WARNING in snd_ctl_led_register

Status: fixed on 2025/05/06 15:33
Subsystems: sound
[Documentation on labels]
Reported-by: syzbot+4e7919b09c67ffd198ae@syzkaller.appspotmail.com
Fix commit: b2e538a9827d ALSA: control: Avoid WARN() for symlink errors
First crash: 597d, last: 597d
▶ ▼ Discussions (3)
Title Replies (including bot) Last reply
[PATCH 5.15.y] ALSA: control: Avoid WARN() for symlink errors 1 (1) 2026/03/09 07:21
[PATCH 6.1] ALSA: control: Avoid WARN() for symlink errors 1 (1) 2025/03/21 18:27
[syzbot] [sound?] WARNING in snd_ctl_led_register 0 (1) 2024/12/09 03:32

Sample crash report:
usb 5-1: Quirk or no altset; falling back to MIDI 1.0
FAULT_INJECTION: forcing a failure.
name failslab, interval 1, probability 0, space 0, times 1
CPU: 0 UID: 0 PID: 5314 Comm: syz.0.0 Not tainted 6.13.0-rc1-syzkaller-00025-gfeffde684ac2 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 fail_dump lib/fault-inject.c:53 [inline]
 should_fail_ex+0x3b0/0x4e0 lib/fault-inject.c:154
 should_failslab+0xac/0x100 mm/failslab.c:46
 slab_pre_alloc_hook mm/slub.c:4057 [inline]
 slab_alloc_node mm/slub.c:4133 [inline]
 __do_kmalloc_node mm/slub.c:4282 [inline]
 __kmalloc_node_track_caller_noprof+0xdc/0x4c0 mm/slub.c:4302
 __kmemdup_nul mm/util.c:61 [inline]
 kstrdup+0x39/0xb0 mm/util.c:81
 __kernfs_new_node+0x9d/0x870 fs/kernfs/dir.c:620
 kernfs_new_node+0x137/0x240 fs/kernfs/dir.c:700
 kernfs_create_link+0xa5/0x1f0 fs/kernfs/symlink.c:39
 sysfs_do_create_link_sd+0x85/0x110 fs/sysfs/symlink.c:44
 snd_ctl_led_sysfs_add sound/core/control_led.c:671 [inline]
 snd_ctl_led_register+0x5a2/0x8c0 sound/core/control_led.c:347
 snd_ctl_dev_register+0xcb/0x140 sound/core/control.c:2300
 __snd_device_register sound/core/device.c:149 [inline]
 snd_device_register_all+0xc9/0x1a0 sound/core/device.c:197
 snd_card_register+0x1d9/0x6e0 sound/core/init.c:895
 try_to_register_card+0x2f9/0x3d0 sound/usb/card.c:766
 usb_audio_probe+0x1ae2/0x2100 sound/usb/card.c:931
 usb_probe_interface+0x641/0xbb0 drivers/usb/core/driver.c:396
 really_probe+0x2b8/0xad0 drivers/base/dd.c:658
 __driver_probe_device+0x1a2/0x390 drivers/base/dd.c:800
 driver_probe_device+0x50/0x430 drivers/base/dd.c:830
 __device_attach_driver+0x2d6/0x530 drivers/base/dd.c:958
 bus_for_each_drv+0x24e/0x2e0 drivers/base/bus.c:459
 __device_attach+0x333/0x520 drivers/base/dd.c:1030
 proc_ioctl+0x463/0x650 drivers/usb/core/devio.c:2368
 usbdev_ioctl+0x2cf8/0x6120 drivers/usb/core/devio.c:2827
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8215d7ff19
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:00007f8216ad8058 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f8215f45fa0 RCX: 00007f8215d7ff19
RDX: 0000000020000200 RSI: 00000000c0105512 RDI: 0000000000000004
RBP: 00007f8216ad80a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
R13: 0000000000000000 R14: 00007f8215f45fa0 R15: 00007fff8889e228
 </TASK>
------------[ cut here ]------------
can't create symlink to controlC3 device
WARNING: CPU: 0 PID: 5314 at sound/core/control_led.c:672 snd_ctl_led_sysfs_add sound/core/control_led.c:671 [inline]
WARNING: CPU: 0 PID: 5314 at sound/core/control_led.c:672 snd_ctl_led_register+0x6b6/0x8c0 sound/core/control_led.c:347
Modules linked in:
CPU: 0 UID: 0 PID: 5314 Comm: syz.0.0 Not tainted 6.13.0-rc1-syzkaller-00025-gfeffde684ac2 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:snd_ctl_led_sysfs_add sound/core/control_led.c:671 [inline]
RIP: 0010:snd_ctl_led_register+0x6b6/0x8c0 sound/core/control_led.c:347
Code: b8 00 00 00 00 00 fc ff df 48 8b 4c 24 28 0f b6 04 01 84 c0 0f 85 01 01 00 00 41 8b 37 48 c7 c7 c0 76 00 8d e8 3b fc 0e f8 90 <0f> 0b 90 90 e9 fb fe ff ff e8 dc 54 4e f8 90 48 b8 00 00 00 00 00
RSP: 0018:ffffc9000d506ec0 EFLAGS: 00010246
RAX: 65b6d429077b2500 RBX: 00000000fffffff4 RCX: ffff888000a64880
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000d506fd0 R08: ffffffff81601c02 R09: fffffbfff1cfa210
R10: dffffc0000000000 R11: fffffbfff1cfa210 R12: ffff88801e30c1b0
R13: ffff888012157000 R14: 0000000000000001 R15: ffff88801e30c000
FS:  00007f8216ad86c0(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000557104264490 CR3: 0000000043c40000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 snd_ctl_dev_register+0xcb/0x140 sound/core/control.c:2300
 __snd_device_register sound/core/device.c:149 [inline]
 snd_device_register_all+0xc9/0x1a0 sound/core/device.c:197
 snd_card_register+0x1d9/0x6e0 sound/core/init.c:895
 try_to_register_card+0x2f9/0x3d0 sound/usb/card.c:766
 usb_audio_probe+0x1ae2/0x2100 sound/usb/card.c:931
 usb_probe_interface+0x641/0xbb0 drivers/usb/core/driver.c:396
 really_probe+0x2b8/0xad0 drivers/base/dd.c:658
 __driver_probe_device+0x1a2/0x390 drivers/base/dd.c:800
 driver_probe_device+0x50/0x430 drivers/base/dd.c:830
 __device_attach_driver+0x2d6/0x530 drivers/base/dd.c:958
 bus_for_each_drv+0x24e/0x2e0 drivers/base/bus.c:459
 __device_attach+0x333/0x520 drivers/base/dd.c:1030
 proc_ioctl+0x463/0x650 drivers/usb/core/devio.c:2368
 usbdev_ioctl+0x2cf8/0x6120 drivers/usb/core/devio.c:2827
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8215d7ff19
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:00007f8216ad8058 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f8215f45fa0 RCX: 00007f8215d7ff19
RDX: 0000000020000200 RSI: 00000000c0105512 RDI: 0000000000000004
RBP: 00007f8216ad80a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
R13: 0000000000000000 R14: 00007f8215f45fa0 R15: 00007fff8889e228
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/12/05 03:25 upstream feffde684ac2 29f61fce .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in snd_ctl_led_register
* Struck through repros no longer work on HEAD.