Extracting prog: 2m21.471936306s
Minimizing prog: 14m32.525082233s
Simplifying prog options: 0s
Extracting C: 1m9.334294901s
Simplifying C: 8m27.530910218s


extracting reproducer from 1 programs
testing a last program of every proc
single: executing 1 programs separately with timeout 30s
testing program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE-write$input_event
detailed listing:
executing program 0:
r0 = syz_open_dev$tty20(0xc, 0x4, 0x0)
ioctl$VT_ACTIVATE(r0, 0x5606, 0x14)
ioctl$KDSKBENT(r0, 0x4b47, &(0x7f0000000000)={0x0, 0x1c, 0x20f})
r1 = openat$uinput(0xffffffffffffff9c, &(0x7f0000000040), 0x2, 0x0)
ioctl$UI_SET_EVBIT(r1, 0x40045564, 0x1)
ioctl$UI_SET_KEYBIT(r1, 0x40045565, 0x1c)
ioctl$UI_DEV_SETUP(r1, 0x405c5503, &(0x7f0000000080)={{}, 'syz0\x00', 0x1})
ioctl$UI_DEV_CREATE(r1, 0x5501)
write$input_event(r1, &(0x7f0000000100)={{}, 0x1, 0x1c, 0x1}, 0x18)

program crashed: possible deadlock in n_tty_flush_buffer
single: successfully extracted reproducer
found reproducer with 9 syscalls
minimizing guilty program
testing program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE
detailed listing:
executing program 0:
r0 = syz_open_dev$tty20(0xc, 0x4, 0x0)
ioctl$VT_ACTIVATE(r0, 0x5606, 0x14)
ioctl$KDSKBENT(r0, 0x4b47, &(0x7f0000000000)={0x0, 0x1c, 0x20f})
r1 = openat$uinput(0xffffffffffffff9c, &(0x7f0000000040), 0x2, 0x0)
ioctl$UI_SET_EVBIT(r1, 0x40045564, 0x1)
ioctl$UI_SET_KEYBIT(r1, 0x40045565, 0x1c)
ioctl$UI_DEV_SETUP(r1, 0x405c5503, &(0x7f0000000080)={{}, 'syz0\x00', 0x1})
ioctl$UI_DEV_CREATE(r1, 0x5501)

program did not crash
testing program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-write$input_event
detailed listing:
executing program 0:
r0 = syz_open_dev$tty20(0xc, 0x4, 0x0)
ioctl$VT_ACTIVATE(r0, 0x5606, 0x14)
ioctl$KDSKBENT(r0, 0x4b47, &(0x7f0000000000)={0x0, 0x1c, 0x20f})
r1 = openat$uinput(0xffffffffffffff9c, &(0x7f0000000040), 0x2, 0x0)
ioctl$UI_SET_EVBIT(r1, 0x40045564, 0x1)
ioctl$UI_SET_KEYBIT(r1, 0x40045565, 0x1c)
ioctl$UI_DEV_SETUP(r1, 0x405c5503, &(0x7f0000000080)={{}, 'syz0\x00', 0x1})
write$input_event(r1, &(0x7f0000000100)={{}, 0x1, 0x1c, 0x1}, 0x18)

program did not crash
testing program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_CREATE-write$input_event
detailed listing:
executing program 0:
r0 = syz_open_dev$tty20(0xc, 0x4, 0x0)
ioctl$VT_ACTIVATE(r0, 0x5606, 0x14)
ioctl$KDSKBENT(r0, 0x4b47, &(0x7f0000000000)={0x0, 0x1c, 0x20f})
r1 = openat$uinput(0xffffffffffffff9c, &(0x7f0000000040), 0x2, 0x0)
ioctl$UI_SET_EVBIT(r1, 0x40045564, 0x1)
ioctl$UI_SET_KEYBIT(r1, 0x40045565, 0x1c)
ioctl$UI_DEV_CREATE(r1, 0x5501)
write$input_event(r1, &(0x7f0000000100)={{}, 0x1, 0x1c, 0x1}, 0x18)

