4 30 4c 89 e0 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 e7 e8 10 0b 83 fe 49 8b 34 24 4c 89 ff
RSP: 0018:ffffc90002767708 EFLAGS: 00010206
RAX: 0000000000000006 RBX: ffff8880605d4560 RCX: 0000000000000000
RDX: ffff88802cde8000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff88802cde8000 R09: 0000000000000003
R10: 0000000000000406 R11: 0000000000000000 R12: 0000000000000030
R13: dffffc0000000000 R14: ffff8880764a6538 R15: ffff8880605d3b18
FS: 000055556403c500(0000) GS:ffff888125436000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b30263fff CR3: 0000000074cae000 CR4: 00000000003526f0
Call Trace:
<TASK>
nilfs_clean_segments+0x162/0xa50 fs/nilfs2/segment.c:2521
nilfs_ioctl_clean_segments fs/nilfs2/ioctl.c:916 [inline]
nilfs_ioctl+0x261f/0x2780 fs/nilfs2/ioctl.c:1346
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd2a5f9c799
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd6d77cd18 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fd2a6215fa0 RCX: 00007fd2a5f9c799
RDX: 0000200000000640 RSI: 0000000040786e88 RDI: 0000000000000004
RBP: 00007fd2a6032c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd2a6215fac R14: 00007fd2a6215fa0 R15: 00007fd2a6215fa0
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:nilfs_mdt_save_to_shadow_map+0x141/0x1c0 fs/nilfs2/mdt.c:559
Code: 3f 4c 8d 63 d8 4c 89 e0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 e7 e8 2e 0b 83 fe 4d 8b 24 24 49 83 c4 30 4c 89 e0 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 e7 e8 10 0b 83 fe 49 8b 34 24 4c 89 ff
RSP: 0018:ffffc90002767708 EFLAGS: 00010206
RAX: 0000000000000006 RBX: ffff8880605d4560 RCX: 0000000000000000
RDX: ffff88802cde8000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff88802cde8000 R09: 0000000000000003
R10: 0000000000000406 R11: 0000000000000000 R12: 0000000000000030
R13: dffffc0000000000 R14: ffff8880764a6538 R15: ffff8880605d3b18
FS: 000055556403c500(0000) GS:ffff888125536000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1536619000 CR3: 0000000074cae000 CR4: 00000000003526f0
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 4c 8d 63 d8 lea -0x28(%rbx),%r12
4: 4c 89 e0 mov %r12,%rax
7: 48 c1 e8 03 shr $0x3,%rax
b: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1)
10: 74 08 je 0x1a
12: 4c 89 e7 mov %r12,%rdi
15: e8 2e 0b 83 fe call 0xfe830b48
1a: 4d 8b 24 24 mov (%r12),%r12
1e: 49 83 c4 30 add $0x30,%r12
22: 4c 89 e0 mov %r12,%rax
25: 48 c1 e8 03 shr $0x3,%rax
* 29: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) <-- trapping instruction
2e: 74 08 je 0x38
30: 4c 89 e7 mov %r12,%rdi
33: e8 10 0b 83 fe call 0xfe830b48
38: 49 8b 34 24 mov (%r12),%rsi
3c: 4c 89 ff mov %r15,%rdi
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
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.
