Extracting prog: 3m19.607012275s Minimizing prog: 10m36.557789771s Simplifying prog options: 0s Extracting C: 37.289386562s Simplifying C: 9m32.89570986s 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$tty1-ioctl$KDSKBENT-syz_open_dev$evdev-write$evdev detailed listing: executing program 0: r0 = syz_open_dev$tty1(0xc, 0x4, 0x1) ioctl$KDSKBENT(r0, 0x4b47, &(0x7f0000000300)={0x0, 0x7f, 0x20f}) r1 = syz_open_dev$evdev(&(0x7f00000002c0), 0xc000, 0x142) write$evdev(r1, &(0x7f0000000640)=[{{0x77359400}, 0x1, 0x7f, 0x2}], 0x18) program crashed: possible deadlock in n_tty_flush_buffer program crashed: possible deadlock in n_tty_flush_buffer single: successfully extracted reproducer found reproducer with 4 syscalls minimizing guilty program testing program (duration=45.373989448s, {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$tty1-ioctl$KDSKBENT-syz_open_dev$evdev detailed listing: executing program 0: r0 = syz_open_dev$tty1(0xc, 0x4, 0x1) ioctl$KDSKBENT(r0, 0x4b47, &(0x7f0000000300)={0x0, 0x7f, 0x20f}) syz_open_dev$evdev(&(0x7f00000002c0), 0xc000, 0x142) program did not crash testing program (duration=45.373989448s, {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$tty1-ioctl$KDSKBENT-write$evdev detailed listing: executing program 0: r0 = syz_open_dev$tty1(0xc, 0x4, 0x1) ioctl$KDSKBENT(r0, 0x4b47, &(0x7f0000000300)={0x0, 0x7f, 0x20f}) write$evdev(0xffffffffffffffff, &(0x7f0000000640)=[{{0x77359400}, 0x1, 0x7f, 0x2}], 0x18) program did not crash testing program (duration=45.373989448s, {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$tty1-syz_open_dev$evdev-write$evdev detailed listing: executing program 0: syz_open_dev$tty1(0xc, 0x4, 0x1) r0 = syz_open_dev$evdev(&(0x7f00000002c0), 0xc000, 0x142) write$evdev(r0, &(0x7f0000000640)=[{{0x77359400}, 0x1, 0x7f, 0x2}], 0x18) program did not crash testing program (duration=45.373989448s, {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$KDSKBENT-syz_open_dev$evdev-write$evdev detailed listing: executing program 0: ioctl$KDSKBENT(0xffffffffffffffff, 0x4b47, &(0x7f0000000300)={0x0, 0x7f, 0x20f}) r0 = syz_open_dev$evdev(&(0x7f00000002c0), 0xc000, 0x142) write$evdev(r0, &(0x7f0000000640)=[{{0x77359400}, 0x1, 0x7f, 0x2}], 0x18) program did not crash testing program (duration=45.373989448s, {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$tty1-ioctl$KDSKBENT-syz_open_dev$evdev-write$evdev detailed listing: executing program 0: r0 = syz_open_dev$tty1(0xc, 0x4, 0x1) ioctl$KDSKBENT(r0, 0x4b47, 0x0) r1 = syz_open_dev$evdev(&(0x7f00000002c0), 0xc000, 0x142) write$evdev(r1, &(0x7f0000000640)=[{{0x77359400}, 0x1, 0x7f, 0x2}], 0x18) program did not crash testing program (duration=45.373989448s, {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$tty1-ioctl$KDSKBENT-syz_open_dev$evdev-write$evdev detailed listing: executing program 0: r0 = syz_open_dev$tty1(0xc, 0x4, 0x1) ioctl$KDSKBENT(r0, 0x4b47, &(0x7f0000000300)={0x0, 0x7f, 0x20f}) r1 = syz_open_dev$evdev(0x0, 0xc000, 0x142) write$evdev(r1, &(0x7f0000000640)=[{{0x77359400}, 0x1, 0x7f, 0x2}], 0x18) program did not crash testing program (duration=45.373989448s, {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$tty1-ioctl$KDSKBENT-syz_open_dev$evdev-write$evdev detailed listing: executing program 0: r0 = syz_open_dev$tty1(0xc, 0x4, 0x1) ioctl$KDSKBENT(r0, 0x4b47, &(0x7f0000000300)={0x0, 0x7f, 0x20f}) r1 = syz_open_dev$evdev(&(0x7f00000002c0), 0xc000, 