INFO: task hung in ld_usb_write

From: syzbot
Date: Tue Oct 22 2019 - 10:54:09 EST

Hello,

syzbot found the following crash on:

HEAD commit: f0df5c1b usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git usb-fuzzer
console output: https://syzkaller.appspot.com/x/log.txt?x=1346948d600000
kernel config: https://syzkaller.appspot.com/x/.config?x=5c6633fa4ed00be5
dashboard link: https://syzkaller.appspot.com/bug?extid=a4fbb3bb76cda0ea4e58
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12721965600000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1274b9b5600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+a4fbb3bb76cda0ea4e58@xxxxxxxxxxxxxxxxxxxxxxxxx

INFO: task syz-executor952:1721 blocked for more than 143 seconds.
Not tainted 5.3.0-rc7+ #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor952 D28344 1721 1719 0x00000000
Call Trace:
schedule+0xca/0x250 kernel/sched/core.c:3947
schedule_timeout+0x440/0xb20 kernel/time/timer.c:1807
do_wait_for_common kernel/sched/completion.c:83 [inline]
__wait_for_common kernel/sched/completion.c:104 [inline]
wait_for_common kernel/sched/completion.c:115 [inline]
wait_for_completion_timeout+0x282/0x3e0 kernel/sched/completion.c:155
usb_start_wait_urb+0x14b/0x2b0 drivers/usb/core/message.c:62
usb_internal_control_msg drivers/usb/core/message.c:101 [inline]
usb_control_msg+0x31c/0x4a0 drivers/usb/core/message.c:152
ld_usb_write+0x856/0xa10 drivers/usb/misc/ldusb.c:577
__vfs_write+0x76/0x100 fs/read_write.c:494
vfs_write+0x262/0x5c0 fs/read_write.c:558
ksys_write+0x1e8/0x250 fs/read_write.c:611
do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440779
Code: Bad RIP value.
RSP: 002b:00007ffd90a29748 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440779
RDX: 0000000000000092 RSI: 0000000020000140 RDI: 0000000000000004
RBP: 00000000006cb018 R08: 000000000000000f R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402000
R13: 0000000000402090 R14: 0000000000000000 R15: 0000000000000000

Showing all locks held in the system:
1 lock held by khungtaskd/23:
#0: 000000002f4ecff1 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x269 kernel/locking/lockdep.c:5254
1 lock held by rsyslogd/1601:
#0: 0000000072e2a5e4 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xe3/0x100 fs/file.c:801
2 locks held by getty/1691:
#0: 00000000f9586bc9 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272
#1: 000000005e9760e3 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x223/0x1ae0 drivers/tty/n_tty.c:2156
2 locks held by getty/1692:
#0: 00000000a3c38810 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272
#1: 0000000069017299 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x223/0x1ae0 drivers/tty/n_tty.c:2156
2 locks held by getty/1693:
#0: 000000002afc8512 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272
#1: 00000000ea2b3359 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x223/0x1ae0 drivers/tty/n_tty.c:2156
2 locks held by getty/1694:
#0: 00000000b24afe2a (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272
#1: 00000000ae0d5444 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x223/0x1ae0 drivers/tty/n_tty.c:2156
2 locks held by getty/1695:
#0: 000000005e2d099e (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272
#1: 0000000029e8b2e6 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x223/0x1ae0 drivers/tty/n_tty.c:2156
2 locks held by getty/1696:
#0: 0000000015792bef (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272
#1: 00000000d9742d8e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x223/0x1ae0 drivers/tty/n_tty.c:2156
2 locks held by getty/1697:
#0: 00000000cbd4d76e (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272
#1: 0000000017b60d7a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x223/0x1ae0 drivers/tty/n_tty.c:2156
1 lock held by syz-executor952/1721:
#0: 000000009a204c0d (&dev->mutex#3){+.+.}, at: ld_usb_write+0x111/0xa10 drivers/usb/misc/ldusb.c:539

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 23 Comm: khungtaskd Not tainted 5.3.0-rc7+ #0
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+0xca/0x13e lib/dump_stack.c:113
nmi_cpu_backtrace.cold+0x55/0x96 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x1b0/0x1c7 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline]
watchdog+0x9a4/0xe50 kernel/hung_task.c:289
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:60 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:103 [inline]
NMI backtrace for cpu 0 skipped: idling at default_idle+0x28/0x2e0 arch/x86/kernel/process.c:580


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