Re: [syzbot] [ext4?] kernel BUG in ext4_write_inline_data (4)

[syzbot <syzbot+7de5fe447862fc37576f@syzkaller.appspotmail.com>]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

[  115.737028][ T5139] Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
[  115.745623][ T5139] Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
[  115.753680][ T5139] Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
[  115.762195][ T5139] Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
[  115.770008][ T5139] Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
[  117.565426][ T5866] chnl_net:caif_netlink_parms(): no params data found
[  118.101590][ T5866] bridge0: port 1(bridge_slave_0) entered blocking state
[  118.109810][ T5866] bridge0: port 1(bridge_slave_0) entered disabled state
[  118.117325][ T5866] bridge_slave_0: entered allmulticast mode
[  118.147613][ T5866] bridge_slave_0: entered promiscuous mode
[  118.398433][ T5866] bridge0: port 2(bridge_slave_1) entered blocking state
[  118.405848][ T5866] bridge0: port 2(bridge_slave_1) entered disabled state
[  118.413476][ T5866] bridge_slave_1: entered allmulticast mode
[  118.421980][ T5866] bridge_slave_1: entered promiscuous mode
[  118.477269][ T5866] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link
[  118.501071][ T5866] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link
[  118.669335][ T5866] team0: Port device team_slave_0 added
[  118.682494][ T5866] team0: Port device team_slave_1 added
[  118.748530][   T37] wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[  118.776393][   T37] wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
[  118.826104][ T5866] batman_adv: batadv0: Adding interface: batadv_slave_0
[  118.833113][ T5866] batman_adv: batadv0: The MTU of interface batadv_slave_0 is too small (1500) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1532 would solve the problem.
[  118.859988][ T5866] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active
[  118.915653][ T5866] batman_adv: batadv0: Adding interface: batadv_slave_1
[  118.922656][ T5866] batman_adv: batadv0: The MTU of interface batadv_slave_1 is too small (1500) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1532 would solve the problem.
[  118.974696][ T5866] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
[  119.007284][   T37] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[  119.026222][   T37] wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
[  119.114830][ T5866] hsr_slave_0: entered promiscuous mode
[  119.136943][ T5866] hsr_slave_1: entered promiscuous mode
[  119.432503][ T5866] netdevsim netdevsim0 netdevsim0: renamed from eth0
[  119.447497][ T5866] netdevsim netdevsim0 netdevsim1: renamed from eth1
[  119.458834][ T5866] netdevsim netdevsim0 netdevsim2: renamed from eth2
[  119.469701][ T5866] netdevsim netdevsim0 netdevsim3: renamed from eth3
[  119.563018][ T5866] 8021q: adding VLAN 0 to HW filter on device bond0
[  119.586277][ T5866] 8021q: adding VLAN 0 to HW filter on device team0
[  119.601598][   T12] bridge0: port 1(bridge_slave_0) entered blocking state
[  119.608955][   T12] bridge0: port 1(bridge_slave_0) entered forwarding state
[  119.627386][ T2898] bridge0: port 2(bridge_slave_1) entered blocking state
[  119.634550][ T2898] bridge0: port 2(bridge_slave_1) entered forwarding state
[  119.882615][ T5866] 8021q: adding VLAN 0 to HW filter on device batadv0
[  119.931648][ T5866] veth0_vlan: entered promiscuous mode
[  119.947109][ T5866] veth1_vlan: entered promiscuous mode
[  119.979256][ T5866] veth0_macvtap: entered promiscuous mode
[  119.990698][ T5866] veth1_macvtap: entered promiscuous mode
[  120.012667][ T5866] batman_adv: batadv0: Interface activated: batadv_slave_0
[  120.030121][ T5866] batman_adv: batadv0: Interface activated: batadv_slave_1
[  120.047991][   T12] netdevsim netdevsim0 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
[  120.062365][   T12] netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[  120.078098][   T12] netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[  120.087483][   T12] netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
2026/02/03 08:21:00 executed programs: 0
[  120.268277][   T52] Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
[  120.280246][   T52] Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
[  120.282551][   T38] netdevsim netdevsim0 netdevsim3 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[  120.288610][   T52] Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
[  120.308676][   T52] Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
[  120.319659][   T52] Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
[  120.397996][   T38] netdevsim netdevsim0 netdevsim2 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[  120.461411][   T38] netdevsim netdevsim0 netdevsim1 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[  120.566850][   T38] netdevsim netdevsim0 netdevsim0 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[  120.595322][ T5934] chnl_net:caif_netlink_parms(): no params data found
[  120.692126][ T5934] bridge0: port 1(bridge_slave_0) entered blocking state
[  120.700477][ T5934] bridge0: port 1(bridge_slave_0) entered disabled state
[  120.707832][ T5934] bridge_slave_0: entered allmulticast mode
[  120.715437][ T5934] bridge_slave_0: entered promiscuous mode
[  120.727578][ T5934] bridge0: port 2(bridge_slave_1) entered blocking state
[  120.734814][ T5934] bridge0: port 2(bridge_slave_1) entered disabled state
[  120.742283][ T5934] bridge_slave_1: entered allmulticast mode
[  120.750265][ T5934] bridge_slave_1: entered promiscuous mode
[  120.794480][ T5934] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link
[  120.807902][ T5934] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link
[  120.849234][ T5934] team0: Port device team_slave_0 added
[  120.860920][ T5934] team0: Port device team_slave_1 added
[  120.895391][ T5934] batman_adv: batadv0: Adding interface: batadv_slave_0
[  120.903012][ T5934] batman_adv: batadv0: The MTU of interface batadv_slave_0 is too small (1500) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1532 would solve the problem.
