[v6.1] BUG: unable to handle kernel paging request in ext4_free_ext_path
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syzbot
Mar 25, 2026, 10:06:27 AM (3 days ago) Mar 25
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: 1989cd3d56e2 Linux 6.1.167
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1014cfef980000
kernel config: https://syzkaller.appspot.com/x/.config?x=b1adc0bfde2d8a4a
dashboard link: https://syzkaller.appspot.com/bug?extid=261b234ba5e4466cef19
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
userspace arch: arm64
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/edd05d4d1a68/disk-1989cd3d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/bdc3181e838d/vmlinux-1989cd3d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a78aef5a3a25/Image-1989cd3d.gz.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+261b23...@syzkaller.appspotmail.com
Unable to handle kernel paging request at virtual address ffffffffffffffec
KASAN: maybe wild-memory-access in range [0x0003ffffffffff60-0x0003ffffffffff67]
Mem abort info:
ESR = 0x0000000096000004
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x04: level 0 translation fault
Data abort info:
ISV = 0, ISS = 0x00000004
CM = 0, WnR = 0
swapper pgtable: 4k pages, 48-bit VAs, pgdp=000000020dfcc000
[ffffffffffffffec] pgd=0000000000000000, p4d=0000000000000000
Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 6324 Comm: syz.2.552 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/26/2026
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : ext4_ext_drop_refs fs/ext4/extents.c:119 [inline]
pc : ext4_free_ext_path+0x40/0xf4 fs/ext4/extents.c:128
lr : ext4_free_ext_path+0x24/0xf4 fs/ext4/extents.c:127
sp : ffff800021ab7550
x29: ffff800021ab7550 x28: 1ffff00004356edc x27: dfff800000000000
x26: ffff700004356eb8 x25: ffff800021ab76e4 x24: ffffffffffffffe4
x23: ffff0000e0ba5258 x22: dfff800000000000 x21: 0000000000000001
x20: 1ffff00004356ede x19: ffffffffffffffe4 x18: ffff800011b9bf60
x17: ffff80001835a000 x16: ffff8000082d92bc x15: ffff8000089f00b4
x14: 0000000000000001 x13: 1fffe0001c174a4b x12: 0000000000080000
x11: 0000000000016a6e x10: ffff8000263eb000 x9 : ffff800008d173c4
x8 : 0000000000000000 x7 : ffff80000805983c x6 : ffff800008059a4c
x5 : ffff0000e4b918d8 x4 : ffff800021ab7040 x3 : ffff8000082d27a8
x2 : 0000000000000001 x1 : 0000000000000008 x0 : ffffffffffffffec
Call trace:
ext4_ext_drop_refs fs/ext4/extents.c:119 [inline]
ext4_free_ext_path+0x40/0xf4 fs/ext4/extents.c:128
finish_range+0x200/0x2f8 fs/ext4/migrate.c:60
ext4_ext_migrate+0x8e4/0xc08 fs/ext4/migrate.c:544
__ext4_ioctl fs/ext4/ioctl.c:1399 [inline]
ext4_ioctl+0x1b04/0x4328 fs/ext4/ioctl.c:1617
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
Code: d343fc08 f2fbfff6 38f66908 35000508 (79401277)
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
0: d343fc08 lsr x8, x0, #3
4: f2fbfff6 movk x22, #0xdfff, lsl #48
8: 38f66908 ldrsb w8, [x8, x22]
c: 35000508 cbnz w8, 0xac
* 10: 79401277 ldrh w23, [x19, #8] <-- trapping instruction
---
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: 1989cd3d56e2 Linux 6.1.167
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1014cfef980000
kernel config: https://syzkaller.appspot.com/x/.config?x=b1adc0bfde2d8a4a
dashboard link: https://syzkaller.appspot.com/bug?extid=261b234ba5e4466cef19
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
userspace arch: arm64
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/edd05d4d1a68/disk-1989cd3d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/bdc3181e838d/vmlinux-1989cd3d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a78aef5a3a25/Image-1989cd3d.gz.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+261b23...@syzkaller.appspotmail.com
Unable to handle kernel paging request at virtual address ffffffffffffffec
