ci2 starts bisection 2025-09-30 05:49:10.050190211 +0000 UTC m=+68006.726771296
bisecting fixing commit since a29967be967eebf049e89edb14c4edf9991bc929
building syzkaller on e28266709dd2a1d1452d4a5bbf271700e10335c6
ensuring issue is reproducible on original commit a29967be967eebf049e89edb14c4edf9991bc929

testing commit a29967be967eebf049e89edb14c4edf9991bc929 gcc
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
kernel signature: 210823cc3a956fe37a61bce5bb67048946d1afa796900fe03d5c90acb6adf41b
all runs: crashed: INFO: task hung in mISDN_ioctl
representative crash: INFO: task hung in mISDN_ioctl, types: [HANG]
check whether we can drop unnecessary instrumentation
disabling configs for [bug_or_warning kasan locking atomic_sleep memleak ubsan], they are not needed
testing commit a29967be967eebf049e89edb14c4edf9991bc929 gcc
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
kernel signature: 8ed12d0d5e806c9ced1be8a91c22f6b803d01755848491597f6c274ea23a9f12
all runs: crashed: INFO: task hung in mISDN_ioctl
representative crash: INFO: task hung in mISDN_ioctl, types: [HANG]
the bug reproduces without the instrumentation
disabling configs for [memleak ubsan bug_or_warning kasan locking atomic_sleep], they are not needed
kconfig minimization: base=4092 full=8255 leaves diff=2142
split chunks (needed=false): <2142>
split chunk #0 of len 2142 into 5 parts
testing without sub-chunk 1/5
disabling configs for [bug_or_warning kasan locking atomic_sleep memleak ubsan], they are not needed
testing commit a29967be967eebf049e89edb14c4edf9991bc929 gcc
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
kernel signature: edfa546d92cdd6a4ce32a6b0a66dfcf6596e9bc425c6d2f29eb7c8197eda0fcb
all runs: crashed: INFO: task hung in mISDN_ioctl
representative crash: INFO: task hung in mISDN_ioctl, types: [HANG]
the chunk can be dropped
testing without sub-chunk 2/5
disabling configs for [atomic_sleep memleak ubsan bug_or_warning kasan locking], they are not needed
testing commit a29967be967eebf049e89edb14c4edf9991bc929 gcc
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
kernel signature: 2f39349a87f3e3d7a10f1ee9a74a70413c3e96bde2540722b48f035e2b8eb7c8
all runs: crashed: INFO: task hung in mISDN_ioctl
representative crash: INFO: task hung in mISDN_ioctl, types: [HANG]
the chunk can be dropped
testing without sub-chunk 3/5
disabling configs for [atomic_sleep memleak ubsan bug_or_warning kasan locking], they are not needed
testing commit a29967be967eebf049e89edb14c4edf9991bc929 gcc
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