program did not crash
testing program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE-write$input_event
detailed listing:
executing program 0:
r0 = syz_open_dev$tty20(0xc, 0x4, 0x0)
ioctl$VT_ACTIVATE(r0, 0x5606, 0x14)
ioctl$KDSKBENT(r0, 0x4b47, &(0x7f0000000000)={0x0, 0x1c, 0x20f})
r1 = openat$uinput(0xffffffffffffff9c, &(0x7f0000000040), 0x2, 0x0)
ioctl$UI_SET_EVBIT(r1, 0x40045564, 0x1)
ioctl$UI_DEV_SETUP(r1, 0x405c5503, &(0x7f0000000080)={{}, 'syz0\x00', 0x1})
ioctl$UI_DEV_CREATE(r1, 0x5501)
write$input_event(r1, &(0x7f0000000100)={{}, 0x1, 0x1c, 0x1}, 0x18)

program did not crash
testing program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE-write$input_event
detailed listing:
executing program 0:
r0 = syz_open_dev$tty20(0xc, 0x4, 0x0)
ioctl$VT_ACTIVATE(r0, 0x5606, 0x14)
ioctl$KDSKBENT(r0, 0x4b47, &(0x7f0000000000)={0x0, 0x1c, 0x20f})
r1 = openat$uinput(0xffffffffffffff9c, &(0x7f0000000040), 0x2, 0x0)
ioctl$UI_SET_KEYBIT(r1, 0x40045565, 0x1c)
ioctl$UI_DEV_SETUP(r1, 0x405c5503, &(0x7f0000000080)={{}, 'syz0\x00', 0x1})
ioctl$UI_DEV_CREATE(r1, 0x5501)
write$input_event(r1, &(0x7f0000000100)={{}, 0x1, 0x1c, 0x1}, 0x18)

program did not crash
testing program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-ioctl$KDSKBENT-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE-write$input_event
detailed listing:
executing program 0:
r0 = syz_open_dev$tty20(0xc, 0x4, 0x0)
ioctl$VT_ACTIVATE(r0, 0x5606, 0x14)
ioctl$KDSKBENT(r0, 0x4b47, &(0x7f0000000000)={0x0, 0x1c, 0x20f})
ioctl$UI_SET_EVBIT(0xffffffffffffffff, 0x40045564, 0x1)
ioctl$UI_SET_KEYBIT(0xffffffffffffffff, 0x40045565, 0x1c)
ioctl$UI_DEV_SETUP(0xffffffffffffffff, 0x405c5503, &(0x7f0000000080)={{}, 'syz0\x00', 0x1})
ioctl$UI_DEV_CREATE(0xffffffffffffffff, 0x5501)
write$input_event(0xffffffffffffffff, &(0x7f0000000100)={{}, 0x1, 0x1c, 0x1}, 0x18)

program did not crash
testing program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE-write$input_event
detailed listing:
executing program 0:
r0 = syz_open_dev$tty20(0xc, 0x4, 0x0)
ioctl$VT_ACTIVATE(r0, 0x5606, 0x14)
r1 = openat$uinput(0xffffffffffffff9c, &(0x7f0000000040), 0x2, 0x0)
ioctl$UI_SET_EVBIT(r1, 0x40045564, 0x1)
ioctl$UI_SET_KEYBIT(r1, 0x40045565, 0x1c)
ioctl$UI_DEV_SETUP(r1, 0x405c5503, &(0x7f0000000080)={{}, 'syz0\x00', 0x1})
ioctl$UI_DEV_CREATE(r1, 0x5501)
write$input_event(r1, &(0x7f0000000100)={{}, 0x1, 0x1c, 0x1}, 0x18)

program did not crash
testing program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE-write$input_event
detailed listing:
executing program 0:
r0 = syz_open_dev$tty20(0xc, 0x4, 0x0)
ioctl$KDSKBENT(r0, 0x4b47, &(0x7f0000000000)={0x0, 0x1c, 0x20f})
r1 = openat$uinput(0xffffffffffffff9c, &(0x7f0000000040), 0x2, 0x0)
ioctl$UI_SET_EVBIT(r1, 0x40045564, 0x1)
ioctl$UI_SET_KEYBIT(r1, 0x40045565, 0x1c)
ioctl$UI_DEV_SETUP(r1, 0x405c5503, &(0x7f0000000080)={{}, 'syz0\x00', 0x1})
ioctl$UI_DEV_CREATE(r1, 0x5501)
write$input_event(r1, &(0x7f0000000100)={{}, 0x1, 0x1c, 0x1}, 0x18)