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [syzbot] [nilfs?] general protection fault in nilfs_mdt_save_to_shadow_map
[not found] <20260317034023.572191-1-kartikey406@gmail.com>
@ 2026-03-17 4:06 ` syzbot
0 siblings, 0 replies; 9+ messages in thread
From: syzbot @ 2026-03-17 4:06 UTC (permalink / raw)
To: kartikey406, linux-kernel, syzkaller-bugs
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
general protection fault in nilfs_mdt_save_to_shadow_map
loop0: detected capacity change from 0 to 4096
NILFS (loop0): invalid segment: Checksum error in segment payload
NILFS (loop0): trying rollback from an earlier position
NILFS (loop0): recovery complete
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
CPU: 1 UID: 0 PID: 6533 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:nilfs_mdt_save_to_shadow_map+0x141/0x1c0 fs/nilfs2/mdt.c:559
Code: 3f 4c 8d 63 d8 4c 89 e0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 e7 e8 de c8 82 fe 4d 8b 24 24 49 83 c4 30 4c 89 e0 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 e7 e8 c0 c8 82 fe 49 8b 34 24 4c 89 ff
RSP: 0018:ffffc90003467708 EFLAGS: 00010206
RAX: 0000000000000006 RBX: ffff888058b3c560 RCX: 0000000000000000
RDX: ffff888031629e80 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff888031629e80 R09: 0000000000000003
R10: 0000000000000406 R11: 0000000000000000 R12: 0000000000000030
R13: dffffc0000000000 R14: ffff88801cadd138 R15: ffff888058b3bb18
FS: 00007f88139416c0(0000) GS:ffff888125537000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2e963fff CR3: 0000000023756000 CR4: 00000000003526f0
Call Trace:
<TASK>
nilfs_clean_segments+0x162/0xa50 fs/nilfs2/segment.c:2521
nilfs_ioctl_clean_segments fs/nilfs2/ioctl.c:916 [inline]
nilfs_ioctl+0x261f/0x2780 fs/nilfs2/ioctl.c:1346
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f881299c799
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8813941028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f8812c15fa0 RCX: 00007f881299c799
RDX: 0000200000000640 RSI: 0000000040786e88 RDI: 0000000000000004
RBP: 00007f8812a32c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8812c16038 R14: 00007f8812c15fa0 R15: 00007fff51656638
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:nilfs_mdt_save_to_shadow_map+0x141/0x1c0 fs/nilfs2/mdt.c:559
Code: 3f 4c 8d 63 d8 4c 89 e0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 e7 e8 de c8 82 fe 4d 8b 24 24 49 83 c4 30 4c 89 e0 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 e7 e8 c0 c8 82 fe 49 8b 34 24 4c 89 ff
RSP: 0018:ffffc90003467708 EFLAGS: 00010206
RAX: 0000000000000006 RBX: ffff888058b3c560 RCX: 0000000000000000
RDX: ffff888031629e80 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff888031629e80 R09: 0000000000000003
R10: 0000000000000406 R11: 0000000000000000 R12: 0000000000000030
R13: dffffc0000000000 R14: ffff88801cadd138 R15: ffff888058b3bb18
FS: 00007f88139416c0(0000) GS:ffff888125437000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f88129e9e80 CR3: 0000000023756000 CR4: 00000000003526f0
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 4c 8d 63 d8 lea -0x28(%rbx),%r12
4: 4c 89 e0 mov %r12,%rax
7: 48 c1 e8 03 shr $0x3,%rax
b: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1)
10: 74 08 je 0x1a
12: 4c 89 e7 mov %r12,%rdi
15: e8 de c8 82 fe call 0xfe82c8f8
1a: 4d 8b 24 24 mov (%r12),%r12
1e: 49 83 c4 30 add $0x30,%r12
22: 4c 89 e0 mov %r12,%rax
25: 48 c1 e8 03 shr $0x3,%rax
* 29: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) <-- trapping instruction
2e: 74 08 je 0x38
30: 4c 89 e7 mov %r12,%rdi
33: e8 c0 c8 82 fe call 0xfe82c8f8
38: 49 8b 34 24 mov (%r12),%rsi
3c: 4c 89 ff mov %r15,%rdi
Tested on:
commit: 95c541dd Add linux-next specific files for 20260316
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=12f93d52580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ed431987028345c6
dashboard link: https://syzkaller.appspot.com/bug?extid=4b4093b1f24ad789bf37
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch: https://syzkaller.appspot.com/x/patch.diff?x=1650a8da580000
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [syzbot] [nilfs?] general protection fault in nilfs_mdt_save_to_shadow_map
