KASAN: slab-use-after-free Read in k90_backlight_work

Status: upstream: reported on 2026/08/28 15:14
Subsystems: input usb
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+abcedffc9201f2bb66c2@syzkaller.appspotmail.com
First crash: 6d09h, last: 2h35m
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
8afba160 assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ KASAN: slab-use-after-free Read in k90_backlight_work 2026/08/26 00:01 2026/08/26 00:01 2026/08/26 00:42 ee98d2fd
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [input?] [usb?] KASAN: slab-use-after-free Read in k90_backlight_work 0 (1) 2026/08/28 15:14

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in k90_backlight_work+0x174/0x1c0 drivers/hid/hid-corsair.c:209
Read of size 1 at addr ffff88803d363300 by task kworker/1:4/5703

CPU: 1 UID: 0 PID: 5703 Comm: kworker/1:4 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events k90_backlight_work
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 k90_backlight_work+0x174/0x1c0 drivers/hid/hid-corsair.c:209
 process_one_work kernel/workqueue.c:3387 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3470
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3551
 kthread+0x38b/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>

Allocated by task 36:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x3d5/0x680 mm/slub.c:5563
 _kmalloc_noprof include/linux/slab.h:991 [inline]
 _kzalloc_noprof include/linux/slab.h:1312 [inline]
 k90_init_backlight drivers/hid/hid-corsair.c:430 [inline]
 corsair_probe+0x627/0xbc0 drivers/hid/hid-corsair.c:589
 __hid_device_probe drivers/hid/hid-core.c:2839 [inline]
 hid_device_probe+0x46a/0x870 drivers/hid/hid-core.c:2878
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x254/0xae0 drivers/base/dd.c:706
 __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:898
 __device_attach_driver+0x270/0x410 drivers/base/dd.c:1026
 bus_for_each_drv+0x25b/0x2f0 drivers/base/bus.c:500
 __device_attach+0x2c7/0x450 drivers/base/dd.c:1098
 device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1153
 bus_probe_device+0x12d/0x220 drivers/base/bus.c:620
 device_add+0x7d7/0xb80 drivers/base/core.c:3776
 hid_add_device+0x272/0x3e0 drivers/hid/hid-core.c:3065
 usbhid_probe+0x9dc/0xde0 drivers/hid/usbhid/hid-core.c:1452
 usb_probe_interface+0x788/0xe50 drivers/usb/core/driver.c:399
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x254/0xae0 drivers/base/dd.c:706
 __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:898
 __device_attach_driver+0x270/0x410 drivers/base/dd.c:1026
 bus_for_each_drv+0x25b/0x2f0 drivers/base/bus.c:500
 __device_attach+0x2c7/0x450 drivers/base/dd.c:1098
 device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1153
 bus_probe_device+0x12d/0x220 drivers/base/bus.c:620
 device_add+0x7d7/0xb80 drivers/base/core.c:3776
 usb_set_configuration+0x1ad8/0x2180 drivers/usb/core/message.c:2268
 usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:250
 usb_probe_device+0x1c3/0x3b0 drivers/usb/core/driver.c:293
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x254/0xae0 drivers/base/dd.c:706
 __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:898
 __device_attach_driver+0x270/0x410 drivers/base/dd.c:1026
 bus_for_each_drv+0x25b/0x2f0 drivers/base/bus.c:500
 __device_attach+0x2c7/0x450 drivers/base/dd.c:1098
 device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1153
 bus_probe_device+0x12d/0x220 drivers/base/bus.c:620
 device_add+0x7d7/0xb80 drivers/base/core.c:3776
 usb_new_device+0x99a/0x1680 drivers/usb/core/hub.c:2708
 hub_port_connect drivers/usb/core/hub.c:5580 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5720 [inline]
 port_event drivers/usb/core/hub.c:5884 [inline]
 hub_event+0x28cf/0x4cf0 drivers/usb/core/hub.c:5966
 process_one_work kernel/workqueue.c:3387 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3470
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3551
 kthread+0x38b/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

