* [syzbot] [serial?] possible deadlock in tty_buffer_flush (3)
@ 2024-09-09 4:46 syzbot
2024-12-31 22:34 ` syzbot
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: syzbot @ 2024-09-09 4:46 UTC (permalink / raw)
To: gregkh, jirislaby, linux-kernel, linux-serial, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: c7fb1692dc01 Merge tag 'for-linus' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17ba5f33980000
kernel config: https://syzkaller.appspot.com/x/.config?x=8524e833fed2d47b
dashboard link: https://syzkaller.appspot.com/bug?extid=52cf91760dcb1dac6376
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: i386
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-c7fb1692.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c786784c3a2b/vmlinux-c7fb1692.xz
kernel image: https://storage.googleapis.com/syzbot-assets/21174af2f4f3/bzImage-c7fb1692.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+52cf91760dcb1dac6376@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
6.11.0-rc6-syzkaller-00048-gc7fb1692dc01 #0 Not tainted
------------------------------------------------------
kworker/1:2/1884 is trying to acquire lock:
ffff88801acb10b8 (&buf->lock){+.+.}-{3:3}, at: tty_buffer_flush+0x72/0x310 drivers/tty/tty_buffer.c:229
but task is already holding lock:
ffffffff8dda7160 (console_lock){+.+.}-{0:0}, at: vc_SAK+0x13/0x310 drivers/tty/vt/vt_ioctl.c:983
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (console_lock){+.+.}-{0:0}:
console_lock+0x7a/0xa0 kernel/printk/printk.c:2735
con_flush_chars+0x5e/0x80 drivers/tty/vt/vt.c:3503
n_tty_write+0xe27/0x1150 drivers/tty/n_tty.c:2405
iterate_tty_write drivers/tty/tty_io.c:1021 [inline]
file_tty_write.constprop.0+0x518/0x9b0 drivers/tty/tty_io.c:1096
new_sync_write fs/read_write.c:497 [inline]
vfs_write+0x6b6/0x1140 fs/read_write.c:590
ksys_write+0x12f/0x260 fs/read_write.c:643
do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
__do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386
do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
-> #1 (&tty->termios_rwsem){++++}-{3:3}:
down_write+0x93/0x200 kernel/locking/rwsem.c:1579
tty_unthrottle+0x1f/0x110 drivers/tty/tty_ioctl.c:103
hci_uart_tty_receive+0x394/0x780 drivers/bluetooth/hci_ldisc.c:625
tty_ldisc_receive_buf+0x153/0x190 drivers/tty/tty_buffer.c:391
tty_port_default_receive_buf+0x70/0xb0 drivers/tty/tty_port.c:37
receive_buf drivers/tty/tty_buffer.c:445 [inline]
flush_to_ldisc+0x264/0x780 drivers/tty/tty_buffer.c:495
process_one_work+0x958/0x1ad0 kernel/workqueue.c:3231
process_scheduled_works kernel/workqueue.c:3312 [inline]
worker_thread+0x6c8/0xed0 kernel/workqueue.c:3389
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
-> #0 (&buf->lock){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3133 [inline]
check_prevs_add kernel/locking/lockdep.c:3252 [inline]
validate_chain kernel/locking/lockdep.c:3868 [inline]
__lock_acquire+0x24ed/0x3cb0 kernel/locking/lockdep.c:5142
lock_acquire kernel/locking/lockdep.c:5759 [inline]
lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5724
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
tty_buffer_flush+0x72/0x310 drivers/tty/tty_buffer.c:229
tty_ldisc_flush+0x64/0xe0 drivers/tty/tty_ldisc.c:388
__do_SAK+0x6a1/0x800 drivers/tty/tty_io.c:3038
vc_SAK+0x7f/0x310 drivers/tty/vt/vt_ioctl.c:993
process_one_work+0x958/0x1ad0 kernel/workqueue.c:3231
process_scheduled_works kernel/workqueue.c:3312 [inline]
worker_thread+0x6c8/0xed0 kernel/workqueue.c:3389
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
other info that might help us debug this:
Chain exists of:
&buf->lock --> &tty->termios_rwsem --> console_lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(console_lock);
lock(&tty->termios_rwsem);
lock(console_lock);
lock(&buf->lock);
*** DEADLOCK ***
4 locks held by kworker/1:2/1884:
#0: ffff88801ac88948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x11f0/0x1ad0 kernel/workqueue.c:3206
