ci2 starts bisection 2026-09-14 06:38:39.2662957 +0000 UTC m=+193782.262588035 bisecting fixing commit since e4f7d8be268ecf717f94ee2e242afa79ddeacaed building syzkaller on 5d63f80b763910b40ae04a96c13dc75d621bea67 ensuring issue is reproducible on original commit e4f7d8be268ecf717f94ee2e242afa79ddeacaed testing commit e4f7d8be268ecf717f94ee2e242afa79ddeacaed gcc compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 kernel signature: 1cef30a240d61b8833a793927751a8d0dad77360da24d636882d607896b3425d all runs: crashed: possible deadlock in n_tty_flush_buffer representative crash: possible deadlock in n_tty_flush_buffer, types: [LOCKDEP] check whether we can drop unnecessary instrumentation disabling configs for [hang memleak ubsan bug_or_warning kasan atomic_sleep], they are not needed testing commit e4f7d8be268ecf717f94ee2e242afa79ddeacaed gcc compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 kernel signature: 9740b545e931d270a159d95745c8b3edd4d65ce3aec6d8f4cbaaf63ed94ec26a all runs: crashed: possible deadlock in n_tty_flush_buffer representative crash: possible deadlock in n_tty_flush_buffer, types: [LOCKDEP] the bug reproduces without the instrumentation disabling configs for [bug_or_warning kasan atomic_sleep hang memleak ubsan], they are not needed kconfig minimization: base=3829 full=7621 leaves diff=2129 split chunks (needed=false): <2129> split chunk #0 of len 2129 into 5 parts testing without sub-chunk 1/5 disabling configs for [kasan atomic_sleep hang memleak ubsan bug_or_warning], they are not needed testing commit e4f7d8be268ecf717f94ee2e242afa79ddeacaed gcc compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 kernel signature: 555a83e203800e582514fb9fb708804fb723f3d1f3dfca31e1ff7370e060a0b8 all runs: crashed: possible deadlock in n_tty_flush_buffer representative crash: possible deadlock in n_tty_flush_buffer, types: [LOCKDEP] the chunk can be dropped testing without sub-chunk 2/5 disabling configs for [memleak ubsan bug_or_warning kasan atomic_sleep hang], they are not needed testing commit e4f7d8be268ecf717f94ee2e242afa79ddeacaed gcc compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 kernel signature: e1fa6ead2a587efba82b1991d7048fc7473c8a927804ceac593175828b67df5d all runs: OK false negative chance: 0.000 testing without sub-chunk 3/5 disabling configs for [hang memleak ubsan bug_or_warning kasan atomic_sleep], they are not needed testing commit e4f7d8be268ecf717f94ee2e242afa79ddeacaed gcc compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 kernel signature: 1705cb6cfb074f74c01af0934f0362953cccaef18bd62db6fa696f01129401a1 run #0: crashed: possible deadlock