[not found] <20260317042458.573641-1-kartikey406@gmail.com>
@ 2026-03-17 5:34 ` syzbot
0 siblings, 0 replies; 9+ messages in thread
From: syzbot @ 2026-03-17 5:34 UTC (permalink / raw)
To: kartikey406, linux-kernel, syzkaller-bugs
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
general protection fault in nilfs_mdt_save_to_shadow_map
loop0: detected capacity change from 0 to 4096
NILFS (loop0): invalid segment: Checksum error in segment payload
NILFS (loop0): trying rollback from an earlier position
NILFS (loop0): recovery complete
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
CPU: 0 UID: 0 PID: 6523 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:nilfs_mdt_save_to_shadow_map+0x141/0x1c0 fs/nilfs2/mdt.c:559
Code: 3f 4c 8d 63 d8 4c 89 e0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 e7 e8 2e c9 82 fe 4d 8b 24 24 49 83 c4 30 4c 89 e0 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 e7 e8 10 c9 82 fe 49 8b 34 24 4c 89 ff
RSP: 0018:ffffc90003277708 EFLAGS: 00010206
RAX: 0000000000000006 RBX: ffff88807317c560 RCX: 0000000000000000
RDX: ffff888035688000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff888035688000 R09: 0000000000000003
R10: 0000000000000406 R11: 0000000000000000 R12: 0000000000000030
R13: dffffc0000000000 R14: ffff8880207a1938 R15: ffff88807317bb18
FS: 00007f2a5c0606c0(0000) GS:ffff888125437000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2f663fff CR3: 000000005f52c000 CR4: 00000000003526f0
Call Trace:
<TASK>
nilfs_clean_segments+0x162/0xa50 fs/nilfs2/segment.c:2521
nilfs_ioctl_clean_segments fs/nilfs2/ioctl.c:916 [inline]
nilfs_ioctl+0x261f/0x2780 fs/nilfs2/ioctl.c:1346
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2a5b19c799
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f2a5c060028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f2a5b415fa0 RCX: 00007f2a5b19c799
RDX: 0000200000000640 RSI: 0000000040786e88 RDI: 0000000000000004
RBP: 00007f2a5b232c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2a5b416038 R14: 00007f2a5b415fa0 R15: 00007ffc84e2c978
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:nilfs_mdt_save_to_shadow_map+0x141/0x1c0 fs/nilfs2/mdt.c:559
Code: 3f 4c 8d 63 d8 4c 89 e0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 e7 e8 2e c9 82 fe 4d 8b 24 24 49 83 c4 30 4c 89 e0 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 e7 e8 10 c9 82 fe 49 8b 34 24 4c 89 ff
RSP: 0018:ffffc90003277708 EFLAGS: 00010206
RAX: 0000000000000006 RBX: ffff88807317c560 RCX: 0000000000000000
RDX: ffff888035688000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff888035688000 R09: 0000000000000003
R10: 0000000000000406 R11: 0000000000000000 R12: 0000000000000030
R13: dffffc0000000000 R14: ffff8880207a1938 R15: ffff88807317bb18
FS: 00007f2a5c0606c0(0000) GS:ffff888125437000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2a5b1e9e80 CR3: 000000005f52c000 CR4: 00000000003526f0
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 4c 8d 63 d8 lea -0x28(%rbx),%r12
4: 4c 89 e0 mov %r12,%rax
7: 48 c1 e8 03 shr $0x3,%rax
b: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1)
10: 74 08 je 0x1a
12: 4c 89 e7 mov %r12,%rdi
15: e8 2e c9 82 fe call 0xfe82c948
1a: 4d 8b 24 24 mov (%r12),%r12
1e: 49 83 c4 30 add $0x30,%r12
22: 4c 89 e0 mov %r12,%rax
25: 48 c1 e8 03 shr $0x3,%rax
* 29: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) <-- trapping instruction
2e: 74 08 je 0x38
30: 4c 89 e7 mov %r12,%rdi
33: e8 10 c9 82 fe call 0xfe82c948
38: 49 8b 34 24 mov (%r12),%rsi
3c: 4c 89 ff mov %r15,%rdi
Tested on:
commit: 95c541dd Add linux-next specific files for 20260316
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=177f5602580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ed431987028345c6
dashboard link: https://syzkaller.appspot.com/bug?extid=4b4093b1f24ad789bf37
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch: https://syzkaller.appspot.com/x/patch.diff?x=111962d6580000
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [syzbot] [nilfs?] general protection fault in nilfs_mdt_save_to_shadow_map
[not found] <20260317062513.612142-1-kartikey406@gmail.com>
@ 2026-03-17 6:43 ` syzbot
0 siblings, 0 replies; 9+ messages in thread
From: syzbot @ 2026-03-17 6:43 UTC (permalink / raw)
