syzbot


BUG: unable to handle kernel paging request in kernfs_remove_by_name_ns

Status: upstream: reported on 2025/08/04 08:38
Subsystems: kernfs
[Documentation on labels]
Reported-by: syzbot+4faa3fd832279bd35a81@syzkaller.appspotmail.com
First crash: 30d, last: 7h58m
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [kernfs?] BUG: unable to handle kernel paging request in kernfs_remove_by_name_ns 0 (1) 2025/08/04 08:38
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 KASAN: global-out-of-bounds Read in kernfs_remove_by_name_ns 17 1 8d00h 8d00h 0/2 upstream: reported on 2025/07/27 16:29

Sample crash report:
comedi comedi3: c6xdigio: I/O port conflict (0xcf7,3)
BUG: unable to handle page fault for address: ffffffff9ee57158
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD e387067 P4D e387067 PUD e388063 PMD 0 
Oops: Oops: 0000 [#1] SMP KASAN NOPTI
CPU: 1 UID: 0 PID: 8309 Comm: syz.5.701 Not tainted 6.16.0-rc7-syzkaller-00120-g5f33ebd2018c #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:variable_test_bit arch/x86/include/asm/bitops.h:227 [inline]
RIP: 0010:arch_test_bit arch/x86/include/asm/bitops.h:239 [inline]
RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:142 [inline]
RIP: 0010:__lock_acquire+0x46e/0x1c90 kernel/locking/lockdep.c:5210
Code: 78 5d 3f 03 0f b6 54 24 28 85 c0 74 10 44 8b 1d 48 0b 11 0f 45 85 db 0f 84 db 05 00 00 90 31 c9 e9 8a fe ff ff 48 63 44 24 10 <48> 0f a3 05 0a 5c 3e 14 0f 82 7b ff ff ff 90 e8 3e 5d 3f 03 85 c0
RSP: 0018:ffffc9000336f7a0 EFLAGS: 00010046
RAX: 00000000487561e4 RBX: 0000000000000003 RCX: 0000000000000008
RDX: 0000000000000000 RSI: ffff888029e02fa8 RDI: ffff888029e02440
RBP: ffff888029e02440 R08: ffffffff95d842a8 R09: 0000000000000001
R10: 0000000000000010 R11: 0000000000000005 R12: ffff888029e02f30
R13: ffff888029e02fa8 R14: 0000000000000003 R15: 0000000000000003
FS:  00007f603693a6c0(0000) GS:ffff8880d6820000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffff9ee57158 CR3: 000000006039a000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 lock_acquire kernel/locking/lockdep.c:5871 [inline]
 lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5828
 down_write+0x92/0x200 kernel/locking/rwsem.c:1577
 kernfs_remove_by_name_ns+0x3d/0x110 fs/kernfs/dir.c:1712
 sysfs_remove_file include/linux/sysfs.h:777 [inline]
 driver_remove_file drivers/base/driver.c:201 [inline]
 driver_remove_file+0x4a/0x60 drivers/base/driver.c:197
 remove_bind_files drivers/base/bus.c:605 [inline]
 bus_remove_driver+0x224/0x2c0 drivers/base/bus.c:743
 driver_unregister+0x76/0xb0 drivers/base/driver.c:277
 comedi_device_detach+0x13d/0x9e0 drivers/comedi/drivers.c:207
 comedi_device_attach+0x43d/0x900 drivers/comedi/drivers.c:1003
 do_devconfig_ioctl+0x1a7/0x580 drivers/comedi/comedi_fops.c:855
 comedi_unlocked_ioctl+0x165d/0x2f00 drivers/comedi/comedi_fops.c:2156
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl fs/ioctl.c:893 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6035b8e9a9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f603693a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f6035db5fa0 RCX: 00007f6035b8e9a9
RDX: 00002000000000c0 RSI: 0000000040946400 RDI: 0000000000000003
RBP: 00007f6035c10d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f6035db5fa0 R15: 00007ffe08e77888
 </TASK>
Modules linked in:
CR2: ffffffff9ee57158
---[ end trace 0000000000000000 ]---
RIP: 0010:variable_test_bit arch/x86/include/asm/bitops.h:227 [inline]
RIP: 0010:arch_test_bit arch/x86/include/asm/bitops.h:239 [inline]
RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:142 [inline]
RIP: 0010:__lock_acquire+0x46e/0x1c90 kernel/locking/lockdep.c:5210
Code: 78 5d 3f 03 0f b6 54 24 28 85 c0 74 10 44 8b 1d 48 0b 11 0f 45 85 db 0f 84 db 05 00 00 90 31 c9 e9 8a fe ff ff 48 63 44 24 10 <48> 0f a3 05 0a 5c 3e 14 0f 82 7b ff ff ff 90 e8 3e 5d 3f 03 85 c0
RSP: 0018:ffffc9000336f7a0 EFLAGS: 00010046
RAX: 00000000487561e4 RBX: 0000000000000003 RCX: 0000000000000008
RDX: 0000000000000000 RSI: ffff888029e02fa8 RDI: ffff888029e02440
RBP: ffff888029e02440 R08: ffffffff95d842a8 R09: 0000000000000001
R10: 0000000000000010 R11: 0000000000000005 R12: ffff888029e02f30
R13: ffff888029e02fa8 R14: 0000000000000003 R15: 0000000000000003
FS:  00007f603693a6c0(0000) GS:ffff8880d6820000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffff9ee57158 CR3: 000000006039a000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess), 3 bytes skipped:
   0:	03 0f                	add    (%rdi),%ecx
   2:	b6 54                	mov    $0x54,%dh
   4:	24 28                	and    $0x28,%al
   6:	85 c0                	test   %eax,%eax
   8:	74 10                	je     0x1a
   a:	44 8b 1d 48 0b 11 0f 	mov    0xf110b48(%rip),%r11d        # 0xf110b59
  11:	45 85 db             	test   %r11d,%r11d
  14:	0f 84 db 05 00 00    	je     0x5f5
  1a:	90                   	nop
  1b:	31 c9                	xor    %ecx,%ecx
  1d:	e9 8a fe ff ff       	jmp    0xfffffeac
  22:	48 63 44 24 10       	movslq 0x10(%rsp),%rax
* 27:	48 0f a3 05 0a 5c 3e 	bt     %rax,0x143e5c0a(%rip)        # 0x143e5c39 <-- trapping instruction
  2e:	14
  2f:	0f 82 7b ff ff ff    	jb     0xffffffb0
  35:	90                   	nop
  36:	e8 3e 5d 3f 03       	call   0x33f5d79
  3b:	85 c0                	test   %eax,%eax

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/26 05:34 upstream 5f33ebd2018c fb8f743d .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream BUG: unable to handle kernel paging request in kernfs_remove_by_name_ns
2025/07/05 10:31 linux-next 26ffb3d6f02c 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce BUG: unable to handle kernel paging request in kernfs_remove_by_name_ns
2025/07/24 10:04 upstream 01a412d06bc5 0c1d6ded .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root general protection fault in kernfs_remove_by_name_ns
2025/07/17 08:38 upstream e2291551827f 44f8051e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root general protection fault in kernfs_remove_by_name_ns
2025/08/04 08:37 linux-next 5c5a10f0be96 7368264b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in kernfs_remove_by_name_ns
* Struck through repros no longer work on HEAD.