From: Yanfei Xu <yanfei.xu@xxxxxxxxxxxxx> Locking slock-AF_BLUETOOTH-BTPROTO_SCO may happen in process context or BH context. If in process context, we should use lock_sock(). As blow warning, sco_conn_del() is called in process context, so let's use lock_sock() instead of bh_lock_sock(). ================================ WARNING: inconsistent lock state 5.9.0-rc4-syzkaller #0 Not tainted -------------------------------- inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage. syz-executor675/31233 [HC0[0]:SC0[0]:HE1:SE1] takes: ffff8880a75c50a0 (slock-AF_BLUETOOTH-BTPROTO_SCO){+.?.}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline] ffff8880a75c50a0 (slock-AF_BLUETOOTH-BTPROTO_SCO){+.?.}-{2:2}, at: sco_conn_del+0x128/0x270 net/bluetooth/sco.c:176 {IN-SOFTIRQ-W} state was registered at: lock_acquire+0x1f3/0xae0 kernel/locking/lockdep.c:5006 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:354 [inline] sco_sock_timeout+0x24/0x140 net/bluetooth/sco.c:83 call_timer_fn+0x1ac/0x760 kernel/time/timer.c:1413 expire_timers kernel/time/timer.c:1458 [inline] __run_timers.part.0+0x67c/0xaa0 kernel/time/timer.c:1755 __run_timers kernel/time/timer.c:1736 [inline] run_timer_softirq+0xae/0x1a0 kernel/time/timer.c:1768 __do_softirq+0x1f7/0xa91 kernel/softirq.c:298 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline] do_softirq_own_stack+0x9d/0xd0 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:393 [inline] __irq_exit_rcu kernel/softirq.c:423 [inline] irq_exit_rcu+0x235/0x280 kernel/softirq.c:435 sysvec_apic_timer_interrupt+0x51/0xf0 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581 unwind_next_frame+0x139a/0x1f90 arch/x86/kernel/unwind_orc.c:607 arch_stack_walk+0x81/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:123 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 slab_post_alloc_hook mm/slab.h:518 [inline] slab_alloc mm/slab.c:3312 [inline] kmem_cache_alloc+0x13a/0x3a0 mm/slab.c:3482 __d_alloc+0x2a/0x950 fs/dcache.c:1709 d_alloc+0x4a/0x230 fs/dcache.c:1788 d_alloc_parallel+0xe9/0x18e0 fs/dcache.c:2540 lookup_open.isra.0+0x9ac/0x1350 fs/namei.c:3030 open_last_lookups fs/namei.c:3177 [inline] path_openat+0x96d/0x2730 fs/namei.c:3365 do_filp_open+0x17e/0x3c0 fs/namei.c:3395 do_sys_openat2+0x16d/0x420 fs/open.c:1168 do_sys_open fs/open.c:1184 [inline] __do_sys_open fs/open.c:1192 [inline] __se_sys_open fs/open.c:1188 [inline] __x64_sys_open+0x119/0x1c0 fs/open.c:1188 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 irq event stamp: 853 hardirqs last enabled at (853): [<ffffffff87f733af>] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline] hardirqs last enabled at (853): [<ffffffff87f733af>] _raw_spin_unlock_irq+0x1f/0x80 kernel/locking/spinlock.c:199 hardirqs last disabled at (852): [<ffffffff87f73764>] __raw_spin_lock_irq include/linux/spinlock_api_smp.h:126 [inline] hardirqs last disabled at (852): [<ffffffff87f73764>] _raw_spin_lock_irq+0xa4/0xd0 kernel/locking/spinlock.c:167 softirqs last enabled at (0): [<ffffffff8144c929>] copy_process+0x1a99/0x6920 kernel/fork.c:2018 softirqs last disabled at (0): [<0000000000000000>] 0x0 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(slock-AF_BLUETOOTH-BTPROTO_SCO); <Interrupt> lock(slock-AF_BLUETOOTH-BTPROTO_SCO); *** DEADLOCK *** 3 locks held by syz-executor675/31233: #0: ffff88809f104f40 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0xf5/0x1080 net/bluetooth/hci_core.c:1720 #1: ffff88809f104078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_do_close+0x253/0x1080 net/bluetooth/hci_core.c:1757 #2: ffffffff8a9188c8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1435 [inline] #2: ffffffff8a9188c8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xc7/0x220 net/bluetooth/hci_conn.c:1557 stack backtrace: CPU: 1 PID: 31233 Comm: syz-executor675 Not tainted 5.9.0-rc4-syzkaller Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x198/0x1fd lib/dump_stack.c:118 print_usage_bug kernel/locking/lockdep.c:4020 [inline] valid_state kernel/locking/lockdep.c:3361 [inline] mark_lock_irq kernel/locking/lockdep.c:3560 [inline] mark_lock.cold+0x7a/0x7f kernel/locking/lockdep.c:4006 mark_usage kernel/locking/lockdep.c:3923 [inline] __lock_acquire+0x876/0x5570 kernel/locking/lockdep.c:4380 lock_acquire+0x1f3/0xae0 kernel/locking/lockdep.c:5006 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:354 [inline] sco_conn_del+0x128/0x270 net/bluetooth/sco.c:176 sco_disconn_cfm net/bluetooth/sco.c:1178 [inline] sco_disconn_cfm+0x62/0x80 net/bluetooth/sco.c:1171 hci_disconn_cfm include/net/bluetooth/hci_core.h:1438 [inline] hci_conn_hash_flush+0x114/0x220 net/bluetooth/hci_conn.c:1557 hci_dev_do_close+0x5c6/0x1080 net/bluetooth/hci_core.c:1770 hci_unregister_dev+0x1bd/0xe30 net/bluetooth/hci_core.c:3790 vhci_release+0x70/0xe0 drivers/bluetooth/hci_vhci.c:340 __fput+0x285/0x920 fs/file_table.c:281 task_work_run+0xdd/0x190 kernel/task_work.c:141 exit_task_work include/linux/task_work.h:25 [inline] do_exit+0xb7d/0x29f0 kernel/exit.c:806 do_group_exit+0x125/0x310 kernel/exit.c:903 get_signal+0x428/0x1f00 kernel/signal.c:2757 arch_do_signal+0x82/0x2520 arch/x86/kernel/signal.c:811 exit_to_user_mode_loop kernel/entry/common.c:159 [inline] exit_to_user_mode_prepare+0x1ae/0x200 kernel/entry/common.c:190 syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:265 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x447279 Reported-by: syzbot+65684128cd7c35bc66a1@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Yanfei Xu <yanfei.xu@xxxxxxxxxxxxx> --- net/bluetooth/sco.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c index dcf7f96ff417..559b883c815f 100644 --- a/net/bluetooth/sco.c +++ b/net/bluetooth/sco.c @@ -173,10 +173,10 @@ static void sco_conn_del(struct hci_conn *hcon, int err) if (sk) { sock_hold(sk); - bh_lock_sock(sk); + lock_sock(sk); sco_sock_clear_timer(sk); sco_chan_del(sk, err); - bh_unlock_sock(sk); + release_sock(sk); sco_sock_kill(sk); sock_put(sk); } -- 2.18.2