#1: ffffc9000ca8fd80 ((work_completion)(&vc_cons[currcons].SAK_work)){+.+.}-{0:0}, at: process_one_work+0x8bb/0x1ad0 kernel/workqueue.c:3207
#2: ffffffff8dda7160 (console_lock){+.+.}-{0:0}, at: vc_SAK+0x13/0x310 drivers/tty/vt/vt_ioctl.c:983
#3: ffff88801281e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref drivers/tty/tty_ldisc.c:263 [inline]
#3: ffff88801281e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_flush+0x1c/0xe0 drivers/tty/tty_ldisc.c:386
stack backtrace:
CPU: 1 UID: 0 PID: 1884 Comm: kworker/1:2 Not tainted 6.11.0-rc6-syzkaller-00048-gc7fb1692dc01 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: events vc_SAK
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:93 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:119
check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2186
check_prev_add kernel/locking/lockdep.c:3133 [inline]
check_prevs_add kernel/locking/lockdep.c:3252 [inline]
validate_chain kernel/locking/lockdep.c:3868 [inline]
__lock_acquire+0x24ed/0x3cb0 kernel/locking/lockdep.c:5142
lock_acquire kernel/locking/lockdep.c:5759 [inline]
lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5724
__mutex_lock_common kernel/locking/mutex.c:608 [inline]
__mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752
tty_buffer_flush+0x72/0x310 drivers/tty/tty_buffer.c:229
tty_ldisc_flush+0x64/0xe0 drivers/tty/tty_ldisc.c:388
__do_SAK+0x6a1/0x800 drivers/tty/tty_io.c:3038
vc_SAK+0x7f/0x310 drivers/tty/vt/vt_ioctl.c:993
process_one_work+0x958/0x1ad0 kernel/workqueue.c:3231
process_scheduled_works kernel/workqueue.c:3312 [inline]
worker_thread+0x6c8/0xed0 kernel/workqueue.c:3389
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
</TASK>
tty tty1: SAK: killed process 11375 (syz.3.1667): by fd#10
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
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(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [syzbot] [serial?] possible deadlock in tty_buffer_flush (3)
2024-09-09 4:46 [syzbot] [serial?] possible deadlock in tty_buffer_flush (3) syzbot
@ 2024-12-31 22:34 ` syzbot
2025-01-18 19:12 ` syzbot
2025-01-20 6:18 ` syzbot
2 siblings, 0 replies; 4+ messages in thread
From: syzbot @ 2024-12-31 22:34 UTC (permalink / raw)
To: gregkh, jirislaby, linux-kernel, linux-serial, syzkaller-bugs
syzbot has found a reproducer for the following issue on:
HEAD commit: ccb98ccef0e5 Merge tag 'platform-drivers-x86-v6.13-4' of g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11615818580000
kernel config: https://syzkaller.appspot.com/x/.config?x=dc863cc90857c683
dashboard link: https://syzkaller.appspot.com/bug?extid=52cf91760dcb1dac6376
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10b9c8b0580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/409ce1fd1fbc/disk-ccb98cce.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3919529a8a5e/vmlinux-ccb98cce.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f6a9eb51806d/bzImage-ccb98cce.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+52cf91760dcb1dac6376@syzkaller.appspotmail.com
input: HID 0926:3333 as /devices/platform/dummy_hcd.0/usb1/1-1/1-1:0.0/0003:0926:3333.0001/input/input5
keytouch 0003:0926:3333.0001: input,hidraw0: USB HID v0.00 Keyboard [HID 0926:3333] on usb-dummy_hcd.0-1/input0
======================================================
WARNING: possible circular locking dependency detected
6.13.0-rc5-syzkaller-00004-gccb98ccef0e5 #0 Not tainted
------------------------------------------------------
kworker/1:3/6008 is trying to acquire lock:
ffff88801b0990b8 (&buf->lock){+.+.}-{4:4}, at: tty_buffer_flush+0x72/0x310 drivers/tty/tty_buffer.c:229
but task is already holding lock:
ffffffff8e1a9040 (console_lock){+.+.}-{0:0}, at: vc_SAK+0x13/0x310 drivers/tty/vt/vt_ioctl.c:983
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (console_lock){+.+.}-{0:0}:
console_lock+0x7a/0xa0 kernel/printk/printk.c:2833
con_flush_chars+0x5e/0x80 drivers/tty/vt/vt.c:3503
