==================================================================
BUG: KASAN: slab-use-after-free in __list_del_entry_valid_or_report+0x84/0x130 lib/list_debug.c:62
Read of size 8 at addr ffff888079687070 by task syz.0.76/6193

CPU: 1 PID: 6193 Comm: syz.0.76 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
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
 __list_del_entry_valid_or_report+0x84/0x130 lib/list_debug.c:62
 __list_del_entry_valid include/linux/list.h:124 [inline]
 __list_del_entry include/linux/list.h:222 [inline]
 list_del include/linux/list.h:236 [inline]
 roccat_release+0xd2/0x370 drivers/hid/hid-roccat.c:228
 __fput+0x221/0x940 fs/file_table.c:418
 task_work_run+0x1d4/0x260 kernel/task_work.c:245
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:180
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:213
 __syscall_exit_to_user_mode_work kernel/entry/common.c:294 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:305
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb5b519f559
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd0d8d7af8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffd0d8d7be0 RCX: 00007fb5b519f559
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 000000000001e175 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b2f820000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb5b5425fac R14: 00007fb5b5425fa8 R15: 00007fb5b5425fa0
 </TASK>

Allocated by task 972:
 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]
 roccat_connect+0x5d/0x490 drivers/hid/hid-roccat.c:315
 savu_init_specials drivers/hid/hid-roccat-savu.c:84 [inline]
 savu_probe+0x18e/0x330 drivers/hid/hid-roccat-savu.c:134
 __hid_device_probe drivers/hid/hid-core.c:2714 [inline]
 hid_device_probe+0x283/0x5b0 drivers/hid/hid-core.c:2753
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x24a/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:3768
 hid_add_device+0x365/0x500 drivers/hid/hid-core.c:2899
 usbhid_probe+0xe43/0x1260 drivers/hid/usbhid/hid-core.c:1448
 usb_probe_interface+0x6eb/0xcf0 drivers/usb/core/driver.c:395
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x24a/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:3768
 usb_set_configuration+0x1bad/0x2220 drivers/usb/core/message.c:2271
 usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:238
 usb_probe_device+0x12a/0x260 drivers/usb/core/driver.c:291
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x24a/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:3768
 usb_new_device+0x995/0x1550 drivers/usb/core/hub.c:2670
 hub_port_connect drivers/usb/core/hub.c:5539 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5679 [inline]
 port_event drivers/usb/core/hub.c:5843 [inline]
 hub_event+0x29d5/0x4a80 drivers/usb/core/hub.c:5925
 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 42:
 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:1833 [inline]
 slab_free_freelist_hook+0x154/0x240 mm/slub.c:1859
 slab_free mm/slub.c:3853 [inline]
 __kmem_cache_free+0xba/0x1f0 mm/slub.c:3866
 savu_remove_specials drivers/hid/hid-roccat-savu.c:110 [inline]
 savu_remove+0xe9/0x160 drivers/hid/hid-roccat-savu.c:150
 hid_device_remove+0xbe/0x1c0 drivers/hid/hid-core.c:2772
 device_remove drivers/base/dd.c:626 [inline]
 __device_release_driver drivers/base/dd.c:1351 [inline]
 device_release_driver_internal+0x408/0x6f0 drivers/base/dd.c:1374
 bus_remove_device+0x43b/0x520 drivers/base/bus.c:624
 device_del+0x51f/0x910 drivers/base/core.c:3957
 hid_remove_device drivers/hid/hid-core.c:2950 [inline]
 hid_destroy_device+0x6a/0x100 drivers/hid/hid-core.c:2970
 usbhid_disconnect+0x9f/0xc0 drivers/hid/usbhid/hid-core.c:1475
 usb_unbind_interface+0x204/0x870 drivers/usb/core/driver.c:457
 device_remove drivers/base/dd.c:628 [inline]
 __device_release_driver drivers/base/dd.c:1351 [inline]
 device_release_driver_internal+0x458/0x6f0 drivers/base/dd.c:1374
 bus_remove_device+0x43b/0x520 drivers/base/bus.c:624
 device_del+0x51f/0x910 drivers/base/core.c:3957
 usb_disable_device+0x3ee/0x8a0 drivers/usb/core/message.c:1480
 usb_disconnect+0x340/0x8a0 drivers/usb/core/hub.c:2325
 hub_port_connect drivers/usb/core/hub.c:5379 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5679 [inline]
 port_event drivers/usb/core/hub.c:5843 [inline]
 hub_event+0x1d69/0x4a80 drivers/usb/core/hub.c:5925
 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 ffff888079687000
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 112 bytes inside of
 freed 1024-byte region [ffff888079687000, ffff888079687400)

