==================================================================
BUG: KASAN: use-after-free in __lock_acquire+0x3d86/0x54a0 kernel/locking/lockdep.c:4885
Read of size 8 at addr ffff88801c6f60a0 by task syz-executor.0/8465

CPU: 0 PID: 8465 Comm: syz-executor.0 Not tainted 5.14.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105
 print_address_description.constprop.0.cold+0x6c/0x309 mm/kasan/report.c:233
 __kasan_report mm/kasan/report.c:419 [inline]
 kasan_report.cold+0x83/0xdf mm/kasan/report.c:436
 __lock_acquire+0x3d86/0x54a0 kernel/locking/lockdep.c:4885
 lock_acquire kernel/locking/lockdep.c:5625 [inline]
 lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
 _raw_spin_lock_bh+0x2f/0x40 kernel/locking/spinlock.c:175
 spin_lock_bh include/linux/spinlock.h:359 [inline]
 lock_sock_nested+0x40/0x120 net/core/sock.c:3162
 l2cap_sock_teardown_cb+0xa1/0x660 net/bluetooth/l2cap_sock.c:1528
 l2cap_chan_del+0xbc/0xa80 net/bluetooth/l2cap_core.c:622
 l2cap_conn_del+0x3c0/0x7b0 net/bluetooth/l2cap_core.c:1898
 l2cap_disconn_cfm net/bluetooth/l2cap_core.c:8177 [inline]
 l2cap_disconn_cfm+0x95/0xd0 net/bluetooth/l2cap_core.c:8170
 hci_disconn_cfm include/net/bluetooth/hci_core.h:1501 [inline]
 hci_conn_hash_flush+0x127/0x260 net/bluetooth/hci_conn.c:1608
 hci_dev_do_close+0x528/0x1130 net/bluetooth/hci_core.c:1778
 hci_unregister_dev+0x1c0/0x5a0 net/bluetooth/hci_core.c:4015
 vhci_release+0x70/0xe0 drivers/bluetooth/hci_vhci.c:340
 __fput+0x288/0x920 fs/file_table.c:280
 task_work_run+0xdd/0x1a0 kernel/task_work.c:164
 exit_task_work include/linux/task_work.h:32 [inline]
 do_exit+0xbd4/0x2a60 kernel/exit.c:825
 do_group_exit+0x125/0x310 kernel/exit.c:922
 __do_sys_exit_group kernel/exit.c:933 [inline]
 __se_sys_exit_group kernel/exit.c:931 [inline]
 __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:931
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665e9
Code: Unable to access opcode bytes at RIP 0x4665bf.
RSP: 002b:00007ffe82b64368 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 000000000000061b RCX: 00000000004665e9
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000043
RBP: 0000000000000000 R08: 0000000000000014 R09: 000000000000061b
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004bfe0f
R13: 0000000000000000 R14: 0000000000000005 R15: 00007ffe82b64560

Allocated by task 10521:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc mm/kasan/common.c:513 [inline]
 ____kasan_kmalloc mm/kasan/common.c:472 [inline]
 __kasan_kmalloc+0x9b/0xd0 mm/kasan/common.c:522
 kmalloc include/linux/slab.h:596 [inline]
 sk_prot_alloc+0x110/0x290 net/core/sock.c:1808
 sk_alloc+0x32/0xbc0 net/core/sock.c:1861
 l2cap_sock_alloc.constprop.0+0x31/0x230 net/bluetooth/l2cap_sock.c:1813
 l2cap_sock_create+0x123/0x1f0 net/bluetooth/l2cap_sock.c:1859
 bt_sock_create+0x17c/0x340 net/bluetooth/af_bluetooth.c:130
 __sock_create+0x353/0x790 net/socket.c:1450
 sock_create net/socket.c:1501 [inline]
 __sys_socket+0xef/0x200 net/socket.c:1543
 __do_sys_socket net/socket.c:1552 [inline]
 __se_sys_socket net/socket.c:1550 [inline]
 __x64_sys_socket+0x6f/0xb0 net/socket.c:1550
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Freed by task 10520:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360
 ____kasan_slab_free mm/kasan/common.c:366 [inline]
 ____kasan_slab_free mm/kasan/common.c:328 [inline]
 __kasan_slab_free+0xfb/0x130 mm/kasan/common.c:374
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1628 [inline]
 slab_free_freelist_hook+0xdf/0x240 mm/slub.c:1653
 slab_free mm/slub.c:3213 [inline]
 kfree+0xe4/0x540 mm/slub.c:4267
 sk_prot_free net/core/sock.c:1844 [inline]
 __sk_destruct+0x6a8/0x900 net/core/sock.c:1929
 sk_destruct+0xbd/0xe0 net/core/sock.c:1944
 __sk_free+0xef/0x3d0 net/core/sock.c:1955
 sk_free+0x78/0xa0 net/core/sock.c:1966
 sock_put include/net/sock.h:1816 [inline]
 l2cap_sock_kill+0x203/0x240 net/bluetooth/l2cap_sock.c:1227
 l2cap_sock_release+0x184/0x200 net/bluetooth/l2cap_sock.c:1397
 __sock_release+0xcd/0x280 net/socket.c:648
 sock_close+0x18/0x20 net/socket.c:1300
 __fput+0x288/0x920 fs/file_table.c:280
 task_work_run+0xdd/0x1a0 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x27e/0x290 kernel/entry/common.c:209
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302
 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Last potentially related work creation:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_record_aux_stack+0xe5/0x110 mm/kasan/generic.c:348
 __call_rcu kernel/rcu/tree.c:3029 [inline]
 call_rcu+0xb1/0x750 kernel/rcu/tree.c:3109
 netlink_release+0xdd4/0x1dd0 net/netlink/af_netlink.c:812
 __sock_release+0xcd/0x280 net/socket.c:648
 sock_close+0x18/0x20 net/socket.c:1300
 __fput+0x288/0x920 fs/file_table.c:280
 task_work_run+0xdd/0x1a0 kernel/task_work.c:164
 exit_task_work include/linux/task_work.h:32 [inline]
 do_exit+0xbd4/0x2a60 kernel/exit.c:825
 do_group_exit+0x125/0x310 kernel/exit.c:922
 __do_sys_exit_group kernel/exit.c:933 [inline]
 __se_sys_exit_group kernel/exit.c:931 [inline]
 __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:931
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