program did not crash
testing program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): ioctl$VT_ACTIVATE-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE-write$input_event
detailed listing:
executing program 0:
ioctl$VT_ACTIVATE(0xffffffffffffffff, 0x5606, 0x14)
ioctl$KDSKBENT(0xffffffffffffffff, 0x4b47, &(0x7f0000000000)={0x0, 0x1c, 0x20f})
r0 = openat$uinput(0xffffffffffffff9c, &(0x7f0000000040), 0x2, 0x0)
ioctl$UI_SET_EVBIT(r0, 0x40045564, 0x1)
ioctl$UI_SET_KEYBIT(r0, 0x40045565, 0x1c)
ioctl$UI_DEV_SETUP(r0, 0x405c5503, &(0x7f0000000080)={{}, 'syz0\x00', 0x1})
ioctl$UI_DEV_CREATE(r0, 0x5501)
write$input_event(r0, &(0x7f0000000100)={{}, 0x1, 0x1c, 0x1}, 0x18)

program did not crash
testing program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE-write$input_event
detailed listing:
executing program 0:
r0 = syz_open_dev$tty20(0xc, 0x4, 0x0)
ioctl$VT_ACTIVATE(r0, 0x5606, 0x14)
ioctl$KDSKBENT(r0, 0x4b47, 0x0)
r1 = openat$uinput(0xffffffffffffff9c, &(0x7f0000000040), 0x2, 0x0)
ioctl$UI_SET_EVBIT(r1, 0x40045564, 0x1)
ioctl$UI_SET_KEYBIT(r1, 0x40045565, 0x1c)
ioctl$UI_DEV_SETUP(r1, 0x405c5503, &(0x7f0000000080)={{}, 'syz0\x00', 0x1})
ioctl$UI_DEV_CREATE(r1, 0x5501)
write$input_event(r1, &(0x7f0000000100)={{}, 0x1, 0x1c, 0x1}, 0x18)

program did not crash
testing program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE-write$input_event
detailed listing:
executing program 0:
r0 = syz_open_dev$tty20(0xc, 0x4, 0x0)
ioctl$VT_ACTIVATE(r0, 0x5606, 0x14)
ioctl$KDSKBENT(r0, 0x4b47, &(0x7f0000000000)={0x0, 0x1c, 0x20f})
r1 = openat$uinput(0xffffffffffffff9c, 0x0, 0x2, 0x0)
ioctl$UI_SET_EVBIT(r1, 0x40045564, 0x1)
ioctl$UI_SET_KEYBIT(r1, 0x40045565, 0x1c)
ioctl$UI_DEV_SETUP(r1, 0x405c5503, &(0x7f0000000080)={{}, 'syz0\x00', 0x1})
ioctl$UI_DEV_CREATE(r1, 0x5501)
write$input_event(r1, &(0x7f0000000100)={{}, 0x1, 0x1c, 0x1}, 0x18)

program did not crash
testing program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE-write$input_event
detailed listing:
executing program 0:
r0 = syz_open_dev$tty20(0xc, 0x4, 0x0)
ioctl$VT_ACTIVATE(r0, 0x5606, 0x14)
ioctl$KDSKBENT(r0, 0x4b47, &(0x7f0000000000)={0x0, 0x1c, 0x20f})
r1 = openat$uinput(0xffffffffffffff9c, &(0x7f0000000040), 0x2, 0x0)
ioctl$UI_SET_EVBIT(r1, 0x40045564, 0x1)
ioctl$UI_SET_KEYBIT(r1, 0x40045565, 0x1c)
ioctl$UI_DEV_SETUP(r1, 0x405c5503, 0x0)
ioctl$UI_DEV_CREATE(r1, 0x5501)
write$input_event(r1, &(0x7f0000000100)={{}, 0x1, 0x1c, 0x1}, 0x18)

program did not crash
testing program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE-write$input_event
detailed listing:
executing program 0:
r0 = syz_open_dev$tty20(0xc, 0x4, 0x0)
ioctl$VT_ACTIVATE(r0, 0x5606, 0x14)
ioctl$KDSKBENT(r0, 0x4b47, &(0x7f0000000000)={0x0, 0x1c, 0x20f})
r1 = openat$uinput(0xffffffffffffff9c, &(0x7f0000000040), 0x2, 0x0)
ioctl$UI_SET_EVBIT(r1, 0x40045564, 0x1)
ioctl$UI_SET_KEYBIT(r1, 0x40045565, 0x1c)
ioctl$UI_DEV_SETUP(r1, 0x405c5503, &(0x7f0000000080)={{}, 'syz0\x00', 0x1})
ioctl$UI_DEV_CREATE(r1, 0x5501)
write$input_event(r1, 0x0, 0x0)

