WARNING: proc registration bug in unregister_irq_proc (2)

Status: upstream: reported C repro on 2026/07/25 22:42
Subsystems: kernel
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+690d666eb12fca6e1e61@syzkaller.appspotmail.com
Fix commit: 790ea6844593 comedi: comedi_parport: validate the IRQ supplied by userspace
Patched on: [ci-qemu-gce-upstream-auto ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-qemu2-riscv64 ci-snapshot-upstream-root ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-linux-next-kasan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci-upstream-rust-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce ci2-upstream-usb], missing on: [ci-qemu-native-arm64-kvm ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root]
First crash: 150d, last: 12d
▶ ▼ ✨ AI Jobs (8)
ID Workflow Result Correct Bug Created Started Finished Revision
941d060b repro-c Reproduced: ✅ ❓ WARNING: proc registration bug in unregister_irq_proc (2) 2026/08/26 14:01 2026/08/26 14:57 2026/08/26 15:48 a2b77b9e
fe8774b5 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ✅ VMHostTrigger: ❌ ❓ WARNING: proc registration bug in unregister_irq_proc (2) 2026/08/13 00:36 2026/08/13 00:36 2026/08/13 01:19 a56bc0a5
54735bc9 assessment-security 💥 WARNING: proc registration bug in unregister_irq_proc (2) 2026/07/14 00:21 2026/07/14 00:21 2026/07/14 00:21 2130f682
3e50fb3d assessment-security 💥 WARNING: proc registration bug in unregister_irq_proc (2) 2026/06/27 01:50 2026/06/27 01:50 2026/06/27 01:50 7ff32d8b
6e86188c assessment-security 💥 WARNING: proc registration bug in unregister_irq_proc (2) 2026/06/18 09:32 2026/06/18 09:32 2026/06/18 09:32 b62b3ded
49b8cbcf assessment-security 💥 WARNING: proc registration bug in unregister_irq_proc (2) 2026/06/14 00:05 2026/06/14 00:05 2026/06/14 00:05 4f06757f
7d265d24 assessment-security 💥 WARNING: proc registration bug in unregister_irq_proc (2) 2026/06/12 00:03 2026/06/12 00:03 2026/06/12 00:03 d93a6ab6
a26d5efa assessment-security 💥 WARNING: proc registration bug in unregister_irq_proc (2) 2026/06/10 06:13 2026/06/10 06:13 2026/06/10 06:13 34dab4be
▶ ▼ Discussions (3)
Title Replies (including bot) Last reply
[PATCH 1/6] comedi: comedi_parport: validate the IRQ supplied by userspace 1 (1) 2026/09/09 10:48
[PATCH 0/6] comedi: validate the IRQ numbers supplied by userspace 1 (1) 2026/09/09 10:48
[syzbot] [kernel?] WARNING: proc registration bug in unregister_irq_proc (2) 4 (6) 2026/08/26 17:01
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING: proc registration bug in unregister_irq_proc kernel -1 1 285d 281d 0/29 auto-obsoleted due to no activity on 2026/04/25 11:10
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2026/08/26 16:16 12m nogikh@google.com git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 818bebeb63dd6bf5f4e07e145f6cdbace520a34c report job log log

Sample crash report:
------------[ cut here ]------------
remove_proc_entry: removing non-empty directory 'irq/17', leaking at least 'comedi_parport'
WARNING: fs/proc/generic.c:747 at remove_proc_entry+0x4e7/0x610 fs/proc/generic.c:747, CPU#0: syz-executor143/6008
Modules linked in:
CPU: 0 UID: 0 PID: 6008 Comm: syz-executor143 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:remove_proc_entry+0x4f5/0x610 fs/proc/generic.c:747
Code: 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 c7 00 00 00 48 8d 3d 39 b7 88 0e 49 8b 95 d0 00 00 00 48 c7 c6 80 39 0b 8c <67> 48 0f b9 3a e9 2a fe ff ff e8 4c 2b 4a ff 48 8d 7d 18 48 b8 00
RSP: 0018:ffffc900032af7b8 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: dffffc0000000000 RCX: ffff88803dac74dc
RDX: ffff88801cb025dc RSI: ffffffff8c0b3980 RDI: ffffffff91498da0
RBP: ffff88803dac74b8 R08: ffff88802b20f75c R09: ffffed1007b58e83
R10: ffff88803dac741b R11: 0000000000000000 R12: ffff88803dac7400
R13: ffff88801cb02500 R14: ffff88802b20f738 R15: dffffc0000000000
FS:  000055558ac37400(0000) GS:ffff8880d5ba2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007efe6b5a6130 CR3: 000000002bb43000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 unregister_irq_proc+0x206/0x2a0 kernel/irq/proc.c:406
