[v5.15] possible deadlock in sco_connect_cfm

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May 13, 2024, 3:57:35 PMMay 13
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Hello,

syzbot found the following issue on:

HEAD commit: 284087d4f7d5 Linux 5.15.158
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=13e50798980000
kernel config: https://syzkaller.appspot.com/x/.config?x=ab74f93e8454887c
dashboard link: https://syzkaller.appspot.com/bug?extid=03a15155073eda6f603b
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/0accc7dacf9d/disk-284087d4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fb6b5b110f8c/vmlinux-284087d4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6763bebdbfea/Image-284087d4.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+03a151...@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
5.15.158-syzkaller #0 Not tainted
------------------------------------------------------
kworker/u5:0/144 is trying to acquire lock:
ffff0000ee262120 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1668 [inline]
ffff0000ee262120 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_conn_ready net/bluetooth/sco.c:1106 [inline]
ffff0000ee262120 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_connect_cfm+0x140/0x908 net/bluetooth/sco.c:1197

but task is already holding lock:
ffff800016b7a068 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_connect_cfm include/net/bluetooth/hci_core.h:1507 [inline]
ffff800016b7a068 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_complete_evt+0xa74/0x11f8 net/bluetooth/hci_event.c:2796

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (hci_cb_list_lock){+.+.}-{3:3}:
__mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743
hci_connect_cfm include/net/bluetooth/hci_core.h:1507 [inline]
hci_remote_features_evt+0x480/0x940 net/bluetooth/hci_event.c:3352
hci_event_packet+0x5ec/0x12b4 net/bluetooth/hci_event.c:6421
hci_rx_work+0x1c0/0x7c4 net/bluetooth/hci_core.c:5156
process_one_work+0x790/0x11b8 kernel/workqueue.c:2310
worker_thread+0x910/0x1034 kernel/workqueue.c:2457
kthread+0x37c/0x45c kernel/kthread.c:334
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870

-> #1 (&hdev->lock){+.+.}-{3:3}:
__mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743
sco_sock_connect+0x170/0x848 net/bluetooth/sco.c:587
__sys_connect_file net/socket.c:1918 [inline]
__sys_connect+0x268/0x290 net/socket.c:1935
__do_sys_connect net/socket.c:1945 [inline]
__se_sys_connect net/socket.c:1942 [inline]
__arm64_sys_connect+0x7c/0x94 net/socket.c:1942
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain kernel/locking/lockdep.c:3788 [inline]
__lock_acquire+0x32d4/0x7638 kernel/locking/lockdep.c:5012
lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623
lock_sock_nested+0xec/0x1ec net/core/sock.c:3250
lock_sock include/net/sock.h:1668 [inline]
sco_conn_ready net/bluetooth/sco.c:1106 [inline]
sco_connect_cfm+0x140/0x908 net/bluetooth/sco.c:1197
hci_connect_cfm include/net/bluetooth/hci_core.h:1510 [inline]
hci_conn_complete_evt+0xad8/0x11f8 net/bluetooth/hci_event.c:2796
hci_event_packet+0x8c0/0x12b4 net/bluetooth/hci_event.c:6393
hci_rx_work+0x1c0/0x7c4 net/bluetooth/hci_core.c:5156
process_one_work+0x790/0x11b8 kernel/workqueue.c:2310
worker_thread+0x910/0x1034 kernel/workqueue.c:2457
kthread+0x37c/0x45c kernel/kthread.c:334
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870

other info that might help us debug this:

Chain exists of:
sk_lock-AF_BLUETOOTH-BTPROTO_SCO --> &hdev->lock --> hci_cb_list_lock

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(hci_cb_list_lock);
lock(&hdev->lock);
lock(hci_cb_list_lock);
lock(sk_lock-AF_BLUETOOTH-BTPROTO_SCO);

*** DEADLOCK ***

4 locks held by kworker/u5:0/144:
#0: ffff0000dab05138 ((wq_completion)hci4#2){+.+.}-{0:0}, at: process_one_work+0x66c/0x11b8 kernel/workqueue.c:2283
#1: ffff80001a417c00 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_one_work+0x6ac/0x11b8 kernel/workqueue.c:2285
#2: ffff0000d79f0078 (&hdev->lock){+.+.}-{3:3}, at: hci_conn_complete_evt+0xc0/0x11f8 net/bluetooth/hci_event.c:2672
#3: ffff800016b7a068 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_connect_cfm include/net/bluetooth/hci_core.h:1507 [inline]
#3: ffff800016b7a068 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_complete_evt+0xa74/0x11f8 net/bluetooth/hci_event.c:2796