Freed by task 36:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2748 [inline]
 slab_free mm/slub.c:6499 [inline]
 kfree+0x1c5/0x6d0 mm/slub.c:6792
 hid_device_remove+0xc8/0x1d0 drivers/hid/hid-core.c:2897
 device_remove drivers/base/dd.c:616 [inline]
 __device_release_driver drivers/base/dd.c:1349 [inline]
 device_release_driver_internal+0x48b/0x880 drivers/base/dd.c:1372
 bus_remove_device+0x449/0x560 drivers/base/bus.c:664
 device_del+0x528/0x8f0 drivers/base/core.c:3965
 hid_remove_device drivers/hid/hid-core.c:3126 [inline]
 hid_destroy_device+0x6b/0x1b0 drivers/hid/hid-core.c:3148
 usbhid_disconnect+0x9f/0xc0 drivers/hid/usbhid/hid-core.c:1479
 usb_unbind_interface+0x295/0x9f0 drivers/usb/core/driver.c:461
 device_remove drivers/base/dd.c:618 [inline]
 __device_release_driver drivers/base/dd.c:1349 [inline]
 device_release_driver_internal+0x4f5/0x880 drivers/base/dd.c:1372
 bus_remove_device+0x449/0x560 drivers/base/bus.c:664
 device_del+0x528/0x8f0 drivers/base/core.c:3965
 usb_disable_device+0x3d4/0x8d0 drivers/usb/core/message.c:1478
 usb_disconnect+0x32d/0x990 drivers/usb/core/hub.c:2350
 hub_port_connect drivers/usb/core/hub.c:5420 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5720 [inline]
 port_event drivers/usb/core/hub.c:5884 [inline]
 hub_event+0x1bb7/0x4cf0 drivers/usb/core/hub.c:5966
 process_one_work kernel/workqueue.c:3387 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3470
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3551
 kthread+0x38b/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

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
 insert_work+0x3d/0x330 kernel/workqueue.c:2272
 __queue_work+0xd4b/0x1120 kernel/workqueue.c:2448
 queue_work_on+0x106/0x1d0 kernel/workqueue.c:2501
 led_classdev_unregister+0x113/0x270 drivers/leds/led-class.c:632
 k90_cleanup_backlight drivers/hid/hid-corsair.c:528 [inline]
 corsair_remove+0x1a4/0x260 drivers/hid/hid-corsair.c:603
 hid_device_remove+0xc8/0x1d0 drivers/hid/hid-core.c:2897
 device_remove drivers/base/dd.c:616 [inline]
 __device_release_driver drivers/base/dd.c:1349 [inline]
 device_release_driver_internal+0x48b/0x880 drivers/base/dd.c:1372
 bus_remove_device+0x449/0x560 drivers/base/bus.c:664
 device_del+0x528/0x8f0 drivers/base/core.c:3965
 hid_remove_device drivers/hid/hid-core.c:3126 [inline]
 hid_destroy_device+0x6b/0x1b0 drivers/hid/hid-core.c:3148
 usbhid_disconnect+0x9f/0xc0 drivers/hid/usbhid/hid-core.c:1479
 usb_unbind_interface+0x295/0x9f0 drivers/usb/core/driver.c:461
 device_remove drivers/base/dd.c:618 [inline]
 __device_release_driver drivers/base/dd.c:1349 [inline]
 device_release_driver_internal+0x4f5/0x880 drivers/base/dd.c:1372
 bus_remove_device+0x449/0x560 drivers/base/bus.c:664
 device_del+0x528/0x8f0 drivers/base/core.c:3965
 usb_disable_device+0x3d4/0x8d0 drivers/usb/core/message.c:1478
 usb_disconnect+0x32d/0x990 drivers/usb/core/hub.c:2350
 hub_port_connect drivers/usb/core/hub.c:5420 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5720 [inline]
 port_event drivers/usb/core/hub.c:5884 [inline]
 hub_event+0x1bb7/0x4cf0 drivers/usb/core/hub.c:5966
 process_one_work kernel/workqueue.c:3387 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3470
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3551
 kthread+0x38b/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

