[v6.6] general protection fault in write_all_supers
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syzbot
Jul 26, 2025, 7:00:32 AM7/26/25
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: dbcb8d8e4163 Linux 6.6.100
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=147148a2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=293251cfa8d8100
dashboard link: https://syzkaller.appspot.com/bug?extid=1df6dc78b7815d4d1974
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d0b56817a2c3/disk-dbcb8d8e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f0d646b2f7fa/vmlinux-dbcb8d8e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1e0b752a5011/bzImage-dbcb8d8e.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1df6dc...@syzkaller.appspotmail.com
general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 1 PID: 11530 Comm: syz.2.1322 Not tainted 6.6.100-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:backup_super_roots fs/btrfs/disk-io.c:1668 [inline]
RIP: 0010:write_all_supers+0x8a7/0x3e60 fs/btrfs/disk-io.c:4079
Code: 10 48 8d 9a 9a 00 00 00 48 89 d8 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 53 33 00 00 44 88 33 49 83 c4 18 4c 89 e0 48 c1 e8 03 <42> 80 3c 28 00 74 0d 4c 89 e7 e8 5a 5b 67 fe 48 8b 54 24 10 49 8b
RSP: 0018:ffffc9000390f400 EFLAGS: 00010206
RAX: 0000000000000003 RBX: ffff888059f6ebc5 RCX: 0000000000000000
RDX: ffff888059f6eb2b RSI: 0000000000000004 RDI: ffff88801bf52878
RBP: ffffc9000390f7b0 R08: ffff888027abc063 R09: 1ffff11004f5780c
R10: dffffc0000000000 R11: ffffed1004f5780d R12: 0000000000000018
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff88802a19e018
FS: 00007f086da576c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1ee2813000 CR3: 0000000059238000 CR4: 00000000003506e0
Call Trace:
<TASK>
btrfs_commit_transaction+0x1e95/0x3760 fs/btrfs/transaction.c:2516
btrfs_set_free_space_cache_v1_active+0x71/0x1c0 fs/btrfs/free-space-cache.c:4151
btrfs_remount_cleanup fs/btrfs/super.c:1684 [inline]
btrfs_remount+0xfd1/0x1470 fs/btrfs/super.c:1861
reconfigure_super+0x21e/0x880 fs/super.c:1151
do_remount fs/namespace.c:2905 [inline]
path_mount+0xd19/0xfe0 fs/namespace.c:3690
do_mount fs/namespace.c:3711 [inline]
__do_sys_mount fs/namespace.c:3920 [inline]
__se_sys_mount+0x2da/0x3c0 fs/namespace.c:3897
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f086cb9014a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007f086da56e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f086da56ef0 RCX: 00007f086cb9014a
RDX: 0000200000000180 RSI: 0000200000000380 RDI: 0000000000000000
RBP: 0000200000000180 R08: 00007f086da56ef0 R09: 0000000002042023
R10: 0000000002042023 R11: 0000000000000246 R12: 0000200000000380
R13: 00007f086da56eb0 R14: 0000000000000000 R15: 00002000000002c0
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:backup_super_roots fs/btrfs/disk-io.c:1668 [inline]
RIP: 0010:write_all_supers+0x8a7/0x3e60 fs/btrfs/disk-io.c:4079
Code: 10 48 8d 9a 9a 00 00 00 48 89 d8 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 53 33 00 00 44 88 33 49 83 c4 18 4c 89 e0 48 c1 e8 03 <42> 80 3c 28 00 74 0d 4c 89 e7 e8 5a 5b 67 fe 48 8b 54 24 10 49 8b
RSP: 0018:ffffc9000390f400 EFLAGS: 00010206
RAX: 0000000000000003 RBX: ffff888059f6ebc5 RCX: 0000000000000000
RDX: ffff888059f6eb2b RSI: 0000000000000004 RDI: ffff88801bf52878
RBP: ffffc9000390f7b0 R08: ffff888027abc063 R09: 1ffff11004f5780c
R10: dffffc0000000000 R11: ffffed1004f5780d R12: 0000000000000018
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff88802a19e018
FS: 00007f086da576c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1ee27fb000 CR3: 0000000059238000 CR4: 00000000003506f0
