ci starts bisection 2025-07-04 01:28:22.820039047 +0000 UTC m=+7018.116599317 bisecting cause commit starting from bd475eeaaf3cad1b183418fff7b19c9b1e3d1c4f building syzkaller on 115ceea74e11fcf2b7ad5717ef91980f501cc81b ensuring issue is reproducible on original commit bd475eeaaf3cad1b183418fff7b19c9b1e3d1c4f testing commit bd475eeaaf3cad1b183418fff7b19c9b1e3d1c4f gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 24201a43df6344da00f0a6c5acdfb2f11d643d423fae34b43531f3036ab8c5ed all runs: crashed: general protection fault in qdisc_tree_reduce_backlog representative crash: general protection fault in qdisc_tree_reduce_backlog, types: [DoS] check whether we can drop unnecessary instrumentation disabling configs for [ubsan bug_or_warning kasan locking atomic_sleep hang memleak], they are not needed testing commit bd475eeaaf3cad1b183418fff7b19c9b1e3d1c4f gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 15b931d521990cabdd10a6832c51d217339421c5a3e407c75112b6afb2e46dc6 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in qdisc_tree_reduce_backlog representative crash: BUG: unable to handle kernel NULL pointer dereference in qdisc_tree_reduce_backlog, types: [UNKNOWN] the bug reproduces without the instrumentation disabling configs for [kasan locking atomic_sleep hang memleak ubsan bug_or_warning], they are not needed kconfig minimization: base=4095 full=8363 leaves diff=2126 split chunks (needed=false): <2126> split chunk #0 of len 2126 into 5 parts testing without sub-chunk 1/5 disabling configs for [kasan locking atomic_sleep hang memleak ubsan bug_or_warning], they are not needed testing commit bd475eeaaf3cad1b183418fff7b19c9b1e3d1c4f gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 5fb6a6568080e9f811678b34274fa8214b4b6524c8556ac4c598d21096e24074 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in qdisc_tree_reduce_backlog representative crash: BUG: unable to handle kernel NULL pointer dereference in qdisc_tree_reduce_backlog, types: [UNKNOWN] the chunk can be dropped testing without sub-chunk 2/5 disabling configs for [hang memleak ubsan bug_or_warning kasan locking atomic_sleep], they are not needed testing commit bd475eeaaf3cad1b183418fff7b19c9b1e3d1c4f gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: be144bbc73321ffbf2669c4d79890013cab50827cf1c229251e842edf7a81aa7 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in qdisc_tree_reduce_backlog representative crash: BUG: unable to handle kernel NULL pointer dereference in qdisc_tree_reduce_backlog, types: [UNKNOWN] the chunk can be dropped testing without sub-chunk 3/5 disabling configs for [atomic_sleep hang memleak ubsan bug_or_warning kasan locking], they are not needed testing commit bd475eeaaf3cad1b183418fff7b19c9b1e3d1c4f gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 8c0b60f6640bf198d1e64525a9bb50ad2d06de8a3eee45c1c85b59314a5948b4 all runs: OK false negative chance: 0.000 testing without sub-chunk 4/5 disabling configs for [hang memleak ubsan bug_or_warning kasan locking atomic_sleep], they are not needed testing commit bd475eeaaf3cad1b183418fff7b19c9b1e3d1c4f gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 0a0e552290a0cbf80840085d36bca25ec50d2b35e63eb974de74dfb7b2a0ade8 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in qdisc_tree_reduce_backlog representative crash: BUG: unable to handle kernel NULL pointer dereference in qdisc_tree_reduce_backlog, types: [UNKNOWN] the chunk can be dropped testing without sub-chunk 5/5 disabling configs for [ubsan bug_or_warning kasan locking atomic_sleep hang memleak], they are not needed testing commit bd475eeaaf3cad1b183418fff7b19c9b1e3d1c4f gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: fac2905f40aa6c78135e09f9d453fc47ebc2514ae38e2f7d63d42a41ac4e7ce4 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in qdisc_tree_reduce_backlog representative crash: BUG: unable to handle kernel NULL pointer dereference in qdisc_tree_reduce_backlog, types: [UNKNOWN] the chunk can be dropped minimized to 426 configs; suspects: [AX25 BRIDGE BRIDGE_NETFILTER CAN CFG80211 CHECKPOINT_RESTORE DVB_CORE FB_CORE HAMRADIO HID_LOGITECH HSR INFINIBAND INFINIBAND_ADDR_TRANS INFINIBAND_USER_ACCESS INPUT_JOYSTICK INPUT_MOUSE IP6_NF_RAW IPV6_MULTIPLE_TABLES IP_NF_RAW IP_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_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 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_MMU_LOCKLESS_AGING 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 LEDS_CLASS_MULTICOLOR LEGACY_PTYS 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 MCTP 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 MM_ID 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 NETLABEL 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_CRC32C NET_DEVLINK NET_DEVMEM 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 PAGE_POOL PARTITION_ADVANCED PSAMPLE RC_CORE RC_DEVICES RFKILL SPI USB_GADGET USB_MUSB_HDRC VIDEO_DEV WAN WATCH_QUEUE WIRELESS WLAN WWAN X25] disabling configs for [locking atomic_sleep hang memleak ubsan bug_or_warning kasan], they are not needed picked [v6.15 v6.14 v6.13 v6.11 v6.9 v6.7 v6.5 v6.3 v6.0 v5.17 v5.14 v5.11 v5.8 v5.5 v5.2 v4.20 v4.19] out of 38 release tags testing release v6.15 testing commit 0ff41df1cb268fc69e703a08a57ee14ae967d0ca gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 7e0fad4304953c494517119d25e4730d78624fb76b0225e6f501144ca72698d0 all runs: OK false negative chance: 0.000 # git bisect start bd475eeaaf3cad1b183418fff7b19c9b1e3d1c4f 0ff41df1cb268fc69e703a08a57ee14ae967d0ca Bisecting: 6954 revisions left to test after this (roughly 13 steps) [1b98f357dadd6ea613a435fbaef1a5dd7b35fd21] Merge tag 'net-next-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next testing commit 1b98f357dadd6ea613a435fbaef1a5dd7b35fd21 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 48d8a56e5c9fd8cf1523e97ab0be4fb10172a22a979631cf9527ce9d239406ff all runs: OK false negative chance: 0.000 # git bisect good 1b98f357dadd6ea613a435fbaef1a5dd7b35fd21 Bisecting: 3474 revisions left to test after this (roughly 12 steps) [0fb34422b5c2237e0de41980628b023252912108] Merge tag 'vfs-6.16-rc1.netfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs testing commit 0fb34422b5c2237e0de41980628b023252912108 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 03aea369fe4016249d948203b849ece0bded1acc559c1094c57619a7790e7cdf all runs: OK false negative chance: 0.000 # git bisect good 0fb34422b5c2237e0de41980628b023252912108 Bisecting: 1784 revisions left to test after this (roughly 11 steps) [a100922a3855eb35ecd465f1d558546b1e144445] Merge tag 'staging-6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging testing commit a100922a3855eb35ecd465f1d558546b1e144445 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: b87fd19be181063e4c5670d01d3f5b9e66a3f8fe8ea15437d26b003b8293581d all runs: OK false negative chance: 0.000 # git bisect good a100922a3855eb35ecd465f1d558546b1e144445 Bisecting: 877 revisions left to test after this (roughly 10 steps) [af477f4d5a6c183e2dd44f49dd9a7950bfa7bd50] Merge tag 'sound-fix-6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound testing commit af477f4d5a6c183e2dd44f49dd9a7950bfa7bd50 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 4da371fa2fdcec071c9cbdcc0ba1ee9f5929e3453a108f147e521ed28b37bf97 all runs: OK false negative chance: 0.000 # git bisect good af477f4d5a6c183e2dd44f49dd9a7950bfa7bd50 Bisecting: 