program did not crash
extracting C reproducer
testing compiled C program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE-write$input_event
program crashed: possible deadlock in n_tty_flush_buffer
simplifying C reproducer
testing compiled C program (duration=30s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE-write$input_event
program crashed: possible deadlock in n_tty_flush_buffer
testing compiled C program (duration=30s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:false Cgroups:false BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE-write$input_event
program did not crash
testing compiled C program (duration=30s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:true Wifi:true IEEE802154:true Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE-write$input_event
program did not crash
testing compiled C program (duration=30s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:true Sysctl:true Swap:false UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE-write$input_event
program crashed: possible deadlock in n_tty_flush_buffer
testing compiled C program (duration=30s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:false UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE-write$input_event
program crashed: possible deadlock in n_tty_flush_buffer
testing compiled C program (duration=30s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:false UseTmpDir:false HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE-write$input_event
program crashed: possible deadlock in n_tty_flush_buffer
testing compiled C program (duration=30s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:false UseTmpDir:false HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE-write$input_event
program crashed: possible deadlock in n_tty_flush_buffer
testing compiled C program (duration=30s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:false HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE-write$input_event
program crashed: possible deadlock in n_tty_flush_buffer
testing program (duration=30s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:false HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE-write$input_event
detailed listing:
executing program 0:
r0 = syz_open_dev$tty20(0xc, 0x4, 0x0)
ioctl$VT_ACTIVATE(r0, 0x5606, 0x14)
ioctl$KDSKBENT(r0, 0x4b47, &(0x7f0000000000)={0x0, 0x1c, 0x20f})
r1 = openat$uinput(0xffffffffffffff9c, &(0x7f0000000040), 0x2, 0x0)
ioctl$UI_SET_EVBIT(r1, 0x40045564, 0x1)
ioctl$UI_SET_KEYBIT(r1, 0x40045565, 0x1c)
ioctl$UI_DEV_SETUP(r1, 0x405c5503, &(0x7f0000000080)={{}, 'syz0\x00', 0x1})
ioctl$UI_DEV_CREATE(r1, 0x5501)
write$input_event(r1, &(0x7f0000000100)={{}, 0x1, 0x1c, 0x1}, 0x18)

program crashed: possible deadlock in n_tty_flush_buffer
validation run: crashed=true
testing program (duration=30s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:false HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE-write$input_event
detailed listing:
executing program 0:
r0 = syz_open_dev$tty20(0xc, 0x4, 0x0)
ioctl$VT_ACTIVATE(r0, 0x5606, 0x14)
ioctl$KDSKBENT(r0, 0x4b47, &(0x7f0000000000)={0x0, 0x1c, 0x20f})
r1 = openat$uinput(0xffffffffffffff9c, &(0x7f0000000040), 0x2, 0x0)
ioctl$UI_SET_EVBIT(r1, 0x40045564, 0x1)
ioctl$UI_SET_KEYBIT(r1, 0x40045565, 0x1c)
ioctl$UI_DEV_SETUP(r1, 0x405c5503, &(0x7f0000000080)={{}, 'syz0\x00', 0x1})
ioctl$UI_DEV_CREATE(r1, 0x5501)
write$input_event(r1, &(0x7f0000000100)={{}, 0x1, 0x1c, 0x1}, 0x18)

program crashed: possible deadlock in n_tty_flush_buffer
validation run: crashed=true
testing program (duration=30s, {Threaded:false Repeat:true RepeatTimes:0 Procs:4 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:false HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): syz_open_dev$tty20-ioctl$VT_ACTIVATE-ioctl$KDSKBENT-openat$uinput-ioctl$UI_SET_EVBIT-ioctl$UI_SET_KEYBIT-ioctl$UI_DEV_SETUP-ioctl$UI_DEV_CREATE-write$input_event
detailed listing:
executing program 0:
r0 = syz_open_dev$tty20(0xc, 0x4, 0x0)
ioctl$VT_ACTIVATE(r0, 0x5606, 0x14)
ioctl$KDSKBENT(r0, 0x4b47, &(0x7f0000000000)={0x0, 0x1c, 0x20f})
r1 = openat$uinput(0xffffffffffffff9c, &(0x7f0000000040), 0x2, 0x0)
ioctl$UI_SET_EVBIT(r1, 0x40045564, 0x1)
ioctl$UI_SET_KEYBIT(r1, 0x40045565, 0x1c)
ioctl$UI_DEV_SETUP(r1, 0x405c5503, &(0x7f0000000080)={{}, 'syz0\x00', 0x1})
ioctl$UI_DEV_CREATE(r1, 0x5501)
write$input_event(r1, &(0x7f0000000100)={{}, 0x1, 0x1c, 0x1}, 0x18)