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 48 8d 9a 9a 00 00 00 lea 0x9a(%rdx),%rbx
7: 48 89 d8 mov %rbx,%rax
a: 48 c1 e8 03 shr $0x3,%rax
e: 42 0f b6 04 28 movzbl (%rax,%r13,1),%eax
13: 84 c0 test %al,%al
15: 0f 85 53 33 00 00 jne 0x336e
1b: 44 88 33 mov %r14b,(%rbx)
1e: 49 83 c4 18 add $0x18,%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 0d je 0x3d
30: 4c 89 e7 mov %r12,%rdi
33: e8 5a 5b 67 fe call 0xfe675b92
38: 48 8b 54 24 10 mov 0x10(%rsp),%rdx
3d: 49 rex.WB
3e: 8b .byte 0x8b
---
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 syzk...@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 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
syzbot found the following issue on:
HEAD commit: dbcb8d8e4163 Linux 6.6.100
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=147148a2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=293251cfa8d8100
dashboard link: https://syzkaller.appspot.com/bug?extid=1df6dc78b7815d4d1974
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d0b56817a2c3/disk-dbcb8d8e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f0d646b2f7fa/vmlinux-dbcb8d8e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1e0b752a5011/bzImage-dbcb8d8e.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1df6dc...@syzkaller.appspotmail.com
general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 1 PID: 11530 Comm: syz.2.1322 Not tainted 6.6.100-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:backup_super_roots fs/btrfs/disk-io.c:1668 [inline]
RIP: 0010:write_all_supers+0x8a7/0x3e60 fs/btrfs/disk-io.c:4079
Code: 10 48 8d 9a 9a 00 00 00 48 89 d8 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 53 33 00 00 44 88 33 49 83 c4 18 4c 89 e0 48 c1 e8 03 <42> 80 3c 28 00 74 0d 4c 89 e7 e8 5a 5b 67 fe 48 8b 54 24 10 49 8b
RSP: 0018:ffffc9000390f400 EFLAGS: 00010206
RAX: 0000000000000003 RBX: ffff888059f6ebc5 RCX: 0000000000000000
RDX: ffff888059f6eb2b RSI: 0000000000000004 RDI: ffff88801bf52878
RBP: ffffc9000390f7b0 R08: ffff888027abc063 R09: 1ffff11004f5780c
R10: dffffc0000000000 R11: ffffed1004f5780d R12: 0000000000000018
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff88802a19e018
FS: 00007f086da576c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1ee2813000 CR3: 0000000059238000 CR4: 00000000003506e0
Call Trace:
<TASK>
btrfs_commit_transaction+0x1e95/0x3760 fs/btrfs/transaction.c:2516
btrfs_set_free_space_cache_v1_active+0x71/0x1c0 fs/btrfs/free-space-cache.c:4151
btrfs_remount_cleanup fs/btrfs/super.c:1684 [inline]
btrfs_remount+0xfd1/0x1470 fs/btrfs/super.c:1861
reconfigure_super+0x21e/0x880 fs/super.c:1151
do_remount fs/namespace.c:2905 [inline]
path_mount+0xd19/0xfe0 fs/namespace.c:3690
do_mount fs/namespace.c:3711 [inline]
__do_sys_mount fs/namespace.c:3920 [inline]
__se_sys_mount+0x2da/0x3c0 fs/namespace.c:3897
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f086cb9014a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007f086da56e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f086da56ef0 RCX: 00007f086cb9014a
RDX: 0000200000000180 RSI: 0000200000000380 RDI: 0000000000000000
RBP: 0000200000000180 R08: 00007f086da56ef0 R09: 0000000002042023
R10: 0000000002042023 R11: 0000000000000246 R12: 0000200000000380
R13: 00007f086da56eb0 R14: 0000000000000000 R15: 00002000000002c0
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:backup_super_roots fs/btrfs/disk-io.c:1668 [inline]
RIP: 0010:write_all_supers+0x8a7/0x3e60 fs/btrfs/disk-io.c:4079
Code: 10 48 8d 9a 9a 00 00 00 48 89 d8 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 53 33 00 00 44 88 33 49 83 c4 18 4c 89 e0 48 c1 e8 03 <42> 80 3c 28 00 74 0d 4c 89 e7 e8 5a 5b 67 fe 48 8b 54 24 10 49 8b
