syzbot

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BUG: KASAN: slab-use-after-free in instrument_atomic_read include/linux/instrumented.h:68 [inline]
BUG: KASAN: slab-use-after-free in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
BUG: KASAN: slab-use-after-free in sock_flag include/net/sock.h:986 [inline]
BUG: KASAN: slab-use-after-free in l2cap_sock_kill+0x1f/0x2d0 net/bluetooth/l2cap_sock.c:1237
Read of size 8 at addr ffff8880635a6060 by task syz.0.248/6939

CPU: 2 UID: 0 PID: 6939 Comm: syz.0.248 Not tainted 6.12.0-syzkaller-00233-g9fb2cfa4635a #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
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
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 sock_flag include/net/sock.h:986 [inline]
 l2cap_sock_kill+0x1f/0x2d0 net/bluetooth/l2cap_sock.c:1237
 l2cap_sock_cleanup_listen+0x3d/0x2a0 net/bluetooth/l2cap_sock.c:1448
 l2cap_sock_release+0x5c/0x210 net/bluetooth/l2cap_sock.c:1411
 __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
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0xadd/0x2d70 kernel/exit.c:938
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1087
 get_signal+0x2658/0x26d0 kernel/signal.c:2918
 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:328 [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_fast_syscall_32+0x80/0x120 arch/x86/entry/common.c:389
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf747e579
Code: Unable to access opcode bytes at 0xf747e54f.
RSP: 002b:00000000f576655c EFLAGS: 00000296 ORIG_RAX: 0000000000000003
RAX: 0000000000018ff8 RBX: 0000000000000003 RCX: 0000000020019680
RDX: 0000000000018ff8 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

Allocated by task 66:
 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:4264 [inline]
 __kmalloc_noprof+0x1e8/0x410 mm/slub.c:4276
 kmalloc_noprof include/linux/slab.h:882 [inline]
 sk_prot_alloc+0x1a8/0x2a0 net/core/sock.c:2170
 sk_alloc+0x36/0xb90 net/core/sock.c:2223
 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_new_connection_cb+0x101/0x240 net/bluetooth/l2cap_sock.c:1468
 l2cap_connect_cfm+0x4c9/0xf90 net/bluetooth/l2cap_core.c:7261
 hci_connect_cfm include/net/bluetooth/hci_core.h:1960 [inline]
 le_conn_complete_evt+0x15f9/0x1cf0 net/bluetooth/hci_event.c:5758
 hci_le_conn_complete_evt+0x23c/0x370 net/bluetooth/hci_event.c:5784
 hci_le_meta_evt+0x2e2/0x5d0 net/bluetooth/hci_event.c:7132
 hci_event_func net/bluetooth/hci_event.c:7440 [inline]
 hci_event_packet+0x666/0x1190 net/bluetooth/hci_event.c:7495
 hci_rx_work+0x2c6/0x1610 net/bluetooth/hci_core.c:4029
 process_one_work+0x958/0x1b30 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

