KASAN: slab-use-after-free Read in bt_accept

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	general protection fault in bt_accept_unlink (2) bluetooth				1	1313d	1309d	0/28	auto-closed as invalid on 2021/07/01 06:33
==================================================================
BUG: KASAN: slab-use-after-free in __list_del_entry_valid_or_report+0x1a6/0x1c0 lib/list_debug.c:62
Read of size 8 at addr ffff888060bda550 by task kworker/u33:4/5348

CPU: 1 UID: 0 PID: 5348 Comm: kworker/u33:4 Not tainted 6.12.0-rc1-syzkaller-00031-ge32cde8d2bd7 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: hci6 hci_error_reset
Call Trace:
 <TASK>
 __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:377 [inline]
 print_report+0xc3/0x620 mm/kasan/report.c:488
 kasan_report+0xd9/0x110 mm/kasan/report.c:601
 __list_del_entry_valid_or_report+0x1a6/0x1c0 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+0x34/0x2e0 net/bluetooth/af_bluetooth.c:234
 l2cap_sock_teardown_cb+0x1a3/0x3c0 net/bluetooth/l2cap_sock.c:1599
 l2cap_chan_del+0xba/0x900 net/bluetooth/l2cap_core.c:658
 l2cap_conn_del+0x37c/0x730 net/bluetooth/l2cap_core.c:1785
 l2cap_disconn_cfm net/bluetooth/l2cap_core.c:7307 [inline]
 l2cap_disconn_cfm+0x96/0xd0 net/bluetooth/l2cap_core.c:7300
 hci_disconn_cfm include/net/bluetooth/hci_core.h:1975 [inline]
 hci_conn_hash_flush+0x114/0x260 net/bluetooth/hci_conn.c:2589
 hci_dev_close_sync+0x59e/0x1110 net/bluetooth/hci_sync.c:5195
 hci_dev_do_close+0x2e/0x90 net/bluetooth/hci_core.c:483
 hci_error_reset+0xbf/0x320 net/bluetooth/hci_core.c:1016
 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3229
 process_scheduled_works kernel/workqueue.c:3310 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391
 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
 </TASK>

Allocated by task 6828:
 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:257 [inline]
 __do_kmalloc_node mm/slub.c:4265 [inline]
 __kmalloc_noprof+0x1e8/0x400 mm/slub.c:4277
 kmalloc_noprof include/linux/slab.h:882 [inline]
 sk_prot_alloc+0x1a8/0x2a0 net/core/sock.c:2164
 sk_alloc+0x36/0xb90 net/core/sock.c:2217
 bt_sock_alloc+0x3b/0x3a0 net/bluetooth/af_bluetooth.c:148
 l2cap_sock_alloc.constprop.0+0x35/0x180 net/bluetooth/l2cap_sock.c:1877
 l2cap_sock_create+0x123/0x1f0 net/bluetooth/l2cap_sock.c:1917
 bt_sock_create+0x182/0x350 net/bluetooth/af_bluetooth.c:132
 __sock_create+0x32e/0x800 net/socket.c:1576
 sock_create net/socket.c:1627 [inline]
 __sys_socket_create net/socket.c:1664 [inline]
 __sys_socket+0x14f/0x260 net/socket.c:1711
 __do_sys_socket net/socket.c:1725 [inline]
 __se_sys_socket net/socket.c:1723 [inline]
 __x64_sys_socket+0x72/0xb0 net/socket.c:1723
 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

Freed by task 6826:
 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:579
 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:230 [inline]
 slab_free_hook mm/slub.c:2343 [inline]
 slab_free mm/slub.c:4580 [inline]
 kfree+0x14f/0x4b0 mm/slub.c:4728
 sk_prot_free net/core/sock.c:2200 [inline]
 __sk_destruct+0x5eb/0x720 net/core/sock.c:2292
 sk_destruct+0xc2/0xf0 net/core/sock.c:2307
 __sk_free+0xf4/0x3e0 net/core/sock.c:2318
 sk_free+0x6a/0x90 net/core/sock.c:2329
 sock_put include/net/sock.h:1886 [inline]
 l2cap_sock_kill net/bluetooth/l2cap_sock.c:1250 [inline]
 l2cap_sock_kill+0x171/0x2d0 net/bluetooth/l2cap_sock.c:1235
 l2cap_sock_release+0x189/0x210 net/bluetooth/l2cap_sock.c:1421
 __sock_release+0xb0/0x270 net/socket.c:658
 sock_close+0x1c/0x30 net/socket.c:1426
 __fput+0x3f6/0xb60 fs/file_table.c:431
 task_work_run+0x14e/0x250 kernel/task_work.c:228
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x27b/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 ffff888060bda000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1360 bytes inside of
 freed 2048-byte region [ffff888060bda000, ffff888060bda800)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x60bd8
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 ffff88801b042f00 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000080008 00000001f5000000 0000000000000000
head: 00fff00000000040 ffff88801b042f00 dead000000000100 dead000000000122
head: 0000000000000000 0000000000080008 00000001f5000000 0000000000000000
head: 00fff00000000003 ffffea000182f601 ffffffffffffffff 0000000000000000
head: 0000000000000008 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 69, tgid 69 (kworker/u32:4), ts 99405147984, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1537
 prep_new_page mm/page_alloc.c:1545 [inline]
 get_page_from_freelist+0x101e/0x3070 mm/page_alloc.c:3457
 __alloc_pages_noprof+0x223/0x25c0 mm/page_alloc.c:4733
 alloc_pages_mpol_noprof+0x2c9/0x610 mm/mempolicy.c:2265
 alloc_slab_page mm/slub.c:2413 [inline]
 allocate_slab mm/slub.c:2579 [inline]
 new_slab+0x2ba/0x3f0 mm/slub.c:2632
 ___slab_alloc+0xdac/0x1880 mm/slub.c:3819
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3909
 __slab_alloc_node mm/slub.c:3962 [inline]
 slab_alloc_node mm/slub.c:4123 [inline]
 __do_kmalloc_node mm/slub.c:4264 [inline]
 __kmalloc_node_track_caller_noprof+0x355/0x430 mm/slub.c:4284
 kmalloc_reserve+0xef/0x2c0 net/core/skbuff.c:609
 __alloc_skb+0x164/0x380 net/core/skbuff.c:678
 alloc_skb include/linux/skbuff.h:1322 [inline]
 alloc_skb_with_frags+0xe4/0x850 net/core/skbuff.c:6612
 sock_alloc_send_pskb+0x7f1/0x980 net/core/sock.c:2883
 sock_alloc_send_skb include/net/sock.h:1780 [inline]
 mld_newpack.isra.0+0x1ed/0x790 net/ipv6/mcast.c:1747
 add_grhead+0x299/0x340 net/ipv6/mcast.c:1850
 add_grec+0x111e/0x1670 net/ipv6/mcast.c:1988
 mld_send_initial_cr.part.0+0xe2/0x260 net/ipv6/mcast.c:2234
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888060bda400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888060bda480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888060bda500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff888060bda580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888060bda600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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