KASAN: maybe wild-memory-access in range [0x0003ffffffffff60-0x0003ffffffffff67]
Mem abort info:
ESR = 0x0000000096000004
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x04: level 0 translation fault
Data abort info:
ISV = 0, ISS = 0x00000004
CM = 0, WnR = 0
swapper pgtable: 4k pages, 48-bit VAs, pgdp=000000020dfcc000
[ffffffffffffffec] pgd=0000000000000000, p4d=0000000000000000
Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 6324 Comm: syz.2.552 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/26/2026
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : ext4_ext_drop_refs fs/ext4/extents.c:119 [inline]
pc : ext4_free_ext_path+0x40/0xf4 fs/ext4/extents.c:128
lr : ext4_free_ext_path+0x24/0xf4 fs/ext4/extents.c:127
sp : ffff800021ab7550
x29: ffff800021ab7550 x28: 1ffff00004356edc x27: dfff800000000000
x26: ffff700004356eb8 x25: ffff800021ab76e4 x24: ffffffffffffffe4
x23: ffff0000e0ba5258 x22: dfff800000000000 x21: 0000000000000001
x20: 1ffff00004356ede x19: ffffffffffffffe4 x18: ffff800011b9bf60
x17: ffff80001835a000 x16: ffff8000082d92bc x15: ffff8000089f00b4
x14: 0000000000000001 x13: 1fffe0001c174a4b x12: 0000000000080000
x11: 0000000000016a6e x10: ffff8000263eb000 x9 : ffff800008d173c4
x8 : 0000000000000000 x7 : ffff80000805983c x6 : ffff800008059a4c
x5 : ffff0000e4b918d8 x4 : ffff800021ab7040 x3 : ffff8000082d27a8
x2 : 0000000000000001 x1 : 0000000000000008 x0 : ffffffffffffffec
Call trace:
ext4_ext_drop_refs fs/ext4/extents.c:119 [inline]
ext4_free_ext_path+0x40/0xf4 fs/ext4/extents.c:128
finish_range+0x200/0x2f8 fs/ext4/migrate.c:60
ext4_ext_migrate+0x8e4/0xc08 fs/ext4/migrate.c:544
__ext4_ioctl fs/ext4/ioctl.c:1399 [inline]
ext4_ioctl+0x1b04/0x4328 fs/ext4/ioctl.c:1617
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
Code: d343fc08 f2fbfff6 38f66908 35000508 (79401277)
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
0: d343fc08 lsr x8, x0, #3
4: f2fbfff6 movk x22, #0xdfff, lsl #48
8: 38f66908 ldrsb w8, [x8, x22]
c: 35000508 cbnz w8, 0xac
* 10: 79401277 ldrh w23, [x19, #8] <-- trapping instruction
---
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
Mar 25, 2026, 3:29:24 PM (3 days ago) Mar 25
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: c09fbcd31ae6 Linux 6.6.130
syzbot found the following issue on:
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1063506a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=c5b35c4db8465904
dashboard link: https://syzkaller.appspot.com/bug?extid=70d4ea98aacdba9554cd
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/58165bbf9941/disk-c09fbcd3.raw.xz
Downloadable assets:
vmlinux: https://storage.googleapis.com/syzbot-assets/73cbb84fb36b/vmlinux-c09fbcd3.xz
kernel image: https://storage.googleapis.com/syzbot-assets/744ea33ec44b/bzImage-c09fbcd3.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
ext4 filesystem being mounted at /204/file0aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa supports timestamps until 2038-01-19 (0x7fffffff)
BUG: unable to handle page fault for address: ffffffffffffffec
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD cf35067 P4D cf35067 PUD cf37067 PMD 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 9322 Comm: syz.1.845 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:ext4_ext_drop_refs fs/ext4/extents.c:119 [inline]
RIP: 0010:ext4_free_ext_path+0x45/0x110 fs/ext4/extents.c:128
Code: 85 db 0f 84 b0 00 00 00 49 bf 00 00 00 00 00 fc ff df 48 8d 7b 08 48 89 f8 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 a9 00 00 00 <0f> b7 43 08 c1 e0 04 48 8d 04 40 48 89 44 24 08 48 8d 43 28 48 89
RSP: 0018:ffffc9000c49f638 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffffffffffffe4 RCX: 0000000000080000
RDX: ffffc9000d1b9000 RSI: 000000000000aff8 RDI: ffffffffffffffec
RBP: ffffc9000c49f758 R08: ffff88807721dc1f R09: 1ffff1100ee43b83
R10: dffffc0000000000 R11: ffffed100ee43b84 R12: ffff88807721dcb0
