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BUG: unable to handle kernel paging request in ext4_free_ext_path

Status: upstream: reported C repro on 2026/03/25 19:29
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+70d4ea98aacdba9554cd@syzkaller.appspotmail.com
First crash: 76d, last: 16h53m
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2026/03/27 linux-6.6.y (ToT) c09fbcd31ae6 C [report] BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/03/27 upstream (ToT) 46b513250491 C Didn't crash
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-6-1 BUG: unable to handle kernel paging request in ext4_free_ext_path origin:lts 8 C 33 18d 42d 0/2 upstream: reported C repro on 2026/04/28 04:07
linux-6.1 BUG: unable to handle kernel paging request in ext4_free_ext_path 8 C error 7 76d 76d 0/3 upstream: reported C repro on 2026/03/25 14:06
▶ ▼ Fix bisection attempts (2)
Created Duration User Patch Repo Result
2026/05/27 19:26 23m fix candidate upstream error job log
2026/03/29 14:30 1m fix candidate upstream error job log

Sample crash report:
syz.0.17[5920]: memfd_create() called without MFD_EXEC or MFD_NOEXEC_SEAL set
loop0: detected capacity change from 0 to 128
EXT4-fs (loop0): mounted filesystem 76b65be2-f6da-4727-8c75-0525a5b65a09 r/w without journal. Quota mode: none.
ext4 filesystem being mounted at /0/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: 5920 Comm: syz.0.17 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:ffffc900020af638 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffffffffffffe4 RCX: ffff88802b548000
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffffffffffec
RBP: ffffc900020af758 R08: ffff88805e93821f R09: 1ffff1100bd27043
R10: dffffc0000000000 R11: ffffed100bd27044 R12: ffff88805e9382b0
R13: ffffffffffffffe4 R14: dffffc0000000000 R15: dffffc0000000000
FS:  000055557ab4e500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffec CR3: 0000000030129000 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: 0033:0x7f87ab99c799
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:00007fff647e3a48 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f87abc15fa0 RCX: 00007f87ab99c799
RDX: 0000000000000000 RSI: 0000000000006609 RDI: 0000000000000004
RBP: 00007f87aba32c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f87abc15fac R14: 00007f87abc15fa0 R15: 00007f87abc15fa0
 </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:ffffc900020af638 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffffffffffffe4 RCX: ffff88802b548000
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffffffffffec
RBP: ffffc900020af758 R08: ffff88805e93821f R09: 1ffff1100bd27043
R10: dffffc0000000000 R11: ffffed100bd27044 R12: ffff88805e9382b0
R13: ffffffffffffffe4 R14: dffffc0000000000 R15: dffffc0000000000
FS:  000055557ab4e500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffec CR3: 0000000030129000 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

Crashes (103):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/27 02:28 linux-6.6.y c09fbcd31ae6 766b6434 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/03/27 01:46 linux-6.6.y c09fbcd31ae6 766b6434 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/06/09 09:30 linux-6.6.y 924b4a879cbb 656e94c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/06/08 00:10 linux-6.6.y 924b4a879cbb cc095639 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/06/07 23:49 linux-6.6.y 924b4a879cbb cc095639 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/06/07 13:31 linux-6.6.y 924b4a879cbb cc095639 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/06/06 06:21 linux-6.6.y 924b4a879cbb cc095639 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/06/05 08:36 linux-6.6.y 924b4a879cbb 197909be .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/06/04 00:01 linux-6.6.y 924b4a879cbb 234057e5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/06/03 11:19 linux-6.6.y 924b4a879cbb 3c0d2131 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/06/03 07:54 linux-6.6.y 924b4a879cbb 3c0d2131 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/06/02 21:48 linux-6.6.y 924b4a879cbb 62fe1528 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/06/02 05:21 linux-6.6.y 924b4a879cbb 1095583b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/30 18:24 linux-6.6.y 0a40c6fbd105 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/29 20:04 linux-6.6.y 0a40c6fbd105 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/27 19:59 linux-6.6.y 0a40c6fbd105 8777bdc3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/27 05:56 linux-6.6.y 0a40c6fbd105 2b01f00e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/25 03:16 linux-6.6.y 0a40c6fbd105 c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/24 02:20 linux-6.6.y 0a40c6fbd105 c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/20 20:55 linux-6.6.y eac8889a3a1c 62fb93a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/17 10:44 linux-6.6.y 4d922539ad7d de5aae85 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/17 10:43 linux-6.6.y 4d922539ad7d de5aae85 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/17 04:10 linux-6.6.y 4d922539ad7d de5aae85 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/16 17:15 linux-6.6.y 4d922539ad7d a15a64a6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/15 06:30 linux-6.6.y 3b9f64db0496 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/14 20:17 linux-6.6.y 3b9f64db0496 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/12 04:53 linux-6.6.y 3b9f64db0496 d168f260 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/12 03:44 linux-6.6.y 3b9f64db0496 d168f260 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/11 13:46 linux-6.6.y 3b9f64db0496 845acb1c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/07 23:46 linux-6.6.y 258cf62a6dfd cbf9e0fc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/07 08:35 linux-6.6.y 258cf62a6dfd f250db59 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/07 08:35 linux-6.6.y 258cf62a6dfd f250db59 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/07 08:34 linux-6.6.y 258cf62a6dfd f250db59 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/05 04:45 linux-6.6.y 258cf62a6dfd a898ba9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/05 04:45 linux-6.6.y 258cf62a6dfd a898ba9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/02 02:39 linux-6.6.y 258cf62a6dfd 753c55b9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/02 02:39 linux-6.6.y 258cf62a6dfd 753c55b9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/02 02:27 linux-6.6.y 258cf62a6dfd 753c55b9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/02 02:24 linux-6.6.y 258cf62a6dfd 753c55b9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/01 23:00 linux-6.6.y 258cf62a6dfd 753c55b9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/05/01 12:23 linux-6.6.y 258cf62a6dfd 753c55b9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/04/30 08:43 linux-6.6.y 142cd8382222 005438fc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/04/30 08:41 linux-6.6.y 142cd8382222 005438fc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/04/29 18:54 linux-6.6.y 142cd8382222 7ca9e4d8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/04/29 18:54 linux-6.6.y 142cd8382222 7ca9e4d8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
2026/03/25 19:28 linux-6.6.y c09fbcd31ae6 8ee77f7d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan BUG: unable to handle kernel paging request in ext4_free_ext_path
* Struck through repros no longer work on HEAD.