================================================================== BUG: KASAN: use-after-free in hci_chan_del+0x36/0x1a0 net/bluetooth/hci_conn.c:2780 Read of size 8 at addr ffff888078987318 by task krfcommd/3346 CPU: 0 PID: 3346 Comm: krfcommd 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_release+0x7b/0x140 net/socket.c:682 rfcomm_session_del+0x141/0x200 net/bluetooth/rfcomm/core.c:781 rfcomm_process_sessions net/bluetooth/rfcomm/core.c:-1 [inline] rfcomm_run+0x46e1/0x5f10 net/bluetooth/rfcomm/core.c:2254 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Allocated by task 4293: 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 5004: 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_unregister_dev+0x216/0x520 net/bluetooth/hci_core.c:2720 vhci_release+0x7f/0xd0 drivers/bluetooth/hci_vhci.c:565 __fput+0x20a/0x8b0 fs/file_table.c:320 task_work_run+0x1d0/0x260 kernel/task_work.c:203 exit_task_work include/linux/task_work.h:39 [inline] do_exit+0x9d5/0x2570 kernel/exit.c:887 do_group_exit+0x229/0x2e0 kernel/exit.c:1030 get_signal+0x1259/0x1340 kernel/signal.c:2884 arch_do_signal_or_restart+0xc4/0x1310 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:177 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 Last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46 __kasan_record_aux_stack+0xb2/0xc0 mm/kasan/generic.c:486 kvfree_call_rcu+0x103/0x890 kernel/rcu/tree.c:3405 kernfs_unlink_open_file+0x456/0x500 fs/kernfs/file.c:653 kernfs_fop_release+0x12a/0x190 fs/kernfs/file.c:825 __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 The buggy address belongs to the object at ffff888078987300 which belongs to the cache kmalloc-128 of size 128 The buggy address is located 24 bytes inside of 128-byte region [ffff888078987300, ffff888078987380) The buggy address belongs to the physical page: page:ffffea0001e261c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x78987 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 0000000000000000 dead000000000001 ffff8880184418c0 raw: 0000000000000000 0000000000100010 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 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 3642, tgid 3642 (udevd), ts 47323225366, free_ts 47249477248 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] kernfs_get_open_node fs/kernfs/file.c:592 [inline] kernfs_fop_open+0x78c/0xc60 fs/kernfs/file.c:760 do_dentry_open+0x7dd/0x10b0 fs/open.c:882 do_open fs/namei.c:3677 [inline] path_openat+0x2674/0x2f10 fs/namei.c:3838 do_filp_open+0x1ee/0x420 fs/namei.c:3865 do_sys_openat2+0x14b/0x4f0 fs/open.c:1320 do_sys_open fs/open.c:1336 [inline] __do_sys_openat fs/open.c:1352 [inline] __se_sys_openat fs/open.c:1347 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1347 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 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 free_slab mm/slub.c:2042 [inline] discard_slab mm/slub.c:2048 [inline] __unfreeze_partials+0x188/0x1e0 mm/slub.c:2598 put_cpu_partial+0x17c/0x250 mm/slub.c:2674 qlink_free mm/kasan/quarantine.c:166 [inline] qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:185 kasan_quarantine_reduce+0x144/0x160 mm/kasan/quarantine.c:292 __kasan_slab_alloc+0x1e/0x80 mm/kasan/common.c:306 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook+0x4b/0x490 mm/slab.h:742 slab_alloc_node mm/slub.c:3366 [inline] __kmem_cache_alloc_node+0x19d/0x270 mm/slub.c:3405 __do_kmalloc_node mm/slab_common.c:935 [inline] __kmalloc_node+0xa2/0x240 mm/slab_common.c:943 kmalloc_node include/linux/slab.h:589 [inline] kvmalloc_node+0x6c/0x180 mm/util.c:581 kvmalloc include/linux/slab.h:716 [inline] seq_buf_alloc fs/seq_file.c:38 [inline] seq_read_iter+0x1de/0xc50 fs/seq_file.c:210 call_read_iter include/linux/fs.h:2265 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x471/0x960 fs/read_write.c:470 ksys_read+0x14d/0x260 fs/read_write.c:613 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 Memory state around the buggy address: ffff888078987200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888078987280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888078987300: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888078987380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888078987400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================