in n_tty_flush_buffer run #1: crashed: possible deadlock in n_tty_flush_buffer run #2: crashed: possible deadlock in n_tty_flush_buffer run #3: crashed: possible deadlock in n_tty_flush_buffer run #4: crashed: possible deadlock in n_tty_flush_buffer run #5: crashed: possible deadlock in n_tty_flush_buffer run #6: crashed: possible deadlock in tty_buffer_flush run #7: crashed: possible deadlock in n_tty_flush_buffer run #8: crashed: possible deadlock in n_tty_flush_buffer run #9: crashed: possible deadlock in n_tty_flush_buffer representative crash: possible deadlock in n_tty_flush_buffer, types: [LOCKDEP] the chunk can be dropped testing without sub-chunk 4/5 disabling configs for [hang memleak ubsan bug_or_warning kasan atomic_sleep], they are not needed testing commit e4f7d8be268ecf717f94ee2e242afa79ddeacaed gcc compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 kernel signature: 29898311aa630543eba64eafab330ab7f3efe98b8ffa4f7dbe3d791a833aaddf all runs: crashed: possible deadlock in n_tty_flush_buffer representative crash: possible deadlock in n_tty_flush_buffer, types: [LOCKDEP] the chunk can be dropped testing without sub-chunk 5/5 disabling configs for [hang memleak ubsan bug_or_warning kasan atomic_sleep], they are not needed testing commit e4f7d8be268ecf717f94ee2e242afa79ddeacaed gcc compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 kernel signature: 2e7ef0f13d5da57d8845d45b4fec8ae8683c33e216b8a147a92c704e78fc1d06 all runs: crashed: possible deadlock in n_tty_flush_buffer representative crash: possible deadlock in n_tty_flush_buffer, types: [LOCKDEP] the chunk can be dropped minimized to 426 configs; suspects: [6LOWPAN ARCH_ENABLE_MEMORY_HOTREMOVE ASUS_WMI BLK_DEV_ZONED CHARGER_BQ24190 CMA COMMON_CLK DAX DEVICE_PRIVATE DEV_COREDUMP DEV_DAX DIMLIB DLM DLN2_ADC DMABUF_HEAPS DMABUF_HEAPS_CMA DMABUF_HEAPS_SYSTEM DMABUF_MOVE_NOTIFY DMA_CMA DMA_ENGINE_RAID DM_AUDIT DM_BIO_PRISON DM_BUFIO DM_CACHE DM_CACHE_SMQ DM_CLONE DM_CRYPT DM_FLAKEY DM_INTEGRITY DM_MULTIPATH DM_MULTIPATH_QL DM_MULTIPATH_ST DM_PERSISTENT_DATA DM_RAID DM_SNAPSHOT DM_THIN_PROVISIONING DM_UEVENT DM_VERITY DM_VERITY_FEC DM_WRITECACHE DM_ZONED DRAGONRISE_FF DRM DRM_BOCHS DRM_BRIDGE DRM_BUDDY DRM_CIRRUS_QEMU DRM_DEBUG_MM DRM_DISPLAY_DP_HELPER DRM_DISPLAY_HDCP_HELPER DRM_DISPLAY_HDMI_HELPER DRM_DISPLAY_HELPER DRM_DP_AUX_BUS DRM_DP_AUX_CHARDEV DRM_FBDEV_EMULATION DRM_GEM_SHMEM_HELPER DRM_GM12U320 DRM_GUD DRM_I915 DRM_I915_CAPTURE_ERROR DRM_I915_COMPRESS_ERROR DRM_I915_USERPTR DRM_KMS_HELPER DRM_MIPI_DSI DRM_NOMODESET DRM_PANEL DRM_PANEL_BRIDGE DRM_PANEL_EDP DRM_PANEL_ORIENTATION_QUIRKS DRM_SIMPLEDRM DRM_TTM DRM_TTM_HELPER