0x142) write$evdev(r1, 0x0, 0x0) program did not crash extracting C reproducer testing compiled C program (duration=45.373989448s, {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$tty1-ioctl$KDSKBENT-syz_open_dev$evdev-write$evdev program crashed: possible deadlock in n_tty_flush_buffer simplifying C reproducer testing compiled C program (duration=45.373989448s, {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$tty1-ioctl$KDSKBENT-syz_open_dev$evdev-write$evdev program crashed: possible deadlock in n_tty_flush_buffer testing compiled C program (duration=45.373989448s, {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$tty1-ioctl$KDSKBENT-syz_open_dev$evdev-write$evdev program did not crash testing compiled C program (duration=45.373989448s, {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$tty1-ioctl$KDSKBENT-syz_open_dev$evdev-write$evdev program crashed: possible deadlock in n_tty_flush_buffer testing compiled C program (duration=45.373989448s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 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$tty1-ioctl$KDSKBENT-syz_open_dev$evdev-write$evdev program crashed: possible deadlock in n_tty_flush_buffer testing compiled C program (duration=45.373989448s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 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$tty1-ioctl$KDSKBENT-syz_open_dev$evdev-write$evdev program crashed: possible deadlock in n_tty_flush_buffer testing compiled C program (duration=45.373989448s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 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$tty1-ioctl$KDSKBENT-syz_open_dev$evdev-write$evdev program crashed: possible deadlock in n_tty_flush_buffer testing compiled C program (duration=45.373989448s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 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$tty1-ioctl$KDSKBENT-syz_open_dev$evdev-write$evdev program crashed: possible deadlock in n_tty_flush_buffer testing compiled C program (duration=45.373989448s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 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$tty1-ioctl$KDSKBENT-syz_open_dev$evdev-write$evdev program crashed: possible deadlock in n_tty_flush_buffer testing program (duration=45.373989448s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 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$tty1-ioctl$KDSKBENT-syz_open_dev$evdev-write$evdev detailed listing: executing program 0: r0 = syz_open_dev$tty1(0xc, 0x4, 0x1) ioctl$KDSKBENT(r0, 0x4b47, &(0x7f0000000300)={0x0, 0x7f, 0x20f}) r1 = syz_open_dev$evdev(&(0x7f00000002c0), 0xc000, 0x142) write$evdev(r1, &(0x7f0000000640)=[{{0x77359400}, 0x1, 0x7f, 0x2}], 0x18) program crashed: possible deadlock in n_tty_flush_buffer validation run: crashed=true testing program (duration=45.373989448s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 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$tty1-ioctl$KDSKBENT-syz_open_dev$evdev-write$evdev detailed listing: executing program 0: r0 = syz_open_dev$tty1(0xc, 0x4, 0x1) ioctl$KDSKBENT(r0, 0x4b47, &(0x7f0000000300)={0x0, 0x7f, 0x20f}) r1 = syz_open_dev$evdev(&(0x7f00000002c0), 0xc000, 0x142) write$evdev(r1, &(0x7f0000000640)=[{{0x77359400}, 0x1, 0x7f, 0x2}], 0x18) program crashed: possible deadlock in n_tty_flush_buffer validation run: crashed=true testing program (duration=45.373989448s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 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$tty1-ioctl$KDSKBENT-syz_open_dev$evdev-write$evdev detailed listing: executing program 0: r0 = syz_open_dev$tty1(0xc, 0x4, 0x1) ioctl$KDSKBENT(r0, 0x4b47, &(0x7f0000000300)={0x0, 0x7f, 0x20f}) r1 = syz_open_dev$evdev(&(0x7f00000002c0), 0xc000, 0x142) write$evdev(r1, &(0x7f0000000640)=[{{0x77359400}, 0x1, 0x7f, 0x2}], 0x18) program crashed: possible deadlock in n_tty_flush_buffer validation run: crashed=true reproducing took 28m43.643591796s repro crashed as (corrupted=false): ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ kworker/0:1/10 is trying to acquire lock: ffff88807e3472e8 (&tty->termios_rwsem){++++}-{4:4}, at: n_tty_flush_buffer+0x30/0x230 drivers/tty/n_tty.c:352 but task is already holding lock: ffff88813fec10b8 (&buf->lock){+.+.}-{4:4}, at: tty_buffer_flush+0x74/0x2b0 drivers/tty/tty_buffer.c:229 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&buf->lock){+.+.}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760 tty_buffer_flush+0x74/0x2b0 drivers/tty/tty_buffer.c:229 tty_ldisc_flush+0x6b/0xc0 drivers/tty/tty_ldisc.c:388 __do_SAK+0xf2/0x6e0 drivers/tty/tty_io.c:3025 vc_SAK+0x78/0x220 drivers/tty/vt/vt_ioctl.c:994 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #2 (console_lock){+.+.}-{0:0}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 console_lock+0x76/0x90 kernel/printk/printk.c:2822 uart_configure_port drivers/tty/serial/serial_core.c:2547 [inline] serial_core_add_one_port drivers/tty/serial/serial_core.c:3105 [inline] serial_core_register_port+0xbe1/0x2800 drivers/tty/serial/serial_core.c:3331 serial8250_register_8250_port+0x16db/0x2080 drivers/tty/serial/8250/8250_core.c:818 serial_pnp_probe+0x527/0x790 drivers/tty/serial/8250/8250_pnp.c:480 pnp_device_probe+0x30b/0x4c0 drivers/pnp/driver.c:111 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x26d/0x9e0 drivers/base/dd.c:659 __driver_probe_device+0x18c/0x2f0 drivers/base/dd.c:801 driver_probe_device+0x4f/0x430 drivers/base/dd.c:831 __driver_attach+0x452/0x700 drivers/base/dd.c:1217 bus_for_each_dev+0x233/0x2b0 drivers/base/bus.c:370 bus_add_driver+0x345/0x640 drivers/base/bus.c:678 driver_register+0x23a/0x320 drivers/base/driver.c:249 serial8250_init+0x8f/0x160 drivers/tty/serial/8250/8250_platform.c:320 do_one_initcall+0x236/0x820 init/main.c:1283 do_initcall_level+0x104/0x190 init/main.c:1345 do_initcalls+0x59/0xa0 init/main.c:1361 kernel_init_freeable+0x334/0x4b0 init/main.c:1593 kernel_init+0x1d/0x1d0 init/main.c:1483 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #1 (&port->mutex){+.+.}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760 class_mutex_constructor include/linux/mutex.h:228 [inline] uart_set_termios+0x82/0x730 drivers/tty/serial/serial_core.c:1670 tty_set_termios+0xca8/0x17e0 drivers/tty/tty_ioctl.c:341 set_termios+0x516/0x6c0 drivers/tty/tty_ioctl.c:516 tty_mode_ioctl+0x47e/0x740 drivers/tty/tty_ioctl.c:-1 tty_ioctl+0x9c6/0xde0 drivers/tty/tty_io.c:2801 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:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&tty->termios_rwsem){++++}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 down_write+0x96/0x1f0 kernel/locking/rwsem.c:1590 n_tty_flush_buffer+0x30/0x230 drivers/tty/n_tty.c:352 tty_buffer_flush+0x1ec/0x2b0 drivers/tty/tty_buffer.c:241 tty_ldisc_flush+0x6b/0xc0 drivers/tty/tty_ldisc.c:388 __do_SAK+0xf2/0x6e0 drivers/tty/tty_io.c:3025 vc_SAK+0x78/0x220 drivers/tty/vt/vt_ioctl.c:994 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 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 *** 5 locks held by kworker/0:1/10: #0: ffff88813fe55948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff88813fe55948 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc900000f7ba0 ((work_completion)(&vc_cons[currcons].SAK_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc900000f7ba0 ((work_completion)(&vc_cons[currcons].SAK_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 #2: ffffffff8e1312c0 (console_lock){+.+.}-{0:0}, at: class_console_lock_constructor include/linux/console.h:669 [inline] #2: ffffffff8e1312c0 (console_lock){+.+.}-{0:0}, at: vc_SAK+0x28/0x220 drivers/tty/vt/vt_ioctl.c:985 #3: ffff88807e3470a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref drivers/tty/tty_ldisc.c:263 [inline] #3: ffff88807e3470a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_flush+0x20/0xc0 drivers/tty/tty_ldisc.c:386 #4: ffff88813fec10b8 (&buf->lock){+.+.}-{4:4}, at: tty_buffer_flush+0x74/0x2b0 drivers/tty/tty_buffer.c:229 stack backtrace: CPU: 0 UID: 0 PID: 10 Comm: kworker/0:1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: events vc_SAK Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043 check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 down_write+0x96/0x1f0 kernel/locking/rwsem.c:1590 n_tty_flush_buffer+0x30/0x230 drivers/tty/n_tty.c:352 tty_buffer_flush+0x1ec/0x2b0 drivers/tty/tty_buffer.c:241 tty_ldisc_flush+0x6b/0xc0 drivers/tty/tty_ldisc.c:388 __do_SAK+0xf2/0x6e0 drivers/tty/tty_io.c:3025 vc_SAK+0x78/0x220 drivers/tty/vt/vt_ioctl.c:994 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 tty tty1: SAK: killed process 6060 (syz.0.24): by fd#3 tty tty1: SAK: killed process 6135 (syz.0.48): by fd#3 tty tty1: SAK: killed process 6399 (syz.0.296): by fd#3 final repro crashed as (corrupted=false): ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ kworker/0:1/10 is trying to acquire lock: ffff88807e3472e8 (&tty->termios_rwsem){++++}-{4:4}, at: n_tty_flush_buffer+0x30/0x230 drivers/tty/n_tty.c:352 but task is already holding lock: ffff88813fec10b8 (&buf->lock){+.+.}-{4:4}, at: tty_buffer_flush+0x74/0x2b0 drivers/tty/tty_buffer.c:229 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&buf->lock){+.+.}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760 tty_buffer_flush+0x74/0x2b0 drivers/tty/tty_buffer.c:229 tty_ldisc_flush+0x6b/0xc0 drivers/tty/tty_ldisc.c:388 __do_SAK+0xf2/0x6e0 drivers/tty/tty_io.c:3025 vc_SAK+0x78/0x220 drivers/tty/vt/vt_ioctl.c:994 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #2 (console_lock){+.+.}-{0:0}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 console_lock+0x76/0x90 kernel/printk/printk.c:2822 uart_configure_port drivers/tty/serial/serial_core.c:2547 [inline] serial_core_add_one_port drivers/tty/serial/serial_core.c:3105 [inline] serial_core_register_port+0xbe1/0x2800 drivers/tty/serial/serial_core.c:3331 serial8250_register_8250_port+0x16db/0x2080 drivers/tty/serial/8250/8250_core.c:818 serial_pnp_probe+0x527/0x790 drivers/tty/serial/8250/8250_pnp.c:480 pnp_device_probe+0x30b/0x4c0 drivers/pnp/driver.c:111 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x26d/0x9e0 drivers/base/dd.c:659 __driver_probe_device+0x18c/0x2f0 drivers/base/dd.c:801 driver_probe_device+0x4f/0x430 