To: kartikey406, linux-kernel, syzkaller-bugs
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
general protection fault in nilfs_mdt_save_to_shadow_map
NILFS (loop0): invalid segment: Checksum error in segment payload
NILFS (loop0): trying rollback from an earlier position
NILFS DEBUG: s_inode=ffff888073b0bf30 I_NEW=1 i_assoc=0000000000000000
NILFS (loop0): recovery complete
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
CPU: 1 UID: 0 PID: 6570 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:nilfs_mdt_save_to_shadow_map+0x141/0x1c0 fs/nilfs2/mdt.c:559
Code: 3f 4c 8d 63 d8 4c 89 e0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 e7 e8 de c8 82 fe 4d 8b 24 24 49 83 c4 30 4c 89 e0 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 e7 e8 c0 c8 82 fe 49 8b 34 24 4c 89 ff
RSP: 0018:ffffc90003567708 EFLAGS: 00010206
RAX: 0000000000000006 RBX: ffff888073b0c560 RCX: 0000000000000000
RDX: ffff888079f78000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff888079f78000 R09: 0000000000000003
R10: 0000000000000406 R11: 0000000000000000 R12: 0000000000000030
R13: dffffc0000000000 R14: ffff88807d17c538 R15: ffff888073b0bb18
FS: 00007f607df766c0(0000) GS:ffff888125537000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31a63fff CR3: 000000006ae06000 CR4: 00000000003526f0
Call Trace:
<TASK>
nilfs_clean_segments+0x162/0xa50 fs/nilfs2/segment.c:2521
nilfs_ioctl_clean_segments fs/nilfs2/ioctl.c:916 [inline]
nilfs_ioctl+0x261f/0x2780 fs/nilfs2/ioctl.c:1346
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f607d19c799
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f607df76028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f607d415fa0 RCX: 00007f607d19c799
RDX: 0000200000000640 RSI: 0000000040786e88 RDI: 0000000000000004
RBP: 00007f607d232c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f607d416038 R14: 00007f607d415fa0 R15: 00007ffce886a6e8
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:nilfs_mdt_save_to_shadow_map+0x141/0x1c0 fs/nilfs2/mdt.c:559
Code: 3f 4c 8d 63 d8 4c 89 e0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 e7 e8 de c8 82 fe 4d 8b 24 24 49 83 c4 30 4c 89 e0 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 e7 e8 c0 c8 82 fe 49 8b 34 24 4c 89 ff
RSP: 0018:ffffc90003567708 EFLAGS: 00010206
RAX: 0000000000000006 RBX: ffff888073b0c560 RCX: 0000000000000000
RDX: ffff888079f78000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff888079f78000 R09: 0000000000000003
R10: 0000000000000406 R11: 0000000000000000 R12: 0000000000000030
R13: dffffc0000000000 R14: ffff88807d17c538 R15: ffff888073b0bb18
FS: 00007f607df766c0(0000) GS:ffff888125537000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f607d1e9e80 CR3: 000000006ae06000 CR4: 00000000003526f0
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 4c 8d 63 d8 lea -0x28(%rbx),%r12
4: 4c 89 e0 mov %r12,%rax
7: 48 c1 e8 03 shr $0x3,%rax
b: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1)
10: 74 08 je 0x1a
12: 4c 89 e7 mov %r12,%rdi
15: e8 de c8 82 fe call 0xfe82c8f8
1a: 4d 8b 24 24 mov (%r12),%r12
1e: 49 83 c4 30 add $0x30,%r12
22: 4c 89 e0 mov %r12,%rax
25: 48 c1 e8 03 shr $0x3,%rax
* 29: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) <-- trapping instruction
2e: 74 08 je 0x38
30: 4c 89 e7 mov %r12,%rdi
33: e8 c0 c8 82 fe call 0xfe82c8f8
38: 49 8b 34 24 mov (%r12),%rsi
3c: 4c 89 ff mov %r15,%rdi
Tested on:
commit: 95c541dd Add linux-next specific files for 20260316
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1134a8da580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ed431987028345c6
dashboard link: https://syzkaller.appspot.com/bug?extid=4b4093b1f24ad789bf37
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch: https://syzkaller.appspot.com/x/patch.diff?x=14b778da580000
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [syzbot] [nilfs?] general protection fault in nilfs_mdt_save_to_shadow_map
[not found] <20260317064737.657774-1-kartikey406@gmail.com>
@ 2026-03-17 7:05 ` syzbot
0 siblings, 0 replies; 9+ messages in thread
From: syzbot @ 2026-03-17 7:05 UTC (permalink / raw)
To: kartikey406, linux-kernel, syzkaller-bugs
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
general protection fault in nilfs_mdt_save_to_shadow_map