program crashed: possible deadlock in n_tty_flush_buffer
validation run: crashed=true
reproducing took 29m56.83769397s
repro crashed as (corrupted=false):
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
kworker/1:1/32 is trying to acquire lock:
ffff888079fde2c8 (&tty->termios_rwsem){++++}-{4:4}, at: class_rwsem_write_constructor include/linux/rwsem.h:270 [inline]
ffff888079fde2c8 (&tty->termios_rwsem){++++}-{4:4}, at: n_tty_flush_buffer+0x30/0x230 drivers/tty/n_tty.c:349

but task is already holding lock:
ffff88807e8650b8 (&buf->lock){+.+.}-{4:4}, at: tty_buffer_flush+0x74/0x2b0 drivers/tty/tty_buffer.c:236

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&buf->lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x197/0x15a0 kernel/locking/mutex.c:821
       tty_buffer_flush+0x74/0x2b0 drivers/tty/tty_buffer.c:236
       tty_ldisc_flush+0x6b/0xc0 drivers/tty/tty_ldisc.c:388
       __do_SAK+0x25e/0x680 drivers/tty/tty_io.c:3015
       vc_SAK+0x78/0x220 drivers/tty/vt/vt_ioctl.c:998
       process_one_work kernel/workqueue.c:3495 [inline]
       process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578
       worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659
       kthread+0x38b/0x480 kernel/kthread.c:436
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #2 (console_lock){+.+.}-{0:0}:
       console_lock+0x71/0x90 kernel/printk/printk.c:2896
       uart_configure_port drivers/tty/serial/serial_core.c:2590 [inline]
       serial_core_add_one_port drivers/tty/serial/serial_core.c:3174 [inline]
       serial_core_register_port+0xe23/0x2b80 drivers/tty/serial/serial_core.c:3353
       serial8250_register_8250_port+0x1a28/0x2420 drivers/tty/serial/8250/8250_core.c:900
       serial_pnp_probe+0x576/0x800 drivers/tty/serial/8250/8250_pnp.c:480
       pnp_device_probe+0x313/0x4d0 drivers/pnp/driver.c:111
       call_driver_probe drivers/base/dd.c:-1 [inline]
       really_probe+0x254/0xae0 drivers/base/dd.c:706
       __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868
       driver_probe_device+0x4f/0x240 drivers/base/dd.c:898
       __driver_attach+0x339/0x600 drivers/base/dd.c:1292
       bus_for_each_dev+0x23b/0x2c0 drivers/base/bus.c:386
       bus_add_driver+0x345/0x670 drivers/base/bus.c:766
       driver_register+0x23a/0x320 drivers/base/driver.c:174
       serial8250_init+0x8f/0x160 drivers/tty/serial/8250/8250_platform.c:318
       do_one_initcall+0x250/0x870 init/main.c:1360
       do_initcall_level+0x10a/0x1a0 init/main.c:1422
       do_initcalls+0x59/0xa0 init/main.c:1438
       kernel_init_freeable+0x29d/0x3e0 init/main.c:1673
       kernel_init+0x22/0x1d0 init/main.c:1563
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #1 (&port->mutex){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x197/0x15a0 kernel/locking/mutex.c:821
       class_mutex_constructor include/linux/mutex.h:253 [inline]
       uart_set_termios+0x83/0x1330 drivers/tty/serial/serial_core.c:1661
       tty_set_termios+0xcaf/0x1800 drivers/tty/tty_ioctl.c:341
       set_termios+0x538/0x6c0 drivers/tty/tty_ioctl.c:516
       tty_mode_ioctl+0x49c/0x7c0 drivers/tty/tty_ioctl.c:-1
       tty_ioctl+0x9bd/0xde0 drivers/tty/tty_io.c:2791
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:597 [inline]
       __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&tty->termios_rwsem){++++}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3209 [inline]
       check_prevs_add kernel/locking/lockdep.c:3328 [inline]
       validate_chain kernel/locking/lockdep.c:3952 [inline]
       __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288
       lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942
       down_write+0x91/0x200 kernel/locking/rwsem.c:1631
       class_rwsem_write_constructor include/linux/rwsem.h:270 [inline]
       n_tty_flush_buffer+0x30/0x230 drivers/tty/n_tty.c:349
       tty_buffer_flush+0x1ec/0x2b0 drivers/tty/tty_buffer.c:248
       tty_ldisc_flush+0x6b/0xc0 drivers/tty/tty_ldisc.c:388
       __do_SAK+0x25e/0x680 drivers/tty/tty_io.c:3015
       vc_SAK+0x78/0x220 drivers/tty/vt/vt_ioctl.c:998
       process_one_work kernel/workqueue.c:3495 [inline]
       process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578
       worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659
       kthread+0x38b/0x480 kernel/kthread.c:436
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