DRM_UDL DRM_VGEM DRM_VIRTIO_GPU DRM_VKMS DRM_VMWGFX DRM_VRAM_HELPER DUMMY DVB_AF9013 DVB_AF9033 DVB_AS102 DVB_AS102_FE DVB_B2C2_FLEXCOP DVB_B2C2_FLEXCOP_USB DVB_CORE DVB_DIB3000MB DVB_DIB3000MC DVB_EC100 DVB_GP8PSK_FE DVB_RTL2830 DVB_RTL2832 DVB_RTL2832_SDR DVB_TEST_DRIVERS DVB_TTUSB_BUDGET DVB_TTUSB_DEC DVB_USB DVB_USB_A800 DVB_USB_AF9005 DVB_USB_AF9005_REMOTE DVB_USB_AF9015 DVB_USB_AF9035 DVB_USB_ANYSEE DVB_USB_AU6610 DVB_USB_AZ6007 DVB_USB_AZ6027 DVB_USB_CE6230 DVB_USB_CINERGY_T2 DVB_USB_CXUSB DVB_USB_CXUSB_ANALOG DVB_USB_DIB0700 DVB_USB_DIB3000MC DVB_USB_DIBUSB_MB DVB_USB_DIBUSB_MC DVB_USB_DIGITV DVB_USB_DTT200U DVB_USB_DTV5100 DVB_USB_DVBSKY DVB_USB_DW2102 DVB_USB_EC168 DVB_USB_GL861 DVB_USB_GP8PSK DVB_USB_LME2510 DVB_USB_M920X DVB_USB_MXL111SF DVB_USB_NOVA_T_USB2 DVB_USB_OPERA1 DVB_USB_PCTV452E DVB_USB_RTL28XXU DVB_USB_TECHNISAT_USB2 DVB_USB_TTUSB2 DVB_USB_UMT_010 DVB_USB_V2 DVB_USB_VP702X DVB_USB_VP7045 DVB_USB_ZD1301 DVB_VIDTV DVB_ZL10353 ECRYPT_FS ECRYPT_FS_MESSAGING EDAC EEPROM_93CX6 EFS_FS ENCRYPTED_KEYS EQUALIZER EROFS_FS EROFS_FS_POSIX_ACL EROFS_FS_SECURITY EROFS_FS_XATTR EROFS_FS_ZIP EVM EVM_ADD_XATTRS EVM_ATTR_FSUUID EXFAT_FS EXPORTFS_BLOCK_OPS EXT3_FS EXT3_FS_POSIX_ACL EXT3_FS_SECURITY EXTCON EXTCON_INTEL_CHT_WC EXTCON_PTN5150 EXTCON_USBC_TUSB320 F2FS_CHECK_FS F2FS_FAULT_INJECTION F2FS_FS F2FS_FS_COMPRESSION F2FS_FS_LZ4 F2FS_FS_LZ4HC F2FS_FS_LZO F2FS_FS_LZORLE F2FS_FS_POSIX_ACL F2FS_FS_SECURITY F2FS_FS_XATTR F2FS_FS_ZSTD F2FS_STAT_FS FANOTIFY FANOTIFY_ACCESS_PERMISSIONS FB FB_CFB_COPYAREA FB_CFB_FILLRECT FB_CFB_IMAGEBLIT FB_CMDLINE FB_DEFERRED_IO FB_NOTIFY FB_SYS_COPYAREA FB_SYS_FILLRECT FB_SYS_FOPS FB_SYS_IMAGEBLIT FB_TILEBLITTING FB_VESA FB_VGA16 FB_VIRTUAL FDDI FIREWIRE FIREWIRE_NET FIREWIRE_OHCI FIREWIRE_SBP2 FONT_8x16 FONT_8x8 FONT_SUPPORT FRAMEBUFFER_CONSOLE FRAMEBUFFER_CONSOLE_DETECT_PRIMARY FRAMEBUFFER_CONSOLE_ROTATION FRONTSWAP FS_DAX FS_DAX_PMD FS_ENCRYPTION FS_ENCRYPTION_ALGS FS_VERITY FS_VERITY_BUILTIN_SIGNATURES FTL FUSE_DAX FUSE_FS FW_LOADER_COMPRESS FW_LOADER_PAGED_BUF FW_LOADER_SYSFS FW_LOADER_USER_HELPER FW_LOADER_USER_HELPER_FALLBACK GACT_PROB GARP GENERIC_PHY GET_FREE_REGION GFS2_FS GFS2_FS_LOCKING_DLM GNSS GNSS_USB GOOGLE_COREBOOT_TABLE GOOGLE_FIRMWARE GOOGLE_MEMCONSOLE GOOGLE_MEMCONSOLE_COREBOOT GOOGLE_VPD GPIOLIB GPIOLIB_IRQCHIP GPIO_ACPI GPIO_DLN2 GPIO_VIPERBOARD GREENASIA_FF GREYBUS GREYBUS_BRIDGED_PHY GREYBUS_ES2 GREYBUS_HID GREYBUS_USB GTP GUEST_PERF_EVENTS HAVE_ARCH_NODE_DEV_GROUP HAVE_ARCH_USERFAULTFD_MINOR HAVE_ARCH_USERFAULTFD_WP HAVE_BOOTMEM_INFO_NODE HAVE_CLK_PREPARE HAVE_KVM_CPU_RELAX_INTERCEPT HAVE_KVM_DIRTY_RING HAVE_KVM_DIRTY_RING_ACQ_REL