================================================================== BUG: KASAN: slab-use-after-free in __list_del_entry_valid_or_report+0x8c/0x1b4 lib/list_debug.c:62 Read of size 8 at addr ffff0000c620e558 by task syz-executor/6530 CPU: 0 UID: 0 PID: 6530 Comm: syz-executor Not tainted 6.16.0-rc7-syzkaller-g82af5ea7c611 #0 PREEMPT Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C) __dump_stack+0x30/0x40 lib/dump_stack.c:94 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120 print_address_description+0xa8/0x220 mm/kasan/report.c:378 print_report+0x68/0x84 mm/kasan/report.c:480 kasan_report+0xb0/0x110 mm/kasan/report.c:593 __asan_report_load8_noabort+0x20/0x2c mm/kasan/report_generic.c:381 __list_del_entry_valid_or_report+0x8c/0x1b4 lib/list_debug.c:62 __list_del_entry_valid include/linux/list.h:124 [inline] __list_del_entry include/linux/list.h:215 [inline] list_del_init include/linux/list.h:287 [inline] bt_accept_unlink+0x40/0x248 net/bluetooth/af_bluetooth.c:259 l2cap_sock_teardown_cb+0x148/0x360 net/bluetooth/l2cap_sock.c:1613 l2cap_chan_del+0xb8/0x470 net/bluetooth/l2cap_core.c:655 l2cap_conn_del+0x2f8/0x5f0 net/bluetooth/l2cap_core.c:1787 l2cap_disconn_cfm+0x90/0xe0 net/bluetooth/l2cap_core.c:7325 hci_disconn_cfm include/net/bluetooth/hci_core.h:2074 [inline] hci_conn_hash_flush+0x104/0x214 net/bluetooth/hci_conn.c:2560 hci_dev_close_sync+0x89c/0x1154 net/bluetooth/hci_sync.c:5294 hci_dev_do_close net/bluetooth/hci_core.c:501 [inline] hci_unregister_dev+0x200/0x4bc net/bluetooth/hci_core.c:2717 vhci_release+0x7c/0xd0 drivers/bluetooth/hci_vhci.c:665 __fput+0x340/0x75c fs/file_table.c:465 ____fput+0x20/0x58 fs/file_table.c:493 task_work_run+0x1dc/0x260 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x524/0x19fc kernel/exit.c:964 do_group_exit+0x194/0x22c kernel/exit.c:1105 __do_sys_exit_group kernel/exit.c:1116 [inline] __se_sys_exit_group kernel/exit.c:1114 [inline] pid_child_should_wake+0x0/0x1dc kernel/exit.c:1114 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x58/0x180 arch/arm64/kernel/entry-common.c:879 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:898 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 Allocated by task 8622: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x40/0x78 mm/kasan/common.c:68 kasan_save_alloc_info+0x44/0x54 mm/kasan/generic.c:562 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x9c/0xb4 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4328 [inline] __kmalloc_node_track_caller_noprof+0x304/0x4d0 mm/slub.c:4347 kmalloc_reserve+0x124/0x268 net/core/skbuff.c:601 __alloc_skb+0x170/0x2ec net/core/skbuff.c:670 alloc_skb include/linux/skbuff.h:1336 [inline] nlmsg_new include/net/netlink.h:1041 [inline] rtmsg_ifinfo_build_skb+0x90/0x24c net/core/rtnetlink.c:4390 unregister_netdevice_many_notify+0x12e4/0x1fac net/core/dev.c:12080 unregister_netdevice_many net/core/dev.c:12140 [inline] unregister_netdevice_queue+0x2b4/0x300 net/core/dev.c:11984 unregister_netdevice include/linux/netdevice.h:3379 [inline] __tun_detach+0x5b8/0x12a4 drivers/net/tun.c:620 tun_detach drivers/net/tun.c:636 [inline] tun_chr_close+0x118/0x1f8 drivers/net/tun.c:3396 __fput+0x340/0x75c fs/file_table.c:465 ____fput+0x20/0x58 fs/file_table.c:493 task_work_run+0x1dc/0x260 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] do_notify_resume+0x174/0x1f4 arch/arm64/kernel/entry-common.c:155 exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:173 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:182 [inline] el0_svc+0xb8/0x180 arch/arm64/kernel/entry-common.c:880 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:898 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 Freed by task 8622: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x40/0x78 mm/kasan/common.c:68 kasan_save_free_info+0x58/0x70 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x68/0x88 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2381 [inline] slab_free mm/slub.c:4643 [inline] kfree+0x17c/0x474 mm/slub.c:4842 skb_kfree_head net/core/skbuff.c:1048 [inline] skb_free_head+0xe4/0x198 net/core/skbuff.c:1060 skb_release_data+0x4d4/0x664 net/core/skbuff.c:1087 skb_release_all net/core/skbuff.c:1152 [inline] __kfree_skb net/core/skbuff.c:1166 [inline] consume_skb+0xb0/0x130 net/core/skbuff.c:1398 netlink_broadcast_filtered+0xf74/0x10d4 net/netlink/af_netlink.c:1537 nlmsg_multicast_filtered include/net/netlink.h:1151 [inline] nlmsg_multicast include/net/netlink.h:1170 [inline] nlmsg_notify+0xfc/0x1e0 net/netlink/af_netlink.c:2595 rtnl_notify net/core/rtnetlink.c:958 [inline] rtmsg_ifinfo_send+0xb8/0xec net/core/rtnetlink.c:4419 unregister_netdevice_many_notify+0x1854/0x1fac net/core/dev.c:12105 unregister_netdevice_many net/core/dev.c:12140 [inline] unregister_netdevice_queue+0x2b4/0x300 net/core/dev.c:11984 unregister_netdevice include/linux/netdevice.h:3379 [inline] __tun_detach+0x5b8/0x12a4 drivers/net/tun.c:620 tun_detach drivers/net/tun.c:636 [inline] tun_chr_close+0x118/0x1f8 drivers/net/tun.c:3396 __fput+0x340/0x75c fs/file_table.c:465 ____fput+0x20/0x58 fs/file_table.c:493 task_work_run+0x1dc/0x260 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] do_notify_resume+0x174/0x1f4 arch/arm64/kernel/entry-common.c:155 exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:173 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:182 [inline] el0_svc+0xb8/0x180 arch/arm64/kernel/entry-common.c:880 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:898 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 The buggy address belongs to the object at ffff0000c620e000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1368 bytes inside of freed 2048-byte region [ffff0000c620e000, ffff0000c620e800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x106208 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 anon flags: 0x5ffc00000000040(head|node=0|zone=2|lastcpupid=0x7ff) page_type: f5(slab) raw: 05ffc00000000040 ffff0000c0002000 0000000000000000 dead000000000001 raw: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000 head: 05ffc00000000040 ffff0000c0002000 0000000000000000 dead000000000001 head: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000 head: 05ffc00000000003 fffffdffc3188201 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000c620e400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000c620e480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff0000c620e500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000c620e580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000c620e600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== slab kmalloc-2k start ffff0000c620e000 pointer offset 1368 size 2048 list_del corruption. prev->next should be ffff0000d2341558, but was 0000000000000000. (prev=ffff0000c620e558) ------------[ cut here ]------------ kernel BUG at lib/list_debug.c:64! Internal error: Oops - BUG: 00000000f2000800 [#1] SMP Modules linked in: CPU: 0 UID: 0 PID: 6530 Comm: syz-executor Tainted: G B 6.16.0-rc7-syzkaller-g82af5ea7c611 #0 PREEMPT Tainted: [B]=BAD_PAGE Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : __list_del_entry_valid_or_report+0x17c/0x1b4 lib/list_debug.c:62 lr : __list_del_entry_valid_or_report+0x17c/0x1b4 lib/list_debug.c:62 sp : ffff8000a3ac7670 x29: ffff8000a3ac7670 x28: 0000000000000003 x27: ffff0000f432b00c x26: ffff0000f432b000 x25: 1fffe0001e865602 x24: dfff800000000000 x23: 1fffe00018c41cab x22: dfff800000000000 x21: ffff0000c620e558 x20: ffff0000c620e558 x19: ffff0000d2341558 x18: 1fffe000337d1c76 x17: 20747562202c3835 x16: ffff80008ae69508 x15: ffff700011ee0158 x14: 1ffff00011ee0158 x13: 0000000000000004 x12: ffffffffffffffff x11: ffff700011ee0158 x10: 0000000000ff0100 x9 : 6c85227afd71f600 x8 : 6c85227afd71f600 x7 : 0000000000000001 x6 : 0000000000000001 x5 : ffff8000a3ac6ff8 x4 : ffff80008f776bc0 x3 : ffff80008054bdfc x2 : 0000000000000000 x1 : 0000000100000000 x0 : 000000000000006d Call trace: __list_del_entry_valid_or_report+0x17c/0x1b4 lib/list_debug.c:62 (P) __list_del_entry_valid include/linux/list.h:124 [inline] __list_del_entry include/linux/list.h:215 [inline] list_del_init include/linux/list.h:287 [inline] bt_accept_unlink+0x40/0x248 net/bluetooth/af_bluetooth.c:259 l2cap_sock_teardown_cb+0x148/0x360 net/bluetooth/l2cap_sock.c:1613 l2cap_chan_del+0xb8/0x470 net/bluetooth/l2cap_core.c:655 l2cap_conn_del+0x2f8/0x5f0 net/bluetooth/l2cap_core.c:1787 l2cap_disconn_cfm+0x90/0xe0 net/bluetooth/l2cap_core.c:7325 hci_disconn_cfm include/net/bluetooth/hci_core.h:2074 [inline] hci_conn_hash_flush+0x104/0x214 net/bluetooth/hci_conn.c:2560 hci_dev_close_sync+0x89c/0x1154 net/bluetooth/hci_sync.c:5294 hci_dev_do_close net/bluetooth/hci_core.c:501 [inline] hci_unregister_dev+0x200/0x4bc net/bluetooth/hci_core.c:2717 vhci_release+0x7c/0xd0 drivers/bluetooth/hci_vhci.c:665 __fput+0x340/0x75c fs/file_table.c:465 ____fput+0x20/0x58 fs/file_table.c:493 task_work_run+0x1dc/0x260 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x524/0x19fc kernel/exit.c:964 do_group_exit+0x194/0x22c kernel/exit.c:1105 __do_sys_exit_group kernel/exit.c:1116 [inline] __se_sys_exit_group kernel/exit.c:1114 [inline] pid_child_should_wake+0x0/0x1dc kernel/exit.c:1114 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x58/0x180 arch/arm64/kernel/entry-common.c:879 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:898 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 Code: 910d8000 aa1303e1 aa1503e3 9741c60c (d4210000) ---[ end trace 0000000000000000 ]---