R13: ffffffffffffffe4 R14: dffffc0000000000 R15: dffffc0000000000
FS: 00007f32f9ff06c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffec CR3: 00000000560f6000 CR4: 00000000003506f0
Call Trace:
<TASK>
finish_range+0x234/0x340 fs/ext4/migrate.c:60
update_extent_range fs/ext4/migrate.c:83 [inline]
update_ind_extent_range+0x2e3/0x520 fs/ext4/migrate.c:106
ext4_ext_migrate+0xb07/0x1080 fs/ext4/migrate.c:522
__ext4_ioctl fs/ext4/ioctl.c:1412 [inline]
ext4_ioctl+0x1ee3/0x3b80 fs/ext4/ioctl.c:1630
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:871 [inline]
__se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f32f919c799
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:00007f32f9ff0028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f32f9415fa0 RCX: 00007f32f919c799
RDX: 0000000000000000 RSI: 0000000000006609 RDI: 0000000000000004
RBP: 00007f32f9232c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f32f9416038 R14: 00007f32f9415fa0 R15: 00007fff6c17de68
</TASK>
Modules linked in:
CR2: ffffffffffffffec
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_ext_drop_refs fs/ext4/extents.c:119 [inline]
RIP: 0010:ext4_free_ext_path+0x45/0x110 fs/ext4/extents.c:128
Code: 85 db 0f 84 b0 00 00 00 49 bf 00 00 00 00 00 fc ff df 48 8d 7b 08 48 89 f8 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 a9 00 00 00 <0f> b7 43 08 c1 e0 04 48 8d 04 40 48 89 44 24 08 48 8d 43 28 48 89
RSP: 0018:ffffc9000c49f638 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffffffffffffe4 RCX: 0000000000080000
RDX: ffffc9000d1b9000 RSI: 000000000000aff8 RDI: ffffffffffffffec
RBP: ffffc9000c49f758 R08: ffff88807721dc1f R09: 1ffff1100ee43b83
R10: dffffc0000000000 R11: ffffed100ee43b84 R12: ffff88807721dcb0
R13: ffffffffffffffe4 R14: dffffc0000000000 R15: dffffc0000000000
FS: 00007f32f9ff06c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffec CR3: 00000000560f6000 CR4: 00000000003506f0
----------------
Code disassembly (best guess):
0: 85 db test %ebx,%ebx
Code disassembly (best guess):
2: 0f 84 b0 00 00 00 je 0xb8
8: 49 bf 00 00 00 00 00 movabs $0xdffffc0000000000,%r15
f: fc ff df
12: 48 8d 7b 08 lea 0x8(%rbx),%rdi
16: 48 89 f8 mov %rdi,%rax
19: 48 c1 e8 03 shr $0x3,%rax
1d: 42 0f b6 04 38 movzbl (%rax,%r15,1),%eax
22: 84 c0 test %al,%al
24: 0f 85 a9 00 00 00 jne 0xd3
* 2a: 0f b7 43 08 movzwl 0x8(%rbx),%eax <-- trapping instruction
2e: c1 e0 04 shl $0x4,%eax
31: 48 8d 04 40 lea (%rax,%rax,2),%rax
35: 48 89 44 24 08 mov %rax,0x8(%rsp)
3a: 48 8d 43 28 lea 0x28(%rbx),%rax
3e: 48 rex.W
3f: 89 .byte 0x89
syzbot
Mar 25, 2026, 3:38:22 PM (3 days ago) Mar 25
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following issue on:
HEAD commit: 1989cd3d56e2 Linux 6.1.167
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=12a57af6580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15a8eada580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/edd05d4d1a68/disk-1989cd3d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/bdc3181e838d/vmlinux-1989cd3d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a78aef5a3a25/Image-1989cd3d.gz.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/cea53140c34a/mount_0.gz
fsck result: OK (log: https://syzkaller.appspot.com/x/fsck.log?x=14bcd752580000)
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+261b23...@syzkaller.appspotmail.com
loop0: detected capacity change from 0 to 512
EXT4-fs (loop0): mounted filesystem without journal. Quota mode: writeback.
x29: ffff8000211b7550 x28: 1ffff00004236edc x27: dfff800000000000
x26: ffff700004236eb8 x25: ffff8000211b76e4 x24: ffffffffffffffe4
x23: ffff0000eaa75258 x22: dfff800000000000 x21: 0000000000000001
x20: 1ffff00004236ede x19: ffffffffffffffe4 x18: ffff800011b9bf60
x11: ff00800008d173c4 x10: 0000000000000000 x9 : ffff800008d173c4
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.
