================================================================== BUG: KASAN: use-after-free in hci_chan_del+0x36/0x1a0 net/bluetooth/hci_conn.c:2780 Read of size 8 at addr ffff88805f880a18 by task syz.4.2986/14950 CPU: 0 PID: 14950 Comm: syz.4.2986 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026 Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 print_address_description mm/kasan/report.c:316 [inline] print_report+0xa8/0x210 mm/kasan/report.c:420 kasan_report+0x10b/0x140 mm/kasan/report.c:524 hci_chan_del+0x36/0x1a0 net/bluetooth/hci_conn.c:2780 l2cap_conn_free net/bluetooth/l2cap_core.c:1868 [inline] kref_put include/linux/kref.h:65 [inline] l2cap_conn_put net/bluetooth/l2cap_core.c:1882 [inline] l2cap_chan_destroy net/bluetooth/l2cap_core.c:502 [inline] kref_put include/linux/kref.h:65 [inline] l2cap_chan_put+0x1f5/0x300 net/bluetooth/l2cap_core.c:529 l2cap_sock_release+0x179/0x1e0 net/bluetooth/l2cap_sock.c:1494 __sock_release net/socket.c:654 [inline] sock_close+0xbf/0x210 net/socket.c:1400 __fput+0x20a/0x8b0 fs/file_table.c:320 task_work_run+0x1d0/0x260 kernel/task_work.c:203 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:295 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:306 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fa5863a94d9 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:00007ffe0d997f58 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007fa586627da0 RCX: 00007fa5863a94d9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007fa586627da0 R08: 0000000000000006 R09: 0000000000000000 R10: 00000000003ff53c R11: 0000000000000246 R12: 000000000008e0c7 R13: 00007fa58662609c R14: 000000000008de56 R15: 00007fa586626090 Allocated by task 4281: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:384 kmalloc include/linux/slab.h:563 [inline] kzalloc include/linux/slab.h:699 [inline] hci_chan_create+0xc5/0x300 net/bluetooth/hci_conn.c:2765 l2cap_conn_add+0x5d/0x910 net/bluetooth/l2cap_core.c:7211 l2cap_connect_cfm+0x131/0x1230 net/bluetooth/l2cap_core.c:7598 hci_connect_cfm include/net/bluetooth/hci_core.h:1822 [inline] hci_remote_features_evt+0x4cc/0xa10 net/bluetooth/hci_event.c:3756 hci_event_func net/bluetooth/hci_event.c:7304 [inline] hci_event_packet+0x66a/0xe60 net/bluetooth/hci_event.c:7353 hci_rx_work+0x3eb/0xd40 net/bluetooth/hci_core.c:4041 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Freed by task 14936: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x27/0x40 mm/kasan/generic.c:516 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1735 [inline] slab_free_freelist_hook+0x133/0x1b0 mm/slub.c:1761 slab_free mm/slub.c:3694 [inline] __kmem_cache_free+0xb6/0x200 mm/slub.c:3707 hci_chan_list_flush net/bluetooth/hci_conn.c:2805 [inline] hci_conn_cleanup+0x171/0x750 net/bluetooth/hci_conn.c:149 hci_conn_del+0x4df/0x6e0 net/bluetooth/hci_conn.c:1234 hci_conn_hash_flush+0x203/0x290 net/bluetooth/hci_conn.c:2610 hci_dev_close_sync+0x989/0x10a0 net/bluetooth/hci_sync.c:5328 hci_dev_do_close net/bluetooth/hci_core.c:523 [inline] hci_rfkill_set_block+0x117/0x1e0 net/bluetooth/hci_core.c:925 rfkill_set_block+0x1c1/0x3c0 net/rfkill/core.c:360 rfkill_fop_write+0x453/0x560 net/rfkill/core.c:1318 vfs_write+0x2dc/0x9a0 fs/read_write.c:582 ksys_write+0x14d/0x260 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 The buggy address belongs to the object at ffff88805f880a00 which belongs to the cache kmalloc-128 of size 128 The buggy address is located 24 bytes inside of 128-byte region [ffff88805f880a00, ffff88805f880a80) The buggy address belongs to the physical page: page:ffffea00017e2000 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88805f880700 pfn:0x5f880 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 0000000000000000 dead000000000001 ffff8880184418c0 raw: ffff88805f880700 0000000080100008 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 14711, tgid 14709 (syz.2.2924), ts 568364851330, free_ts 567297999738 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2560 prep_new_page mm/page_alloc.c:2567 [inline] get_page_from_freelist+0x206b/0x2180 mm/page_alloc.c:4358 __alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5658 alloc_slab_page+0x5d/0x180 mm/slub.c:1805 allocate_slab mm/slub.c:1950 [inline] new_slab+0x87/0x2d0 mm/slub.c:2003 ___slab_alloc+0xbc5/0x1240 mm/slub.c:3161 __slab_alloc mm/slub.c:3247 [inline] slab_alloc_node mm/slub.c:3332 [inline] __kmem_cache_alloc_node+0x126/0x270 mm/slub.c:3405 kmalloc_trace+0x26/0xe0 mm/slab_common.c:1026 kmalloc include/linux/slab.h:563 [inline] kzalloc include/linux/slab.h:699 [inline] nf_nat_masq_schedule+0x238/0x560 net/netfilter/nf_nat_masquerade.c:118 masq_device_event+0x9e/0xd0 net/netfilter/nf_nat_masquerade.c:162 notifier_call_chain kernel/notifier.c:87 [inline] raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:455 call_netdevice_notifiers_extack net/core/dev.c:2052 [inline] call_netdevice_notifiers net/core/dev.c:2066 [inline] __dev_notify_flags+0x16b/0x310 net/core/dev.c:8736 dev_change_flags+0xda/0x1a0 net/core/dev.c:8772 do_setlink+0xbc7/0x29c0 net/core/rtnetlink.c:2845 rtnl_group_changelink net/core/rtnetlink.c:3375 [inline] __rtnl_newlink net/core/rtnetlink.c:3632 [inline] rtnl_newlink+0x10bc/0x1f90 net/core/rtnetlink.c:3669 rtnetlink_rcv_msg+0x863/0xfb0 net/core/rtnetlink.c:6166 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1487 [inline] free_pcp_prepare mm/page_alloc.c:1537 [inline] free_unref_page_prepare+0x8e5/0x9e0 mm/page_alloc.c:3414 free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3509 kasan_depopulate_vmalloc_pte+0x67/0x80 mm/kasan/shadow.c:456 apply_to_pte_range mm/memory.c:2660 [inline] apply_to_pmd_range mm/memory.c:2704 [inline] apply_to_pud_range mm/memory.c:2740 [inline] apply_to_p4d_range mm/memory.c:2776 [inline] __apply_to_page_range+0x98d/0xd10 mm/memory.c:2812 kasan_release_vmalloc+0x93/0xb0 mm/kasan/shadow.c:573 __purge_vmap_area_lazy+0xf72/0x1920 mm/vmalloc.c:1839 drain_vmap_area_work+0x3c/0xd0 mm/vmalloc.c:1868 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Memory state around the buggy address: ffff88805f880900: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88805f880980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88805f880a00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88805f880a80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88805f880b00: fa fb fb fb fb fb fb fb fb 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