NILFS (loop0): trying rollback from an earlier position
NILFS DEBUG: s_inode=ffff888058f1bf30 I_NEW=1 i_assoc=0000000000000000
NILFS DEBUG btnc: btnc=ffff888058f1b900 I_NEW=1
NILFS (loop0): recovery complete
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
CPU: 0 UID: 0 PID: 6529 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:nilfs_mdt_save_to_shadow_map+0x141/0x1c0 fs/nilfs2/mdt.c:559
Code: 3f 4c 8d 63 d8 4c 89 e0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 e7 e8 ce ca 82 fe 4d 8b 24 24 49 83 c4 30 4c 89 e0 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 e7 e8 b0 ca 82 fe 49 8b 34 24 4c 89 ff
RSP: 0018:ffffc900040a7708 EFLAGS: 00010206
RAX: 0000000000000006 RBX: ffff888058f1c560 RCX: 0000000000000000
RDX: ffff88803798bd00 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff88803798bd00 R09: 0000000000000003
R10: 0000000000000406 R11: 0000000000000000 R12: 0000000000000030
R13: dffffc0000000000 R14: ffff88802bac9138 R15: ffff888058f1bb18
FS: 00007f1d2e3856c0(0000) GS:ffff888125437000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2e263fff CR3: 00000000373ba000 CR4: 00000000003526f0
Call Trace:
<TASK>
nilfs_clean_segments+0x162/0xa50 fs/nilfs2/segment.c:2521
nilfs_ioctl_clean_segments fs/nilfs2/ioctl.c:916 [inline]
nilfs_ioctl+0x261f/0x2780 fs/nilfs2/ioctl.c:1346
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1d2d59c799
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1d2e385028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f1d2d815fa0 RCX: 00007f1d2d59c799
RDX: 0000200000000640 RSI: 0000000040786e88 RDI: 0000000000000004
RBP: 00007f1d2d632c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1d2d816038 R14: 00007f1d2d815fa0 R15: 00007ffc09d78608
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:nilfs_mdt_save_to_shadow_map+0x141/0x1c0 fs/nilfs2/mdt.c:559
Code: 3f 4c 8d 63 d8 4c 89 e0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 e7 e8 ce ca 82 fe 4d 8b 24 24 49 83 c4 30 4c 89 e0 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 e7 e8 b0 ca 82 fe 49 8b 34 24 4c 89 ff
RSP: 0018:ffffc900040a7708 EFLAGS: 00010206
RAX: 0000000000000006 RBX: ffff888058f1c560 RCX: 0000000000000000
RDX: ffff88803798bd00 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff88803798bd00 R09: 0000000000000003
R10: 0000000000000406 R11: 0000000000000000 R12: 0000000000000030
R13: dffffc0000000000 R14: ffff88802bac9138 R15: ffff888058f1bb18
FS: 00007f1d2e3856c0(0000) GS:ffff888125537000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000556adf0f25e0 CR3: 00000000373ba000 CR4: 00000000003526f0
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 4c 8d 63 d8 lea -0x28(%rbx),%r12
4: 4c 89 e0 mov %r12,%rax
7: 48 c1 e8 03 shr $0x3,%rax
b: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1)
10: 74 08 je 0x1a
12: 4c 89 e7 mov %r12,%rdi
15: e8 ce ca 82 fe call 0xfe82cae8
1a: 4d 8b 24 24 mov (%r12),%r12
1e: 49 83 c4 30 add $0x30,%r12
22: 4c 89 e0 mov %r12,%rax
25: 48 c1 e8 03 shr $0x3,%rax
* 29: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) <-- trapping instruction
2e: 74 08 je 0x38
30: 4c 89 e7 mov %r12,%rdi
33: e8 b0 ca 82 fe call 0xfe82cae8
38: 49 8b 34 24 mov (%r12),%rsi
3c: 4c 89 ff mov %r15,%rdi
Tested on:
commit: 95c541dd Add linux-next specific files for 20260316
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=17ecc216580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ed431987028345c6
dashboard link: https://syzkaller.appspot.com/bug?extid=4b4093b1f24ad789bf37
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch: https://syzkaller.appspot.com/x/patch.diff?x=1530d602580000
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [syzbot] [nilfs?] general protection fault in nilfs_mdt_save_to_shadow_map
2026-03-17 3:14 syzbot
@ 2026-03-17 8:09 ` Edward Adam Davis
2026-03-17 8:41 ` syzbot
0 siblings, 1 reply; 9+ messages in thread
From: Edward Adam Davis @ 2026-03-17 8:09 UTC (permalink / raw)
To: syzbot+4b4093b1f24ad789bf37; +Cc: linux-kernel, syzkaller-bugs
#syz test
diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index 1491a4d4b1e1..7e0b24361d0b 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -2518,9 +2518,11 @@ int nilfs_clean_segments(struct super_block *sb, struct nilfs_argv *argv,