HAVE_KVM_DIRTY_RING_TSO HAVE_KVM_EVENTFD HAVE_KVM_IRQCHIP HAVE_KVM_IRQFD HAVE_KVM_IRQ_BYPASS HAVE_KVM_IRQ_ROUTING HAVE_KVM_MSI HAVE_KVM_NO_POLL HAVE_KVM_PFNCACHE HAVE_KVM_PM_NOTIFIER HAVE_SCHED_AVG_IRQ HDLC HDLC_CISCO HDLC_FR HDLC_PPP HDLC_RAW HDLC_RAW_ETH HDLC_X25 HDMI HFSPLUS_FS HFS_FS HID_ACCUTOUCH HID_ACRUX HID_ACRUX_FF HID_ALPS HID_APPLEIR HID_ASUS HID_AUREAL HID_BATTERY_STRENGTH HID_BETOP_FF HID_BIGBEN_FF HID_CMEDIA HID_CORSAIR HID_COUGAR HID_CP2112 HID_CREATIVE_SB0540 HID_DRAGONRISE HID_ELAN HID_ELECOM HID_ELO HID_EMS_FF HID_FT260 HID_GEMBIRD HID_GFRM HID_GLORIOUS HID_GREENASIA HID_GT683R HID_HOLTEK HID_ICADE HID_JABRA HID_KEYTOUCH HID_KYE HID_LCPOWER HID_LED HID_LENOVO HID_LETSKETCH HID_LOGITECH_DJ HID_LOGITECH_HIDPP HID_MACALLY HID_MAGICMOUSE HID_MALTRON HID_MAYFLASH HID_MCP2221 HID_MEGAWORLD_FF HID_MULTITOUCH HID_NTI HID_ORTEK HID_PENMOUNT HID_PICOLCD HID_PICOLCD_BACKLIGHT HID_PICOLCD_CIR HID_PICOLCD_FB HID_PICOLCD_LCD HID_PICOLCD_LEDS HID_PLANTRONICS HID_PRIMAX HID_PRODIKEYS HID_PXRC HID_RAZER HID_RETRODE HID_RMI HID_ROCCAT HID_SAITEK HID_SEMITEK HID_SENSOR_ACCEL_3D HID_SENSOR_ALS HID_SENSOR_CUSTOM_INTEL_HINGE HID_SENSOR_CUSTOM_SENSOR HID_SENSOR_DEVICE_ROTATION HID_SENSOR_GYRO_3D HID_SENSOR_HUB HID_SENSOR_HUMIDITY HID_SENSOR_IIO_COMMON HID_SENSOR_IIO_TRIGGER HID_SENSOR_INCLINOMETER_3D HID_SENSOR_MAGNETOMETER_3D HID_SENSOR_PRESS HID_SENSOR_PROX HID_SENSOR_TEMP HID_SIGMAMICRO HID_SPEEDLINK HID_STEAM HID_STEELSERIES HID_THINGM HID_TIVO HID_TOPRE HID_TWINHAN HID_U2FZERO HID_UCLOGIC HID_UDRAW_PS3 HID_VIEWSONIC HID_VIVALDI HID_VIVALDI_COMMON HID_VRC2 HID_WACOM HID_WALTOP HID_WIIMOTE HID_XIAOMI HID_XINMO HID_ZYDACRON HMM_MIRROR HOLTEK_FF HOTPLUG_PCI_PCIE HPET_MMAP HPET_MMAP_DEFAULT HPFS_FS I2C_ALGOBIT I2C_CHARDEV I2C_CP2615 I2C_DESIGNWARE_CORE I2C_DESIGNWARE_PLATFORM I2C_DIOLAN_U2C I2C_DLN2 I2C_MUX I2C_MUX_REG I2C_ROBOTFUZZ_OSIF I2C_SI4713 I2C_SLAVE I2C_SLAVE_EEPROM I2C_TINY_USB I2C_VIPERBOARD IEEE802154 IEEE802154_6LOWPAN IEEE802154_ATUSB IEEE802154_DRIVERS IEEE802154_HWSIM IEEE802154_NL802154_EXPERIMENTAL IEEE802154_SOCKET IFB IIO IIO_BUFFER IIO_KFIFO_BUF IIO_TRIGGER IIO_TRIGGERED_BUFFER IKCONFIG IKCONFIG_PROC IMA IMA_APPRAISE IMA_APPRAISE_MODSIG IMA_DEFAULT_HASH_SHA256 IMA_LSM_RULES IMA_MEASURE_ASYMMETRIC_KEYS IMA_NG_TEMPLATE IMA_QUEUE_EARLY_BOOT_KEYS IMA_READ_POLICY IMA_WRITE_POLICY INET6_ESPINTCP INET6_ESP_OFFLOAD INET6_IPCOMP INET6_TUNNEL INET6_XFRM_TUNNEL INET_AH INET_DCCP_DIAG INET_DIAG INET_DIAG_DESTROY INET_ESP INET_ESPINTCP INET_ESP_OFFLOAD INET_IPCOMP INET_MPTCP_DIAG INET_RAW_DIAG INET_SCTP_DIAG INET_TCP_DIAG INET_UDP_DIAG INET_XFRM_TUNNEL INFINIBAND INFINIBAND_ADDR_TRANS INFINIBAND_ADDR_TRANS_CONFIGFS