kernel signature: d03ca7b0d5cabb6ad49e2d085c77fc00538df6848ba8690f11a1d68e7a34f444
all runs: OK
false negative chance: 0.000
testing without sub-chunk 4/5
disabling configs for [ubsan bug_or_warning kasan locking atomic_sleep memleak], they are not needed
testing commit a29967be967eebf049e89edb14c4edf9991bc929 gcc
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
kernel signature: ad3e5df785c9e86e121f8a5beb57be91f815526b7ef05c4dff679367158957d3
run #0: crashed: BUG: soft lockup in mISDN_ioctl
run #1: crashed: BUG: soft lockup in mISDN_ioctl
run #2: crashed: BUG: soft lockup in mISDN_ioctl
run #3: crashed: BUG: soft lockup in mISDN_ioctl
run #4: crashed: INFO: task hung in mISDN_ioctl
run #5: crashed: BUG: soft lockup in mISDN_ioctl
run #6: crashed: BUG: soft lockup in mISDN_ioctl
run #7: crashed: BUG: soft lockup in mISDN_ioctl
run #8: crashed: BUG: soft lockup in mISDN_ioctl
run #9: crashed: BUG: soft lockup in mISDN_ioctl
representative crash: BUG: soft lockup in mISDN_ioctl, types: [HANG]
the chunk can be dropped
testing without sub-chunk 5/5
disabling configs for [locking atomic_sleep memleak ubsan bug_or_warning kasan], they are not needed
testing commit a29967be967eebf049e89edb14c4edf9991bc929 gcc
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
kernel signature: b7cb001b1085d1aa8f48a4339f1a89bca069a2763ab83532d4e2dfa864e7aa7d
all runs: crashed: BUG: soft lockup in mISDN_ioctl
representative crash: BUG: soft lockup in mISDN_ioctl, types: [HANG]
the chunk can be dropped
minimized to 429 configs; suspects: [AX25 BRIDGE BRIDGE_NETFILTER CAN CC_HAS_SANCOV_TRACE_PC CFG80211 CHECKPOINT_RESTORE DVB_CORE FB_CORE HAMRADIO HID_LOGITECH HID_NINTENDO HSR INFINIBAND INFINIBAND_ADDR_TRANS INFINIBAND_USER_ACCESS INPUT_JOYSTICK INPUT_MOUSE IP6_NF_RAW IPV6_MULTIPLE_TABLES IP_NF_RAW IP_SET IP_SET_LIST_SET IP_VS IP_VS_DH IP_VS_FO IP_VS_FTP IP_VS_IPV6 IP_VS_LBLC IP_VS_LBLCR IP_VS_LC IP_VS_MH IP_VS_NFCT IP_VS_NQ IP_VS_OVF IP_VS_PE_SIP IP_VS_PROTO_AH IP_VS_PROTO_AH_ESP IP_VS_PROTO_ESP IP_VS_PROTO_SCTP IP_VS_PROTO_TCP IP_VS_PROTO_UDP IP_VS_RR IP_VS_SED IP_VS_SH IP_VS_TWOS IP_VS_WLC IP_VS_WRR IRQ_BYPASS_MANAGER IRQ_MSI_IOMMU IRQ_POLL IR_IGORPLUGUSB IR_IGUANA IR_IMON IR_IMON_RAW IR_MCEUSB IR_REDRAT3 IR_STREAMZAP IR_TOY IR_TTUSBIR ISDN ISDN_CAPI JFFS2_CMODE_PRIORITY JFFS2_COMPRESSION_OPTIONS JFFS2_FS JFFS2_FS_POSIX_ACL JFFS2_FS_SECURITY JFFS2_FS_WRITEBUFFER JFFS2_FS_XATTR JFFS2_LZO JFFS2_RTIME JFFS2_RUBIN JFFS2_SUMMARY JFFS2_ZLIB JFS_DEBUG JFS_FS JFS_POSIX_ACL JFS_SECURITY JOYSTICK_IFORCE