HEAD commit: 1989cd3d56e2 Linux 6.1.167
git tree: linux-6.1.y
kernel config: https://syzkaller.appspot.com/x/.config?x=b1adc0bfde2d8a4a
dashboard link: https://syzkaller.appspot.com/bug?extid=261b234ba5e4466cef19
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11a66a06580000
dashboard link: https://syzkaller.appspot.com/bug?extid=261b234ba5e4466cef19
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
userspace arch: arm64
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15a8eada580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/edd05d4d1a68/disk-1989cd3d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/bdc3181e838d/vmlinux-1989cd3d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a78aef5a3a25/Image-1989cd3d.gz.xz
fsck result: OK (log: https://syzkaller.appspot.com/x/fsck.log?x=14bcd752580000)
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+261b23...@syzkaller.appspotmail.com
EXT4-fs (loop0): mounted filesystem without journal. Quota mode: writeback.
Unable to handle kernel paging request at virtual address ffffffffffffffec
KASAN: maybe wild-memory-access in range [0x0003ffffffffff60-0x0003ffffffffff67]
Mem abort info:
ESR = 0x0000000096000004
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x04: level 0 translation fault
Data abort info:
ISV = 0, ISS = 0x00000004
CM = 0, WnR = 0
swapper pgtable: 4k pages, 48-bit VAs, pgdp=000000020dfcc000
[ffffffffffffffec] pgd=0000000000000000, p4d=0000000000000000
Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 4456 Comm: syz.0.17 Not tainted syzkaller #0
KASAN: maybe wild-memory-access in range [0x0003ffffffffff60-0x0003ffffffffff67]
Mem abort info:
ESR = 0x0000000096000004
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x04: level 0 translation fault
Data abort info:
ISV = 0, ISS = 0x00000004
CM = 0, WnR = 0
swapper pgtable: 4k pages, 48-bit VAs, pgdp=000000020dfcc000
[ffffffffffffffec] pgd=0000000000000000, p4d=0000000000000000
Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
Modules linked in:
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/26/2026
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : ext4_ext_drop_refs fs/ext4/extents.c:119 [inline]
pc : ext4_free_ext_path+0x40/0xf4 fs/ext4/extents.c:128
lr : ext4_free_ext_path+0x24/0xf4 fs/ext4/extents.c:127
sp : ffff8000211b7550
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : ext4_ext_drop_refs fs/ext4/extents.c:119 [inline]
pc : ext4_free_ext_path+0x40/0xf4 fs/ext4/extents.c:128
lr : ext4_free_ext_path+0x24/0xf4 fs/ext4/extents.c:127
x29: ffff8000211b7550 x28: 1ffff00004236edc x27: dfff800000000000
x26: ffff700004236eb8 x25: ffff8000211b76e4 x24: ffffffffffffffe4
x23: ffff0000eaa75258 x22: dfff800000000000 x21: 0000000000000001
x20: 1ffff00004236ede x19: ffffffffffffffe4 x18: ffff800011b9bf60
x17: ffff80001835a000 x16: ffff8000082d92bc x15: ffff8000089f00b4
x14: 0000000000000001 x13: 1fffe0001d54ea4b x12: 0000000000ff0100
x11: ff00800008d173c4 x10: 0000000000000000 x9 : ffff800008d173c4
x8 : 0000000000000000 x7 : ffff80000805983c x6 : ffff800008059a4c
x5 : ffff0000d1e15ee8 x4 : ffff8000211b7040 x3 : ffff8000082d27a8
#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
Mar 26, 2026, 9:47:34 PM (2 days ago) Mar 26
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following issue on:
HEAD commit: c09fbcd31ae6 Linux 6.6.130
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=10483752580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12058102580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/58165bbf9941/disk-c09fbcd3.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/73cbb84fb36b/vmlinux-c09fbcd3.xz