INFINIBAND_IPOIB INFINIBAND_IPOIB_CM INFINIBAND_IPOIB_DEBUG INFINIBAND_ISER INFINIBAND_ON_DEMAND_PAGING INFINIBAND_RTRS INFINIBAND_SRP INFINIBAND_USER_ACCESS INFINIBAND_USER_MAD INFINIBAND_USER_MEM INPUT_ATI_REMOTE2 INPUT_CM109 INPUT_IMS_PCU INPUT_JOYDEV INPUT_KEYSPAN_REMOTE INPUT_LEDS INPUT_MOUSEDEV INPUT_MOUSEDEV_PSAUX INPUT_POWERMATE INPUT_UINPUT INPUT_YEALINK INTEGRITY INTEGRITY_ASYMMETRIC_KEYS INTEGRITY_AUDIT INTEGRITY_SIGNATURE INTEGRITY_TRUSTED_KEYRING INTEL_CHTWC_INT33FE INTEL_IDMA64 INTEL_IOATDMA INTEL_IOMMU_DEFAULT_ON INTEL_IOMMU_SVM INTEL_SOC_PMIC_CHTWC INTERVAL_TREE IOMMU_SVA IP6_NF_MATCH_AH IP6_NF_MATCH_EUI64 IP6_NF_MATCH_FRAG IP6_NF_MATCH_HL IP6_NF_MATCH_MH IP6_NF_MATCH_OPTS IP6_NF_MATCH_RPFILTER IP6_NF_MATCH_RT IP6_NF_MATCH_SRH IP6_NF_NAT IP6_NF_RAW IP6_NF_SECURITY IP6_NF_TARGET_HL IP6_NF_TARGET_MASQUERADE IP6_NF_TARGET_NPT IP6_NF_TARGET_SYNPROXY IPV6_FOU IPV6_FOU_TUNNEL IPV6_GRE IPV6_ILA IPV6_MIP6 IPV6_MROUTE IPV6_MROUTE_MULTIPLE_TABLES IPV6_MULTIPLE_TABLES IPV6_OPTIMISTIC_DAD IPV6_PIMSM_V2 IPV6_ROUTER_PREF IPV6_ROUTE_INFO IPV6_RPL_LWTUNNEL IPV6_SEG6_BPF IPV6_SEG6_HMAC IPV6_SEG6_LWTUNNEL IPV6_SIT_6RD IPV6_SUBTREES IPV6_TUNNEL IPV6_VTI IPVLAN IPVLAN_L3S IPVTAP IP_DCCP IP_DCCP_CCID3 IP_DCCP_TFRC_LIB IP_FIB_TRIE_STATS IP_MROUTE_MULTIPLE_TABLES IP_NF_ARPFILTER IP_NF_ARPTABLES IP_NF_ARP_MANGLE IP_NF_MATCH_AH IP_NF_MATCH_ECN IP_NF_MATCH_RPFILTER IP_NF_MATCH_TTL IP_NF_RAW IP_SCTP IRQ_TIME_ACCOUNTING LAPB LCD_CLASS_DEVICE MAC802154 MEDIA_DIGITAL_TV_SUPPORT MEDIA_RADIO_SUPPORT MEDIA_SDR_SUPPORT MEDIA_SUPPORT MEDIA_TEST_SUPPORT MEDIA_USB_SUPPORT MEMORY_HOTPLUG MEMORY_HOTREMOVE MFD_DLN2 MFD_VIPERBOARD MPTCP MTD NETFILTER_ADVANCED NET_ACT_GACT NET_ACT_MIRRED NET_IPGRE_DEMUX NFT_FWD_NETDEV NF_TABLES NF_TABLES_NETDEV RADIO_ADAPTERS RADIO_SI4713 RAS RC_CORE REGULATOR RFKILL SND SOUND STAGING TRANSPARENT_HUGEPAGE TRUSTED_KEYS TYPEC TYPEC_MUX_PI3USB30532 USB_ROLES_INTEL_XHCI USB_ROLE_SWITCH VIDEO_DEV VIRTIO_FS WAN ZONE_DEVICE] disabling configs for [hang memleak ubsan bug_or_warning kasan atomic_sleep], they are not needed testing current HEAD cf82dcca96346600c7068cf3f841335f9fa08f54 testing commit cf82dcca96346600c7068cf3f841335f9fa08f54 gcc compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 kernel signature: 13215b57e177b831add0817621571bf4eac015e1e16dc7c3edd9f39dbc2259d4 all runs: crashed: possible deadlock in n_tty_flush_buffer representative crash: possible deadlock in n_tty_flush_buffer, types: [LOCKDEP] crash still not fixed/happens on the oldest tested release revisions tested: 8, total time: 2h16m1.333066472s (build: 1h8m59.436943715s, test: 55m46.429460411s) crash still not fixed or there were kernel test errors commit msg: Linux 6.1.187 crash: possible deadlock in n_tty_flush_buffer ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ kworker/0:1/13 is trying to acquire lock: ffff888104b5f2e8 (&tty->termios_rwsem){++++}-{3:3}, at: n_tty_flush_buffer+0x18/0x150 drivers/tty/n_tty.c:370 but task is already holding lock: ffff8881001280b8 (&buf->lock){+.