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:

ecase to linux-mm@kvack.org if you depend on this functionality.
[  114.073401][ T4254] wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[  114.085556][ T4254] wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
[  114.455712][   T36] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[  114.459277][ T5846] chnl_net:caif_netlink_parms(): no params data found
[  114.466207][   T36] wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
[  115.053719][ T5846] bridge0: port 1(bridge_slave_0) entered blocking state
[  115.061847][   T52] Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
[  115.071240][ T5846] bridge0: port 1(bridge_slave_0) entered disabled state
[  115.078730][   T52] Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
[  115.088375][   T52] Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
[  115.097293][ T5846] bridge_slave_0: entered allmulticast mode
[  115.103662][   T52] Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
[  115.111761][   T52] Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
[  115.122627][ T5846] bridge_slave_0: entered promiscuous mode
[  115.193824][ T5846] bridge0: port 2(bridge_slave_1) entered blocking state
[  115.221916][ T5846] bridge0: port 2(bridge_slave_1) entered disabled state
[  115.238429][ T5846] bridge_slave_1: entered allmulticast mode
[  115.256077][ T5846] bridge_slave_1: entered promiscuous mode
[  115.418143][ T5846] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link
[  115.539292][ T5846] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link
[  115.921187][ T5846] team0: Port device team_slave_0 added
[  115.990599][ T5846] team0: Port device team_slave_1 added
[  116.082646][ T5846] batman_adv: batadv0: Adding interface: batadv_slave_0
[  116.089665][ T5846] 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.
[  116.115753][ T5846] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active
[  116.182624][ T5846] batman_adv: batadv0: Adding interface: batadv_slave_1
[  116.190052][ T5846] 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.
[  116.216125][ T5846] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
[  116.716438][ T5846] hsr_slave_0: entered promiscuous mode
[  116.723317][ T5846] hsr_slave_1: entered promiscuous mode
[  117.794383][ T5846] netdevsim netdevsim1 netdevsim0: renamed from eth0
[  117.826987][ T5846] netdevsim netdevsim1 netdevsim1: renamed from eth1
[  117.850245][ T5846] netdevsim netdevsim1 netdevsim2: renamed from eth2
[  117.871711][ T5846] netdevsim netdevsim1 netdevsim3: renamed from eth3
[  118.071567][ T5846] 8021q: adding VLAN 0 to HW filter on device bond0
[  118.108915][ T5846] 8021q: adding VLAN 0 to HW filter on device team0
[  118.124345][   T71] bridge0: port 1(bridge_slave_0) entered blocking state
[  118.131771][   T71] bridge0: port 1(bridge_slave_0) entered forwarding state
[  118.151778][   T36] bridge0: port 2(bridge_slave_1) entered blocking state
[  118.158912][   T36] bridge0: port 2(bridge_slave_1) entered forwarding state
[  118.473114][ T5846] 8021q: adding VLAN 0 to HW filter on device batadv0
[  118.523374][ T5846] veth0_vlan: entered promiscuous mode
[  118.537313][ T5846] veth1_vlan: entered promiscuous mode
[  118.570513][ T5846] veth0_macvtap: entered promiscuous mode
[  118.582126][ T5846] veth1_macvtap: entered promiscuous mode
[  118.604595][ T5846] batman_adv: batadv0: Interface activated: batadv_slave_0
[  118.620480][ T5846] batman_adv: batadv0: Interface activated: batadv_slave_1
[  118.637368][   T36] netdevsim netdevsim1 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
[  118.646465][   T36] netdevsim netdevsim1 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[  118.655243][   T36] netdevsim netdevsim1 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[  118.668163][   T36] netdevsim netdevsim1 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
2026/02/03 07:41:24 executed programs: 0
[  118.879052][ T5140] Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
[  118.888068][ T5140] Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
[  118.895798][ T5140] Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
[  118.905059][ T5140] Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
[  118.915748][ T5140] Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
[  119.211615][ T5934] chnl_net:caif_netlink_parms(): no params data found
[  119.307633][ T5934] bridge0: port 1(bridge_slave_0) entered blocking state
[  119.314846][ T5934] bridge0: port 1(bridge_slave_0) entered disabled state
[  119.322307][ T5934] bridge_slave_0: entered allmulticast mode
[  119.329835][ T5934] bridge_slave_0: entered promiscuous mode
[  119.339059][ T5934] bridge0: port 2(bridge_slave_1) entered blocking state
[  119.348163][ T5934] bridge0: port 2(bridge_slave_1) entered disabled state
[  119.355500][ T5934] bridge_slave_1: entered allmulticast mode
[  119.363298][ T5934] bridge_slave_1: entered promiscuous mode
[  119.400333][ T5934] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link
[  119.413209][ T5934] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link
[  119.453708][ T5934] team0: Port device team_slave_0 added
[  119.463066][ T5934] team0: Port device team_slave_1 added
[  119.497209][ T5934] batman_adv: batadv0: Adding interface: batadv_slave_0
[  119.504175][ 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.