The buggy address belongs to the object at ffff88803d363000
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 768 bytes inside of
 freed 1024-byte region [ffff88803d363000, ffff88803d363400)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3d360
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff88813ffbbdc0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 0080000000000040 ffff88813ffbbdc0 dead000000000100 dead000000000122
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 0080000000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 48, tgid 48 (kworker/u8:2), ts 137696787447
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1871
 prep_new_page mm/page_alloc.c:1879 [inline]
 get_page_from_freelist+0x2591/0x2600 mm/page_alloc.c:3943
 __alloc_frozen_pages_noprof+0x230/0x5c0 mm/page_alloc.c:5436
 alloc_slab_page mm/slub.c:3347 [inline]
 allocate_slab+0x7d/0x620 mm/slub.c:3462
 new_slab mm/slub.c:3513 [inline]
 refill_objects+0x2d8/0x350 mm/slub.c:7410
 refill_sheaf mm/slub.c:2885 [inline]
 __pcs_replace_empty_main+0x339/0x690 mm/slub.c:4774
 alloc_from_pcs mm/slub.c:4850 [inline]
 slab_alloc_node mm/slub.c:4984 [inline]
 __do_kmalloc_node mm/slub.c:5413 [inline]
 __kmalloc_noprof+0x54b/0x790 mm/slub.c:5439
 _kmalloc_noprof include/linux/slab.h:995 [inline]
 _kzalloc_noprof include/linux/slab.h:1312 [inline]
 ieee802_11_parse_elems_full+0x14b/0x2de0 net/mac80211/parse.c:1071
 ieee802_11_parse_elems net/mac80211/ieee80211_i.h:2548 [inline]
 ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1542 [inline]
 ieee80211_ibss_rx_queued_mgmt+0x509/0x2c40 net/mac80211/ibss.c:1573
 ieee80211_iface_process_skb net/mac80211/iface.c:1769 [inline]
 ieee80211_iface_work+0x78a/0x1010 net/mac80211/iface.c:1823
 cfg80211_wiphy_work+0x29e/0x420 net/wireless/core.c:541
 process_one_work kernel/workqueue.c:3387 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3470
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3551
 kthread+0x38b/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
page last free pid 5593 tgid 5593 ts 137632538587 stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 __free_pages_prepare mm/page_alloc.c:1418 [inline]
 __free_frozen_pages+0xf8e/0x1070 mm/page_alloc.c:2962
 __slab_free+0x250/0x2a0 mm/slub.c:5815
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4683 [inline]
 slab_alloc_node mm/slub.c:4996 [inline]
 __do_kmalloc_node mm/slub.c:5413 [inline]
 __kmalloc_noprof+0x3b9/0x790 mm/slub.c:5439
 _kmalloc_noprof include/linux/slab.h:995 [inline]
 tomoyo_realpath_from_path+0xef/0x640 security/tomoyo/realpath.c:251
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_number_perm+0x246/0x5f0 security/tomoyo/file.c:728
 security_file_ioctl+0xc3/0x2a0 security/security.c:2512
 __do_sys_ioctl fs/ioctl.c:591 [inline]
 __se_sys_ioctl+0x47/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88803d363200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88803d363280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88803d363300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff88803d363380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88803d363400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (10):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/30 21:30 upstream a23cbb05744b 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: slab-use-after-free Read in k90_backlight_work
2026/08/27 07:48 upstream 73e3f0710014 a2b77b9e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: slab-use-after-free Read in k90_backlight_work
2026/08/25 10:35 upstream 66498c75b4f8 614e416a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: slab-use-after-free Read in k90_backlight_work
2026/08/25 03:50 upstream 66498c75b4f8 23caa175 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: slab-use-after-free Read in k90_backlight_work
2026/08/25 03:46 upstream 66498c75b4f8 23caa175 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: slab-use-after-free Read in k90_backlight_work
2026/08/24 21:00 upstream 0a0d1d55dad5 23caa175 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: slab-use-after-free Read in k90_backlight_work
2026/08/24 16:39 upstream 0a0d1d55dad5 23caa175 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: slab-use-after-free Read in k90_backlight_work
2026/08/24 15:05 upstream 0a0d1d55dad5 23caa175 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: slab-use-after-free Read in k90_backlight_work
2026/08/24 18:22 upstream 0a0d1d55dad5 23caa175 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 KASAN: slab-use-after-free Read in k90_backlight_work
2026/08/26 23:35 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 45c13f3f9e3b a2b77b9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb KASAN: slab-use-after-free Read in k90_backlight_work
* Struck through repros no longer work on HEAD.