[  120.930037][ T5934] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active
[  120.944593][ T5934] batman_adv: batadv0: Adding interface: batadv_slave_1
[  120.951991][ T5934] batman_adv: batadv0: The MTU of interface batadv_slave_1 is too small (1500) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1532 would solve the problem.
[  120.978209][ T5934] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
[  121.040031][ T5934] hsr_slave_0: entered promiscuous mode
[  121.047352][ T5934] hsr_slave_1: entered promiscuous mode
[  121.053630][ T5934] debugfs: 'hsr0' already exists in 'hsr'
[  121.059660][ T5934] Cannot create hsr debugfs directory
[  122.376418][ T5139] Bluetooth: hci0: command tx timeout
[  122.795041][   T38] bridge_slave_1: left allmulticast mode
[  122.801314][   T38] bridge_slave_1: left promiscuous mode
[  122.809322][   T38] bridge0: port 2(bridge_slave_1) entered disabled state
[  122.822491][   T38] bridge_slave_0: left allmulticast mode
[  122.829206][   T38] bridge_slave_0: left promiscuous mode
[  122.834952][   T38] bridge0: port 1(bridge_slave_0) entered disabled state
[  123.048250][   T38] bond0 (unregistering): (slave bond_slave_0): Releasing backup interface
[  123.060120][   T38] bond0 (unregistering): (slave bond_slave_1): Releasing backup interface
[  123.078027][   T38] bond0 (unregistering): Released all slaves
[  123.183531][   T38] hsr_slave_0: left promiscuous mode
[  123.193152][   T38] hsr_slave_1: left promiscuous mode
[  123.199945][   T38] batman_adv: batadv0: Interface deactivated: batadv_slave_0
[  123.209756][   T38] batman_adv: batadv0: Removing interface: batadv_slave_0
[  123.223968][   T38] batman_adv: batadv0: Interface deactivated: batadv_slave_1
[  123.231842][   T38] batman_adv: batadv0: Removing interface: batadv_slave_1
[  123.255322][   T38] veth1_macvtap: left promiscuous mode
[  123.261256][   T38] veth0_macvtap: left promiscuous mode
[  123.269082][   T38] veth1_vlan: left promiscuous mode
[  123.274496][   T38] veth0_vlan: left promiscuous mode
[  123.779508][   T38] team0 (unregistering): Port device team_slave_1 removed
[  123.809216][   T38] team0 (unregistering): Port device team_slave_0 removed
[  124.223362][ T5934] netdevsim netdevsim0 netdevsim0: renamed from eth0
[  124.251383][ T5934] netdevsim netdevsim0 netdevsim1: renamed from eth1
[  124.264544][ T5934] netdevsim netdevsim0 netdevsim2: renamed from eth2
[  124.277620][ T5934] netdevsim netdevsim0 netdevsim3: renamed from eth3
[  124.421915][ T5934] 8021q: adding VLAN 0 to HW filter on device bond0
[  124.447497][ T5934] 8021q: adding VLAN 0 to HW filter on device team0
[  124.456324][ T5139] Bluetooth: hci0: command tx timeout
[  124.471199][   T72] bridge0: port 1(bridge_slave_0) entered blocking state
[  124.478408][   T72] bridge0: port 1(bridge_slave_0) entered forwarding state
[  124.498560][   T38] bridge0: port 2(bridge_slave_1) entered blocking state
[  124.505754][   T38] bridge0: port 2(bridge_slave_1) entered forwarding state
[  124.853982][ T5934] 8021q: adding VLAN 0 to HW filter on device batadv0
[  124.921020][ T5934] veth0_vlan: entered promiscuous mode
[  124.932906][ T5934] veth1_vlan: entered promiscuous mode
[  124.965922][ T5934] veth0_macvtap: entered promiscuous mode
[  124.979333][ T5934] veth1_macvtap: entered promiscuous mode
[  124.999208][ T5934] batman_adv: batadv0: Interface activated: batadv_slave_0
[  125.015270][ T5934] batman_adv: batadv0: Interface activated: batadv_slave_1
[  125.032513][   T13] netdevsim netdevsim0 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
[  125.042018][   T13] netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[  125.057876][   T13] netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[  125.067233][   T13] netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
[  125.137953][   T13] wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[  125.153560][   T13] wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
[  125.188192][   T38] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[  125.196770][   T38] wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
[  126.761790][ T2898] netdevsim netdevsim0 netdevsim3 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[  128.218574][ T2898] netdevsim netdevsim0 netdevsim2 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[  128.308291][ T2898] netdevsim netdevsim0 netdevsim1 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[  128.398270][ T2898] netdevsim netdevsim0 netdevsim0 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[  128.550848][ T2898] bridge_slave_1: left allmulticast mode
[  128.562154][ T2898] bridge_slave_1: left promiscuous mode
[  128.568697][ T2898] bridge0: port 2(bridge_slave_1) entered disabled state
[  128.578506][ T2898] bridge_slave_0: left allmulticast mode
[  128.584282][ T2898] bridge_slave_0: left promiscuous mode
[  128.591339][ T2898] bridge0: port 1(bridge_slave_0) entered disabled state
[  128.826554][ T2898] bond0 (unregistering): (slave bond_slave_0): Releasing backup interface
[  128.838167][ T2898] bond0 (unregistering): (slave bond_slave_1): Releasing backup interface
[  128.848407][ T2898] bond0 (unregistering): Released all slaves
[  129.180084][ T2898] hsr_slave_0: left promiscuous mode
[  129.190184][ T2898] hsr_slave_1: left promiscuous mode
[  129.197878][ T2898] batman_adv: batadv0: Interface deactivated: batadv_slave_0
[  129.205281][ T2898] batman_adv: batadv0: Removing interface: batadv_slave_0
[  129.213895][ T2898] batman_adv: batadv0: Interface deactivated: batadv_slave_1
[  129.221811][ T2898] batman_adv: batadv0: Removing interface: batadv_slave_1
[  129.246390][ T2898] veth1_macvtap: left promiscuous mode
[  129.255979][ T2898] veth0_macvtap: left promiscuous mode
[  129.261712][ T2898] veth1_vlan: left promiscuous mode
[  129.267406][ T2898] veth0_vlan: left promiscuous mode
[  129.689185][ T2898] team0 (unregistering): Port device team_slave_1 removed
[  129.721369][ T2898] team0 (unregistering): Port device team_slave_0 removed