 free_desc+0x89/0x330 kernel/irq/irqdesc.c:482
 irq_free_descs kernel/irq/irqdesc.c:874 [inline]
 irq_free_descs+0x84/0xc0 kernel/irq/irqdesc.c:865
 irq_domain_free_irqs+0x46a/0x5c0 kernel/irq/irqdomain.c:1919
 mp_unmap_irq+0xf8/0x130 arch/x86/kernel/apic/io_apic.c:1061
 acpi_unregister_gsi_ioapic+0x40/0x60 arch/x86/kernel/acpi/boot.c:722
 acpi_unregister_gsi+0x25/0x40 arch/x86/kernel/acpi/boot.c:751
 acpi_pci_irq_disable+0x275/0x360 drivers/acpi/pci_irq.c:517
 pcibios_disable_device arch/x86/pci/common.c:706 [inline]
 pcibios_disable_device+0x89/0xb0 arch/x86/pci/common.c:703
 do_pci_disable_device+0x9f/0x100 drivers/pci/pci.c:2192
 pci_disable_device+0x130/0x270 drivers/pci/pci.c:2228
 enable_store+0x219/0x260 drivers/pci/pci-sysfs.c:342
 dev_attr_store+0x58/0x80 drivers/base/core.c:2509
 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145
 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6af/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8d19fda9f7
Code: 48 89 fa 4c 89 df e8 98 1d 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffff688d7b0 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000055558ac37400 RCX: 00007f8d19fda9f7
RDX: 0000000000000002 RSI: 00007f8d1a0120f4 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007f8d1a012129
R13: 00007f8d1a014458 R14: 00007f8d1a0120f4 R15: 0000000000000015
 </TASK>
----------------
Code disassembly (best guess):
   0:	00 fc                	add    %bh,%ah
   2:	ff                   	lcall  (bad)
   3:	df 48 89             	fisttps -0x77(%rax)
   6:	fa                   	cli
   7:	48 c1 ea 03          	shr    $0x3,%rdx
   b:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   f:	0f 85 c7 00 00 00    	jne    0xdc
  15:	48 8d 3d 39 b7 88 0e 	lea    0xe88b739(%rip),%rdi        # 0xe88b755
  1c:	49 8b 95 d0 00 00 00 	mov    0xd0(%r13),%rdx
  23:	48 c7 c6 80 39 0b 8c 	mov    $0xffffffff8c0b3980,%rsi
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	e9 2a fe ff ff       	jmp    0xfffffe5e
  34:	e8 4c 2b 4a ff       	call   0xff4a2b85
  39:	48 8d 7d 18          	lea    0x18(%rbp),%rdi
  3d:	48                   	rex.W
  3e:	b8                   	.byte 0xb8

Crashes (138):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/26 17:00 git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 818bebeb63dd 4a865b71 .config console log report C ci-qemu-upstream WARNING: proc registration bug in unregister_irq_proc
2026/10/24 23:52 upstream 5b0764a53235 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: proc registration bug in unregister_irq_proc
2026/10/24 22:38 upstream 5b0764a53235 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: proc registration bug in unregister_irq_proc
2026/10/24 21:22 upstream 5b0764a53235 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: proc registration bug in unregister_irq_proc
2026/10/24 18:03 upstream 5b0764a53235 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: proc registration bug in unregister_irq_proc
2026/10/24 16:56 upstream 5b0764a53235 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: proc registration bug in unregister_irq_proc
2026/10/24 14:06 upstream 4da9dedf3fc5 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: proc registration bug in unregister_irq_proc
2026/10/24 08:07 upstream 4da9dedf3fc5 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: proc registration bug in unregister_irq_proc
2026/10/24 02:54 upstream 4da9dedf3fc5 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: proc registration bug in unregister_irq_proc
2026/10/23 22:53 upstream 734bef548a96 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: proc registration bug in unregister_irq_proc
2026/10/23 20:28 upstream 734bef548a96 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: proc registration bug in unregister_irq_proc
2026/10/23 18:53 upstream 734bef548a96 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: proc registration bug in unregister_irq_proc