440 revisions left to test after this (roughly 9 steps) [fb4d33ab452ea254e2c319bac5703d1b56d895bf] Merge tag '6.16-rc2-ksmbd-server-fixes' of git://git.samba.org/ksmbd testing commit fb4d33ab452ea254e2c319bac5703d1b56d895bf gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 9a57ae2abf1b55ba99319448da75577d103bdb3c282ba495f3b354dd89f1acfc all runs: OK false negative chance: 0.000 # git bisect good fb4d33ab452ea254e2c319bac5703d1b56d895bf Bisecting: 221 revisions left to test after this (roughly 8 steps) [afa3d8b6e01b4637d494bf1b1b8b531fddd1e452] Merge tag 'rcu/fixes-for-6.16-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux testing commit afa3d8b6e01b4637d494bf1b1b8b531fddd1e452 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 86ce861bea580c7cf7579bb20d9a1cb8ebd8662ee6423576dfe5b3bc41240275 all runs: OK false negative chance: 0.000 # git bisect good afa3d8b6e01b4637d494bf1b1b8b531fddd1e452 Bisecting: 107 revisions left to test after this (roughly 7 steps) [5ca7fe213ba3113dde19c4cd46347c16d9e69f81] Merge tag 'for-6.16-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux testing commit 5ca7fe213ba3113dde19c4cd46347c16d9e69f81 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 1dd0f23eb909b59b924e35c0f2d0f2c9c047b6a973a0ec28d5d7d9bfa53cd993 all runs: OK false negative chance: 0.000 # git bisect good 5ca7fe213ba3113dde19c4cd46347c16d9e69f81 Bisecting: 64 revisions left to test after this (roughly 6 steps) [85720e04d9af0b77f8092b12a06661a8d459d4a0] net: libwx: fix the creation of page_pool testing commit 85720e04d9af0b77f8092b12a06661a8d459d4a0 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 5363c1543b14ddf7a0103bfb0a1688b7f4b57a6ce921776841adda71869f18f6 all runs: OK false negative chance: 0.000 # git bisect good 85720e04d9af0b77f8092b12a06661a8d459d4a0 Bisecting: 28 revisions left to test after this (roughly 5 steps) [ee88bddf7f2f5d1f1da87dd7bedc734048b70e88] Merge tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf testing commit ee88bddf7f2f5d1f1da87dd7bedc734048b70e88 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: caad1ed4d23c45aba1e72d198cad72f8ea0bfde1f06f126d8190851b810628f3 all runs: OK false negative chance: 0.000 # git bisect good ee88bddf7f2f5d1f1da87dd7bedc734048b70e88 Bisecting: 12 revisions left to test after this (roughly 4 steps) [72fb83735c71e3f6f025ab7f5dbfec7c9e26b6cc] Merge tag 'for-net-2025-06-27' of git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth testing commit 72fb83735c71e3f6f025ab7f5dbfec7c9e26b6cc gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: fb8e12ecc8b7b70537e20abcd025c1519a97fe34dad98baf818501546a8aa658 all runs: OK false negative chance: 0.000 # git bisect good 72fb83735c71e3f6f025ab7f5dbfec7c9e26b6cc Bisecting: 6 revisions left to test after this (roughly 3 steps) [103406b38c600fec1fe375a77b27d87e314aea09] net/sched: Always pass notifications when child class becomes empty testing commit 103406b38c600fec1fe375a77b27d87e314aea09 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 688de694243a739366b0e3e87aa666f4eaa57b34c094858d9539885496f01065 all runs: crashed: BUG: unable to handle kernel NULL pointer dereference in qdisc_tree_reduce_backlog representative crash: BUG: unable to handle kernel NULL pointer dereference in qdisc_tree_reduce_backlog, types: [UNKNOWN] # git bisect bad 103406b38c600fec1fe375a77b27d87e314aea09 Bisecting: 2 revisions left to test after this (roughly 2 steps) [aaf2b2480375099c022a82023e1cd772bf1c6a5d] enic: fix incorrect MTU comparison in enic_change_mtu() testing commit aaf2b2480375099c022a82023e1cd772bf1c6a5d gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: b6b3146808c79d37df1a619948d84e6dec4263e703800230ac5c6319280c2311 all runs: OK