The buggy address belongs to the object at ffff88801c6f6000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 160 bytes inside of
 2048-byte region [ffff88801c6f6000, ffff88801c6f6800)
The buggy address belongs to the page:
page:ffffea000071bc00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1c6f0
head:ffffea000071bc00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 dead000000000100 dead000000000122 ffff888010842000
raw: 0000000000000000 0000000000080008 00000001ffffffff 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 8605, ts 1584523777016, free_ts 1584487668141
 prep_new_page mm/page_alloc.c:2436 [inline]
 get_page_from_freelist+0xa72/0x2f80 mm/page_alloc.c:4169
 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5391
 alloc_pages+0x18c/0x2a0 mm/mempolicy.c:2244
 alloc_slab_page mm/slub.c:1691 [inline]
 allocate_slab+0x32e/0x4b0 mm/slub.c:1831
 new_slab mm/slub.c:1894 [inline]
 new_slab_objects mm/slub.c:2640 [inline]
 ___slab_alloc+0x4ba/0x820 mm/slub.c:2803
 __slab_alloc.constprop.0+0xa7/0xf0 mm/slub.c:2843
 slab_alloc_node mm/slub.c:2925 [inline]
 __kmalloc_node_track_caller+0x2e3/0x360 mm/slub.c:4653
 kmalloc_reserve net/core/skbuff.c:355 [inline]
 __alloc_skb+0xde/0x340 net/core/skbuff.c:426
 alloc_skb include/linux/skbuff.h:1112 [inline]
 alloc_skb_with_frags+0x93/0x620 net/core/skbuff.c:6019
 sock_alloc_send_pskb+0x783/0x910 net/core/sock.c:2461
 mld_newpack+0x1df/0x770 net/ipv6/mcast.c:1751
 add_grhead+0x265/0x330 net/ipv6/mcast.c:1854
 add_grec+0x1053/0x14e0 net/ipv6/mcast.c:1992
 mld_send_initial_cr.part.0+0xf6/0x230 net/ipv6/mcast.c:2239
 mld_send_initial_cr net/ipv6/mcast.c:1227 [inline]
 mld_dad_work+0x1d3/0x690 net/ipv6/mcast.c:2265
 process_one_work+0x98d/0x1630 kernel/workqueue.c:2276
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1346 [inline]
 free_pcp_prepare+0x2c5/0x780 mm/page_alloc.c:1397
 free_unref_page_prepare mm/page_alloc.c:3332 [inline]
 free_unref_page+0x19/0x690 mm/page_alloc.c:3411
 unfreeze_partials+0x17c/0x1d0 mm/slub.c:2421
 put_cpu_partial+0x13d/0x230 mm/slub.c:2457
 qlink_free mm/kasan/quarantine.c:146 [inline]
 qlist_free_all+0x5a/0xc0 mm/kasan/quarantine.c:165
 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:272
 __kasan_slab_alloc+0x8e/0xa0 mm/kasan/common.c:444
 kasan_slab_alloc include/linux/kasan.h:254 [inline]
 slab_post_alloc_hook mm/slab.h:519 [inline]
 slab_alloc_node mm/slub.c:2959 [inline]
 slab_alloc mm/slub.c:2967 [inline]
 __kmalloc+0x1f4/0x330 mm/slub.c:4111
 kmalloc_array include/linux/slab.h:631 [inline]
 kcalloc include/linux/slab.h:660 [inline]
 ext4_find_extent+0xa47/0xd00 fs/ext4/extents.c:864
 ext4_ext_map_blocks+0x1e2/0x6070 fs/ext4/extents.c:4061
 ext4_map_blocks+0x653/0x17d0 fs/ext4/inode.c:638
 ext4_getblk+0x13c/0x680 fs/ext4/inode.c:848
 ext4_bread+0x2a/0x1c0 fs/ext4/inode.c:900
 ext4_append+0x177/0x390 fs/ext4/namei.c:67
 ext4_init_new_dir+0x33f/0x5e0 fs/ext4/namei.c:2885
 ext4_mkdir+0x3cf/0xb20 fs/ext4/namei.c:2931

Memory state around the buggy address:
 ffff88801c6f5f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88801c6f6000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88801c6f6080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff88801c6f6100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801c6f6180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================