2026/10/23 17:01 upstream 734bef548a96 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: proc registration bug in unregister_irq_proc
2026/10/23 14:44 upstream 734bef548a96 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: proc registration bug in unregister_irq_proc
2026/10/23 07:19 upstream 3ac032ef6ca8 d566bfda .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: proc registration bug in unregister_irq_proc
2026/10/21 06:22 upstream 4cbdd58dfa7a 61c200c7 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: proc registration bug in unregister_irq_proc
2026/10/20 13:58 upstream f47d223627f8 df8746fb .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: proc registration bug in unregister_irq_proc
2026/07/28 17:42 upstream 62cc90241548 4a865b71 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: proc registration bug in unregister_irq_proc
2026/07/25 22:41 upstream 3dab139d4795 4a865b71 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING: proc registration bug in unregister_irq_proc
2026/10/25 03:50 upstream 5b0764a53235 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/25 01:21 upstream 5b0764a53235 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/24 05:05 upstream 4da9dedf3fc5 1d9ca40b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/23 02:16 upstream 3ac032ef6ca8 d566bfda .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/22 02:21 upstream 4df4d2a577db 4ba27f85 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/21 11:05 upstream 4cbdd58dfa7a 61c200c7 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/21 02:10 upstream 4cbdd58dfa7a 61c200c7 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/20 18:06 upstream f47d223627f8 df8746fb .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/20 06:18 upstream c03c1a14507d 21286ae2 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/20 04:48 upstream c03c1a14507d 21286ae2 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/19 08:35 upstream a0ff06b3a7bd 432c0077 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/19 06:55 upstream a0ff06b3a7bd 432c0077 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/19 05:20 upstream a0ff06b3a7bd 432c0077 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/19 03:15 upstream a0ff06b3a7bd 432c0077 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/17 11:23 upstream 70dd4ee72eb2 432c0077 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/17 09:56 upstream 70dd4ee72eb2 432c0077 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/17 07:55 upstream 70dd4ee72eb2 432c0077 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/15 09:42 upstream 0fcb05b72344 8fb0ae89 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/14 11:06 upstream 4056b3c9d3c9 1a71827b .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/13 18:08 upstream 24a19b953e2a 5a1eeac4 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/13 04:53 upstream 24a19b953e2a 745a967f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/12 23:43 upstream 24a19b953e2a 745a967f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/12 20:53 upstream 24a19b953e2a 745a967f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/10 23:46 upstream 3857c2fe5449 4f92358f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/10 21:23 upstream 3857c2fe5449 4f92358f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/10 11:37 upstream 3857c2fe5449 4f92358f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/10 07:48 upstream 3857c2fe5449 4f92358f .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/06 12:41 upstream 2c3418fffa9d f7710056 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/10/03 21:56 upstream e767a4ea70a3 57bbd979 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/09/29 04:32 upstream 72d3fcf802c4 58f15308 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
2026/06/09 04:11 upstream 2d3090a8aeb5 656e94c6 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING: proc registration bug in unregister_irq_proc
* Struck through repros no longer work on HEAD.