RSP: 0018:ffffc9000390f400 EFLAGS: 00010206
RAX: 0000000000000003 RBX: ffff888059f6ebc5 RCX: 0000000000000000
RDX: ffff888059f6eb2b RSI: 0000000000000004 RDI: ffff88801bf52878
RBP: ffffc9000390f7b0 R08: ffff888027abc063 R09: 1ffff11004f5780c
R10: dffffc0000000000 R11: ffffed1004f5780d R12: 0000000000000018
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff88802a19e018
FS: 00007f086da576c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1ee27fb000 CR3: 0000000059238000 CR4: 00000000003506f0
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 48 8d 9a 9a 00 00 00 lea 0x9a(%rdx),%rbx
7: 48 89 d8 mov %rbx,%rax
a: 48 c1 e8 03 shr $0x3,%rax
e: 42 0f b6 04 28 movzbl (%rax,%r13,1),%eax
13: 84 c0 test %al,%al
15: 0f 85 53 33 00 00 jne 0x336e
1b: 44 88 33 mov %r14b,(%rbx)
1e: 49 83 c4 18 add $0x18,%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 0d je 0x3d
30: 4c 89 e7 mov %r12,%rdi
33: e8 5a 5b 67 fe call 0xfe675b92
38: 48 8b 54 24 10 mov 0x10(%rsp),%rdx
3d: 49 rex.WB
3e: 8b .byte 0x8b
---
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 syzk...@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 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
syzbot
Jul 26, 2025, 7:51:28 AM7/26/25
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following issue on:
HEAD commit: dbcb8d8e4163 Linux 6.6.100
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=158fd4f0580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12b548a2580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d0b56817a2c3/disk-dbcb8d8e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f0d646b2f7fa/vmlinux-dbcb8d8e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1e0b752a5011/bzImage-dbcb8d8e.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/f9cfe58a9179/mount_0.gz
fsck result: OK (log: https://syzkaller.appspot.com/x/fsck.log?x=118fd4f0580000)
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1df6dc...@syzkaller.appspotmail.com
workqueue: max_active 2097158 requested for btrfs-endio-write is out of range, clamping between 1 and 512
workqueue: max_active 2097158 requested for btrfs-compressed-write is out of range, clamping between 1 and 512
BTRFS info (device loop0: state C): enabling ssd optimizations
RAX: 0000000000000003 RBX: ffff88802c8f4bc5 RCX: 0000000000000000
RDX: ffff88802c8f4b2b RSI: 0000000000000004 RDI: ffff888076fcd388
RBP: ffffc900032b77b0 R08: ffff88802e0a8063 R09: 1ffff11005c1500c
R10: dffffc0000000000 R11: ffffed1005c1500d R12: 0000000000000018
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff88807c9f4018
FS: 000055557ab35500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
RAX: ffffffffffffffda RBX: 00007ffcbee33ce0 RCX: 00007f4b29f9014a
RAX: 0000000000000003 RBX: ffff88802c8f4bc5 RCX: 0000000000000000
RDX: ffff88802c8f4b2b RSI: 0000000000000004 RDI: ffff888076fcd388
RBP: ffffc900032b77b0 R08: ffff88802e0a8063 R09: 1ffff11005c1500c
R10: dffffc0000000000 R11: ffffed1005c1500d R12: 0000000000000018
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff88807c9f4018
FS: 000055557ab35500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
HEAD commit: dbcb8d8e4163 Linux 6.6.100
git tree: linux-6.6.y
kernel config: https://syzkaller.appspot.com/x/.config?x=293251cfa8d8100
dashboard link: https://syzkaller.appspot.com/bug?extid=1df6dc78b7815d4d1974
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1647a8a2580000
dashboard link: https://syzkaller.appspot.com/bug?extid=1df6dc78b7815d4d1974