other info that might help us debug this:

Chain exists of:
  &tty->termios_rwsem --> console_lock --> &buf->lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&buf->lock);
                               lock(console_lock);
                               lock(&buf->lock);
  lock(&tty->termios_rwsem);

 *** DEADLOCK ***

locks held by kworker/1:1/32: 5, last CPU#1:
 #0: ffff88813fe0ad48 ((wq_completion)events){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff88813fe0ad48 ((wq_completion)events){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff88813fe0ad48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
 #0: ffff88813fe0ad48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
 #1: ffffc90000a77c40 ((work_completion)(&vc_cons[currcons].SAK_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc90000a77c40 ((work_completion)(&vc_cons[currcons].SAK_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc90000a77c40 ((work_completion)(&vc_cons[currcons].SAK_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
 #1: ffffc90000a77c40 ((work_completion)(&vc_cons[currcons].SAK_work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
 #2: ffffffff8f14e880 (console_lock){+.+.}-{0:0}, at: class_console_lock_constructor include/linux/console.h:734 [inline]
 #2: ffffffff8f14e880 (console_lock){+.+.}-{0:0}, at: vc_SAK+0x28/0x220 drivers/tty/vt/vt_ioctl.c:989
 #3: ffff888079fde0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref drivers/tty/tty_ldisc.c:263 [inline]
 #3: ffff888079fde0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_flush+0x20/0xc0 drivers/tty/tty_ldisc.c:386
 #4: ffff88807e8650b8 (&buf->lock){+.+.}-{4:4}, at: tty_buffer_flush+0x74/0x2b0 drivers/tty/tty_buffer.c:236

stack backtrace:
CPU: 1 UID: 0 PID: 32 Comm: kworker/1:1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events vc_SAK
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2087
 check_noncircular+0x12f/0x150 kernel/locking/lockdep.c:2219
 check_prev_add kernel/locking/lockdep.c:3209 [inline]
 check_prevs_add kernel/locking/lockdep.c:3328 [inline]
 validate_chain kernel/locking/lockdep.c:3952 [inline]
 __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288
 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942
 down_write+0x91/0x200 kernel/locking/rwsem.c:1631
 class_rwsem_write_constructor include/linux/rwsem.h:270 [inline]
 n_tty_flush_buffer+0x30/0x230 drivers/tty/n_tty.c:349
 tty_buffer_flush+0x1ec/0x2b0 drivers/tty/tty_buffer.c:248
 tty_ldisc_flush+0x6b/0xc0 drivers/tty/tty_ldisc.c:388
 __do_SAK+0x25e/0x680 drivers/tty/tty_io.c:3015
 vc_SAK+0x78/0x220 drivers/tty/vt/vt_ioctl.c:998
 process_one_work kernel/workqueue.c:3495 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
tty tty20: SAK: killed process 5913 (syz.0.17): by fd#3
tty tty20: SAK: killed process 5917 (syz.0.22): by fd#3
tty tty20: SAK: killed process 5919 (syz.0.24): by fd#3
tty tty20: SAK: killed process 5920 (syz.0.25): by fd#3
tty tty20: SAK: killed process 5937 (syz.0.37): by fd#3
tty tty20: SAK: killed process 5944 (syz.0.43): by fd#3
tty tty20: SAK: killed process 5970 (syz.0.70): by fd#3
tty tty20: SAK: killed process 5989 (syz.0.89): by fd#3
tty tty20: SAK: killed process 5993 (syz.0.93): by fd#3
tty tty20: SAK: killed process 6037 (syz.0.137): by fd#3
tty tty20: SAK: killed process 6047 (syz.0.147): by fd#3

