WARNING in usb_ep_enable

Status: upstream: reported C repro on 2026/07/31 17:13
Subsystems: usb
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+7b70c4a6021fd49c4151@syzkaller.appspotmail.com
First crash: 2d10h, last: 2h28m
Cause bisection: introduced by (bisect log) :
commit 973a57891608a98e894db2887f278777f564de18
Author: Chris Wulff <crwulff@gmail.com>
Date: Thu Jul 25 01:04:20 2024 +0000

  usb: gadget: core: Check for unset descriptor

Crash: WARNING in usb_ep_enable (log)
Repro: C syz .config
  
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
ee053112 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ✅ VMHostTrigger: ❌ WARNING in usb_ep_enable 2026/07/31 02:54 2026/07/31 02:54 2026/07/31 04:00 aaffb173

			
		
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [usb?] WARNING in usb_ep_enable 0 (2) 2026/07/31 22:55
Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 WARNING in usb_ep_enable origin:upstream -1 syz, C 25 18h44m 23h31m 0/3 upstream: reported C repro on 2026/07/31 20:18
android-6-12 WARNING in usb_ep_enable -1 syz, C 10 1d09h 2d06h 0/1 premoderation: reported C repro on 2026/07/30 13:40
linux-6.1 WARNING in usb_ep_enable -1 5 7h46m 10h44m 0/3 upstream: reported on 2026/08/01 09:05
linux-6.6 WARNING in usb_ep_enable -1 syz, C 10 44m 22h40m 0/2 upstream: reported C repro on 2026/07/31 21:09

Sample crash report:
------------[ cut here ]------------
usb_ep_enable: ep129 (ep1in-bulk) has maxpacket 0
WARNING: drivers/usb/gadget/udc/core.c:125 at usb_ep_enable+0x148/0x480 drivers/usb/gadget/udc/core.c:124, CPU#1: ktimers/1/29
Modules linked in:
CPU: 1 UID: 0 PID: 29 Comm: ktimers/1 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:usb_ep_enable+0x1bc/0x480 drivers/usb/gadget/udc/core.c:124
Code: 4a 17 02 fb 49 83 3f 00 48 c7 c0 60 b3 1f 8c 49 c7 c0 80 b3 1f 8c 4c 0f 44 c0 4c 89 f7 48 c7 c6 8b 42 b0 8d 44 89 ea 4c 89 e1 <67> 48 0f b9 3a bd ea ff ff ff 0f 1f 44 00 00 e8 40 a4 98 fa 65 8b
RSP: 0018:ffffc90000a3f6b8 EFLAGS: 00010282
RAX: ffffffff8c1fb360 RBX: ffff88802a08c120 RCX: ffffffff8c1fd1e0
RDX: 0000000000000081 RSI: ffffffff8db0428b RDI: ffffffff8fbc9d40
RBP: dffffc0000000000 R08: ffffffff8c1fb380 R09: 0000000000000100
R10: 0000000000000100 R11: 0000000000000003 R12: ffffffff8c1fd1e0
R13: 0000000000000081 R14: ffffffff8fbc9d40 R15: ffff88802a08c138
FS:  0000000000000000(0000) GS:ffff888125d41000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000563af0aa84a0 CR3: 00000000382cc000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 hidg_set_alt+0x12a/0xa50 drivers/usb/gadget/function/f_hid.c:1042
 set_config+0x749/0x1160 drivers/usb/gadget/composite.c:1018
 composite_setup+0x1de7/0x3480 drivers/usb/gadget/composite.c:1901
 configfs_composite_setup+0xbd/0x100 drivers/usb/gadget/configfs.c:1877
 dummy_timer+0x2f77/0x4d50 drivers/usb/gadget/udc/dummy_hcd.c:1951
 __run_hrtimer kernel/time/hrtimer.c:2032 [inline]
 __hrtimer_run_queues+0x3eb/0xaf0 kernel/time/hrtimer.c:2096
 hrtimer_run_softirq+0x18f/0x260 kernel/time/hrtimer.c:2113
 handle_softirqs+0x1d9/0x6c0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 run_ktimerd+0x69/0x100 kernel/softirq.c:1151
 smpboot_thread_fn+0x57c/0xa80 kernel/smpboot.c:160
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 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:	4a 17                	rex.WX (bad)
   2:	02 fb                	add    %bl,%bh
   4:	49 83 3f 00          	cmpq   $0x0,(%r15)
   8:	48 c7 c0 60 b3 1f 8c 	mov    $0xffffffff8c1fb360,%rax
   f:	49 c7 c0 80 b3 1f 8c 	mov    $0xffffffff8c1fb380,%r8
  16:	4c 0f 44 c0          	cmove  %rax,%r8
  1a:	4c 89 f7             	mov    %r14,%rdi
  1d:	48 c7 c6 8b 42 b0 8d 	mov    $0xffffffff8db0428b,%rsi
  24:	44 89 ea             	mov    %r13d,%edx
  27:	4c 89 e1             	mov    %r12,%rcx
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	bd ea ff ff ff       	mov    $0xffffffea,%ebp
  34:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
  39:	e8 40 a4 98 fa       	call   0xfa98a47e
  3e:	65                   	gs
  3f:	8b                   	.byte 0x8b