false negative chance: 0.000 # git bisect good aaf2b2480375099c022a82023e1cd772bf1c6a5d Bisecting: 0 revisions left to test after this (roughly 1 step) [561aa0e22b70a5e7246b73d62a824b3aef3fc375] nui: Fix dma_mapping_error() check testing commit 561aa0e22b70a5e7246b73d62a824b3aef3fc375 gcc compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 kernel signature: 172774b75a7fd13b80355ccabaf1667f57904b055ed1a912740207f90af63d59 all runs: OK false negative chance: 0.000 # git bisect good 561aa0e22b70a5e7246b73d62a824b3aef3fc375 103406b38c600fec1fe375a77b27d87e314aea09 is the first bad commit commit 103406b38c600fec1fe375a77b27d87e314aea09 Author: Lion Ackermann Date: Mon Jun 30 15:27:30 2025 +0200 net/sched: Always pass notifications when child class becomes empty Certain classful qdiscs may invoke their classes' dequeue handler on an enqueue operation. This may unexpectedly empty the child qdisc and thus make an in-flight class passive via qlen_notify(). Most qdiscs do not expect such behaviour at this point in time and may re-activate the class eventually anyways which will lead to a use-after-free. The referenced fix commit attempted to fix this behavior for the HFSC case by moving the backlog accounting around, though this turned out to be incomplete since the parent's parent may run into the issue too. The following reproducer demonstrates this use-after-free: tc qdisc add dev lo root handle 1: drr tc filter add dev lo parent 1: basic classid 1:1 tc class add dev lo parent 1: classid 1:1 drr tc qdisc add dev lo parent 1:1 handle 2: hfsc def 1 tc class add dev lo parent 2: classid 2:1 hfsc rt m1 8 d 1 m2 0 tc qdisc add dev lo parent 2:1 handle 3: netem tc qdisc add dev lo parent 3:1 handle 4: blackhole echo 1 | socat -u STDIN UDP4-DATAGRAM:127.0.0.1:8888 tc class delete dev lo classid 1:1 echo 1 | socat -u STDIN UDP4-DATAGRAM:127.0.0.1:8888 Since backlog accounting issues leading to a use-after-frees on stale class pointers is a recurring pattern at this point, this patch takes a different approach. Instead of trying to fix the accounting, the patch ensures that qdisc_tree_reduce_backlog always calls qlen_notify when the child qdisc is empty. This solves the problem because deletion of qdiscs always involves a call to qdisc_reset() and / or qdisc_purge_queue() which ultimately resets its qlen to 0 thus causing the following qdisc_tree_reduce_backlog() to report to the parent. Note that this may call qlen_notify on passive classes multiple times. This is not a problem after the recent patch series that made all the classful qdiscs qlen_notify() handlers idempotent. Fixes: 3f981138109f ("sch_hfsc: Fix qlen accounting bug when using peek in hfsc_enqueue()") Signed-off-by: Lion Ackermann Reviewed-by: Jamal Hadi Salim Acked-by: Cong Wang Acked-by: Jamal Hadi Salim Link: https://patch.msgid.link/d912cbd7-193b-4269-9857-525bee8bbb6a@gmail.com Signed-off-by: Jakub Kicinski net/sched/sch_api.c | 19 +++++-------------- 1 file changed, 5 insertions(+), 14 deletions(-) accumulated error probability: 0.00 culprit signature: 688de694243a739366b0e3e87aa666f4eaa57b34c094858d9539885496f01065 parent signature: 172774b75a7fd13b80355ccabaf1667f57904b055ed1a912740207f90af63d59 revisions tested: 21, total time: 7h4m39.597470212s (build: 2h47m39.718104123s, test: 3h44m11.656141524s) first bad commit: 103406b38c600fec1fe375a77b27d87e314aea09 net/sched: Always pass notifications when child class becomes empty recipients (to): ["jhs@mojatatu.com" "kuba@kernel.org" "nnamrec@gmail.com" "xiyou.wangcong@gmail.com"] recipients (cc): [] crash: BUG: unable to handle kernel NULL pointer dereference in qdisc_tree_reduce_backlog BUG: kernel NULL pointer dereference, address: 0000000000000020 