syzbot
KASAN: slab-use-after-free Read in bcmp
Status:
premoderation: reported C repro on 2026/10/12 20:33
Reported-by: syzbot+e4c4d98d5d99760b1526@syzkaller.appspotmail.com
First crash: 17h42m, last: 15h18m
Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in memcmp lib/string.c:683 [inline]
BUG: KASAN: slab-use-after-free in bcmp+0x214/0x240 lib/string.c:704
Read of size 1 at addr ffff888105f6e522 by task kworker/0:2/62
CPU: 0 UID: 0 PID: 62 Comm: kworker/0:2 Not tainted syzkaller #0 bc7b6724338d5534643cc89cfe391bc2161f9bdd
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: usb_hub_wq hub_event
Call Trace:
<TASK>
__dump_stack+0x21/0x30 lib/dump_stack.c:94
dump_stack_lvl+0x140/0x1c0 lib/dump_stack.c:120
print_address_description+0x71/0x210 mm/kasan/report.c:377
print_report+0x4a/0x70 mm/kasan/report.c:481
kasan_report+0x162/0x1a0 mm/kasan/report.c:594
__asan_report_load1_noabort+0x18/0x20 mm/kasan/report_generic.c:378
memcmp lib/string.c:683 [inline]
bcmp+0x214/0x240 lib/string.c:704
memcmp include/linux/fortify-string.h:715 [inline]
sony_check_add_dev_list drivers/hid/hid-sony.c:1723 [inline]
sony_check_add drivers/hid/hid-sony.c:1829 [inline]
sony_input_configured+0x2e0/0x3270 drivers/hid/hid-sony.c:1904
hidinput_connect+0x24a2/0x3290 drivers/hid/hid-input.c:2351
hid_connect+0x4a8/0x1c10 drivers/hid/hid-core.c:2294
hid_hw_start+0xcb/0x160 drivers/hid/hid-core.c:2409
sony_probe+0x236/0x5f0 drivers/hid/hid-sony.c:2102
__hid_device_probe drivers/hid/hid-core.c:2760 [inline]
hid_device_probe+0x2ce/0x5f0 drivers/hid/hid-core.c:2797
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x2e1/0x8b0 drivers/base/dd.c:657
__driver_probe_device+0x193/0x280 drivers/base/dd.c:799
driver_probe_device+0x54/0x3f0 drivers/base/dd.c:829
__device_attach_driver+0x2f1/0x4b0 drivers/base/dd.c:957
bus_for_each_drv+0x264/0x300 drivers/base/bus.c:459
__device_attach+0x2c4/0x3c0 drivers/base/dd.c:1029
device_initial_probe+0x1e/0x30 drivers/base/dd.c:1078
bus_probe_device+0x18b/0x270 drivers/base/bus.c:534
device_add+0x7fd/0xbf0 drivers/base/core.c:3692
hid_add_device+0x3c4/0x5a0 drivers/hid/hid-core.c:2943
usbhid_probe+0xdca/0x1310 drivers/hid/usbhid/hid-core.c:1451
usb_probe_interface+0x6ab/0xbf0 drivers/usb/core/driver.c:400
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x2e1/0x8b0 drivers/base/dd.c:657
__driver_probe_device+0x193/0x280 drivers/base/dd.c:799
driver_probe_device+0x54/0x3f0 drivers/base/dd.c:829
__device_attach_driver+0x2f1/0x4b0 drivers/base/dd.c:957
bus_for_each_drv+0x264/0x300 drivers/base/bus.c:459
__device_attach+0x2c4/0x3c0 drivers/base/dd.c:1029
device_initial_probe+0x1e/0x30 drivers/base/dd.c:1078
bus_probe_device+0x18b/0x270 drivers/base/bus.c:534
device_add+0x7fd/0xbf0 drivers/base/core.c:3692
usb_set_configuration+0x1aad/0x2080 drivers/usb/core/message.c:2268
usb_generic_driver_probe+0x95/0x160 drivers/usb/core/generic.c:254
usb_probe_device+0x1ef/0x3b0 drivers/usb/core/driver.c:295
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x2e1/0x8b0 drivers/base/dd.c:657
__driver_probe_device+0x193/0x280 drivers/base/dd.c:799
driver_probe_device+0x54/0x3f0 drivers/base/dd.c:829
__device_attach_driver+0x2f1/0x4b0 drivers/base/dd.c:957
bus_for_each_drv+0x264/0x300 drivers/base/bus.c:459
__device_attach+0x2c4/0x3c0 drivers/base/dd.c:1029
device_initial_probe+0x1e/0x30 drivers/base/dd.c:1078
bus_probe_device+0x18b/0x270 drivers/base/bus.c:534
device_add+0x7fd/0xbf0 drivers/base/core.c:3692