JOYSTICK_IFORCE_USB JOYSTICK_PXRC JOYSTICK_XPAD JOYSTICK_XPAD_FF JOYSTICK_XPAD_LEDS KALLSYMS_ABSOLUTE_PERCPU KARMA_PARTITION KCOV KCOV_ENABLE_COMPARISONS KCOV_INSTRUMENT_ALL KEYS_REQUEST_CACHE KEY_DH_OPERATIONS KEY_NOTIFICATIONS KSM KVM KVM_AMD KVM_ASYNC_PF KVM_COMMON KVM_COMPAT KVM_ELIDE_TLB_FLUSH_IF_YOUNG KVM_GENERIC_DIRTYLOG_READ_PROTECT KVM_GENERIC_HARDWARE_ENABLING KVM_GENERIC_MEMORY_ATTRIBUTES KVM_GENERIC_MMU_NOTIFIER KVM_GENERIC_PRE_FAULT_MEMORY KVM_GENERIC_PRIVATE_MEM KVM_HYPERV KVM_MMIO KVM_PRIVATE_MEM KVM_PROVE_MMU KVM_SW_PROTECTED_VM KVM_VFIO KVM_X86 KVM_XEN KVM_XFER_TO_GUEST_WORK L2TP L2TP_ETH L2TP_IP L2TP_V3 LAPB LAPBETHER LDM_PARTITION LD_IS_BFD LEGACY_PTYS LIBCRC32C LIBNVDIMM LINEAR_RANGES LLC LLC2 LOGIG940_FF LOGIRUMBLEPAD2_FF LOGITECH_FF LOGIWHEELS_FF LOGO LOGO_LINUX_MONO LOGO_LINUX_VGA16 LPC_ICH LWTUNNEL LWTUNNEL_BPF LZ4HC_COMPRESS LZ4_COMPRESS MAC80211 MAC80211_HAS_RC MAC80211_HWSIM MAC80211_MESH MAC80211_RC_DEFAULT_MINSTREL MAC80211_RC_MINSTREL MACSEC MACVLAN MACVTAP MAC_PARTITION MAPPING_DIRTY_HELPERS MCORE2 MDIO_DEVICE MDIO_DEVRES MDIO_MVUSB MD_RAID0 MD_RAID1 MD_RAID10 MD_RAID456 MEDIA_ANALOG_TV_SUPPORT MEDIA_ATTACH MEDIA_CONTROLLER MEDIA_CONTROLLER_DVB MEDIA_DIGITAL_TV_SUPPORT MEDIA_RADIO_SUPPORT MEDIA_SDR_SUPPORT MEDIA_SUPPORT MEDIA_SUPPORT_FILTER MEDIA_TUNER MEDIA_TUNER_MSI001 MEMORY_BALLOON MEMORY_HOTPLUG MEMORY_ISOLATION MEMREGION MEMSTICK MEMSTICK_REALTEK_USB MEM_SOFT_DIRTY MFD_CORE MFD_SYSCON MHI_BUS MHI_WWAN_CTRL MHP_DEFAULT_ONLINE_TYPE_ONLINE_AUTO MHP_MEMMAP_ON_MEMORY MICROCHIP_PHY MINIX_FS MINIX_SUBPARTITION MIN_HEAP MISC_RTSX MISC_RTSX_USB MISDN MISDN_DSP MISDN_HFCUSB MISDN_L1OIP MKISS MLX4_CORE MLX4_INFINIBAND MMC MMC_REALTEK_USB MMC_USHC MMC_VUB300 MODULE_SRCVERSION_ALL MOST MOST_USB_HDM MOUSE_APPLETOUCH MOUSE_BCM5974 MOUSE_PS2 MOUSE_PS2_ALPS MOUSE_PS2_BYD MOUSE_PS2_CYPRESS MOUSE_PS2_FOCALTECH MOUSE_PS2_LIFEBOOK MOUSE_PS2_LOGIPS2PP MOUSE_PS2_SMBUS MOUSE_PS2_SYNAPTICS MOUSE_PS2_SYNAPTICS_SMBUS MOUSE_PS2_TRACKPOINT MOUSE_SYNAPTICS_USB MPLS MPLS_IPTUNNEL MPLS_ROUTING MPTCP MPTCP_IPV6 MRP MTD MTD_BLKDEVS MTD_BLOCK MTD_BLOCK2MTD MTD_CFI_I1 MTD_CFI_I2 MTD_MAP_BANK_WIDTH_1 MTD_MAP_BANK_WIDTH_2 MTD_MAP_BANK_WIDTH_4 MTD_MTDRAM MTD_PHRAM MTD_SLRAM MUSB_PIO_ONLY ND_BTT ND_CLAIM ND_PFN NETDEVSIM NETFILTER_ADVANCED NETFILTER_BPF_LINK NETFILTER_FAMILY_ARP NETFILTER_FAMILY_BRIDGE NETFILTER_NETLINK_ACCT NETFILTER_NETLINK_GLUE_CT NETFILTER_NETLINK_OSF NETFILTER_NETLINK_QUEUE NETFILTER_SYNPROXY NETFILTER_XTABLES_COMPAT NETFILTER_XT_CONNMARK NETFILTER_XT_MATCH_BPF NETFILTER_XT_MATCH_CGROUP