BUG: sleeping function called from invalid context in tpk_write

From: syzbot
Date: Sat Dec 07 2019 - 12:25:42 EST

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Hello,

syzbot found the following crash on:

HEAD commit: eea2d5da Merge tag 'for-linus' of git://git.armlinux.org.u..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1706d1bce00000
kernel config: https://syzkaller.appspot.com/x/.config?x=f07a23020fd7d21a
dashboard link: https://syzkaller.appspot.com/bug?extid=2eeef62ee31f9460ad65
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1199bb7ae00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=109fd77ae00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+2eeef62ee31f9460ad65@xxxxxxxxxxxxxxxxxxxxxxxxx

BUG: sleeping function called from invalid context at kernel/locking/mutex.c:938
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 0, name: swapper/1
1 lock held by swapper/1/0:
#0: ffffc90000da8d50 ((&sp->resync_t)){+.-.}, at: lockdep_copy_map include/linux/lockdep.h:172 [inline]
#0: ffffc90000da8d50 ((&sp->resync_t)){+.-.}, at: call_timer_fn+0xe0/0x780 kernel/time/timer.c:1394
Preemption disabled at:
[<ffffffff8130614e>] start_secondary+0xde/0x410 arch/x86/kernel/smpboot.c:228
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.4.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x197/0x210 lib/dump_stack.c:118
___might_sleep.cold+0x1fb/0x23e kernel/sched/core.c:6800
__might_sleep+0x95/0x190 kernel/sched/core.c:6753
__mutex_lock_common kernel/locking/mutex.c:938 [inline]
__mutex_lock+0xc5/0x13c0 kernel/locking/mutex.c:1106
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1121
tpk_write+0x5d/0x340 drivers/char/ttyprintk.c:122
resync_tnc+0x1b6/0x320 drivers/net/hamradio/6pack.c:522
call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1404
expire_timers kernel/time/timer.c:1449 [inline]
__run_timers kernel/time/timer.c:1773 [inline]
__run_timers kernel/time/timer.c:1740 [inline]
run_timer_softirq+0x6c3/0x1790 kernel/time/timer.c:1786
__do_softirq+0x262/0x98c kernel/softirq.c:292
invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0x19b/0x1e0 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:536 [inline]
smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1137
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
</IRQ>
RIP: 0010:native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:61
Code: 98 81 eb f9 eb 8a cc cc cc cc cc cc e9 07 00 00 00 0f 00 2d 04 83 61 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d f4 82 61 00 fb f4 <c3> cc 55 48 89 e5 41 57 41 56 41 55 41 54 53 e8 ce 93 9b f9 e8 79
RSP: 0018:ffffc90000d3fd68 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff13266ae RBX: ffff8880a99fa340 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffff8880a99fabd4
RBP: ffffc90000d3fd98 R08: ffff8880a99fa340 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000
R13: ffffffff8a790e80 R14: 0000000000000000 R15: 0000000000000001
arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:690
default_idle_call+0x84/0xb0 kernel/sched/idle.c:94
cpuidle_idle_call kernel/sched/idle.c:154 [inline]
do_idle+0x3c8/0x6e0 kernel/sched/idle.c:269
cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:361
start_secondary+0x2f4/0x410 arch/x86/kernel/smpboot.c:264
secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242

================================
WARNING: inconsistent lock state
5.4.0-syzkaller #0 Tainted: G W
--------------------------------
inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
swapper/1/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
ffffffff8c110ab0 (&tpk_port.port_write_mutex){+.?.}, at: tpk_write+0x5d/0x340 drivers/char/ttyprintk.c:122
{SOFTIRQ-ON-W} state was registered at:
lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4485
__mutex_lock_common kernel/locking/mutex.c:959 [inline]
__mutex_lock+0x156/0x13c0 kernel/locking/mutex.c:1106
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1121
tpk_write+0x5d/0x340 drivers/char/ttyprintk.c:122
tnc_init drivers/net/hamradio/6pack.c:536 [inline]
sixpack_open+0x8d6/0xaaf drivers/net/hamradio/6pack.c:632
tty_ldisc_open.isra.0+0xa3/0x110 drivers/tty/tty_ldisc.c:464
tty_set_ldisc+0x30e/0x6b0 drivers/tty/tty_ldisc.c:591
tiocsetd drivers/tty/tty_io.c:2337 [inline]
tty_ioctl+0xe8d/0x14f0 drivers/tty/tty_io.c:2597
vfs_ioctl fs/ioctl.c:47 [inline]
file_ioctl fs/ioctl.c:545 [inline]
do_vfs_ioctl+0x977/0x14e0 fs/ioctl.c:732
ksys_ioctl+0xab/0xd0 fs/ioctl.c:749
__do_sys_ioctl fs/ioctl.c:756 [inline]
__se_sys_ioctl fs/ioctl.c:754 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
irq event stamp: 195718
hardirqs last enabled at (195718): [<ffffffff81006743>] trace_hardirqs_on_thunk+0x1a/0x1c arch/x86/entry/thunk_64.S:41
hardirqs last disabled at (195717): [<ffffffff8100675f>] trace_hardirqs_off_thunk+0x1a/0x1c arch/x86/entry/thunk_64.S:42
softirqs last enabled at (195642): [<ffffffff814732ac>] _local_bh_enable+0x1c/0x30 kernel/softirq.c:162
softirqs last disabled at (195643): [<ffffffff81475cab>] invoke_softirq kernel/softirq.c:373 [inline]
softirqs last disabled at (195643): [<ffffffff81475cab>] irq_exit+0x19b/0x1e0 kernel/softirq.c:413