+.}-{3:3}, at: tty_buffer_flush+0x2d/0xd0 drivers/tty/tty_buffer.c:230 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&buf->lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x97/0xa10 kernel/locking/mutex.c:747 tty_buffer_flush+0x2d/0xd0 drivers/tty/tty_buffer.c:230 tty_ldisc_flush+0x2f/0x60 drivers/tty/tty_ldisc.c:389 __do_SAK+0x122/0x2d0 drivers/tty/tty_io.c:3011 vc_SAK+0x23/0x70 drivers/tty/vt/vt_ioctl.c:997 process_one_work+0x27d/0x4c0 kernel/workqueue.c:2292 worker_thread+0x221/0x380 kernel/workqueue.c:2439 kthread+0xcc/0xe0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 -> #2 (console_lock){+.+.}-{0:0}: console_lock+0x57/0x80 kernel/printk/printk.c:2629 uart_configure_port drivers/tty/serial/serial_core.c:2576 [inline] uart_add_one_port+0x250/0x760 drivers/tty/serial/serial_core.c:3135 serial8250_register_8250_port+0x496/0x5d0 drivers/tty/serial/8250/8250_core.c:1092 serial_pnp_probe+0x2bd/0x370 drivers/tty/serial/8250/8250_pnp.c:478 pnp_device_probe+0xc6/0x120 drivers/pnp/driver.c:111 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x143/0x470 drivers/base/dd.c:638 __driver_probe_device+0x97/0x120 drivers/base/dd.c:804 driver_probe_device+0x1d/0x1b0 drivers/base/dd.c:834 __driver_attach+0x113/0x250 drivers/base/dd.c:1220 bus_for_each_dev+0x88/0xc0 drivers/base/bus.c:303 bus_add_driver+0x118/0x210 drivers/base/bus.c:620 driver_register+0x81/0x120 drivers/base/driver.c:246 serial8250_init+0x66/0xfa drivers/tty/serial/8250/8250_core.c:1191 do_one_initcall+0x126/0x2d0 init/main.c:1270 do_initcall_level+0x8f/0xeb init/main.c:1343 do_initcalls+0x46/0x6f init/main.c:1359 kernel_init_freeable+0x17a/0x1e4 init/main.c:1598 kernel_init+0x11/0x110 init/main.c:1486 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 -> #1 (&port->mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x97/0xa10 kernel/locking/mutex.c:747 uart_set_termios+0x2e/0x1a0 drivers/tty/serial/serial_core.c:1651 tty_set_termios+0x3fa/0x480 drivers/tty/tty_ioctl.c:363 set_termios+0x25a/0x2a0 drivers/tty/tty_ioctl.c:537 tty_ioctl+0x2e6/0x480 drivers/tty/tty_io.c:2785 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0x65/0xb0 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #0 (&tty->termios_rwsem){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3095 [inline] check_prevs_add kernel/locking/lockdep.c:3214 [inline] validate_chain kernel/locking/lockdep.c:3830 [inline] __lock_acquire+0x151f/0x26c0 kernel/locking/lockdep.c:5063 lock_acquire+0xe9/0x270 kernel/locking/lockdep.c:5676 down_write+0x26/0xc0 kernel/locking/rwsem.c:1573 n_tty_flush_buffer+0x18/0x150 drivers/tty/n_tty.c:370 tty_buffer_flush+0xab/0xd0 drivers/tty/tty_buffer.c:242 tty_ldisc_flush+0x2f/0x60 drivers/tty/tty_ldisc.c:389 __do_SAK+0x122/0x2d0 drivers/tty/tty_io.c:3011 vc_SAK+0x23/0x70 drivers/tty/vt/vt_ioctl.c:997 process_one_work+0x27d/0x4c0 kernel/workqueue.c:2292 worker_thread+0x221/0x380 kernel/workqueue.c:2439 kthread+0xcc/0xe0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 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/0:1/13: #0: ffff888100062538 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x223/0x4c0 kernel/workqueue.c:2267 #1: ffffc90000073e68 ((work_completion)(&vc_cons[currcons].SAK_work)){+.+.}-{0:0}, at: process_one_work+0x223/0x4c0 kernel/workqueue.c:2267 #2: ffffffff833d3b00 (console_lock){+.+.}-{0:0}, at: vc_SAK+0x9/0x70 drivers/tty/vt/vt_ioctl.c:987 #3: ffff888104b5f098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref drivers/tty/tty_ldisc.c:264 [inline] #3: ffff888104b5f098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_flush+0x14/0x60 drivers/tty/tty_ldisc.c:387 #4: ffff8881001280b8 (&buf->lock){+.+.}-{3:3}, at: tty_buffer_flush+0x2d/0xd0 drivers/tty/tty_buffer.c:230 stack backtrace: CPU: 0 PID: 13 Comm: kworker/0:1 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: events vc_SAK Call Trace: dump_stack_lvl+0x7f/0xdb lib/dump_stack.c:106 print_circular_bug+0x2dc/0x310 kernel/locking/lockdep.c:2048 check_noncircular+0xfb/0x110 kernel/locking/lockdep.c:2170 check_prev_add kernel/locking/lockdep.c:3095 [inline] check_prevs_add kernel/locking/lockdep.c:3214 [inline] validate_chain kernel/locking/lockdep.c:3830 [inline] __lock_acquire+0x151f/0x26c0 kernel/locking/lockdep.c:5063 lock_acquire+0xe9/0x270 kernel/locking/lockdep.c:5676 down_write+0x26/0xc0 kernel/locking/rwsem.c:1573 n_tty_flush_buffer+0x18/0x150 drivers/tty/n_tty.c:370 tty_buffer_flush+0xab/0xd0 drivers/tty/tty_buffer.c:242 tty_ldisc_flush+0x2f/0x60 drivers/tty/tty_ldisc.c:389 __do_SAK+0x122/0x2d0 drivers/tty/tty_io.c:3011 vc_SAK+0x23/0x70 drivers/tty/vt/vt_ioctl.c:997 process_one_work+0x27d/0x4c0 kernel/workqueue.c:2292 worker_thread+0x221/0x380 kernel/workqueue.c:2439 kthread+0xcc/0xe0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 tty tty1: SAK: killed process 4290 (syz.1.303): by fd#3 tty tty1: SAK: killed process 4291 (syz.1.303): by fd#3 tty tty1: SAK: killed process 4296 (syz.1.303): by fd#3 tty tty1: SAK: killed process 4293 (syz.7.305): by fd#3 tty tty1: SAK: killed process 4294 (syz.7.305): by fd#3 tty tty1: SAK: killed process 4297 (syz.7.305): by fd#3 tty tty1: SAK: killed process 4301 (syz.1.307): by fd#3 tty tty1: SAK: killed process 4302 (syz.1.307): by fd#3 tty tty1: SAK: killed process 4303 (syz.5.309): by fd#3 tty tty1: SAK: killed process 4306 (syz.5.309): by fd#3 tty tty1: SAK: killed process 4304 (syz.7.308): by fd#3 tty tty1: SAK: killed process 4305 (syz.7.308): by fd#3 tty tty1: SAK: killed process 4400 (syz.5.348): by fd#3 tty tty1: SAK: killed process 4401 (syz.5.348): by fd#3 tty tty1: SAK: killed process 4405 (syz.5.348): by fd#3 tty tty1: SAK: killed process 4402 (syz.6.349): by fd#3 tty tty1: SAK: killed process 4403 (syz.6.349): by fd#3 tty tty1: SAK: killed process 4404 (syz.6.349): by fd#3 tty tty1: SAK: killed process 4412 (syz.5.353): by fd#3 tty tty1: SAK: killed process 4413 (syz.5.353): by fd#3 tty tty1: SAK: killed process 4414 (syz.6.354): by fd#3 tty tty1: SAK: killed process 4415 (syz.6.354): by fd#3 tty tty1: SAK: killed process 4416 (syz.1.355): by fd#3 tty tty1: SAK: killed process 4417 (syz.1.355): by fd#3 tty tty1: SAK: killed process 4454 (syz.5.369): by fd#3 tty tty1: SAK: killed process 4455 (syz.5.369): by fd#3 tty tty1: SAK: killed process 4464 (syz.5.369): by fd#3 tty tty1: SAK: killed process 4458 (syz.7.371): by fd#3 tty tty1: SAK: killed process 4459 (syz.7.371): by fd#3 tty tty1: SAK: killed process 4460 (syz.0.372): by fd#3 tty tty1: SAK: killed process 4461 (syz.0.372): by fd#3 tty tty1: SAK: killed process 4462 (syz.1.373): by fd#3 tty tty1: SAK: killed process 4463 (syz.1.373): by fd#3 tty tty1: SAK: killed process 4505 (syz.5.390): by fd#3 tty tty1: SAK: killed process 4506 (syz.5.390): by fd#3 tty tty1: SAK: killed process 4507 (syz.1.389): by fd#3 tty tty1: SAK: killed process 4510 (syz.1.389): by fd#3 tty tty1: SAK: killed process 4508 (syz.6.391): by fd#3 tty tty1: SAK: killed process 4511 (syz.6.391): by fd#3 tty tty1: SAK: killed process 4524 (syz.1.397): by fd#3 tty tty1: SAK: killed process 4525 (syz.1.397): by fd#3 tty tty1: SAK: killed process 4530 (syz.1.397): by fd#3 tty tty1: SAK: killed process 4527 (syz.5.398): by fd#3 tty tty1: SAK: killed process 4528 (syz.5.398): by fd#3 tty tty1: SAK: killed process 4531 (syz.5.398): by fd#3 tty tty1: SAK: killed process 4532 (syz.6.401): by fd#3 tty tty1: SAK: killed process 4534 (syz.6.401): by fd#3 tty tty1: SAK: killed process 4533 (syz.0.400): by fd#3 tty tty1: SAK: killed process 4536 (syz.0.400): by fd#3