usb_new_device+0x98d/0x1500 drivers/usb/core/hub.c:2703
hub_port_connect drivers/usb/core/hub.c:5574 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5714 [inline]
port_event drivers/usb/core/hub.c:5878 [inline]
hub_event+0x2dbd/0x4360 drivers/usb/core/hub.c:5960
process_one_work kernel/workqueue.c:3273 [inline]
process_scheduled_works+0x7f7/0x1060 kernel/workqueue.c:3354
worker_thread+0xc99/0x13f0 kernel/workqueue.c:3435
kthread+0x2c7/0x360 kernel/kthread.c:389
ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
Allocated by task 10:
kasan_save_stack mm/kasan/common.c:49 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:70
kasan_save_alloc_info+0x3a/0x50 mm/kasan/generic.c:565
poison_kmalloc_redzone mm/kasan/common.c:379 [inline]
__kasan_kmalloc+0x96/0xb0 mm/kasan/common.c:396
kasan_kmalloc include/linux/kasan.h:261 [inline]
__do_kmalloc_node mm/slub.c:4395 [inline]
__kmalloc_node_track_caller_noprof+0x24e/0x4f0 mm/slub.c:4414
alloc_dr drivers/base/devres.c:119 [inline]
devm_kmalloc+0x79/0x250 drivers/base/devres.c:837
devm_kzalloc include/linux/device/devres.h:52 [inline]
sony_probe+0xfa/0x5f0 drivers/hid/hid-sony.c:2070
__hid_device_probe drivers/hid/hid-core.c:2760 [inline]
hid_device_probe+0x2ce/0x5f0 drivers/hid/hid-core.c:2797
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x2e1/0x8b0 drivers/base/dd.c:657
__driver_probe_device+0x193/0x280 drivers/base/dd.c:799
driver_probe_device+0x54/0x3f0 drivers/base/dd.c:829
__device_attach_driver+0x2f1/0x4b0 drivers/base/dd.c:957
bus_for_each_drv+0x264/0x300 drivers/base/bus.c:459
__device_attach+0x2c4/0x3c0 drivers/base/dd.c:1029
device_initial_probe+0x1e/0x30 drivers/base/dd.c:1078
bus_probe_device+0x18b/0x270 drivers/base/bus.c:534
device_add+0x7fd/0xbf0 drivers/base/core.c:3692
hid_add_device+0x3c4/0x5a0 drivers/hid/hid-core.c:2943
usbhid_probe+0xdca/0x1310 drivers/hid/usbhid/hid-core.c:1451
usb_probe_interface+0x6ab/0xbf0 drivers/usb/core/driver.c:400
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x2e1/0x8b0 drivers/base/dd.c:657
__driver_probe_device+0x193/0x280 drivers/base/dd.c:799
driver_probe_device+0x54/0x3f0 drivers/base/dd.c:829
__device_attach_driver+0x2f1/0x4b0 drivers/base/dd.c:957
bus_for_each_drv+0x264/0x300 drivers/base/bus.c:459
__device_attach+0x2c4/0x3c0 drivers/base/dd.c:1029
device_initial_probe+0x1e/0x30 drivers/base/dd.c:1078
bus_probe_device+0x18b/0x270 drivers/base/bus.c:534
device_add+0x7fd/0xbf0 drivers/base/core.c:3692
usb_set_configuration+0x1aad/0x2080 drivers/usb/core/message.c:2268
usb_generic_driver_probe+0x95/0x160 drivers/usb/core/generic.c:254
usb_probe_device+0x1ef/0x3b0 drivers/usb/core/driver.c:295
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x2e1/0x8b0 drivers/base/dd.c:657
__driver_probe_device+0x193/0x280 drivers/base/dd.c:799
driver_probe_device+0x54/0x3f0 drivers/base/dd.c:829
__device_attach_driver+0x2f1/0x4b0 drivers/base/dd.c:957
bus_for_each_drv+0x264/0x300 drivers/base/bus.c:459
__device_attach+0x2c4/0x3c0 drivers/base/dd.c:1029
device_initial_probe+0x1e/0x30 drivers/base/dd.c:1078
bus_probe_device+0x18b/0x270 drivers/base/bus.c:534
device_add+0x7fd/0xbf0 drivers/base/core.c:3692
usb_new_device+0x98d/0x1500 drivers/usb/core/hub.c:2703
hub_port_connect drivers/usb/core/hub.c:5574 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5714 [inline]
port_event drivers/usb/core/hub.c:5878 [inline]
hub_event+0x2dbd/0x4360 drivers/usb/core/hub.c:5960
process_one_work kernel/workqueue.c:3273 [inline]