__receive_buf drivers/tty/n_tty.c:1644 [inline]
n_tty_receive_buf_common+0xa99/0x1980 drivers/tty/n_tty.c:1739
tty_ldisc_receive_buf+0xa2/0x190 drivers/tty/tty_buffer.c:387
tty_port_default_receive_buf+0x70/0xb0 drivers/tty/tty_port.c:37
receive_buf drivers/tty/tty_buffer.c:445 [inline]
flush_to_ldisc+0x264/0x780 drivers/tty/tty_buffer.c:495
process_one_work+0x9c5/0x1ba0 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
-> #1 (&tty->termios_rwsem){++++}-{4:4}:
down_read+0x9a/0x330 kernel/locking/rwsem.c:1524
n_tty_receive_buf_common+0x85/0x1980 drivers/tty/n_tty.c:1702
tty_ldisc_receive_buf+0xa2/0x190 drivers/tty/tty_buffer.c:387
tty_port_default_receive_buf+0x70/0xb0 drivers/tty/tty_port.c:37
receive_buf drivers/tty/tty_buffer.c:445 [inline]
flush_to_ldisc+0x264/0x780 drivers/tty/tty_buffer.c:495
process_one_work+0x9c5/0x1ba0 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
-> #0 (&buf->lock){+.+.}-{4:4}:
check_prev_add kernel/locking/lockdep.c:3161 [inline]
check_prevs_add kernel/locking/lockdep.c:3280 [inline]
validate_chain kernel/locking/lockdep.c:3904 [inline]
__lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226
lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
__mutex_lock_common kernel/locking/mutex.c:585 [inline]
__mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735
tty_buffer_flush+0x72/0x310 drivers/tty/tty_buffer.c:229
tty_ldisc_flush+0x64/0xe0 drivers/tty/tty_ldisc.c:388
__do_SAK+0x6a1/0x800 drivers/tty/tty_io.c:3038
vc_SAK+0x7f/0x310 drivers/tty/vt/vt_ioctl.c:993
process_one_work+0x9c5/0x1ba0 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
other info that might help us debug this:
Chain exists of:
&buf->lock --> &tty->termios_rwsem --> console_lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(console_lock);
lock(&tty->termios_rwsem);
lock(console_lock);
lock(&buf->lock);
*** DEADLOCK ***
4 locks held by kworker/1:3/6008:
#0: ffff88801b078948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3204
#1: ffffc90003cafd80 ((work_completion)(&vc_cons[currcons].SAK_work)){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3205
#2: ffffffff8e1a9040 (console_lock){+.+.}-{0:0}, at: vc_SAK+0x13/0x310 drivers/tty/vt/vt_ioctl.c:983
#3: ffff8880798a40a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref drivers/tty/tty_ldisc.c:263 [inline]
#3: ffff8880798a40a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_flush+0x1c/0xe0 drivers/tty/tty_ldisc.c:386
stack backtrace:
CPU: 1 UID: 0 PID: 6008 Comm: kworker/1:3 Not tainted 6.13.0-rc5-syzkaller-00004-gccb98ccef0e5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: events vc_SAK
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_circular_bug+0x419/0x5d0 kernel/locking/lockdep.c:2074
check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2206
check_prev_add kernel/locking/lockdep.c:3161 [inline]
check_prevs_add kernel/locking/lockdep.c:3280 [inline]
validate_chain kernel/locking/lockdep.c:3904 [inline]
__lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226
lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
__mutex_lock_common kernel/locking/mutex.c:585 [inline]
__mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735
tty_buffer_flush+0x72/0x310 drivers/tty/tty_buffer.c:229
tty_ldisc_flush+0x64/0xe0 drivers/tty/tty_ldisc.c:388
__do_SAK+0x6a1/0x800 drivers/tty/tty_io.c:3038
vc_SAK+0x7f/0x310 drivers/tty/vt/vt_ioctl.c:993
process_one_work+0x9c5/0x1ba0 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
</TASK>
tty tty1: SAK: killed process 6013 (syz.0.16): by fd#3
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [syzbot] [serial?] possible deadlock in tty_buffer_flush (3)
2024-09-09 4:46 [syzbot] [serial?] possible deadlock in tty_buffer_flush (3) syzbot
2024-12-31 22:34 ` syzbot
@ 2025-01-18 19:12 ` syzbot
2025-01-20 6:18 ` syzbot
2 siblings, 0 replies; 4+ messages in thread
From: syzbot @ 2025-01-18 19:12 UTC (permalink / raw)
To: gregkh, jirislaby, linux-kernel, linux-serial, syzkaller-bugs
syzbot has found a reproducer for the following issue on:
HEAD commit: 595523945be0 Merge tag 'devicetree-fixes-for-6.13-2' of gi..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=124d7a18580000
kernel config: https://syzkaller.appspot.com/x/.config?x=d1cb4a1f148c0861
dashboard link: https://syzkaller.appspot.com/bug?extid=52cf91760dcb1dac6376
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=164091f8580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17903fc4580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6f7863c08b5c/disk-59552394.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/06971b2686d0/vmlinux-59552394.xz
kernel image: https://storage.googleapis.com/syzbot-assets/66c751022d90/bzImage-59552394.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+52cf91760dcb1dac6376@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
6.13.0-rc7-syzkaller-00189-g595523945be0 #0 Not tainted
------------------------------------------------------
kworker/1:4/5864 is trying to acquire lock:
ffff88801b0990b8 (&buf->lock){+.+.}-{4:4}, at: tty_buffer_flush+0x72/0x310 drivers/tty/tty_buffer.c:229
but task is already holding lock:
ffffffff8e1a9040 (console_lock){+.+.}-{0:0}, at: vc_SAK+0x13/0x310 drivers/tty/vt/vt_ioctl.c:983
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (console_lock){+.+.}-{0:0}:
console_lock+0x7a/0xa0 kernel/printk/printk.c:2833
con_flush_chars+0x5e/0x80 drivers/tty/vt/vt.c:3503
__receive_buf drivers/tty/n_tty.c:1644 [inline]
n_tty_receive_buf_common+0xa99/0x1980 drivers/tty/n_tty.c:1739
tty_ldisc_receive_buf+0xa2/0x190 drivers/tty/tty_buffer.c:387
tty_port_default_receive_buf+0x70/0xb0 drivers/tty/tty_port.c:37
receive_buf drivers/tty/tty_buffer.c:445 [inline]
flush_to_ldisc+0x264/0x780 drivers/tty/tty_buffer.c:495
process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3236
process_scheduled_works kernel/workqueue.c:3317 [inline]
worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398
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
-> #1 (&tty->termios_rwsem){++++}-{4:4}:
down_read+0x9a/0x330 kernel/locking/rwsem.c:1524
n_tty_receive_buf_common+0x85/0x1980 drivers/tty/n_tty.c:1702
tty_ldisc_receive_buf+0xa2/0x190 drivers/tty/tty_buffer.c:387
tty_port_default_receive_buf+0x70/0xb0 drivers/tty/tty_port.c:37
receive_buf drivers/tty/tty_buffer.c:445 [inline]
flush_to_ldisc+0x264/0x780 drivers/tty/tty_buffer.c:495
process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3236
process_scheduled_works kernel/workqueue.c:3317 [inline]
worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398
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
-> #0 (&buf->lock){+.+.}-{4:4}:
check_prev_add kernel/locking/lockdep.c:3161 [inline]
check_prevs_add kernel/locking/lockdep.c:3280 [inline]
validate_chain kernel/locking/lockdep.c:3904 [inline]
__lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226
lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
__mutex_lock_common kernel/locking/mutex.c:585 [inline]
__mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735
tty_buffer_flush+0x72/0x310 drivers/tty/tty_buffer.c:229
tty_ldisc_flush+0x64/0xe0 drivers/tty/tty_ldisc.c:388
__do_SAK+0x6a1/0x800 drivers/tty/tty_io.c:3038
vc_SAK+0x7f/0x310 drivers/tty/vt/vt_ioctl.c:993
process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3236
process_scheduled_works kernel/workqueue.c:3317 [inline]
worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398
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
other info that might help us debug this:
Chain exists of:
&buf->lock --> &tty->termios_rwsem --> console_lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(console_lock);
lock(&tty->termios_rwsem);
lock(console_lock);
lock(&buf->lock);
*** DEADLOCK ***
4 locks held by kworker/1:4/5864:
#0: ffff88801b078948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3211
#1: ffffc90004a9fd80 ((work_completion)(&vc_cons[currcons].SAK_work)){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3212
