==================================================================
BUG: KASAN: slab-use-after-free in string_nocheck lib/vsprintf.c:645 [inline]
BUG: KASAN: slab-use-after-free in string+0x204/0x290 lib/vsprintf.c:727
Read of size 1 at addr ffff8880782a4cda by task udevd/5139

CPU: 0 PID: 5139 Comm: udevd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 string_nocheck lib/vsprintf.c:645 [inline]
 string+0x204/0x290 lib/vsprintf.c:727
 vsnprintf+0xf72/0x1ba0 lib/vsprintf.c:2823
 add_uevent_var+0x1d1/0x460 lib/kobject_uevent.c:680
 input_dev_uevent+0x16e/0xa20 drivers/input/input.c:1767
 dev_uevent+0x53a/0x7c0 drivers/base/core.c:2659
 uevent_show+0x196/0x300 drivers/base/core.c:2706
 dev_attr_show+0x54/0xc0 drivers/base/core.c:2379
 sysfs_kf_seq_show+0x34d/0x4c0 fs/sysfs/file.c:59
 seq_read_iter+0x464/0xc50 fs/seq_file.c:230
 call_read_iter include/linux/fs.h:2012 [inline]
 new_sync_read fs/read_write.c:389 [inline]
 vfs_read+0x486/0x990 fs/read_write.c:470
 ksys_read+0x151/0x260 fs/read_write.c:613
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7faf412a7407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffdee2edb20 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007faf419ec880 RCX: 00007faf412a7407
RDX: 0000000000001000 RSI: 0000561d116cba00 RDI: 000000000000000c
RBP: 00007faf413efff0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000000000000000a
R13: 00007faf413efea0 R14: 0000000000000000 R15: 0000561d116c97a0
 </TASK>

Allocated by task 5819:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 ____kasan_kmalloc mm/kasan/common.c:375 [inline]
 __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:384
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 sur40_probe+0x16d/0xf60 drivers/input/touchscreen/sur40.c:675
 usb_probe_interface+0x5c2/0xaf0 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x247/0xae0 drivers/base/dd.c:717
 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:879
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:909
 __device_attach_driver+0x2ca/0x510 drivers/base/dd.c:1037
 bus_for_each_drv+0x252/0x2e0 drivers/base/bus.c:459
 __device_attach+0x2c1/0x420 drivers/base/dd.c:1109
 bus_probe_device+0x180/0x260 drivers/base/bus.c:580
 device_add+0x87c/0xc40 drivers/base/core.c:3700
 usb_set_configuration+0x1ad0/0x2150 drivers/usb/core/message.c:2265
 usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:238
 usb_probe_device+0x12a/0x260 drivers/usb/core/driver.c:293
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x247/0xae0 drivers/base/dd.c:717
 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:879
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:909
 __device_attach_driver+0x2ca/0x510 drivers/base/dd.c:1037
 bus_for_each_drv+0x252/0x2e0 drivers/base/bus.c:459
 __device_attach+0x2c1/0x420 drivers/base/dd.c:1109
 bus_probe_device+0x180/0x260 drivers/base/bus.c:580
 device_add+0x87c/0xc40 drivers/base/core.c:3700
 usb_new_device+0x995/0x1550 drivers/usb/core/hub.c:2660
 hub_port_connect drivers/usb/core/hub.c:5529 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5669 [inline]
 port_event drivers/usb/core/hub.c:5833 [inline]
 hub_event+0x29d5/0x4a80 drivers/usb/core/hub.c:5915
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

Freed by task 5819:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x28/0x40 mm/kasan/generic.c:522
 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1811 [inline]
 slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837
 slab_free mm/slub.c:3830 [inline]
 __kmem_cache_free+0xba/0x1f0 mm/slub.c:3843
 sur40_probe+0x915/0xf60 drivers/input/touchscreen/sur40.c:816
 usb_probe_interface+0x5c2/0xaf0 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x247/0xae0 drivers/base/dd.c:717
 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:879
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:909
 __device_attach_driver+0x2ca/0x510 drivers/base/dd.c:1037
 bus_for_each_drv+0x252/0x2e0 drivers/base/bus.c:459
 __device_attach+0x2c1/0x420 drivers/base/dd.c:1109
 bus_probe_device+0x180/0x260 drivers/base/bus.c:580
 device_add+0x87c/0xc40 drivers/base/core.c:3700
 usb_set_configuration+0x1ad0/0x2150 drivers/usb/core/message.c:2265
 usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:238
 usb_probe_device+0x12a/0x260 drivers/usb/core/driver.c:293
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x247/0xae0 drivers/base/dd.c:717
 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:879
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:909
 __device_attach_driver+0x2ca/0x510 drivers/base/dd.c:1037
 bus_for_each_drv+0x252/0x2e0 drivers/base/bus.c:459
 __device_attach+0x2c1/0x420 drivers/base/dd.c:1109
 bus_probe_device+0x180/0x260 drivers/base/bus.c:580
 device_add+0x87c/0xc40 drivers/base/core.c:3700
 usb_new_device+0x995/0x1550 drivers/usb/core/hub.c:2660
 hub_port_connect drivers/usb/core/hub.c:5529 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5669 [inline]
 port_event drivers/usb/core/hub.c:5833 [inline]
 hub_event+0x29d5/0x4a80 drivers/usb/core/hub.c:5915
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