stack backtrace:
CPU: 1 PID: 144 Comm: kworker/u5:0 Not tainted 5.15.158-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: hci4 hci_rx_work
Call trace:
dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
dump_stack+0x1c/0x58 lib/dump_stack.c:113
print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2011
check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2133
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain kernel/locking/lockdep.c:3788 [inline]
__lock_acquire+0x32d4/0x7638 kernel/locking/lockdep.c:5012
lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623
lock_sock_nested+0xec/0x1ec net/core/sock.c:3250
lock_sock include/net/sock.h:1668 [inline]
sco_conn_ready net/bluetooth/sco.c:1106 [inline]
sco_connect_cfm+0x140/0x908 net/bluetooth/sco.c:1197
hci_connect_cfm include/net/bluetooth/hci_core.h:1510 [inline]
hci_conn_complete_evt+0xad8/0x11f8 net/bluetooth/hci_event.c:2796
hci_event_packet+0x8c0/0x12b4 net/bluetooth/hci_event.c:6393
hci_rx_work+0x1c0/0x7c4 net/bluetooth/hci_core.c:5156
process_one_work+0x790/0x11b8 kernel/workqueue.c:2310
worker_thread+0x910/0x1034 kernel/workqueue.c:2457
kthread+0x37c/0x45c kernel/kthread.c:334
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870
==================================================================
BUG: KASAN: use-after-free in debug_spin_lock_before kernel/locking/spinlock_debug.c:85 [inline]
BUG: KASAN: use-after-free in do_raw_spin_lock+0x244/0x35c kernel/locking/spinlock_debug.c:114
Read of size 4 at addr ffff0000ee26208c by task kworker/u5:0/144

CPU: 1 PID: 144 Comm: kworker/u5:0 Not tainted 5.15.158-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: hci4 hci_rx_work
Call trace:
dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
print_address_description+0x7c/0x3f0 mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:434 [inline]
kasan_report+0x174/0x1e4 mm/kasan/report.c:451
__asan_report_load4_noabort+0x44/0x50 mm/kasan/report_generic.c:308
debug_spin_lock_before kernel/locking/spinlock_debug.c:85 [inline]
do_raw_spin_lock+0x244/0x35c kernel/locking/spinlock_debug.c:114
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:136 [inline]
_raw_spin_lock_bh+0x12c/0x1c4 kernel/locking/spinlock.c:178
spin_lock_bh include/linux/spinlock.h:368 [inline]
lock_sock_nested+0x108/0x1ec net/core/sock.c:3253
lock_sock include/net/sock.h:1668 [inline]
sco_conn_ready net/bluetooth/sco.c:1106 [inline]
sco_connect_cfm+0x140/0x908 net/bluetooth/sco.c:1197
hci_connect_cfm include/net/bluetooth/hci_core.h:1510 [inline]
hci_conn_complete_evt+0xad8/0x11f8 net/bluetooth/hci_event.c:2796
hci_event_packet+0x8c0/0x12b4 net/bluetooth/hci_event.c:6393
hci_rx_work+0x1c0/0x7c4 net/bluetooth/hci_core.c:5156
process_one_work+0x790/0x11b8 kernel/workqueue.c:2310
worker_thread+0x910/0x1034 kernel/workqueue.c:2457
kthread+0x37c/0x45c kernel/kthread.c:334
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870