#2: ffffffff8e1a9040 (console_lock){+.+.}-{0:0}, at: vc_SAK+0x13/0x310 drivers/tty/vt/vt_ioctl.c:983
#3: ffff8880698950a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref drivers/tty/tty_ldisc.c:263 [inline]
#3: ffff8880698950a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_flush+0x1c/0xe0 drivers/tty/tty_ldisc.c:386
stack backtrace:
CPU: 1 UID: 0 PID: 5864 Comm: kworker/1:4 Not tainted 6.13.0-rc7-syzkaller-00189-g595523945be0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: events vc_SAK
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_circular_bug+0x419/0x5d0 kernel/locking/lockdep.c:2074
check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2206
check_prev_add kernel/locking/lockdep.c:3161 [inline]
check_prevs_add kernel/locking/lockdep.c:3280 [inline]
validate_chain kernel/locking/lockdep.c:3904 [inline]
__lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226
lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
__mutex_lock_common kernel/locking/mutex.c:585 [inline]
__mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735
tty_buffer_flush+0x72/0x310 drivers/tty/tty_buffer.c:229
tty_ldisc_flush+0x64/0xe0 drivers/tty/tty_ldisc.c:388
__do_SAK+0x6a1/0x800 drivers/tty/tty_io.c:3038
vc_SAK+0x7f/0x310 drivers/tty/vt/vt_ioctl.c:993
process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3236
process_scheduled_works kernel/workqueue.c:3317 [inline]
worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398
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
</TASK>
tty tty1: SAK: killed process 5889 (syz-executor496): by fd#4
usb 2-1: USB disconnect, device number 3
usb 2-1: new high-speed USB device number 4 using dummy_hcd
usb 2-1: config 0 interface 0 altsetting 0 endpoint 0x81 has an invalid bInterval 0, changing to 7
usb 2-1: New USB device found, idVendor=0926, idProduct=3333, bcdDevice= 0.40
usb 2-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
usb 2-1: config 0 descriptor??
keytouch 0003:0926:3333.000F: fixing up Keytouch IEC report descriptor
input: HID 0926:3333 as /devices/platform/dummy_hcd.1/usb2/2-1/2-1:0.0/0003:0926:3333.000F/input/input19
keytouch 0003:0926:3333.000F: input,hidraw2: USB HID v0.00 Keyboard [HID 0926:3333] on usb-dummy_hcd.1-1/input0
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [syzbot] [serial?] possible deadlock in tty_buffer_flush (3)
2024-09-09 4:46 [syzbot] [serial?] possible deadlock in tty_buffer_flush (3) syzbot
2024-12-31 22:34 ` syzbot
2025-01-18 19:12 ` syzbot
@ 2025-01-20 6:18 ` syzbot
2 siblings, 0 replies; 4+ messages in thread
From: syzbot @ 2025-01-20 6:18 UTC (permalink / raw)
To: elic, gregkh, jasowang, jirislaby, linux-kernel, linux-serial,
mst, parav, syzkaller-bugs
syzbot has bisected this issue to:
commit a3c06ae158dd6fa8336157c31d9234689d068d02
Author: Parav Pandit <parav@nvidia.com>
Date: Tue Jan 5 10:32:03 2021 +0000
vdpa_sim_net: Add support for user supported devices
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=101452b0580000
start commit: 595523945be0 Merge tag 'devicetree-fixes-for-6.13-2' of gi..
git tree: upstream
final oops: https://syzkaller.appspot.com/x/report.txt?x=121452b0580000
console output: https://syzkaller.appspot.com/x/log.txt?x=141452b0580000
kernel config: https://syzkaller.appspot.com/x/.config?x=d1cb4a1f148c0861
dashboard link: https://syzkaller.appspot.com/bug?extid=52cf91760dcb1dac6376
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=164091f8580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17903fc4580000
Reported-by: syzbot+52cf91760dcb1dac6376@syzkaller.appspotmail.com
Fixes: a3c06ae158dd ("vdpa_sim_net: Add support for user supported devices")
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2025-01-20 6:18 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2024-09-09 4:46 [syzbot] [serial?] possible deadlock in tty_buffer_flush (3) syzbot
2024-12-31 22:34 ` syzbot
2025-01-18 19:12 ` syzbot
2025-01-20 6:18 ` syzbot
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