nilfs_transaction_lock(sb, &ti, 1);
- err = nilfs_mdt_save_to_shadow_map(nilfs->ns_dat);
- if (unlikely(err))
- goto out_unlock;
+ if (argv[0].v_nmembs > 0) {
+ err = nilfs_mdt_save_to_shadow_map(nilfs->ns_dat);
+ if (unlikely(err))
+ goto out_unlock;
+ }
err = nilfs_ioctl_prepare_clean_segments(nilfs, argv, kbufs);
if (unlikely(err)) {
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [syzbot] [nilfs?] general protection fault in nilfs_mdt_save_to_shadow_map
[not found] <20260317073633.732124-1-kartikey406@gmail.com>
@ 2026-03-17 8:15 ` syzbot
0 siblings, 0 replies; 9+ messages in thread
From: syzbot @ 2026-03-17 8:15 UTC (permalink / raw)
To: kartikey406, linux-kernel, syzkaller-bugs
Hello,
syzbot has tested the proposed patch and the reproducer did not trigger any issue:
Reported-by: syzbot+4b4093b1f24ad789bf37@syzkaller.appspotmail.com
Tested-by: syzbot+4b4093b1f24ad789bf37@syzkaller.appspotmail.com
Tested on:
commit: 95c541dd Add linux-next specific files for 20260316
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=10a362d6580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ed431987028345c6
dashboard link: https://syzkaller.appspot.com/bug?extid=4b4093b1f24ad789bf37
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch: https://syzkaller.appspot.com/x/patch.diff?x=16bcc216580000
Note: testing is done by a robot and is best-effort only.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [syzbot] [nilfs?] general protection fault in nilfs_mdt_save_to_shadow_map
2026-03-17 8:09 ` Edward Adam Davis
@ 2026-03-17 8:41 ` syzbot
0 siblings, 0 replies; 9+ messages in thread
From: syzbot @ 2026-03-17 8:41 UTC (permalink / raw)
To: eadavis, linux-kernel, syzkaller-bugs
Hello,
syzbot has tested the proposed patch and the reproducer did not trigger any issue:
Reported-by: syzbot+4b4093b1f24ad789bf37@syzkaller.appspotmail.com
Tested-by: syzbot+4b4093b1f24ad789bf37@syzkaller.appspotmail.com
Tested on:
commit: 95c541dd Add linux-next specific files for 20260316
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=13a2006a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ed431987028345c6
dashboard link: https://syzkaller.appspot.com/bug?extid=4b4093b1f24ad789bf37
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch: https://syzkaller.appspot.com/x/patch.diff?x=13533d52580000
Note: testing is done by a robot and is best-effort only.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [syzbot] [nilfs?] general protection fault in nilfs_mdt_save_to_shadow_map
[not found] <20260317082620.825333-1-kartikey406@gmail.com>
@ 2026-03-17 8:56 ` syzbot
0 siblings, 0 replies; 9+ messages in thread
From: syzbot @ 2026-03-17 8:56 UTC (permalink / raw)
To: kartikey406, linux-kernel, syzkaller-bugs
Hello,
syzbot has tested the proposed patch and the reproducer did not trigger any issue:
Reported-by: syzbot+4b4093b1f24ad789bf37@syzkaller.appspotmail.com
Tested-by: syzbot+4b4093b1f24ad789bf37@syzkaller.appspotmail.com
Tested on:
commit: 95c541dd Add linux-next specific files for 20260316
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1692c216580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ed431987028345c6
dashboard link: https://syzkaller.appspot.com/bug?extid=4b4093b1f24ad789bf37
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch: https://syzkaller.appspot.com/x/patch.diff?x=10733d52580000
Note: testing is done by a robot and is best-effort only.
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2026-03-17 8:56 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz follow: Atom feed
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2026-03-17 8:56 ` [syzbot] [nilfs?] general protection fault in nilfs_mdt_save_to_shadow_map syzbot
[not found] <20260317073633.732124-1-kartikey406@gmail.com>
2026-03-17 8:15 ` syzbot
[not found] <20260317064737.657774-1-kartikey406@gmail.com>
2026-03-17 7:05 ` syzbot
[not found] <20260317062513.612142-1-kartikey406@gmail.com>
2026-03-17 6:43 ` syzbot
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2026-03-17 4:06 ` syzbot
2026-03-17 3:14 syzbot
2026-03-17 8:09 ` Edward Adam Davis
2026-03-17 8:41 ` syzbot
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