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12b548a2580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d0b56817a2c3/disk-dbcb8d8e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f0d646b2f7fa/vmlinux-dbcb8d8e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1e0b752a5011/bzImage-dbcb8d8e.xz
fsck result: OK (log: https://syzkaller.appspot.com/x/fsck.log?x=118fd4f0580000)
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1df6dc...@syzkaller.appspotmail.com
workqueue: max_active 2097158 requested for btrfs-compressed-write is out of range, clamping between 1 and 512
BTRFS info (device loop0: state C): enabling ssd optimizations
general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
CPU: 1 PID: 5941 Comm: syz.0.16 Not tainted 6.6.100-syzkaller #0
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:backup_super_roots fs/btrfs/disk-io.c:1668 [inline]
RIP: 0010:write_all_supers+0x8a7/0x3e60 fs/btrfs/disk-io.c:4079
Code: 10 48 8d 9a 9a 00 00 00 48 89 d8 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 53 33 00 00 44 88 33 49 83 c4 18 4c 89 e0 48 c1 e8 03 <42> 80 3c 28 00 74 0d 4c 89 e7 e8 5a 5b 67 fe 48 8b 54 24 10 49 8b
RSP: 0018:ffffc900032b7400 EFLAGS: 00010206
RIP: 0010:backup_super_roots fs/btrfs/disk-io.c:1668 [inline]
RIP: 0010:write_all_supers+0x8a7/0x3e60 fs/btrfs/disk-io.c:4079
Code: 10 48 8d 9a 9a 00 00 00 48 89 d8 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 53 33 00 00 44 88 33 49 83 c4 18 4c 89 e0 48 c1 e8 03 <42> 80 3c 28 00 74 0d 4c 89 e7 e8 5a 5b 67 fe 48 8b 54 24 10 49 8b
RAX: 0000000000000003 RBX: ffff88802c8f4bc5 RCX: 0000000000000000
RDX: ffff88802c8f4b2b RSI: 0000000000000004 RDI: ffff888076fcd388
RBP: ffffc900032b77b0 R08: ffff88802e0a8063 R09: 1ffff11005c1500c
R10: dffffc0000000000 R11: ffffed1005c1500d R12: 0000000000000018
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff88807c9f4018
FS: 000055557ab35500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3d53ff82f8 CR3: 0000000076dc1000 CR4: 00000000003506e0
Call Trace:
<TASK>
btrfs_commit_transaction+0x1e95/0x3760 fs/btrfs/transaction.c:2516
btrfs_set_free_space_cache_v1_active+0x71/0x1c0 fs/btrfs/free-space-cache.c:4151
btrfs_remount_cleanup fs/btrfs/super.c:1684 [inline]
btrfs_remount+0xfd1/0x1470 fs/btrfs/super.c:1861
reconfigure_super+0x21e/0x880 fs/super.c:1151
do_remount fs/namespace.c:2905 [inline]
path_mount+0xd19/0xfe0 fs/namespace.c:3690
do_mount fs/namespace.c:3711 [inline]
__do_sys_mount fs/namespace.c:3920 [inline]
__se_sys_mount+0x2da/0x3c0 fs/namespace.c:3897
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f4b29f9014a
<TASK>
btrfs_commit_transaction+0x1e95/0x3760 fs/btrfs/transaction.c:2516
btrfs_set_free_space_cache_v1_active+0x71/0x1c0 fs/btrfs/free-space-cache.c:4151
btrfs_remount_cleanup fs/btrfs/super.c:1684 [inline]
btrfs_remount+0xfd1/0x1470 fs/btrfs/super.c:1861
reconfigure_super+0x21e/0x880 fs/super.c:1151
do_remount fs/namespace.c:2905 [inline]
path_mount+0xd19/0xfe0 fs/namespace.c:3690
do_mount fs/namespace.c:3711 [inline]
__do_sys_mount fs/namespace.c:3920 [inline]
__se_sys_mount+0x2da/0x3c0 fs/namespace.c:3897
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007ffcbee33c58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffcbee33ce0 RCX: 00007f4b29f9014a
RDX: 0000200000000180 RSI: 0000200000000380 RDI: 0000000000000000
RBP: 0000200000000180 R08: 00007ffcbee33ce0 R09: 0000000002042023
R10: 0000000002042023 R11: 0000000000000246 R12: 0000200000000380
R13: 00007ffcbee33ca0 R14: 0000000000000000 R15: 00002000000002c0
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:backup_super_roots fs/btrfs/disk-io.c:1668 [inline]
RIP: 0010:write_all_supers+0x8a7/0x3e60 fs/btrfs/disk-io.c:4079