Crashes (45):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/30 17:05 upstream 11028ab62899 2377cd3d .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in usb_ep_enable
2026/07/30 15:18 upstream 11028ab62899 2377cd3d .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in usb_ep_enable
2026/08/01 15:22 upstream 0131b508c0e2 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING in usb_ep_enable
2026/08/01 13:02 upstream 0131b508c0e2 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root WARNING in usb_ep_enable
2026/08/01 09:24 upstream 0131b508c0e2 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in usb_ep_enable
2026/08/01 08:58 upstream 0131b508c0e2 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in usb_ep_enable
2026/08/01 08:57 upstream 0131b508c0e2 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in usb_ep_enable
2026/07/31 15:47 upstream 8ba098e6b6ff 7664cf44 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in usb_ep_enable
2026/07/30 15:51 upstream 11028ab62899 2377cd3d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in usb_ep_enable
2026/07/30 13:42 upstream 11028ab62899 2377cd3d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs WARNING in usb_ep_enable
2026/08/01 10:31 upstream a2cf4ef33184 e611ffe1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in usb_ep_enable
2026/07/31 20:20 upstream 8ba098e6b6ff 7664cf44 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in usb_ep_enable
2026/07/31 19:44 upstream 8ba098e6b6ff 7664cf44 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in usb_ep_enable
2026/07/31 19:28 upstream 8ba098e6b6ff 7664cf44 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in usb_ep_enable
2026/07/31 19:05 upstream 8ba098e6b6ff 7664cf44 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in usb_ep_enable
2026/07/31 17:33 upstream 8ba098e6b6ff 7664cf44 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in usb_ep_enable
2026/07/31 15:10 upstream 8ba098e6b6ff 7664cf44 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in usb_ep_enable
2026/07/31 14:02 upstream 8ba098e6b6ff 7664cf44 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in usb_ep_enable
2026/07/31 08:45 upstream e05b559f9cda aaffb173 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in usb_ep_enable
2026/07/31 08:45 upstream e05b559f9cda aaffb173 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in usb_ep_enable
2026/07/31 08:17 upstream e05b559f9cda aaffb173 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in usb_ep_enable
2026/07/31 07:51 upstream e05b559f9cda aaffb173 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in usb_ep_enable
2026/07/31 04:33 upstream e05b559f9cda aaffb173 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in usb_ep_enable
2026/07/31 04:19 upstream e05b559f9cda aaffb173 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in usb_ep_enable
2026/07/31 03:04 upstream e05b559f9cda aaffb173 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in usb_ep_enable
2026/07/30 22:11 upstream 11028ab62899 0a1bc234 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in usb_ep_enable
2026/07/30 18:16 upstream 11028ab62899 0a1bc234 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in usb_ep_enable
2026/07/30 09:46 upstream fc46aed51f62 2377cd3d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in usb_ep_enable
2026/08/01 01:42 upstream a2cf4ef33184 e611ffe1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in usb_ep_enable
2026/08/01 01:40 upstream a2cf4ef33184 e611ffe1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in usb_ep_enable
2026/07/30 13:54 upstream 11028ab62899 abc81b93 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in usb_ep_enable
2026/08/01 17:21 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci e2d5e23967d0 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in usb_ep_enable
2026/08/01 02:03 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci e2d5e23967d0 7664cf44 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in usb_ep_enable
2026/08/01 00:38 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci e2d5e23967d0 7664cf44 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in usb_ep_enable
2026/07/31 17:52 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 365f9c7a6b81 7664cf44 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in usb_ep_enable
2026/07/31 17:46 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 365f9c7a6b81 7664cf44 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in usb_ep_enable
2026/07/31 17:45 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 365f9c7a6b81 7664cf44 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in usb_ep_enable
2026/07/31 17:44 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 365f9c7a6b81 7664cf44 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in usb_ep_enable
2026/07/31 17:43 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 365f9c7a6b81 7664cf44 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in usb_ep_enable
2026/07/30 13:41 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 365f9c7a6b81 2377cd3d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in usb_ep_enable
2026/07/30 13:41 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 365f9c7a6b81 2377cd3d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in usb_ep_enable
2026/08/01 09:33 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master a2cf4ef33184 e611ffe1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte WARNING in usb_ep_enable
2026/08/01 09:11 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master a2cf4ef33184 e611ffe1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte WARNING in usb_ep_enable
* Struck through repros no longer work on HEAD.