other info that might help us debug this:
Possible unsafe locking scenario:

CPU0
----
lock(&tpk_port.port_write_mutex);
<Interrupt>
lock(&tpk_port.port_write_mutex);

*** DEADLOCK ***

1 lock held by swapper/1/0:
#0: ffffc90000da8d50 ((&sp->resync_t)){+.-.}, at: lockdep_copy_map include/linux/lockdep.h:172 [inline]
#0: ffffc90000da8d50 ((&sp->resync_t)){+.-.}, at: call_timer_fn+0xe0/0x780 kernel/time/timer.c:1394

stack backtrace:
CPU: 1 PID: 0 Comm: swapper/1 Tainted: G W 5.4.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x197/0x210 lib/dump_stack.c:118
print_usage_bug.cold+0x327/0x378 kernel/locking/lockdep.c:3101
valid_state kernel/locking/lockdep.c:3112 [inline]
mark_lock_irq kernel/locking/lockdep.c:3309 [inline]
mark_lock+0xbb4/0x1220 kernel/locking/lockdep.c:3666
mark_usage kernel/locking/lockdep.c:3566 [inline]
__lock_acquire+0x1e8e/0x4a00 kernel/locking/lockdep.c:3909
lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4485
__mutex_lock_common kernel/locking/mutex.c:959 [inline]
__mutex_lock+0x156/0x13c0 kernel/locking/mutex.c:1106
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1121
tpk_write+0x5d/0x340 drivers/char/ttyprintk.c:122
resync_tnc+0x1b6/0x320 drivers/net/hamradio/6pack.c:522
call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1404
expire_timers kernel/time/timer.c:1449 [inline]
__run_timers kernel/time/timer.c:1773 [inline]
__run_timers kernel/time/timer.c:1740 [inline]
run_timer_softirq+0x6c3/0x1790 kernel/time/timer.c:1786
__do_softirq+0x262/0x98c kernel/softirq.c:292
invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0x19b/0x1e0 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:536 [inline]
smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1137
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
</IRQ>
RIP: 0010:native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:61
Code: 98 81 eb f9 eb 8a cc cc cc cc cc cc e9 07 00 00 00 0f 00 2d 04 83 61 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d f4 82 61 00 fb f4 <c3> cc 55 48 89 e5 41 57 41 56 41 55 41 54 53 e8 ce 93 9b f9 e8 79
RSP: 0018:ffffc90000d3fd68 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff13266ae RBX: ffff8880a99fa340 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000006 RDI: ffff8880a99fabd4
RBP: ffffc90000d3fd98 R08: ffff8880a99fa340 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000
R13: ffffffff8a790e80 R14: 0000000000000000 R15: 0000000000000001
arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:690
default_idle_call+0x84/0xb0 kernel/sched/idle.c:94
cpuidle_idle_call kernel/sched/idle.c:154 [inline]
do_idle+0x3c8/0x6e0 kernel/sched/idle.c:269
cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:361
start_secondary+0x2f4/0x410 arch/x86/kernel/smpboot.c:264
secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242
------------[ cut here ]------------
WARNING: CPU: 1 PID: 0 at kernel/locking/mutex.c:737 mutex_unlock+0x1d/0x30 kernel/locking/mutex.c:744

---
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Next message: Jeffrin Jose: "[PROBLEM]: WARNING: lock held when returning to user space! (5.4.1 #16 Tainted: G )"
Previous message: syzbot: "INFO: task hung in tty_ldisc_hangup"
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