NETFILTER_XT_MATCH_CLUSTER NETFILTER_XT_MATCH_COMMENT NETFILTER_XT_MATCH_CONNBYTES NETFILTER_XT_MATCH_CONNLABEL NETFILTER_XT_MATCH_CONNLIMIT NETFILTER_XT_MATCH_CONNMARK NETFILTER_XT_MATCH_CPU NETFILTER_XT_MATCH_DCCP NETFILTER_XT_MATCH_DEVGROUP NETFILTER_XT_MATCH_DSCP NETFILTER_XT_MATCH_ECN NETFILTER_XT_MATCH_ESP NETFILTER_XT_MATCH_HASHLIMIT NETFILTER_XT_MATCH_HELPER NETFILTER_XT_MATCH_HL NETFILTER_XT_MATCH_IPCOMP NETFILTER_XT_MATCH_IPRANGE NETFILTER_XT_MATCH_IPVS NETFILTER_XT_MATCH_L2TP NETFILTER_XT_MATCH_LENGTH NETFILTER_XT_MATCH_LIMIT NETFILTER_XT_MATCH_MAC NETFILTER_XT_MATCH_MARK NETFILTER_XT_MATCH_MULTIPORT NETFILTER_XT_MATCH_NFACCT NETFILTER_XT_MATCH_OSF NETFILTER_XT_MATCH_OWNER NETFILTER_XT_MATCH_PHYSDEV NETFILTER_XT_MATCH_PKTTYPE NETFILTER_XT_MATCH_QUOTA NETFILTER_XT_MATCH_RATEEST NETFILTER_XT_MATCH_REALM NETFILTER_XT_MATCH_RECENT NETFILTER_XT_MATCH_SCTP NETFILTER_XT_MATCH_SOCKET NETFILTER_XT_MATCH_STATISTIC NETFILTER_XT_MATCH_STRING NETFILTER_XT_MATCH_TCPMSS NETFILTER_XT_MATCH_TIME NETFILTER_XT_MATCH_U32 NETFILTER_XT_SET NETFILTER_XT_TARGET_AUDIT NETFILTER_XT_TARGET_CHECKSUM NETFILTER_XT_TARGET_CLASSIFY NETFILTER_XT_TARGET_CONNMARK NETFILTER_XT_TARGET_CT NETFILTER_XT_TARGET_DSCP NETFILTER_XT_TARGET_HL NETFILTER_XT_TARGET_HMARK NETFILTER_XT_TARGET_IDLETIMER NETFILTER_XT_TARGET_LED NETFILTER_XT_TARGET_MARK NETFILTER_XT_TARGET_NETMAP NETFILTER_XT_TARGET_NFQUEUE NETFILTER_XT_TARGET_NOTRACK NETFILTER_XT_TARGET_RATEEST NETFILTER_XT_TARGET_REDIRECT NETFILTER_XT_TARGET_TCPOPTSTRIP NETFILTER_XT_TARGET_TEE NETFILTER_XT_TARGET_TPROXY NETFILTER_XT_TARGET_TRACE NETLINK_DIAG NETROM NET_9P_RDMA NET_ACT_BPF NET_ACT_CONNMARK NET_ACT_CSUM NET_ACT_CT NET_ACT_CTINFO NET_ACT_GATE NET_ACT_IFE NET_ACT_MPLS NET_ACT_NAT NET_ACT_PEDIT NET_ACT_POLICE NET_ACT_SAMPLE NET_ACT_SIMP NET_ACT_SKBEDIT NET_ACT_SKBMOD NET_ACT_TUNNEL_KEY NET_ACT_VLAN NET_CLS_BASIC NET_CLS_BPF NET_CLS_FLOW NET_CLS_FLOWER NET_CLS_FW NET_CLS_MATCHALL NET_CLS_ROUTE4 NET_DEVLINK NET_DROP_MONITOR NET_DSA NET_DSA_TAG_BRCM NET_DSA_TAG_BRCM_COMMON NET_DSA_TAG_BRCM_PREPEND NET_DSA_TAG_MTK NET_DSA_TAG_QCA NET_DSA_TAG_RTL4_A NET_EMATCH_CANID NET_EMATCH_CMP NET_EMATCH_IPSET NET_EMATCH_IPT NET_EMATCH_META NET_EMATCH_NBYTE NET_EMATCH_TEXT NET_EMATCH_U32 NET_FC NET_FOU NET_FOU_IP_TUNNELS NET_IFE NET_IFE_SKBMARK NET_IFE_SKBPRIO NET_IFE_SKBTCINDEX NET_IPGRE NET_IPGRE_BROADCAST NET_IPGRE_DEMUX NET_IPIP NET_IPVTI NET_KEY NET_KEY_MIGRATE NET_L3_MASTER_DEV NET_MPLS_GSO NET_NCSI NET_NSH NET_REDIRECT NET_SCH_CAKE NET_SCH_CBS NET_SCH_CHOKE NET_SCH_CODEL NET_SCH_DRR