final repro crashed as (corrupted=false):
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
kworker/1:1/32 is trying to acquire lock:
ffff888079fde2c8 (&tty->termios_rwsem){++++}-{4:4}, at: class_rwsem_write_constructor include/linux/rwsem.h:270 [inline]
ffff888079fde2c8 (&tty->termios_rwsem){++++}-{4:4}, at: n_tty_flush_buffer+0x30/0x230 drivers/tty/n_tty.c:349

but task is already holding lock:
ffff88807e8650b8 (&buf->lock){+.+.}-{4:4}, at: tty_buffer_flush+0x74/0x2b0 drivers/tty/tty_buffer.c:236

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&buf->lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x197/0x15a0 kernel/locking/mutex.c:821
       tty_buffer_flush+0x74/0x2b0 drivers/tty/tty_buffer.c:236
       tty_ldisc_flush+0x6b/0xc0 drivers/tty/tty_ldisc.c:388
       __do_SAK+0x25e/0x680 drivers/tty/tty_io.c:3015
       vc_SAK+0x78/0x220 drivers/tty/vt/vt_ioctl.c:998
       process_one_work kernel/workqueue.c:3495 [inline]
       process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578
       worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659
       kthread+0x38b/0x480 kernel/kthread.c:436
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #2 (console_lock){+.+.}-{0:0}:
       console_lock+0x71/0x90 kernel/printk/printk.c:2896
       uart_configure_port drivers/tty/serial/serial_core.c:2590 [inline]
       serial_core_add_one_port drivers/tty/serial/serial_core.c:3174 [inline]
       serial_core_register_port+0xe23/0x2b80 drivers/tty/serial/serial_core.c:3353
       serial8250_register_8250_port+0x1a28/0x2420 drivers/tty/serial/8250/8250_core.c:900
       serial_pnp_probe+0x576/0x800 drivers/tty/serial/8250/8250_pnp.c:480
       pnp_device_probe+0x313/0x4d0 drivers/pnp/driver.c:111
       call_driver_probe drivers/base/dd.c:-1 [inline]
       really_probe+0x254/0xae0 drivers/base/dd.c:706
       __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868
       driver_probe_device+0x4f/0x240 drivers/base/dd.c:898
       __driver_attach+0x339/0x600 drivers/base/dd.c:1292
       bus_for_each_dev+0x23b/0x2c0 drivers/base/bus.c:386
       bus_add_driver+0x345/0x670 drivers/base/bus.c:766
       driver_register+0x23a/0x320 drivers/base/driver.c:174
       serial8250_init+0x8f/0x160 drivers/tty/serial/8250/8250_platform.c:318
       do_one_initcall+0x250/0x870 init/main.c:1360
       do_initcall_level+0x10a/0x1a0 init/main.c:1422
       do_initcalls+0x59/0xa0 init/main.c:1438
       kernel_init_freeable+0x29d/0x3e0 init/main.c:1673
       kernel_init+0x22/0x1d0 init/main.c:1563
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #1 (&port->mutex){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x197/0x15a0 kernel/locking/mutex.c:821
       class_mutex_constructor include/linux/mutex.h:253 [inline]
       uart_set_termios+0x83/0x1330 drivers/tty/serial/serial_core.c:1661
       tty_set_termios+0xcaf/0x1800 drivers/tty/tty_ioctl.c:341
       set_termios+0x538/0x6c0 drivers/tty/tty_ioctl.c:516
       tty_mode_ioctl+0x49c/0x7c0 drivers/tty/tty_ioctl.c:-1
       tty_ioctl+0x9bd/0xde0 drivers/tty/tty_io.c:2791
       vfs_ioctl fs/ioctl.c:51 [inline]
       __do_sys_ioctl fs/ioctl.c:597 [inline]
       __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&tty->termios_rwsem){++++}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3209 [inline]
       check_prevs_add kernel/locking/lockdep.c:3328 [inline]
       validate_chain kernel/locking/lockdep.c:3952 [inline]
       __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288
       lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942
       down_write+0x91/0x200 kernel/locking/rwsem.c:1631
       class_rwsem_write_constructor include/linux/rwsem.h:270 [inline]
       n_tty_flush_buffer+0x30/0x230 drivers/tty/n_tty.c:349
       tty_buffer_flush+0x1ec/0x2b0 drivers/tty/tty_buffer.c:248
       tty_ldisc_flush+0x6b/0xc0 drivers/tty/tty_ldisc.c:388
       __do_SAK+0x25e/0x680 drivers/tty/tty_io.c:3015
       vc_SAK+0x78/0x220 drivers/tty/vt/vt_ioctl.c:998
       process_one_work kernel/workqueue.c:3495 [inline]
       process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578
       worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659
       kthread+0x38b/0x480 kernel/kthread.c:436
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