The buggy address belongs to the physical page:
page:ffffea0001e5a000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x79680
head:ffffea0001e5a000 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 ffff888018c41dc0 ffffea0001e5a800 dead000000000002
raw: 0000000000000000 0000000000100010 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5813, tgid 5813 (syz-executor), ts 81758269419, free_ts 80652234880
 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:1903
 allocate_slab mm/slub.c:2050 [inline]
 new_slab+0x87/0x2d0 mm/slub.c:2103
 ___slab_alloc+0xc5c/0x12f0 mm/slub.c:3275
 __slab_alloc mm/slub.c:3361 [inline]
 __slab_alloc_node mm/slub.c:3414 [inline]
 slab_alloc_node mm/slub.c:3508 [inline]
 __kmem_cache_alloc_node+0x122/0x260 mm/slub.c:3557
 kmalloc_trace+0x2a/0xe0 mm/slab_common.c:1098
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 fqdir_init+0x5a/0x180 net/ipv4/inet_fragment.c:191
 nf_ct_net_init+0x3b/0x2b0 net/ipv6/netfilter/nf_conntrack_reasm.c:511
 ops_init+0x391/0x640 net/core/net_namespace.c:139
 setup_net+0x3b6/0xa20 net/core/net_namespace.c:343
 copy_net_ns+0x361/0x530 net/core/net_namespace.c:524
 create_new_namespaces+0x3ce/0x700 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x11a/0x160 kernel/nsproxy.c:228
 ksys_unshare+0x4fa/0x8f0 kernel/fork.c:3444
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
 napi_frag_unref include/linux/skbuff.h:3547 [inline]
 skb_release_data+0x3ca/0x7f0 net/core/skbuff.c:982
 skb_release_all net/core/skbuff.c:1054 [inline]
 __kfree_skb+0x57/0x70 net/core/skbuff.c:1068
 tcp_clean_rtx_queue net/ipv4/tcp_input.c:3444 [inline]
 tcp_ack+0x2308/0x6870 net/ipv4/tcp_input.c:4034
 tcp_rcv_established+0xfc2/0x1dd0 net/ipv4/tcp_input.c:6127
 tcp_v4_do_rcv+0x6d3/0xba0 net/ipv4/tcp_ipv4.c:1741
 sk_backlog_rcv include/net/sock.h:1146 [inline]
 __release_sock+0x1ea/0x460 net/core/sock.c:3042
 __sk_flush_backlog+0x26/0x40 net/core/sock.c:3065
 sk_flush_backlog include/net/sock.h:1244 [inline]
 tcp_sendmsg_locked+0x3a15/0x4ab0 net/ipv4/tcp.c:1154
 tcp_sendmsg+0x2f/0x50 net/ipv4/tcp.c:1348
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 sock_write_iter+0x2dc/0x420 net/socket.c:1161
 call_write_iter include/linux/fs.h:2019 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x474/0x9a0 fs/read_write.c:584
 ksys_write+0x151/0x260 fs/read_write.c:637
 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

Memory state around the buggy address:
 ffff888079686f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888079686f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888079687000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                             ^
 ffff888079687080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888079687100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================