NET_SCH_ETF NET_SCH_ETS NET_SCH_FQ NET_SCH_FQ_CODEL NET_SCH_FQ_PIE NET_SCH_GRED NET_SCH_HFSC NET_SCH_HHF NET_SCH_HTB NET_SCH_INGRESS NET_SCH_MQPRIO NET_SCH_MQPRIO_LIB NET_SCH_MULTIQ NET_SCH_NETEM NET_SCH_PIE NET_SCH_PLUG NET_SCH_PRIO NET_SCH_QFQ NET_SCH_RED NET_SCH_SFB NET_SCH_SFQ NET_SCH_SKBPRIO NET_SCH_TAPRIO NET_SCH_TBF NET_SCH_TEQL NET_SHAPER NET_SOCK_MSG NET_SWITCHDEV NET_TC_SKB_EXT NET_TEAM NET_TEAM_MODE_ACTIVEBACKUP NET_TEAM_MODE_BROADCAST NET_TEAM_MODE_LOADBALANCE NET_TEAM_MODE_RANDOM NET_TEAM_MODE_ROUNDROBIN NET_UDP_TUNNEL NET_VRF NFC NFC_DIGITAL NFC_FDP NFC_HCI NFC_MRVL NFC_MRVL_USB NFC_NCI NFC_NCI_UART NFC_PN533 NFC_PN533_USB NFC_PORT100 NFC_SHDLC NFC_SIM NFC_VIRTUAL_NCI NFSD NFSD_BLOCKLAYOUT NFSD_FLEXFILELAYOUT NFSD_PNFS NFSD_SCSILAYOUT NFSD_V3_ACL NFSD_V4 NFSD_V4_2_INTER_SSC NFSD_V4_SECURITY_LABEL NFS_FSCACHE NFS_V4_1 NFS_V4_2 NFS_V4_2_READ_PLUS NFS_V4_2_SSC_HELPER NFS_V4_SECURITY_LABEL NFT_BRIDGE_META NFT_BRIDGE_REJECT NFT_COMPAT NFT_CONNLIMIT NFT_CT NFT_DUP_IPV4 NFT_DUP_IPV6 NFT_DUP_NETDEV NFT_FIB NFT_FIB_INET NFT_FIB_IPV4 NFT_FIB_IPV6 NFT_FIB_NETDEV NFT_FLOW_OFFLOAD NFT_HASH NFT_LIMIT NFT_LOG NFT_MASQ NFT_NAT NFT_NUMGEN NFT_OSF NFT_QUEUE NFT_QUOTA NFT_REDIR NFT_REJECT NFT_REJECT_INET NFT_REJECT_IPV4 NFT_REJECT_IPV6 NFT_REJECT_NETDEV NFT_SOCKET NFT_SYNPROXY NFT_TPROXY NFT_TUNNEL NFT_XFRM NF_CONNTRACK_AMANDA NF_CONNTRACK_BRIDGE NF_CONNTRACK_BROADCAST NF_CONNTRACK_EVENTS NF_CONNTRACK_H323 NF_CONNTRACK_LABELS NF_CONNTRACK_MARK NF_CONNTRACK_NETBIOS_NS NF_CONNTRACK_OVS NF_CONNTRACK_PPTP NF_CONNTRACK_SANE NF_CONNTRACK_SNMP NF_CONNTRACK_TFTP NF_CONNTRACK_TIMEOUT NF_CONNTRACK_TIMESTAMP NF_CONNTRACK_ZONES NF_CT_NETLINK_HELPER NF_CT_NETLINK_TIMEOUT NF_CT_PROTO_DCCP NF_CT_PROTO_GRE NF_CT_PROTO_SCTP NF_CT_PROTO_UDPLITE NF_DUP_IPV4 NF_DUP_IPV6 NF_DUP_NETDEV NF_FLOW_TABLE NF_FLOW_TABLE_INET NF_NAT_AMANDA NF_NAT_H323 NF_NAT_OVS NF_NAT_PPTP NF_NAT_REDIRECT NF_NAT_SNMP_BASIC NF_NAT_TFTP NF_SOCKET_IPV4 NF_SOCKET_IPV6 NF_TABLES NF_TABLES_BRIDGE NF_TABLES_INET NF_TABLES_IPV4 NF_TABLES_IPV6 NF_TABLES_NETDEV NF_TPROXY_IPV4 NF_TPROXY_IPV6 NILFS2_FS NINTENDO_FF NLMON NLS_CODEPAGE_1250 PARTITION_ADVANCED PSAMPLE RC_CORE RC_DEVICES RFKILL SPI USB_GADGET USB_MUSB_HDRC VIDEO_DEV WAN WATCH_QUEUE WIRELESS WLAN WWAN X25 X86_X32_ABI]
disabling configs for [memleak ubsan bug_or_warning kasan locking atomic_sleep], they are not needed
testing current HEAD 30d4efb2f5a515a60fe6b0ca85362cbebea21e2f
testing commit 30d4efb2f5a515a60fe6b0ca85362cbebea21e2f gcc
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