Code: 10 48 8d 9a 9a 00 00 00 48 89 d8 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 53 33 00 00 44 88 33 49 83 c4 18 4c 89 e0 48 c1 e8 03 <42> 80 3c 28 00 74 0d 4c 89 e7 e8 5a 5b 67 fe 48 8b 54 24 10 49 8b
RSP: 0018:ffffc900032b7400 EFLAGS: 00010206
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:backup_super_roots fs/btrfs/disk-io.c:1668 [inline]
RIP: 0010:write_all_supers+0x8a7/0x3e60 fs/btrfs/disk-io.c:4079
Code: 10 48 8d 9a 9a 00 00 00 48 89 d8 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 53 33 00 00 44 88 33 49 83 c4 18 4c 89 e0 48 c1 e8 03 <42> 80 3c 28 00 74 0d 4c 89 e7 e8 5a 5b 67 fe 48 8b 54 24 10 49 8b
RAX: 0000000000000003 RBX: ffff88802c8f4bc5 RCX: 0000000000000000
RDX: ffff88802c8f4b2b RSI: 0000000000000004 RDI: ffff888076fcd388
RBP: ffffc900032b77b0 R08: ffff88802e0a8063 R09: 1ffff11005c1500c
R10: dffffc0000000000 R11: ffffed1005c1500d R12: 0000000000000018
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff88807c9f4018
FS: 000055557ab35500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffb8a966000 CR3: 0000000076dc1000 CR4: 00000000003506f0
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 48 8d 9a 9a 00 00 00 lea 0x9a(%rdx),%rbx
7: 48 89 d8 mov %rbx,%rax
a: 48 c1 e8 03 shr $0x3,%rax
e: 42 0f b6 04 28 movzbl (%rax,%r13,1),%eax
13: 84 c0 test %al,%al
15: 0f 85 53 33 00 00 jne 0x336e
1b: 44 88 33 mov %r14b,(%rbx)
1e: 49 83 c4 18 add $0x18,%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 0d je 0x3d
30: 4c 89 e7 mov %r12,%rdi
33: e8 5a 5b 67 fe call 0xfe675b92
38: 48 8b 54 24 10 mov 0x10(%rsp),%rdx
3d: 49 rex.WB
3e: 8b .byte 0x8b
---
If you want syzbot to run the reproducer, reply with:
Code disassembly (best guess), 1 bytes skipped:
0: 48 8d 9a 9a 00 00 00 lea 0x9a(%rdx),%rbx
7: 48 89 d8 mov %rbx,%rax
a: 48 c1 e8 03 shr $0x3,%rax
e: 42 0f b6 04 28 movzbl (%rax,%r13,1),%eax
13: 84 c0 test %al,%al
15: 0f 85 53 33 00 00 jne 0x336e
1b: 44 88 33 mov %r14b,(%rbx)
1e: 49 83 c4 18 add $0x18,%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 0d je 0x3d
30: 4c 89 e7 mov %r12,%rdi
33: e8 5a 5b 67 fe call 0xfe675b92
38: 48 8b 54 24 10 mov 0x10(%rsp),%rdx
3d: 49 rex.WB
3e: 8b .byte 0x8b
---
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
syzbot
Sep 30, 2025, 11:17:04 AM9/30/25
to syzkaller...@googlegroups.com
syzbot suspects this issue could be fixed by backporting the following commit:
commit ad21f15b0f795daf8723dddbcb61797d4f1c2aed
git tree: upstream
Author: Josef Bacik <jo...@toxicpanda.com>
Date: Wed Nov 22 17:17:50 2023 +0000
btrfs: switch to the new mount API
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=171096e2580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13e44034580000
Please keep in mind that other backports might be required as well.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
commit ad21f15b0f795daf8723dddbcb61797d4f1c2aed
git tree: upstream
Author: Josef Bacik <jo...@toxicpanda.com>
Date: Wed Nov 22 17:17:50 2023 +0000
btrfs: switch to the new mount API
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=171096e2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=293251cfa8d8100
dashboard link: https://syzkaller.appspot.com/bug?extid=1df6dc78b7815d4d1974
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11d0c8a2580000
dashboard link: https://syzkaller.appspot.com/bug?extid=1df6dc78b7815d4d1974
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13e44034580000
Please keep in mind that other backports might be required as well.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
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