Freed by task 7163:
 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:2342 [inline]
 slab_free mm/slub.c:4579 [inline]
 kfree+0x14f/0x4b0 mm/slub.c:4727
 sk_prot_free net/core/sock.c:2206 [inline]
 __sk_destruct+0x5eb/0x720 net/core/sock.c:2298
 sk_destruct+0xc2/0xf0 net/core/sock.c:2313
 __sk_free+0xf4/0x3e0 net/core/sock.c:2324
 sk_free+0x6a/0x90 net/core/sock.c:2335
 sock_put include/net/sock.h:1888 [inline]
 l2cap_sock_kill net/bluetooth/l2cap_sock.c:1250 [inline]
 l2cap_sock_kill+0x171/0x2d0 net/bluetooth/l2cap_sock.c:1235
 l2cap_sock_close_cb+0x44/0x60 net/bluetooth/l2cap_sock.c:1557
 l2cap_conn_del+0x3bb/0x730 net/bluetooth/l2cap_core.c:1787
 l2cap_disconn_cfm net/bluetooth/l2cap_core.c:7299 [inline]
 l2cap_disconn_cfm+0x96/0xd0 net/bluetooth/l2cap_core.c:7292
 hci_disconn_cfm include/net/bluetooth/hci_core.h:1975 [inline]
 hci_conn_hash_flush+0x114/0x260 net/bluetooth/hci_conn.c:2592
 hci_dev_close_sync+0x59e/0x1260 net/bluetooth/hci_sync.c:5205
 hci_dev_do_close+0x2e/0x90 net/bluetooth/hci_core.c:483
 hci_unregister_dev+0x213/0x620 net/bluetooth/hci_core.c:2698
 vhci_release+0x79/0xf0 drivers/bluetooth/hci_vhci.c:664
 __fput+0x3f8/0xb60 fs/file_table.c:450
 task_work_run+0x14e/0x250 kernel/task_work.c:239
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0xadd/0x2d70 kernel/exit.c:938
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1087
 get_signal+0x2658/0x26d0 kernel/signal.c:2918
 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:328 [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_fast_syscall_32+0x80/0x120 arch/x86/entry/common.c:389
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

The buggy address belongs to the object at ffff8880635a6000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 96 bytes inside of
 freed 2048-byte region [ffff8880635a6000, ffff8880635a6800)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880635a5000 pfn:0x635a0
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x4fff00000000240(workingset|head|node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000240 ffff88801ac42f00 ffffea0001e6e410 ffffea0001cd3210
raw: ffff8880635a5000 0000000000080006 00000001f5000000 0000000000000000
head: 04fff00000000240 ffff88801ac42f00 ffffea0001e6e410 ffffea0001cd3210
head: ffff8880635a5000 0000000000080006 00000001f5000000 0000000000000000
head: 04fff00000000003 ffffea00018d6801 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 5960, tgid 5960 (syz-executor), ts 37089332562, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1556
 prep_new_page mm/page_alloc.c:1564 [inline]
 get_page_from_freelist+0xfce/0x2f80 mm/page_alloc.c:3474
 __alloc_pages_noprof+0x223/0x25a0 mm/page_alloc.c:4751
 alloc_pages_mpol_noprof+0x2c9/0x610 mm/mempolicy.c:2265
 alloc_slab_page mm/slub.c:2412 [inline]
 allocate_slab mm/slub.c:2578 [inline]
 new_slab+0x2c9/0x410 mm/slub.c:2631
 ___slab_alloc+0xd1d/0x16f0 mm/slub.c:3818
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3908
 __slab_alloc_node mm/slub.c:3961 [inline]
 slab_alloc_node mm/slub.c:4122 [inline]
 __kmalloc_cache_noprof+0x2c5/0x310 mm/slub.c:4290
 kmalloc_noprof include/linux/slab.h:878 [inline]
 kzalloc_noprof include/linux/slab.h:1014 [inline]
 rxrpc_alloc_connection+0x8b/0x6e0 net/rxrpc/conn_object.c:62
 rxrpc_prealloc_service_connection+0x26/0x380 net/rxrpc/conn_service.c:123
 rxrpc_service_prealloc_one+0x2bf/0xee0 net/rxrpc/call_accept.c:87
 rxrpc_kernel_charge_accept+0xd7/0x120 net/rxrpc/call_accept.c:475
 afs_charge_preallocation+0xce/0x330 fs/afs/rxrpc.c:747
 afs_open_socket+0x298/0x350 fs/afs/rxrpc.c:95
 afs_net_init+0x95d/0xc60 fs/afs/main.c:123
 ops_init+0x1df/0x5f0 net/core/net_namespace.c:139
page_owner free stack trace missing

Memory state around the buggy address:
 ffff8880635a5f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880635a5f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880635a6000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                       ^
 ffff8880635a6080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880635a6100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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