================================================================== BUG: KASAN: slab-use-after-free in l2cap_sock_ready_cb+0x16a/0x170 net/bluetooth/l2cap_sock.c:1687 Read of size 8 at addr ffff88802ac07188 by task kworker/u9:4/5851 CPU: 0 UID: 0 PID: 5851 Comm: kworker/u9:4 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Workqueue: hci1 hci_rx_work Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 l2cap_sock_ready_cb+0x16a/0x170 net/bluetooth/l2cap_sock.c:1687 l2cap_chan_ready net/bluetooth/l2cap_core.c:1246 [inline] l2cap_le_start+0x1ea/0xe40 net/bluetooth/l2cap_core.c:1375 l2cap_conn_ready net/bluetooth/l2cap_core.c:1628 [inline] l2cap_connect_cfm+0x8f4/0xf80 net/bluetooth/l2cap_core.c:7304 hci_connect_cfm include/net/bluetooth/hci_core.h:2082 [inline] le_conn_complete_evt+0x1662/0x1d70 net/bluetooth/hci_event.c:5771 hci_le_conn_complete_evt+0x23c/0x370 net/bluetooth/hci_event.c:5797 hci_le_meta_evt+0x354/0x5e0 net/bluetooth/hci_event.c:7234 hci_event_func net/bluetooth/hci_event.c:7542 [inline] hci_event_packet+0x682/0x11c0 net/bluetooth/hci_event.c:7599 hci_rx_work+0x2c5/0x16b0 net/bluetooth/hci_core.c:4071 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:463 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 6268: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:388 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:405 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4376 [inline] __kmalloc_noprof+0x223/0x510 mm/slub.c:4388 kmalloc_noprof include/linux/slab.h:909 [inline] sk_prot_alloc+0x1a8/0x2a0 net/core/sock.c:2239 sk_alloc+0x36/0xc20 net/core/sock.c:2295 bt_sock_alloc+0x3b/0x3a0 net/bluetooth/af_bluetooth.c:151 l2cap_sock_alloc.constprop.0+0x33/0x1d0 net/bluetooth/l2cap_sock.c:1897 l2cap_sock_create+0x123/0x1f0 net/bluetooth/l2cap_sock.c:1939 bt_sock_create+0x182/0x350 net/bluetooth/af_bluetooth.c:135 __sock_create+0x335/0x8d0 net/socket.c:1589 sock_create net/socket.c:1647 [inline] __sys_socket_create net/socket.c:1684 [inline] __sys_socket+0x14d/0x260 net/socket.c:1731 __do_sys_socket net/socket.c:1745 [inline] __se_sys_socket net/socket.c:1743 [inline] __x64_sys_socket+0x72/0xb0 net/socket.c:1743 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 6267: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x60/0x70 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2422 [inline] slab_free mm/slub.c:4695 [inline] kfree+0x2b4/0x4d0 mm/slub.c:4894 sk_prot_free net/core/sock.c:2278 [inline] __sk_destruct+0x75f/0x9a0 net/core/sock.c:2373 sk_destruct+0xc2/0xf0 net/core/sock.c:2401 __sk_free+0xf4/0x3e0 net/core/sock.c:2412 sk_free+0x6a/0x90 net/core/sock.c:2423 sock_put include/net/sock.h:1962 [inline] l2cap_sock_kill net/bluetooth/l2cap_sock.c:1265 [inline] l2cap_sock_kill+0x171/0x2d0 net/bluetooth/l2cap_sock.c:1250 l2cap_sock_release+0x1c7/0x250 net/bluetooth/l2cap_sock.c:1438 __sock_release+0xb0/0x270 net/socket.c:649 sock_close+0x1c/0x30 net/socket.c:1439 __fput+0x3ff/0xb70 fs/file_table.c:468 task_work_run+0x150/0x240 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xeb/0x110 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88802ac07000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 392 bytes inside of freed 2048-byte region [ffff88802ac07000, ffff88802ac07800) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2ac00 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801b842000 0000000000000000 dead000000000001 raw: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b842000 0000000000000000 dead000000000001 head: 0000000000000000 0000000000080008 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea0000ab0001 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5857, tgid 5857 (syz-executor), ts 80127973268, free_ts 80056349469 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1851 prep_new_page mm/page_alloc.c:1859 [inline] get_page_from_freelist+0x132b/0x38e0 mm/page_alloc.c:3858 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:5148 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:2492 [inline] allocate_slab mm/slub.c:2660 [inline] new_slab+0x247/0x330 mm/slub.c:2714 ___slab_alloc+0xcf2/0x1750 mm/slub.c:3901 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3992 __slab_alloc_node mm/slub.c:4067 [inline] slab_alloc_node mm/slub.c:4228 [inline] __kmalloc_cache_node_noprof+0x100/0x420 mm/slub.c:4415 kmalloc_node_noprof include/linux/slab.h:928 [inline] page_pool_create_percpu+0x7a/0xcb0 net/core/page_pool.c:343 nsim_create_page_pool drivers/net/netdevsim/netdev.c:457 [inline] nsim_init_napi drivers/net/netdevsim/netdev.c:480 [inline] nsim_open+0x395/0x9d0 drivers/net/netdevsim/netdev.c:535 __dev_open+0x2e7/0x7c0 net/core/dev.c:1682 __dev_change_flags+0x55d/0x720 net/core/dev.c:9549 netif_change_flags+0x8d/0x160 net/core/dev.c:9612 do_setlink.constprop.0+0xb53/0x4380 net/core/rtnetlink.c:3143 rtnl_changelink net/core/rtnetlink.c:3761 [inline] __rtnl_newlink net/core/rtnetlink.c:3920 [inline] rtnl_newlink+0x1446/0x2000 net/core/rtnetlink.c:4057 rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:6946 page last free pid 5852 tgid 5852 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] __free_frozen_pages+0x7d5/0x10f0 mm/page_alloc.c:2895 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4d/0x120 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:340 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4191 [inline] slab_alloc_node mm/slub.c:4240 [inline] kmem_cache_alloc_lru_noprof+0x1d0/0x3b0 mm/slub.c:4259 sock_alloc_inode+0x25/0x1c0 net/socket.c:309 alloc_inode+0x61/0x240 fs/inode.c:346 new_inode_pseudo include/linux/fs.h:3392 [inline] sock_alloc+0x40/0x280 net/socket.c:624 __sock_create+0xc1/0x8d0 net/socket.c:1553 sock_create net/socket.c:1647 [inline] __sys_socket_create net/socket.c:1684 [inline] __sys_socket+0x14d/0x260 net/socket.c:1731 __do_sys_socket net/socket.c:1745 [inline] __se_sys_socket net/socket.c:1743 [inline] __x64_sys_socket+0x72/0xb0 net/socket.c:1743 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88802ac07080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802ac07100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88802ac07180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802ac07200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802ac07280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================