kernel signature: 293c48623ebde30849779e41e6b0276df8ebd8c157b01626be9fa71bd8fc81db
all runs: crashed: BUG: soft lockup in mISDN_ioctl
representative crash: BUG: soft lockup in mISDN_ioctl, types: [HANG]
crash still not fixed/happens on the oldest tested release
revisions tested: 8, total time: 1h44m1.412730036s (build: 43m2.569213929s, test: 54m10.352285694s)
crash still not fixed or there were kernel test errors
commit msg: Merge tag 'for-linus-6.18-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
crash: BUG: soft lockup in mISDN_ioctl
watchdog: BUG: soft lockup - CPU#0 stuck for 143s! [syz.5.19:5812]
Modules linked in:
CPU: 0 UID: 0 PID: 5812 Comm: syz.5.19 Not tainted syzkaller #0 PREEMPT(none) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:preempt_count_add+0x1c/0x90 kernel/sched/core.c:5829
Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 83 3d b5 8f ac 07 00 75 07 65 8b 05 5c fa c7 03 53 65 01 3d 54 fa c7 03 <83> 3d 9d 8f ac 07 00 75 11 65 8b 05 44 fa c7 03 0f b6 c0 3d f5 00
RSP: 0018:ffffc90001bcba88 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffffea000477ad00 RCX: f10ede42bffbc300
RDX: cad57fb37a47a811 RSI: ffffffff83a2c20b RDI: 0000000000000001
RBP: ffff8881057c2000 R08: 0000000000000000 R09: 0000000000000606
R10: 0000000000000000 R11: ffffffff81c18200 R12: ffff888114acafd8
R13: ffffffff816db37c R14: ffffc90001bcbc50 R15: ffff88810e2ce868
FS:  00007fed4137f6c0(0000) GS:ffff8882b2b46000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000400000001f00 CR3: 0000000105b92000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 percpu_down_read_internal include/linux/percpu-rwsem.h:55 [inline]
 percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline]
 __sb_start_write include/linux/fs.h:1908 [inline]
 sb_start_pagefault include/linux/fs.h:2073 [inline]
 nilfs_page_mkwrite+0xe0/0x590 fs/nilfs2/file.c:57
 do_page_mkwrite+0x6c/0x160 mm/memory.c:3361
 wp_page_shared mm/memory.c:3762 [inline]
 do_wp_page+0x7e4/0x2750 mm/memory.c:3981
 handle_pte_fault mm/memory.c:6068 [inline]
 __handle_mm_fault mm/memory.c:6195 [inline]
 handle_mm_fault+0x683/0x2520 mm/memory.c:6364
 do_user_addr_fault+0x47f/0x10b0 arch/x86/mm/fault.c:1387
 handle_page_fault arch/x86/mm/fault.c:1476 [inline]
 exc_page_fault+0x62/0xa0 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0010:__put_user_4+0xd/0x20 arch/x86/lib/putuser.S:94
Code: 66 89 01 31 c9 0f 01 ca e9 80 78 01 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 48 89 cb 48 c1 fb 3f 48 09 d9 0f 01 cb <89> 01 31 c9 0f 01 ca e9 57 78 01 00 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90001bcbe70 EFLAGS: 00050206