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 8000000124efa067 P4D 8000000124efa067 PUD 0 Oops: Oops: 0000 [#1] SMP PTI CPU: 0 UID: 0 PID: 5170 Comm: syz.2.16 Not tainted 6.16.0-rc3-syzkaller #0 PREEMPT(undef) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:qdisc_tree_reduce_backlog+0xdc/0x180 net/sched/sch_api.c:806 Code: 48 85 c0 0f 84 88 00 00 00 49 89 c7 31 ff 44 89 ee e8 58 ca cb fe 45 85 ed 74 07 e8 0e c6 cb fe eb 3b 49 8b 47 18 4c 8b 68 08 <49> 83 7d 20 00 74 27 e8 f8 c5 cb fe 4d 8b 5d 28 4c 89 ff 44 89 e6 RSP: 0018:ffffc900019cf770 EFLAGS: 00010246 RAX: ffffffff840b7050 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff88810eee0000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000007 R10: 0000000000000000 R11: ffffffff829393a0 R12: 00000000000afff2 R13: 0000000000000000 R14: 0000000000000000 R15: ffff888124fd8400 FS: 00007fe63e70f6c0(0000) GS:ffff8882b2b07000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000020 CR3: 0000000115fe4000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: fq_codel_change+0x460/0x4f0 net/sched/sch_fq_codel.c:450 fq_codel_init+0xd6/0x290 net/sched/sch_fq_codel.c:487 qdisc_create+0x46d/0x7c0 net/sched/sch_api.c:1324 __tc_modify_qdisc net/sched/sch_api.c:-1 [inline] tc_modify_qdisc+0xb42/0xf50 net/sched/sch_api.c:1813 rtnetlink_rcv_msg+0x586/0x610 net/core/rtnetlink.c:6953 netlink_rcv_skb+0x16a/0x240 net/netlink/af_netlink.c:2534 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x3bd/0x480 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x494/0x590 net/netlink/af_netlink.c:1883 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0xc6/0xf0 net/socket.c:727 ____sys_sendmsg+0x257/0x360 net/socket.c:2566 ___sys_sendmsg+0x2de/0x320 net/socket.c:2620 __sys_sendmsg net/socket.c:2652 [inline] __do_sys_sendmsg net/socket.c:2657 [inline] __se_sys_sendmsg net/socket.c:2655 [inline] __x64_sys_sendmsg+0x110/0x1a0 net/socket.c:2655 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: 0033:0x7fe63ec9e929 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:00007fe63e70f038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fe63eec5fa0 RCX: 00007fe63ec9e929 RDX: 0000000000000800 RSI: 0000200000000100 RDI: 0000000000000003 RBP: 00007fe63ed20b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fe63eec5fa0 R15: 00007ffd7f488c58 Modules linked in: CR2: 0000000000000020 ---[ end trace 0000000000000000 ]--- RIP: 0010:qdisc_tree_reduce_backlog+0xdc/0x180 net/sched/sch_api.c:806 Code: 48 85 c0 0f 84 88 00 00 00 49 89 c7 31 ff 44 89 ee e8 58 ca cb fe 45 85 ed 74 07 e8 0e c6 cb fe eb 3b 49 8b 47 18 4c 8b 68 08 <49> 83 7d 20 00 74 27 e8 f8 c5 cb fe 4d 8b 5d 28 4c 89 ff 44 89 e6 RSP: 0018:ffffc900019cf770 EFLAGS: 00010246 RAX: ffffffff840b7050 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff88810eee0000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000007 R10: 0000000000000000 R11: ffffffff829393a0 R12: 00000000000afff2 R13: 0000000000000000 R14: 0000000000000000 R15: ffff888124fd8400 FS: 00007fe63e70f6c0(0000) GS:ffff8882b2b07000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000020 CR3: 0000000115fe4000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 48 85 c0 test %rax,%rax 3: 0f 84 88 00 00 00 je 0x91 9: 49 89 c7 mov %rax,%r15 c: 31 ff xor %edi,%edi e: 44 89 ee mov %r13d,%esi 11: e8 58 ca cb fe call 0xfecbca6e 16: 45 85 ed test %r13d,%r13d 19: 74 07 je 0x22 1b: e8 0e c6 cb fe call 0xfecbc62e 20: eb 3b jmp 0x5d 22: 49 8b 47 18 mov 0x18(%r15),%rax 26: 4c 8b 68 08 mov 0x8(%rax),%r13 * 2a: 49 83 7d 20 00 cmpq $0x0,0x20(%r13) <-- trapping instruction 2f: 74 27 je 0x58 31: e8 f8 c5 cb fe call 0xfecbc62e 36: 4d 8b 5d 28 mov 0x28(%r13),%r11 3a: 4c 89 ff mov %r15,%rdi 3d: 44 89 e6 mov %r12d,%esi