[  119.532328][ T5934] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active
[  119.546512][ T5934] batman_adv: batadv0: Adding interface: batadv_slave_1
[  119.553557][ 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.
[  119.580269][ T5934] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
[  119.639230][ T5934] hsr_slave_0: entered promiscuous mode
[  119.645757][ T5934] hsr_slave_1: entered promiscuous mode
[  119.652723][ T5934] debugfs: 'hsr0' already exists in 'hsr'
[  119.658702][ T5934] Cannot create hsr debugfs directory
[  119.855037][ T5934] netdevsim netdevsim0 netdevsim0: renamed from eth0
[  119.867221][ T5934] netdevsim netdevsim0 netdevsim1: renamed from eth1
[  119.878248][ T5934] netdevsim netdevsim0 netdevsim2: renamed from eth2
[  119.890501][ T5934] netdevsim netdevsim0 netdevsim3: renamed from eth3
[  119.986092][ T5934] 8021q: adding VLAN 0 to HW filter on device bond0
[  120.015814][ T5934] 8021q: adding VLAN 0 to HW filter on device team0
[  120.030411][   T71] bridge0: port 1(bridge_slave_0) entered blocking state
[  120.037743][   T71] bridge0: port 1(bridge_slave_0) entered forwarding state
[  120.053693][   T36] bridge0: port 2(bridge_slave_1) entered blocking state
[  120.060840][   T36] bridge0: port 2(bridge_slave_1) entered forwarding state
[  120.302006][ T5934] 8021q: adding VLAN 0 to HW filter on device batadv0
[  120.354661][ T5934] veth0_vlan: entered promiscuous mode
[  120.369651][ T5934] veth1_vlan: entered promiscuous mode
[  120.402540][ T5934] veth0_macvtap: entered promiscuous mode
[  120.413314][ T5934] veth1_macvtap: entered promiscuous mode
[  120.435142][ T5934] batman_adv: batadv0: Interface activated: batadv_slave_0
[  120.450894][ T5934] batman_adv: batadv0: Interface activated: batadv_slave_1
[  120.465800][   T71] netdevsim netdevsim0 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
[  120.478819][   T71] netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[  120.494866][   T71] netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[  120.504263][   T71] netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
[  120.573104][   T36] wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[  120.581269][   T36] wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
[  120.620694][   T36] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[  120.630246][   T36] wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
[  120.947134][ T5140] Bluetooth: hci0: command tx timeout
[  121.443871][   T50] netdevsim netdevsim1 netdevsim3 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[  122.038891][   T50] netdevsim netdevsim1 netdevsim2 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[  122.111026][   T50] netdevsim netdevsim1 netdevsim1 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[  122.152364][   T50] netdevsim netdevsim1 netdevsim0 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[  122.287821][   T50] bridge_slave_1: left allmulticast mode
[  122.294531][   T50] bridge_slave_1: left promiscuous mode
[  122.301089][   T50] bridge0: port 2(bridge_slave_1) entered disabled state
[  122.313574][   T50] bridge_slave_0: left allmulticast mode
[  122.323553][   T50] bridge_slave_0: left promiscuous mode
[  122.329648][   T50] bridge0: port 1(bridge_slave_0) entered disabled state
[  122.657213][   T50] bond0 (unregistering): (slave bond_slave_0): Releasing backup interface
