syzbot


WARNING: refcount bug in dev_deactivate_many

Status: upstream: reported on 2026/04/01 02:50
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+1bd67523d909320dd9e2@syzkaller.appspotmail.com
First crash: 214d, last: 4d16h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [net?] WARNING: refcount bug in dev_deactivate_many 0 (1) 2026/04/01 02:50
Last patch testing requests (1)
Created Duration User Patch Repo Result
2025/12/10 05:43 17m retest repro https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing OK log

Sample crash report:
------------[ cut here ]------------
refcount_t: decrement hit 0; leaking memory.
WARNING: lib/refcount.c:31 at refcount_warn_saturate+0x7c/0x130 lib/refcount.c:31, CPU#0: kworker/u8:5/93
Modules linked in:
CPU: 0 UID: 0 PID: 93 Comm: kworker/u8:5 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: events_unbound linkwatch_event
RIP: 0010:refcount_warn_saturate+0x7c/0x130 lib/refcount.c:31
Code: c0 51 1a 8c e8 25 17 12 fd 83 fd 02 0f 84 a1 00 00 00 76 27 83 fd 03 74 7d 83 fd 04 75 3e e8 fb 1b 12 fd 48 8d 3d b4 57 ed 0b <67> 48 0f b9 3a e8 ea 1b 12 fd 5b 5d c3 cc cc cc cc 85 ed 74 3a e8
RSP: 0018:ffffc9000215f878 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff88802a98c664 RCX: ffffffff84f6dbcb
RDX: ffff88801e7924c0 RSI: ffffffff84f6dbe5 RDI: ffffffff90e433a0
RBP: 0000000000000004 R08: 0000000000000005 R09: 0000000000000004
R10: 0000000000000004 R11: 0000000000000000 R12: 1ffff9200042bf14
R13: ffff88802a98c664 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88812433c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2ff15ff8 CR3: 000000003954a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __refcount_dec include/linux/refcount.h:461 [inline]
 refcount_dec include/linux/refcount.h:476 [inline]
 ref_tracker_free+0x5cd/0x6c0 lib/ref_tracker.c:303
 netdev_tracker_free include/linux/netdevice.h:4456 [inline]
 netdev_put include/linux/netdevice.h:4473 [inline]
 netdev_put include/linux/netdevice.h:4469 [inline]
 netdev_watchdog_down net/sched/sch_generic.c:575 [inline]
 dev_deactivate_many+0x28f/0xfc0 net/sched/sch_generic.c:1337
 dev_deactivate+0xf8/0x1c0 net/sched/sch_generic.c:1368
 linkwatch_do_dev net/core/link_watch.c:184 [inline]
 linkwatch_do_dev+0xce/0x110 net/core/link_watch.c:166
 __linkwatch_run_queue+0x3a9/0x900 net/core/link_watch.c:240
 linkwatch_event+0x8f/0xc0 net/core/link_watch.c:314
 process_one_work+0xa23/0x19a0 kernel/workqueue.c:3276
 process_scheduled_works kernel/workqueue.c:3359 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3440
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
----------------
Code disassembly (best guess):
   0:	c0 51 1a 8c          	rclb   $0x8c,0x1a(%rcx)
   4:	e8 25 17 12 fd       	call   0xfd12172e
   9:	83 fd 02             	cmp    $0x2,%ebp
   c:	0f 84 a1 00 00 00    	je     0xb3
  12:	76 27                	jbe    0x3b
  14:	83 fd 03             	cmp    $0x3,%ebp
  17:	74 7d                	je     0x96
  19:	83 fd 04             	cmp    $0x4,%ebp
  1c:	75 3e                	jne    0x5c
  1e:	e8 fb 1b 12 fd       	call   0xfd121c1e
  23:	48 8d 3d b4 57 ed 0b 	lea    0xbed57b4(%rip),%rdi        # 0xbed57de
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	e8 ea 1b 12 fd       	call   0xfd121c1e
  34:	5b                   	pop    %rbx
  35:	5d                   	pop    %rbp
  36:	c3                   	ret
  37:	cc                   	int3
  38:	cc                   	int3
  39:	cc                   	int3
  3a:	cc                   	int3
  3b:	85 ed                	test   %ebp,%ebp
  3d:	74 3a                	je     0x79
  3f:	e8                   	.byte 0xe8

Crashes (135):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/30 10:02 upstream f242ac4a0944 356bdfc9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING: refcount bug in dev_deactivate_many
2026/05/15 00:10 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing e18b0dbb6ec6 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/14 17:08 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing e18b0dbb6ec6 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/14 02:33 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing e18b0dbb6ec6 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/13 01:43 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing e18b0dbb6ec6 a0949470 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/12 15:23 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing e18b0dbb6ec6 07aeade5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/12 11:47 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing e18b0dbb6ec6 07aeade5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/11 20:08 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing e18b0dbb6ec6 d168f260 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/11 11:54 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing e18b0dbb6ec6 845acb1c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/11 04:06 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 25bd55f46032 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/11 01:20 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 25bd55f46032 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/09 23:15 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 25bd55f46032 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/09 22:07 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 25bd55f46032 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/09 20:52 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 25bd55f46032 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/09 17:24 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 25bd55f46032 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/09 07:13 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 25bd55f46032 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/08 03:05 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 25bd55f46032 5633175a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/07 19:07 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 25bd55f46032 cbf9e0fc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/07 09:12 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 25bd55f46032 f250db59 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/07 08:09 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 25bd55f46032 f250db59 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/06 12:15 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 25bd55f46032 1dddfd3d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/06 10:30 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 25bd55f46032 26da2c66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/04 11:23 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 25bd55f46032 85f1bcf2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/04 04:42 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 25bd55f46032 a0d91488 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/03 22:08 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 25bd55f46032 a0d91488 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/02 23:15 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 25bd55f46032 a0d91488 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/02 10:53 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 25bd55f46032 a0d91488 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/05/01 04:56 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 25bd55f46032 753c55b9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/04/29 23:16 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 25bd55f46032 005438fc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/04/29 00:37 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 25bd55f46032 95008c03 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/04/26 18:11 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 27d128c1cff6 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/04/26 16:32 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 27d128c1cff6 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/04/26 03:08 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 27d128c1cff6 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/04/25 06:19 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 2e6803928193 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/04/25 05:57 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 2e6803928193 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/04/24 21:56 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 2e6803928193 1c2b9291 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/04/24 12:58 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 2e6803928193 1c2b9291 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/04/24 05:42 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 2e6803928193 9cfb3ca7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/04/23 21:14 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 2e6803928193 4c3406dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/04/23 19:19 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 2e6803928193 4c3406dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/04/23 14:57 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 2e6803928193 4c3406dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/04/23 02:38 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 6596a02b2078 b10da5ec .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/04/22 17:56 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 6596a02b2078 4595e353 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/04/21 23:06 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing c1f49dea2b8f 0b6ab7ec .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/04/20 22:03 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing c1f49dea2b8f e65da4ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/04/20 20:39 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing c1f49dea2b8f e65da4ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2026/04/19 14:20 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 87117347a0e7 303e2802 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
2025/11/25 09:38 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 955a48a5353f 64219f15 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-upstream-usb WARNING: refcount bug in dev_deactivate_many
* Struck through repros no longer work on HEAD.