process_scheduled_works+0x7f7/0x1060 kernel/workqueue.c:3354
worker_thread+0xc99/0x13f0 kernel/workqueue.c:3435
kthread+0x2c7/0x360 kernel/kthread.c:389
ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
Freed by task 10:
kasan_save_stack mm/kasan/common.c:49 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:70
kasan_save_free_info+0x44/0x50 mm/kasan/generic.c:579
poison_slab_object mm/kasan/common.c:249 [inline]
__kasan_slab_free+0x5f/0x80 mm/kasan/common.c:266
kasan_slab_free include/linux/kasan.h:234 [inline]
slab_free_hook mm/slub.c:2445 [inline]
slab_free mm/slub.c:4714 [inline]
kfree+0x158/0x440 mm/slub.c:4875
release_nodes drivers/base/devres.c:506 [inline]
devres_release_group+0x35c/0x4c0 drivers/base/devres.c:689
__hid_device_probe drivers/hid/hid-core.c:2776 [inline]
hid_device_probe+0x52f/0x5f0 drivers/hid/hid-core.c:2797
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x2e1/0x8b0 drivers/base/dd.c:657
__driver_probe_device+0x193/0x280 drivers/base/dd.c:799
driver_probe_device+0x54/0x3f0 drivers/base/dd.c:829
__device_attach_driver+0x2f1/0x4b0 drivers/base/dd.c:957
bus_for_each_drv+0x264/0x300 drivers/base/bus.c:459
__device_attach+0x2c4/0x3c0 drivers/base/dd.c:1029
device_initial_probe+0x1e/0x30 drivers/base/dd.c:1078
bus_probe_device+0x18b/0x270 drivers/base/bus.c:534
device_add+0x7fd/0xbf0 drivers/base/core.c:3692
hid_add_device+0x3c4/0x5a0 drivers/hid/hid-core.c:2943
usbhid_probe+0xdca/0x1310 drivers/hid/usbhid/hid-core.c:1451
usb_probe_interface+0x6ab/0xbf0 drivers/usb/core/driver.c:400
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x2e1/0x8b0 drivers/base/dd.c:657
__driver_probe_device+0x193/0x280 drivers/base/dd.c:799
driver_probe_device+0x54/0x3f0 drivers/base/dd.c:829
__device_attach_driver+0x2f1/0x4b0 drivers/base/dd.c:957
bus_for_each_drv+0x264/0x300 drivers/base/bus.c:459
__device_attach+0x2c4/0x3c0 drivers/base/dd.c:1029
device_initial_probe+0x1e/0x30 drivers/base/dd.c:1078
bus_probe_device+0x18b/0x270 drivers/base/bus.c:534
device_add+0x7fd/0xbf0 drivers/base/core.c:3692
usb_set_configuration+0x1aad/0x2080 drivers/usb/core/message.c:2268
usb_generic_driver_probe+0x95/0x160 drivers/usb/core/generic.c:254
usb_probe_device+0x1ef/0x3b0 drivers/usb/core/driver.c:295
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x2e1/0x8b0 drivers/base/dd.c:657
__driver_probe_device+0x193/0x280 drivers/base/dd.c:799
driver_probe_device+0x54/0x3f0 drivers/base/dd.c:829
__device_attach_driver+0x2f1/0x4b0 drivers/base/dd.c:957
bus_for_each_drv+0x264/0x300 drivers/base/bus.c:459
__device_attach+0x2c4/0x3c0 drivers/base/dd.c:1029
device_initial_probe+0x1e/0x30 drivers/base/dd.c:1078
bus_probe_device+0x18b/0x270 drivers/base/bus.c:534
device_add+0x7fd/0xbf0 drivers/base/core.c:3692
usb_new_device+0x98d/0x1500 drivers/usb/core/hub.c:2703
hub_port_connect drivers/usb/core/hub.c:5574 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5714 [inline]
port_event drivers/usb/core/hub.c:5878 [inline]
hub_event+0x2dbd/0x4360 drivers/usb/core/hub.c:5960
process_one_work kernel/workqueue.c:3273 [inline]
process_scheduled_works+0x7f7/0x1060 kernel/workqueue.c:3354
worker_thread+0xc99/0x13f0 kernel/workqueue.c:3435
kthread+0x2c7/0x360 kernel/kthread.c:389
ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
The buggy address belongs to the object at ffff888105f6e400
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 290 bytes inside of
freed 512-byte region [ffff888105f6e400, ffff888105f6e600)