Allocated by task 5520:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
____kasan_kmalloc+0xbc/0xfc mm/kasan/common.c:513
__kasan_kmalloc+0x10/0x1c mm/kasan/common.c:522
kasan_kmalloc include/linux/kasan.h:264 [inline]
__kmalloc+0x29c/0x4c8 mm/slub.c:4407
kmalloc include/linux/slab.h:596 [inline]
sk_prot_alloc+0xc4/0x1f0 net/core/sock.c:1863
sk_alloc+0x40/0x3e0 net/core/sock.c:1916
sco_sock_alloc net/bluetooth/sco.c:481 [inline]
sco_sock_create+0xb8/0x2d4 net/bluetooth/sco.c:516
bt_sock_create+0x14c/0x248 net/bluetooth/af_bluetooth.c:130
__sock_create+0x43c/0x884 net/socket.c:1486
sock_create net/socket.c:1537 [inline]
__sys_socket+0x168/0x310 net/socket.c:1579
__do_sys_socket net/socket.c:1588 [inline]
__se_sys_socket net/socket.c:1586 [inline]
__arm64_sys_socket+0x7c/0x94 net/socket.c:1586
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Freed by task 5520:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4c/0x84 mm/kasan/common.c:46
kasan_set_free_info+0x28/0x4c mm/kasan/generic.c:360
____kasan_slab_free+0x118/0x164 mm/kasan/common.c:366
__kasan_slab_free+0x18/0x28 mm/kasan/common.c:374
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:1705 [inline]
slab_free_freelist_hook+0x128/0x1ec mm/slub.c:1731
slab_free mm/slub.c:3499 [inline]
kfree+0x178/0x410 mm/slub.c:4559
sk_prot_free net/core/sock.c:1899 [inline]
__sk_destruct+0x418/0x600 net/core/sock.c:1985
sk_destruct net/core/sock.c:2000 [inline]
__sk_free+0x37c/0x4e8 net/core/sock.c:2011
sk_free+0x68/0xdc net/core/sock.c:2022
sock_put include/net/sock.h:1913 [inline]
sco_sock_kill+0x104/0x1c8 net/bluetooth/sco.c:402
sco_sock_release+0x1fc/0x2c0 net/bluetooth/sco.c:1094
__sock_release net/socket.c:649 [inline]
sock_close+0xb8/0x1fc net/socket.c:1336
__fput+0x30c/0x7f0 fs/file_table.c:280
____fput+0x20/0x30 fs/file_table.c:308
task_work_run+0x130/0x1e4 kernel/task_work.c:164
get_signal+0x1450/0x1550 kernel/signal.c:2661
do_signal arch/arm64/kernel/signal.c:890 [inline]
do_notify_resume+0x3d0/0x32b8 arch/arm64/kernel/signal.c:943
prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:133 [inline]
exit_to_user_mode arch/arm64/kernel/entry-common.c:138 [inline]
el0_svc+0xfc/0x1f0 arch/arm64/kernel/entry-common.c:609
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Last potentially related work creation:
kasan_save_stack+0x38/0x68 mm/kasan/common.c:38
kasan_record_aux_stack+0xd4/0x11c mm/kasan/generic.c:348
__call_rcu kernel/rcu/tree.c:3007 [inline]
call_rcu+0x118/0xb40 kernel/rcu/tree.c:3087
in6_dev_finish_destroy+0x154/0x1e0 net/ipv6/addrconf_core.c:278
in6_dev_put include/net/addrconf.h:386 [inline]
addrconf_ifdown+0x1568/0x1814 net/ipv6/addrconf.c:3933
addrconf_notify+0x350/0xc58
notifier_call_chain kernel/notifier.c:83 [inline]
raw_notifier_call_chain+0xd4/0x164 kernel/notifier.c:391
call_netdevice_notifiers_info net/core/dev.c:2018 [inline]
call_netdevice_notifiers_extack net/core/dev.c:2030 [inline]
call_netdevice_notifiers net/core/dev.c:2044 [inline]
unregister_netdevice_many+0xec4/0x189c net/core/dev.c:11093
rtnl_delete_link net/core/rtnetlink.c:3085 [inline]
rtnl_dellink+0x428/0x6cc net/core/rtnetlink.c:3137
rtnetlink_rcv_msg+0xa74/0xdac net/core/rtnetlink.c:5629
netlink_rcv_skb+0x20c/0x3b8 net/netlink/af_netlink.c:2505
rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:5647
netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline]
netlink_unicast+0x664/0x938 net/netlink/af_netlink.c:1356
netlink_sendmsg+0x844/0xb38 net/netlink/af_netlink.c:1924
sock_sendmsg_nosec net/socket.c:704 [inline]
__sock_sendmsg net/socket.c:716 [inline]
____sys_sendmsg+0x584/0x870 net/socket.c:2431
___sys_sendmsg+0x214/0x294 net/socket.c:2485
__sys_sendmsg net/socket.c:2514 [inline]
__do_sys_sendmsg net/socket.c:2523 [inline]
__se_sys_sendmsg net/socket.c:2521 [inline]
__arm64_sys_sendmsg+0x1ac/0x25c net/socket.c:2521
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Second to last potentially related work creation:
kasan_save_stack+0x38/0x68 mm/kasan/common.c:38
kasan_record_aux_stack+0xd4/0x11c mm/kasan/generic.c:348
insert_work+0x64/0x394 kernel/workqueue.c:1366
__queue_work+0xb84/0x114c kernel/workqueue.c:1532
delayed_work_timer_fn+0x74/0x90 kernel/workqueue.c:1657
call_timer_fn+0x19c/0x8f0 kernel/time/timer.c:1451
expire_timers kernel/time/timer.c:1491 [inline]
__run_timers+0x584/0x718 kernel/time/timer.c:1767
run_timer_softirq+0x7c/0x114 kernel/time/timer.c:1780
__do_softirq+0x344/0xdb0 kernel/softirq.c:558

The buggy address belongs to the object at ffff0000ee262000
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 140 bytes inside of
2048-byte region [ffff0000ee262000, ffff0000ee262800)
The buggy address belongs to the page:
page:000000008eaf6d32 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12e260
head:000000008eaf6d32 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000010200 0000000000000000 0000000100000001 ffff0000c0002900
raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff0000ee261f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff0000ee262000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff0000ee262080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff0000ee262100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff0000ee262180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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