other info that might help us debug this:

Chain exists of:
  &tty->termios_rwsem --> console_lock --> &buf->lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&buf->lock);
                               lock(console_lock);
                               lock(&buf->lock);
  lock(&tty->termios_rwsem);

 *** DEADLOCK ***

locks held by kworker/1:1/32: 5, last CPU#1:
 #0: ffff88813fe0ad48 ((wq_completion)events){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff88813fe0ad48 ((wq_completion)events){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff88813fe0ad48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
 #0: ffff88813fe0ad48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
 #1: ffffc90000a77c40 ((work_completion)(&vc_cons[currcons].SAK_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc90000a77c40 ((work_completion)(&vc_cons[currcons].SAK_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc90000a77c40 ((work_completion)(&vc_cons[currcons].SAK_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3460 [inline]
 #1: ffffc90000a77c40 ((work_completion)(&vc_cons[currcons].SAK_work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3578
 #2: ffffffff8f14e880 (console_lock){+.+.}-{0:0}, at: class_console_lock_constructor include/linux/console.h:734 [inline]
 #2: ffffffff8f14e880 (console_lock){+.+.}-{0:0}, at: vc_SAK+0x28/0x220 drivers/tty/vt/vt_ioctl.c:989
 #3: ffff888079fde0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref drivers/tty/tty_ldisc.c:263 [inline]
 #3: ffff888079fde0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_flush+0x20/0xc0 drivers/tty/tty_ldisc.c:386
 #4: ffff88807e8650b8 (&buf->lock){+.+.}-{4:4}, at: tty_buffer_flush+0x74/0x2b0 drivers/tty/tty_buffer.c:236

stack backtrace:
CPU: 1 UID: 0 PID: 32 Comm: kworker/1:1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events vc_SAK
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2087
 check_noncircular+0x12f/0x150 kernel/locking/lockdep.c:2219
 check_prev_add kernel/locking/lockdep.c:3209 [inline]
 check_prevs_add kernel/locking/lockdep.c:3328 [inline]
 validate_chain kernel/locking/lockdep.c:3952 [inline]
 __lock_acquire+0x164c/0x2de0 kernel/locking/lockdep.c:5288
 lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942
 down_write+0x91/0x200 kernel/locking/rwsem.c:1631
 class_rwsem_write_constructor include/linux/rwsem.h:270 [inline]
 n_tty_flush_buffer+0x30/0x230 drivers/tty/n_tty.c:349
 tty_buffer_flush+0x1ec/0x2b0 drivers/tty/tty_buffer.c:248
 tty_ldisc_flush+0x6b/0xc0 drivers/tty/tty_ldisc.c:388
 __do_SAK+0x25e/0x680 drivers/tty/tty_io.c:3015
 vc_SAK+0x78/0x220 drivers/tty/vt/vt_ioctl.c:998
 process_one_work kernel/workqueue.c:3495 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
tty tty20: SAK: killed process 5913 (syz.0.17): by fd#3
tty tty20: SAK: killed process 5917 (syz.0.22): by fd#3
tty tty20: SAK: killed process 5919 (syz.0.24): by fd#3
tty tty20: SAK: killed process 5920 (syz.0.25): by fd#3
tty tty20: SAK: killed process 5937 (syz.0.37): by fd#3
tty tty20: SAK: killed process 5944 (syz.0.43): by fd#3
tty tty20: SAK: killed process 5970 (syz.0.70): by fd#3
tty tty20: SAK: killed process 5989 (syz.0.89): by fd#3
tty tty20: SAK: killed process 5993 (syz.0.93): by fd#3
tty tty20: SAK: killed process 6037 (syz.0.137): by fd#3
tty tty20: SAK: killed process 6047 (syz.0.147): by fd#3