kernel image: https://storage.googleapis.com/syzbot-assets/744ea33ec44b/bzImage-c09fbcd3.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/b1980f7f02eb/mount_0.gz
fsck result: OK (log: https://syzkaller.appspot.com/x/fsck.log?x=1357efef980000)
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+70d4ea...@syzkaller.appspotmail.com
ext4 filesystem being mounted at /0/file0aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa supports timestamps until 2038-01-19 (0x7fffffff)
RAX: 0000000000000000 RBX: ffffffffffffffe4 RCX: ffff88802be73c00
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffffffffffec
RBP: ffffc900031c7758 R08: ffff88805e42661f R09: 1ffff1100bc84cc3
R10: dffffc0000000000 R11: ffffed100bc84cc4 R12: ffff88805e4266b0
RAX: ffffffffffffffda RBX: 00007f4596a15fa0 RCX: 00007f459679c799
RAX: 0000000000000000 RBX: ffffffffffffffe4 RCX: ffff88802be73c00
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffffffffffec
RBP: ffffc900031c7758 R08: ffff88805e42661f R09: 1ffff1100bc84cc3
R10: dffffc0000000000 R11: ffffed100bc84cc4 R12: ffff88805e4266b0
HEAD commit: c09fbcd31ae6 Linux 6.6.130
git tree: linux-6.6.y
kernel config: https://syzkaller.appspot.com/x/.config?x=c5b35c4db8465904
dashboard link: https://syzkaller.appspot.com/bug?extid=70d4ea98aacdba9554cd
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=17cade16580000
dashboard link: https://syzkaller.appspot.com/bug?extid=70d4ea98aacdba9554cd
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12058102580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/58165bbf9941/disk-c09fbcd3.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/73cbb84fb36b/vmlinux-c09fbcd3.xz
kernel image: https://storage.googleapis.com/syzbot-assets/744ea33ec44b/bzImage-c09fbcd3.xz
fsck result: OK (log: https://syzkaller.appspot.com/x/fsck.log?x=1357efef980000)
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+70d4ea...@syzkaller.appspotmail.com
BUG: unable to handle page fault for address: ffffffffffffffec
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD cf35067 P4D cf35067 PUD cf37067 PMD 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 5916 Comm: syz.0.17 Not tainted syzkaller #0
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD cf35067 P4D cf35067 PUD cf37067 PMD 0
Oops: 0000 [#1] PREEMPT SMP KASAN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:ext4_ext_drop_refs fs/ext4/extents.c:119 [inline]
RIP: 0010:ext4_free_ext_path+0x45/0x110 fs/ext4/extents.c:128
Code: 85 db 0f 84 b0 00 00 00 49 bf 00 00 00 00 00 fc ff df 48 8d 7b 08 48 89 f8 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 a9 00 00 00 <0f> b7 43 08 c1 e0 04 48 8d 04 40 48 89 44 24 08 48 8d 43 28 48 89
RSP: 0018:ffffc900031c7638 EFLAGS: 00010246
RIP: 0010:ext4_ext_drop_refs fs/ext4/extents.c:119 [inline]
RIP: 0010:ext4_free_ext_path+0x45/0x110 fs/ext4/extents.c:128
Code: 85 db 0f 84 b0 00 00 00 49 bf 00 00 00 00 00 fc ff df 48 8d 7b 08 48 89 f8 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 a9 00 00 00 <0f> b7 43 08 c1 e0 04 48 8d 04 40 48 89 44 24 08 48 8d 43 28 48 89
RAX: 0000000000000000 RBX: ffffffffffffffe4 RCX: ffff88802be73c00
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffffffffffec
RBP: ffffc900031c7758 R08: ffff88805e42661f R09: 1ffff1100bc84cc3
R10: dffffc0000000000 R11: ffffed100bc84cc4 R12: ffff88805e4266b0
R13: ffffffffffffffe4 R14: dffffc0000000000 R15: dffffc0000000000
FS: 0000555568d9c500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffec CR3: 000000005ecea000 CR4: 00000000003506f0
Call Trace:
<TASK>
finish_range+0x234/0x340 fs/ext4/migrate.c:60
update_extent_range fs/ext4/migrate.c:83 [inline]
update_ind_extent_range+0x2e3/0x520 fs/ext4/migrate.c:106