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x105f6c
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x4000000000000040(head|zone=1)
page_type: f5(slab)
raw: 4000000000000040 ffff888100041c80 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000001f5000000 0000000000000000
head: 4000000000000040 ffff888100041c80 dead000000000100 dead000000000122
head: 0000000000000000 0000000000100010 00000001f5000000 0000000000000000
head: 4000000000000002 ffffea000417db01 ffffffffffffffff 0000000000000000
head: 0000000000000004 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd2000(__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 2820945366, free_ts 0
set_page_owner include/linux/page_owner.h:35 [inline]
post_alloc_hook+0x37d/0x3b0 mm/page_alloc.c:1864
prep_new_page+0x2d/0x180 mm/page_alloc.c:1872
get_page_from_freelist+0x4aea/0x4ba0 mm/page_alloc.c:3949
__alloc_pages_noprof+0x35a/0x7e0 mm/page_alloc.c:5316
alloc_slab_page+0x6b/0x1e0 mm/slub.c:-1
allocate_slab+0x69/0x430 mm/slub.c:2687
new_slab mm/slub.c:2741 [inline]
___slab_alloc+0x591/0x8c0 mm/slub.c:3934
__slab_alloc mm/slub.c:4025 [inline]
__slab_alloc_node mm/slub.c:4078 [inline]
slab_alloc_node mm/slub.c:4239 [inline]
__kmalloc_cache_noprof+0x2cd/0x470 mm/slub.c:4421
kmalloc_noprof include/linux/slab.h:882 [inline]
usb_cache_string+0x7b/0x2c0 drivers/usb/core/message.c:1086
usb_enumerate_device drivers/usb/core/hub.c:2548 [inline]
usb_new_device+0x336/0x1500 drivers/usb/core/hub.c:2673
register_root_hub+0x243/0x470 drivers/usb/core/hcd.c:992
usb_add_hcd+0xc8b/0x10a0 drivers/usb/core/hcd.c:2978
dummy_hcd_probe+0x14e/0x2a0 drivers/usb/gadget/udc/dummy_hcd.c:2708
platform_probe+0x17a/0x200 drivers/base/platform.c:1404
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x2e1/0x8b0 drivers/base/dd.c:657
__driver_probe_device+0x193/0x280 drivers/base/dd.c:799
page_owner free stack trace missing
Memory state around the buggy address:
ffff888105f6e400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888105f6e480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888105f6e500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888105f6e580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888105f6e600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
sony 0003:054C:042F.0002: can't set operational mode: step 3, ignoring
sony 0003:054C:042F.0002: No inputs registered, leaving
sony 0003:054C:042F.0002: hidraw0: USB HID v0.00 Joystick [HID 054c:042f] on usb-dummy_hcd.0-1/input0
sony 0003:054C:042F.0002: failed to claim input
usb 1-1: USB disconnect, device number 5
usb 1-1: new high-speed USB device number 6 using dummy_hcd
usb 1-1: config 0 interface 0 altsetting 12 endpoint 0x81 has an invalid bInterval 0, changing to 7
usb 1-1: config 0 interface 0 altsetting 12 endpoint 0x81 has invalid wMaxPacketSize 0
usb 1-1: config 0 interface 0 altsetting 12 has 1 endpoint descriptor, different from the interface descriptor's value: 2
usb 1-1: config 0 interface 0 has no altsetting 0
usb 1-1: New USB device found, idVendor=054c, idProduct=042f, bcdDevice= 0.00
usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
usb 1-1: config 0 descriptor??
sony 0003:054C:042F.0005: can't set operational mode: step 3, ignoring
sony 0003:054C:042F.0005: No inputs registered, leaving
sony 0003:054C:042F.0005: hidraw0: USB HID v0.00 Joystick [HID 054c:042f] on usb-dummy_hcd.0-1/input0
sony 0003:054C:042F.0005: failed to claim input
* Struck through repros no longer work on HEAD.