[  122.668427][   T50] bond0 (unregistering): (slave bond_slave_1): Releasing backup interface
[  122.685192][   T50] bond0 (unregistering): Released all slaves
[  122.813567][   T50] hsr_slave_0: left promiscuous mode
[  122.824368][   T50] hsr_slave_1: left promiscuous mode
[  122.834742][   T50] batman_adv: batadv0: Interface deactivated: batadv_slave_0
[  122.842240][   T50] batman_adv: batadv0: Removing interface: batadv_slave_0
[  122.851144][   T50] batman_adv: batadv0: Interface deactivated: batadv_slave_1
[  122.859179][   T50] batman_adv: batadv0: Removing interface: batadv_slave_1
[  122.884287][   T50] veth1_macvtap: left promiscuous mode
[  122.890143][   T50] veth0_macvtap: left promiscuous mode
[  122.895990][   T50] veth1_vlan: left promiscuous mode
[  122.901750][   T50] veth0_vlan: left promiscuous mode
[  123.414964][   T50] team0 (unregistering): Port device team_slave_1 removed
[  123.453945][   T50] team0 (unregistering): Port device team_slave_0 removed
[  124.139994][   T50] netdevsim netdevsim0 netdevsim3 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[  124.221715][   T50] netdevsim netdevsim0 netdevsim2 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[  124.292342][   T50] netdevsim netdevsim0 netdevsim1 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[  124.386012][   T50] netdevsim netdevsim0 netdevsim0 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[  124.525472][   T50] bridge_slave_1: left allmulticast mode
[  124.531603][   T50] bridge_slave_1: left promiscuous mode
[  124.538156][   T50] bridge0: port 2(bridge_slave_1) entered disabled state
[  124.550777][   T50] bridge_slave_0: left allmulticast mode
[  124.557808][   T50] bridge_slave_0: left promiscuous mode
[  124.563691][   T50] bridge0: port 1(bridge_slave_0) entered disabled state
[  124.845360][   T50] bond0 (unregistering): (slave bond_slave_0): Releasing backup interface
[  124.859520][   T50] bond0 (unregistering): (slave bond_slave_1): Releasing backup interface
[  124.872053][   T50] bond0 (unregistering): Released all slaves
[  125.146756][   T50] hsr_slave_0: left promiscuous mode
[  125.152946][   T50] hsr_slave_1: left promiscuous mode
[  125.163809][   T50] batman_adv: batadv0: Interface deactivated: batadv_slave_0
[  125.172813][   T50] batman_adv: batadv0: Removing interface: batadv_slave_0
[  125.190084][   T50] batman_adv: batadv0: Interface deactivated: batadv_slave_1
[  125.197620][   T50] batman_adv: batadv0: Removing interface: batadv_slave_1
[  125.221387][   T50] veth1_macvtap: left promiscuous mode
[  125.227178][   T50] veth0_macvtap: left promiscuous mode
[  125.232863][   T50] veth1_vlan: left promiscuous mode
[  125.239905][   T50] veth0_vlan: left promiscuous mode
[  125.713684][   T50] team0 (unregistering): Port device team_slave_1 removed
[  125.742133][   T50] 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-build1470544453=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/syzkaller/jobs/linux/gopath/src/github.com/google/syzkaller/go.mod'
GOMODCACHE='/syzkaller/jobs/linux/gopath/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/syzkaller/jobs/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/ccJTB0zs.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=116ffc5a580000


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=16934402580000