The buggy address belongs to the object at ffff8880782a4000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 3290 bytes inside of
 freed 4096-byte region [ffff8880782a4000, ffff8880782a5000)

The buggy address belongs to the physical page:
page:ffffea0001e0a800 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x782a0
head:ffffea0001e0a800 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888017c42140 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 5819, tgid 5819 (kworker/0:5), ts 90153919185, free_ts 89670153589
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1c1/0x200 mm/page_alloc.c:1582
 prep_new_page mm/page_alloc.c:1589 [inline]
 get_page_from_freelist+0x2181/0x22a0 mm/page_alloc.c:3221
 __alloc_pages+0x1f0/0x460 mm/page_alloc.c:4501
 alloc_slab_page+0x5d/0x180 mm/slub.c:1881
 allocate_slab mm/slub.c:2028 [inline]
 new_slab+0x87/0x2d0 mm/slub.c:2081
 ___slab_alloc+0xc5c/0x12f0 mm/slub.c:3253
 __slab_alloc mm/slub.c:3339 [inline]
 __slab_alloc_node mm/slub.c:3392 [inline]
 slab_alloc_node mm/slub.c:3485 [inline]
 __kmem_cache_alloc_node+0x11f/0x250 mm/slub.c:3534
 kmalloc_trace+0x2a/0xe0 mm/slab_common.c:1098
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 kobject_uevent_env+0x27c/0x890 lib/kobject_uevent.c:539
 wakeup_sysfs_add+0x46/0x50 drivers/base/power/sysfs.c:782
 device_set_wakeup_capable+0xe3/0x190 drivers/base/power/wakeup.c:485
 usb_set_configuration+0x18d4/0x2150 drivers/usb/core/message.c:2233
 usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:238
 usb_probe_device+0x12a/0x260 drivers/usb/core/driver.c:293
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x247/0xae0 drivers/base/dd.c:717
 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:879
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1182 [inline]
 free_unref_page_prepare+0x7d7/0x8f0 mm/page_alloc.c:2366
 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2459
 discard_slab mm/slub.c:2127 [inline]
 __unfreeze_partials+0x1cf/0x210 mm/slub.c:2667
 put_cpu_partial+0x17c/0x250 mm/slub.c:2743
 __slab_free+0x319/0x400 mm/slub.c:3700
 qlink_free mm/kasan/quarantine.c:166 [inline]
 qlist_free_all+0x75/0xd0 mm/kasan/quarantine.c:185
 kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:306
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook+0x6a/0x4d0 mm/slab.h:770
 slab_alloc_node mm/slub.c:3495 [inline]
 slab_alloc mm/slub.c:3503 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3510 [inline]
 kmem_cache_alloc+0x17e/0x2c0 mm/slub.c:3519
 ptlock_alloc+0x20/0x70 mm/memory.c:6177
 ptlock_init include/linux/mm.h:2964 [inline]
 pagetable_pte_ctor include/linux/mm.h:2987 [inline]
 __pte_alloc_one include/asm-generic/pgalloc.h:71 [inline]
 pte_alloc_one+0xcc/0x540 arch/x86/mm/pgtable.c:33
 __pte_alloc+0x22/0x2a0 mm/memory.c:438
 copy_pte_range mm/memory.c:1029 [inline]
 copy_pmd_range mm/memory.c:1168 [inline]
 copy_pud_range mm/memory.c:1205 [inline]
 copy_p4d_range mm/memory.c:1229 [inline]
 copy_page_range+0x2dca/0x3700 mm/memory.c:1323
 dup_mmap kernel/fork.c:769 [inline]
 dup_mm kernel/fork.c:1700 [inline]
 copy_mm+0x1751/0x1e30 kernel/fork.c:1749
 copy_process+0x16c9/0x3da0 kernel/fork.c:2510

Memory state around the buggy address:
 ffff8880782a4b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880782a4c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880782a4c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff8880782a4d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880782a4d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================