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000400000001f00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000080000 R09: 0000000000000608
R10: 0000000000000000 R11: 0000000000000000 R12: 00000000ffffffff
R13: ffffffff8262a210 R14: 0000000000000000 R15: 0000000000000000
 mISDN_ioctl+0x3a0/0x430 drivers/isdn/mISDN/timerdev.c:241
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xb9/0x130 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x8f/0x250 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fed4190d169
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fed4137f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fed41b25fa0 RCX: 00007fed4190d169
RDX: 0000400000001f00 RSI: 0000000080044940 RDI: 0000000000000005
RBP: 00007fed4198e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fed41b25fa0 R15: 00007ffdd22d6458
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 55 Comm: kworker/u8:4 Not tainted syzkaller #0 PREEMPT(none) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0x65c/0xb80 kernel/smp.c:877
Code: 75 00 66 90 41 8b 6e 08 89 ee 83 e6 01 31 ff e8 ba 5a 05 00 83 e5 01 75 07 e8 70 56 05 00 eb 18 f3 90 41 f7 46 08 01 00 00 00 <74> 07 e8 5d 56 05 00 eb ed e8 56 56 05 00 4c 89 e5 ff c3 83 e3 0f
RSP: 0000:ffffc900001dfc30 EFLAGS: 00000202
RAX: ffffffff815391e3 RBX: 0000000000000000 RCX: ffff888102ed0000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: 0000000000000000 R09: 000000000000003a
R10: 0000000000000000 R11: ffffffff8136ef30 R12: ffff888237d2b940
R13: ffff888237c315a0 R14: ffff888237c315a0 R15: 00000000fffffff8
FS:  0000000000000000(0000) GS:ffff8882b2c46000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3b353fe43c CR3: 0000000003c7a000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1044
 on_each_cpu include/linux/smp.h:71 [inline]
 smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2653 [inline]
 smp_text_poke_batch_finish+0x1c3/0x660 arch/x86/kernel/alternative.c:2863
 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
 static_key_enable_cpuslocked kernel/jump_label.c:210 [inline]
 static_key_enable+0x67/0x80 kernel/jump_label.c:223
 toggle_allocation_gate+0x3f/0x150 mm/kfence/core.c:850
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0x3e4/0x8c0 kernel/workqueue.c:3319
 worker_thread+0x36d/0x4e0 kernel/workqueue.c:3400
 kthread+0x2bd/0x300 kernel/kthread.c:463
 ret_from_fork+0x16f/0x290 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>