syzkaller build log:
go env (err=<nil>)
AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE='auto'
GOAMD64='v1'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/syzkaller/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/syzkaller/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build4132501190=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/syzkaller/jobs-2/linux/gopath/src/github.com/google/syzkaller/go.mod'
GOMODCACHE='/syzkaller/jobs-2/linux/gopath/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/syzkaller/jobs-2/linux/gopath'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/syzkaller/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.24.4'
GOWORK=''
PKG_CONFIG='pkg-config'

git status (err=<nil>)
HEAD detached at 6b8752f20c
nothing to commit, working tree clean


tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
go list -f '{{.Stale}}' -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=6b8752f20c06eee857545047ab920e63322bf4c8 -X github.com/google/syzkaller/prog.gitRevisionDate=20260131-204520"  ./sys/syz-sysgen | grep -q false || go install -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=6b8752f20c06eee857545047ab920e63322bf4c8 -X github.com/google/syzkaller/prog.gitRevisionDate=20260131-204520"  ./sys/syz-sysgen
make .descriptions
tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
bin/syz-sysgen
touch .descriptions
GOOS=linux GOARCH=amd64 go build -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=6b8752f20c06eee857545047ab920e63322bf4c8 -X github.com/google/syzkaller/prog.gitRevisionDate=20260131-204520"  -o ./bin/linux_amd64/syz-execprog github.com/google/syzkaller/tools/syz-execprog
mkdir -p ./bin/linux_amd64
g++ -o ./bin/linux_amd64/syz-executor executor/executor.cc \
	-m64 -O2 -pthread -Wall -Werror -Wparentheses -Wunused-const-variable -Wframe-larger-than=16384 -Wno-stringop-overflow -Wno-array-bounds -Wno-format-overflow -Wno-unused-but-set-variable -Wno-unused-command-line-argument -static-pie -std=c++17 -I. -Iexecutor/_include   -DGOOS_linux=1 -DGOARCH_amd64=1 \
	-DHOSTGOOS_linux=1 -DGIT_REVISION=\"6b8752f20c06eee857545047ab920e63322bf4c8\"
/usr/bin/ld: /tmp/cc6AYh6x.o: in function `Connection::Connect(char const*, char const*)':
executor.cc:(.text._ZN10Connection7ConnectEPKcS1_[_ZN10Connection7ConnectEPKcS1_]+0x386): warning: Using 'gethostbyname' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
./tools/check-syzos.sh 2>/dev/null


Error text is too large and was truncated, full error text is at:
https://syzkaller.appspot.com/x/error.txt?x=1298c25a580000


Tested on:

commit:         6bd9ed02 Merge tag 'cgroup-for-6.19-rc8-fixes' of git:..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=fea461e951c03b1b
dashboard link: https://syzkaller.appspot.com/bug?extid=7de5fe447862fc37576f
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1277fbfa580000