drivers/base/dd.c:831 __driver_attach+0x452/0x700 drivers/base/dd.c:1217 bus_for_each_dev+0x233/0x2b0 drivers/base/bus.c:370 bus_add_driver+0x345/0x640 drivers/base/bus.c:678 driver_register+0x23a/0x320 drivers/base/driver.c:249 serial8250_init+0x8f/0x160 drivers/tty/serial/8250/8250_platform.c:320 do_one_initcall+0x236/0x820 init/main.c:1283 do_initcall_level+0x104/0x190 init/main.c:1345 do_initcalls+0x59/0xa0 init/main.c:1361 kernel_init_freeable+0x334/0x4b0 init/main.c:1593 kernel_init+0x1d/0x1d0 init/main.c:1483 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #1 (&port->mutex){+.+.}-{4:4}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __mutex_lock_common kernel/locking/mutex.c:598 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:760 class_mutex_constructor include/linux/mutex.h:228 [inline] uart_set_termios+0x82/0x730 drivers/tty/serial/serial_core.c:1670 tty_set_termios+0xca8/0x17e0 drivers/tty/tty_ioctl.c:341 set_termios+0x516/0x6c0 drivers/tty/tty_ioctl.c:516 tty_mode_ioctl+0x47e/0x740 drivers/tty/tty_ioctl.c:-1 tty_ioctl+0x9c6/0xde0 drivers/tty/tty_io.c:2801 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:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&tty->termios_rwsem){++++}-{4:4}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 down_write+0x96/0x1f0 kernel/locking/rwsem.c:1590 n_tty_flush_buffer+0x30/0x230 drivers/tty/n_tty.c:352 tty_buffer_flush+0x1ec/0x2b0 drivers/tty/tty_buffer.c:241 tty_ldisc_flush+0x6b/0xc0 drivers/tty/tty_ldisc.c:388 __do_SAK+0xf2/0x6e0 drivers/tty/tty_io.c:3025 vc_SAK+0x78/0x220 drivers/tty/vt/vt_ioctl.c:994 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 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 *** 5 locks held by kworker/0:1/10: #0: ffff88813fe55948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff88813fe55948 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc900000f7ba0 ((work_completion)(&vc_cons[currcons].SAK_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc900000f7ba0 ((work_completion)(&vc_cons[currcons].SAK_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 #2: ffffffff8e1312c0 (console_lock){+.+.}-{0:0}, at: class_console_lock_constructor include/linux/console.h:669 [inline] #2: ffffffff8e1312c0 (console_lock){+.+.}-{0:0}, at: vc_SAK+0x28/0x220 drivers/tty/vt/vt_ioctl.c:985 #3: ffff88807e3470a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref drivers/tty/tty_ldisc.c:263 [inline] #3: ffff88807e3470a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_flush+0x20/0xc0 drivers/tty/tty_ldisc.c:386 #4: ffff88813fec10b8 (&buf->lock){+.+.}-{4:4}, at: tty_buffer_flush+0x74/0x2b0 drivers/tty/tty_buffer.c:229 stack backtrace: CPU: 0 UID: 0 PID: 10 Comm: kworker/0:1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: events vc_SAK Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043 check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 down_write+0x96/0x1f0 kernel/locking/rwsem.c:1590 n_tty_flush_buffer+0x30/0x230 drivers/tty/n_tty.c:352 tty_buffer_flush+0x1ec/0x2b0 drivers/tty/tty_buffer.c:241 tty_ldisc_flush+0x6b/0xc0 drivers/tty/tty_ldisc.c:388 __do_SAK+0xf2/0x6e0 drivers/tty/tty_io.c:3025 vc_SAK+0x78/0x220 drivers/tty/vt/vt_ioctl.c:994 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 tty tty1: SAK: killed process 6060 (syz.0.24): by fd#3 tty tty1: SAK: killed process 6135 (syz.0.48): by fd#3 tty tty1: SAK: killed process 6399 (syz.0.296): by fd#3