ext4_ext_migrate+0xb07/0x1080 fs/ext4/migrate.c:522
__ext4_ioctl fs/ext4/ioctl.c:1412 [inline]
ext4_ioctl+0x1ee3/0x3b80 fs/ext4/ioctl.c:1630
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:871 [inline]
__se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f459679c799
<TASK>
finish_range+0x234/0x340 fs/ext4/migrate.c:60
update_extent_range fs/ext4/migrate.c:83 [inline]
update_ind_extent_range+0x2e3/0x520 fs/ext4/migrate.c:106
ext4_ext_migrate+0xb07/0x1080 fs/ext4/migrate.c:522
__ext4_ioctl fs/ext4/ioctl.c:1412 [inline]
ext4_ioctl+0x1ee3/0x3b80 fs/ext4/ioctl.c:1630
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:871 [inline]
__se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
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:00007ffdd9827088 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f4596a15fa0 RCX: 00007f459679c799
RDX: 0000000000000000 RSI: 0000000000006609 RDI: 0000000000000004
RBP: 00007f4596832c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4596a15fac R14: 00007f4596a15fa0 R15: 00007f4596a15fa0
</TASK>
Modules linked in:
CR2: ffffffffffffffec
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_ext_drop_refs fs/ext4/extents.c:119 [inline]
RIP: 0010:ext4_free_ext_path+0x45/0x110 fs/ext4/extents.c:128
Code: 85 db 0f 84 b0 00 00 00 49 bf 00 00 00 00 00 fc ff df 48 8d 7b 08 48 89 f8 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 a9 00 00 00 <0f> b7 43 08 c1 e0 04 48 8d 04 40 48 89 44 24 08 48 8d 43 28 48 89
RSP: 0018:ffffc900031c7638 EFLAGS: 00010246
Modules linked in:
CR2: ffffffffffffffec
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_ext_drop_refs fs/ext4/extents.c:119 [inline]
RIP: 0010:ext4_free_ext_path+0x45/0x110 fs/ext4/extents.c:128
Code: 85 db 0f 84 b0 00 00 00 49 bf 00 00 00 00 00 fc ff df 48 8d 7b 08 48 89 f8 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 a9 00 00 00 <0f> b7 43 08 c1 e0 04 48 8d 04 40 48 89 44 24 08 48 8d 43 28 48 89
RAX: 0000000000000000 RBX: ffffffffffffffe4 RCX: ffff88802be73c00
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffffffffffec
RBP: ffffc900031c7758 R08: ffff88805e42661f R09: 1ffff1100bc84cc3
R10: dffffc0000000000 R11: ffffed100bc84cc4 R12: ffff88805e4266b0
R13: ffffffffffffffe4 R14: dffffc0000000000 R15: dffffc0000000000
FS: 0000555568d9c500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffec CR3: 000000005ecea000 CR4: 00000000003506f0
----------------
Code disassembly (best guess):
0: 85 db test %ebx,%ebx
2: 0f 84 b0 00 00 00 je 0xb8
8: 49 bf 00 00 00 00 00 movabs $0xdffffc0000000000,%r15
f: fc ff df
12: 48 8d 7b 08 lea 0x8(%rbx),%rdi
16: 48 89 f8 mov %rdi,%rax
19: 48 c1 e8 03 shr $0x3,%rax
1d: 42 0f b6 04 38 movzbl (%rax,%r15,1),%eax
22: 84 c0 test %al,%al
24: 0f 85 a9 00 00 00 jne 0xd3
* 2a: 0f b7 43 08 movzwl 0x8(%rbx),%eax <-- trapping instruction
2e: c1 e0 04 shl $0x4,%eax
31: 48 8d 04 40 lea (%rax,%rax,2),%rax
35: 48 89 44 24 08 mov %rax,0x8(%rsp)
3a: 48 8d 43 28 lea 0x28(%rbx),%rax
3e: 48 rex.W
3f: 89 .byte 0x89
---
Code disassembly (best guess):
0: 85 db test %ebx,%ebx
2: 0f 84 b0 00 00 00 je 0xb8
8: 49 bf 00 00 00 00 00 movabs $0xdffffc0000000000,%r15
f: fc ff df
12: 48 8d 7b 08 lea 0x8(%rbx),%rdi
16: 48 89 f8 mov %rdi,%rax
19: 48 c1 e8 03 shr $0x3,%rax
1d: 42 0f b6 04 38 movzbl (%rax,%r15,1),%eax
22: 84 c0 test %al,%al
24: 0f 85 a9 00 00 00 jne 0xd3
* 2a: 0f b7 43 08 movzwl 0x8(%rbx),%eax <-- trapping instruction
2e: c1 e0 04 shl $0x4,%eax
31: 48 8d 04 40 lea (%rax,%rax,2),%rax
35: 48 89 44 24 08 mov %rax,0x8(%rsp)
3a: 48 8d 43 28 lea 0x28(%rbx),%rax
3e: 48 rex.W
3f: 89 .byte 0x89
---
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