================================================================== BUG: KASAN: slab-use-after-free in l2cap_sock_new_connection_cb+0x22a/0x240 net/bluetooth/l2cap_sock.c:1485 Read of size 8 at addr ffff88803a40f580 by task kworker/u9:1/13971 CPU: 1 UID: 0 PID: 13971 Comm: kworker/u9:1 Not tainted 6.13.0-rc7-syzkaller-00189-g595523945be0 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Workqueue: hci5 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+0xc3/0x620 mm/kasan/report.c:489 kasan_report+0xd9/0x110 mm/kasan/report.c:602 l2cap_sock_new_connection_cb+0x22a/0x240 net/bluetooth/l2cap_sock.c:1485 l2cap_connect_cfm+0x85f/0xf10 net/bluetooth/l2cap_core.c:7263 hci_connect_cfm include/net/bluetooth/hci_core.h:2057 [inline] le_conn_complete_evt+0x168d/0x1da0 net/bluetooth/hci_event.c:5763 hci_le_conn_complete_evt+0x23c/0x370 net/bluetooth/hci_event.c:5789 hci_le_meta_evt+0x2e2/0x5d0 net/bluetooth/hci_event.c:7162 hci_event_func net/bluetooth/hci_event.c:7470 [inline] hci_event_packet+0x666/0x1180 net/bluetooth/hci_event.c:7525 hci_rx_work+0x2c5/0x16b0 net/bluetooth/hci_core.c:4035 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3317 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Allocated by task 13971: 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:377 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4298 [inline] __kmalloc_noprof+0x21c/0x510 mm/slub.c:4310 kmalloc_noprof include/linux/slab.h:905 [inline] sk_prot_alloc+0x1a8/0x2a0 net/core/sock.c:2168 sk_alloc+0x36/0xb90 net/core/sock.c:2221 bt_sock_alloc+0x3b/0x3a0 net/bluetooth/af_bluetooth.c:148 l2cap_sock_alloc.constprop.0+0x33/0x1c0 net/bluetooth/l2cap_sock.c:1879 l2cap_sock_new_connection_cb+0x101/0x240 net/bluetooth/l2cap_sock.c:1470 l2cap_connect_cfm+0x85f/0xf10 net/bluetooth/l2cap_core.c:7263 hci_connect_cfm include/net/bluetooth/hci_core.h:2057 [inline] le_conn_complete_evt+0x168d/0x1da0 net/bluetooth/hci_event.c:5763 hci_le_conn_complete_evt+0x23c/0x370 net/bluetooth/hci_event.c:5789 hci_le_meta_evt+0x2e2/0x5d0 net/bluetooth/hci_event.c:7162 hci_event_func net/bluetooth/hci_event.c:7470 [inline] hci_event_packet+0x666/0x1180 net/bluetooth/hci_event.c:7525 hci_rx_work+0x2c5/0x16b0 net/bluetooth/hci_core.c:4035 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3317 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Freed by task 30062: 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:582 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2353 [inline] slab_free mm/slub.c:4613 [inline] kfree+0x14f/0x4b0 mm/slub.c:4761 sk_prot_free net/core/sock.c:2204 [inline] __sk_destruct+0x5eb/0x720 net/core/sock.c:2296 sk_destruct+0xc2/0xf0 net/core/sock.c:2311 __sk_free+0xf4/0x3e0 net/core/sock.c:2322 sk_free+0x6a/0x90 net/core/sock.c:2333 sock_put include/net/sock.h:1910 [inline] l2cap_sock_kill net/bluetooth/l2cap_sock.c:1252 [inline] l2cap_sock_kill+0x171/0x2d0 net/bluetooth/l2cap_sock.c:1237 l2cap_sock_cleanup_listen+0x3d/0x2a0 net/bluetooth/l2cap_sock.c:1450 l2cap_sock_release+0x5c/0x210 net/bluetooth/l2cap_sock.c:1413 __sock_release+0xb0/0x270 net/socket.c:640 sock_close+0x1c/0x30 net/socket.c:1408 __fput+0x3f8/0xb60 fs/file_table.c:450 task_work_run+0x14e/0x250 kernel/task_work.c:239 get_signal+0x1d3/0x26c0 kernel/signal.c:2790 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88803a40f000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1408 bytes inside of freed 2048-byte region [ffff88803a40f000, ffff88803a40f800) The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3a408 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801b042000 ffffea00006fc200 dead000000000002 raw: 0000000000000000 0000000080080008 00000001f5000000 0000000000000000 head: 00fff00000000040 ffff88801b042000 ffffea00006fc200 dead000000000002 head: 0000000000000000 0000000080080008 00000001f5000000 0000000000000000 head: 00fff00000000003 ffffea0000e90201 ffffffffffffffff 0000000000000000 head: ffff888000000008 0000000000000000 00000000ffffffff 0000000000000000 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 27877, tgid 27876 (syz.1.5390), ts 1751985711872, free_ts 1751500820566 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1558 prep_new_page mm/page_alloc.c:1566 [inline] get_page_from_freelist+0xfce/0x2f80 mm/page_alloc.c:3476 __alloc_pages_noprof+0x223/0x25b0 mm/page_alloc.c:4753 alloc_pages_mpol_noprof+0x2c8/0x620 mm/mempolicy.c:2269 alloc_slab_page mm/slub.c:2423 [inline] allocate_slab mm/slub.c:2589 [inline] new_slab+0x2c9/0x410 mm/slub.c:2642 ___slab_alloc+0xd7d/0x17a0 mm/slub.c:3830 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3920 __slab_alloc_node mm/slub.c:3995 [inline] slab_alloc_node mm/slub.c:4156 [inline] __kmalloc_cache_noprof+0xfa/0x410 mm/slub.c:4324 kmalloc_noprof include/linux/slab.h:901 [inline] kzalloc_noprof include/linux/slab.h:1037 [inline] device_create_groups_vargs+0x8a/0x270 drivers/base/core.c:4374 device_create+0xe9/0x130 drivers/base/core.c:4431 bdi_register_va+0x116/0x820 mm/backing-dev.c:1094 super_setup_bdi_name+0x100/0x250 fs/super.c:1873 fuse_bdi_init fs/fuse/inode.c:1493 [inline] fuse_fill_super_common+0x5eb/0x1040 fs/fuse/inode.c:1770 fuse_fill_super+0x1f2/0x2d0 fs/fuse/inode.c:1846 vfs_get_super fs/super.c:1280 [inline] get_tree_nodev+0xda/0x190 fs/super.c:1299 fuse_get_tree+0x26d/0x600 fs/fuse/inode.c:1921 page last free pid 27545 tgid 27545 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1127 [inline] free_unref_page+0x661/0x1080 mm/page_alloc.c:2659 __put_partials+0x14c/0x170 mm/slub.c:3157 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4e/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:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4119 [inline] slab_alloc_node mm/slub.c:4168 [inline] kmem_cache_alloc_noprof+0x226/0x3d0 mm/slub.c:4175 getname_flags.part.0+0x4c/0x550 fs/namei.c:139 getname_flags+0x93/0xf0 include/linux/audit.h:322 user_path_at+0x24/0x60 fs/namei.c:3069 ksys_umount fs/namespace.c:2031 [inline] __do_sys_umount fs/namespace.c:2039 [inline] __se_sys_umount fs/namespace.c:2037 [inline] __x64_sys_umount+0x10b/0x1a0 fs/namespace.c:2037 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88803a40f480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88803a40f500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88803a40f580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88803a40f600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88803a40f680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================