syzbot

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BUG: KASAN: slab-use-after-free in l2cap_sock_new_connection_cb+0x208/0x2f0 net/bluetooth/l2cap_sock.c:1565
Read of size 8 at addr ffff8880112b2830 by task kworker/u9:2/5697

CPU: 0 UID: 0 PID: 5697 Comm: kworker/u9:2 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: hci2 hci_rx_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
 l2cap_sock_new_connection_cb+0x208/0x2f0 net/bluetooth/l2cap_sock.c:1565
 l2cap_connect_cfm+0x368/0x1560 net/bluetooth/l2cap_core.c:7402
 hci_connect_cfm+0x95/0x140 include/net/bluetooth/hci_core.h:2139
 le_conn_complete_evt+0x1134/0x16b0 net/bluetooth/hci_event.c:5865
 hci_le_conn_complete_evt+0x187/0x470 net/bluetooth/hci_event.c:5891
 hci_event_func net/bluetooth/hci_event.c:7793 [inline]
 hci_event_packet+0x659/0xef0 net/bluetooth/hci_event.c:7847
 hci_rx_work+0x3ee/0x1040 net/bluetooth/hci_core.c:4077
 process_one_work kernel/workqueue.c:3314 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
 kthread+0x388/0x470 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 5697:
 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]
 __do_kmalloc_node mm/slub.c:5296 [inline]
 __kmalloc_noprof+0x3e7/0x7b0 mm/slub.c:5308
 kmalloc_noprof include/linux/slab.h:954 [inline]
 sk_prot_alloc+0xe7/0x210 net/core/sock.c:2247
 sk_alloc+0x3a/0x390 net/core/sock.c:2303
 bt_sock_alloc+0x3b/0x340 net/bluetooth/af_bluetooth.c:151
 l2cap_sock_alloc net/bluetooth/l2cap_sock.c:1971 [inline]
 l2cap_sock_new_connection_cb+0xf1/0x2f0 net/bluetooth/l2cap_sock.c:1550
 l2cap_connect_cfm+0x368/0x1560 net/bluetooth/l2cap_core.c:7402
 hci_connect_cfm+0x95/0x140 include/net/bluetooth/hci_core.h:2139
 le_conn_complete_evt+0x1134/0x16b0 net/bluetooth/hci_event.c:5865
 hci_le_conn_complete_evt+0x187/0x470 net/bluetooth/hci_event.c:5891
 hci_event_func net/bluetooth/hci_event.c:7793 [inline]
 hci_event_packet+0x659/0xef0 net/bluetooth/hci_event.c:7847
 hci_rx_work+0x3ee/0x1040 net/bluetooth/hci_core.c:4077
 process_one_work kernel/workqueue.c:3314 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
 kthread+0x388/0x470 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 6077:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 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:2689 [inline]
 slab_free mm/slub.c:6251 [inline]
 kfree+0x1c5/0x6c0 mm/slub.c:6566
 sk_prot_free net/core/sock.c:2286 [inline]
 __sk_destruct+0x74b/0x9d0 net/core/sock.c:2386
 sock_put include/net/sock.h:2010 [inline]
 l2cap_sock_cleanup_listen+0x1d9/0x580 net/bluetooth/l2cap_sock.c:-1
 l2cap_sock_release+0x6e/0x270 net/bluetooth/l2cap_sock.c:1456
 __sock_release net/socket.c:722 [inline]
 sock_close+0xc3/0x240 net/socket.c:1514
 __fput+0x461/0xa70 fs/file_table.c:510
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 get_signal+0x11eb/0x1330 kernel/signal.c:2809
 arch_do_signal_or_restart+0xbc/0x840 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0xa9/0x680 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff8880112b2000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 2096 bytes inside of
 freed 4096-byte region [ffff8880112b2000, ffff8880112b3000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x112b0
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 ffff88813fe0d140 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800040004 00000000f5000000 0000000000000000
head: 0080000000000040 ffff88813fe0d140 dead000000000100 dead000000000122
head: 0000000000000000 0000000800040004 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 92, tgid 92 (kworker/u8:5), ts 128352916664, free_ts 127743180396
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x22d/0x280 mm/page_alloc.c:1853
 prep_new_page mm/page_alloc.c:1861 [inline]
 get_page_from_freelist+0x28b2/0x2930 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 alloc_slab_page mm/slub.c:3278 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3467
 new_slab mm/slub.c:3525 [inline]
 refill_objects+0x33c/0x3d0 mm/slub.c:7272
 refill_sheaf mm/slub.c:2816 [inline]
 __pcs_replace_empty_main+0x373/0x720 mm/slub.c:4652
 alloc_from_pcs mm/slub.c:4750 [inline]
 slab_alloc_node mm/slub.c:4884 [inline]
 __do_kmalloc_node mm/slub.c:5295 [inline]
 __kmalloc_node_track_caller_noprof+0x60b/0x7e0 mm/slub.c:5408
 kmalloc_reserve net/core/skbuff.c:635 [inline]
 __alloc_skb+0x2c1/0x7d0 net/core/skbuff.c:713
 alloc_skb include/linux/skbuff.h:1383 [inline]
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:819 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:876 [inline]
 nsim_dev_trap_report_work+0x29f/0xbd0 drivers/net/netdevsim/dev.c:922
 process_one_work kernel/workqueue.c:3314 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
 kthread+0x388/0x470 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 6070 tgid 6070 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0xfe5/0x10d0 mm/page_alloc.c:2938
 __slab_free+0x252/0x2a0 mm/slub.c:5613
 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:4570 [inline]
 slab_alloc_node mm/slub.c:4899 [inline]
 kmem_cache_alloc_noprof+0x33b/0x680 mm/slub.c:4906
 vm_area_dup+0x2b/0x670 mm/vma_init.c:123
 __split_vma+0x1e4/0xa40 mm/vma.c:516
 split_vma mm/vma.c:599 [inline]
 vma_modify+0x90d/0x1f20 mm/vma.c:1691
 vma_modify_flags+0x24b/0x330 mm/vma.c:1719
 mprotect_fixup+0x62a/0xb60 mm/mprotect.c:789
 do_mprotect_pkey+0x8d5/0xd20 mm/mprotect.c:967
 __do_sys_mprotect mm/mprotect.c:988 [inline]
 __se_sys_mprotect mm/mprotect.c:985 [inline]
 __x64_sys_mprotect+0x80/0x90 mm/mprotect.c:985
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff8880112b2700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880112b2780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880112b2800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff8880112b2880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880112b2900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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