Re: [syzbot] [exfat?] [ocfs2?] kernel BUG in link_path_walk

syzbot
2025-12-04T10:13:03Z

Hello,

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

SYZFAIL: failed to recv rpc

SYZFAIL: failed to recv rpc

Warning: Permanently added '10.128.0.177' (ED25519) to the list of known hosts.
2025/12/04 10:11:47 parsed 1 programs
[ 78.910789][ T5830] cgroup: Unknown subsys name 'net'
[ 79.061524][ T5830] cgroup: Unknown subsys name 'cpuset'
[ 79.071037][ T5830] cgroup: Unknown subsys name 'rlimit'
Setting up swapspace version 1, size = 127995904 bytes
[ 80.470098][ T5830] Adding 124996k swap on ./swap-file. Priority:0 extents:1 across:124996k
[ 83.462586][ T5842] soft_limit_in_bytes is deprecated and will be removed. Please report your usecase to linux-mm@kvack.org if you depend on this functionality.
[ 83.768296][ T1303] wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[ 83.776268][ T1303] wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
[ 84.018160][ T36] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[ 84.026332][ T36] wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
[ 84.079691][ T5149] Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
[ 84.089721][ T5149] Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
[ 84.097886][ T5149] Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
[ 84.120020][ T5149] Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
[ 84.128054][ T5149] Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
[ 86.764273][ T5914] chnl_net:caif_netlink_parms(): no params data found
[ 86.952176][ T10] cfg80211: failed to load regulatory.db
[ 86.970822][ T5914] bridge0: port 1(bridge_slave_0) entered blocking state
[ 86.987663][ T5914] bridge0: port 1(bridge_slave_0) entered disabled state
[ 86.995387][ T5914] bridge_slave_0: entered allmulticast mode
[ 87.004680][ T5914] bridge_slave_0: entered promiscuous mode
[ 87.019597][ T5914] bridge0: port 2(bridge_slave_1) entered blocking state
[ 87.038879][ T5914] bridge0: port 2(bridge_slave_1) entered disabled state
[ 87.046589][ T5914] bridge_slave_1: entered allmulticast mode
[ 87.055691][ T5914] bridge_slave_1: entered promiscuous mode
[ 87.132629][ T5914] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link
[ 87.165237][ T5914] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link
[ 87.263236][ T5914] team0: Port device team_slave_0 added
[ 87.273397][ T5914] team0: Port device team_slave_1 added
[ 87.303206][ T5914] batman_adv: batadv0: Adding interface: batadv_slave_0
[ 87.311015][ T5914] 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.
[ 87.339107][ T5914] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active
[ 87.352524][ T5914] batman_adv: batadv0: Adding interface: batadv_slave_1
[ 87.360592][ T5914] 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.
[ 87.387771][ T5914] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
[ 87.429283][ T5914] hsr_slave_0: entered promiscuous mode
[ 87.436383][ T5914] hsr_slave_1: entered promiscuous mode
[ 87.589866][ T5914] netdevsim netdevsim2 netdevsim0: renamed from eth0
[ 87.602532][ T5914] netdevsim netdevsim2 netdevsim1: renamed from eth1
[ 87.612793][ T5914] netdevsim netdevsim2 netdevsim2: renamed from eth2
[ 87.624712][ T5914] netdevsim netdevsim2 netdevsim3: renamed from eth3
[ 87.702119][ T5914] 8021q: adding VLAN 0 to HW filter on device bond0
[ 87.727060][ T5914] 8021q: adding VLAN 0 to HW filter on device team0
[ 87.742924][ T3460] bridge0: port 1(bridge_slave_0) entered blocking state
[ 87.750338][ T3460] bridge0: port 1(bridge_slave_0) entered forwarding state
[ 87.767840][ T13] bridge0: port 2(bridge_slave_1) entered blocking state
[ 87.775679][ T13] bridge0: port 2(bridge_slave_1) entered forwarding state
[ 87.951069][ T5914] 8021q: adding VLAN 0 to HW filter on device batadv0
[ 87.997784][ T5914] veth0_vlan: entered promiscuous mode
[ 88.011677][ T5914] veth1_vlan: entered promiscuous mode
[ 88.040488][ T5914] veth0_macvtap: entered promiscuous mode
[ 88.050521][ T5914] veth1_macvtap: entered promiscuous mode
[ 88.070672][ T5914] batman_adv: batadv0: Interface activated: batadv_slave_0
[ 88.086679][ T5914] batman_adv: batadv0: Interface activated: batadv_slave_1
[ 88.102451][ T1303] netdevsim netdevsim2 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
[ 88.112929][ T1303] netdevsim netdevsim2 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[ 88.125269][ T1303] netdevsim netdevsim2 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[ 88.138936][ T1303] netdevsim netdevsim2 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
2025/12/04 10:11:58 executed programs: 0
[ 88.265933][ T5149] Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
[ 88.275000][ T5149] Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
[ 88.283928][ T5149] Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
[ 88.294110][ T5149] Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
[ 88.303601][ T5149] Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
[ 88.516655][ T5945] chnl_net:caif_netlink_parms(): no params data found
[ 88.589071][ T5945] bridge0: port 1(bridge_slave_0) entered blocking state
[ 88.597183][ T5945] bridge0: port 1(bridge_slave_0) entered disabled state
[ 88.605206][ T5945] bridge_slave_0: entered allmulticast mode
[ 88.613430][ T5945] bridge_slave_0: entered promiscuous mode
[ 88.621792][ T5945] bridge0: port 2(bridge_slave_1) entered blocking state
[ 88.629190][ T5945] bridge0: port 2(bridge_slave_1) entered disabled state
[ 88.636388][ T5945] bridge_slave_1: entered allmulticast mode
[ 88.644502][ T5945] bridge_slave_1: entered promiscuous mode
[ 88.679834][ T5945] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link
[ 88.693258][ T5945] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link
[ 88.729876][ T5945] team0: Port device team_slave_0 added
[ 88.739741][ T5945] team0: Port device team_slave_1 added
[ 88.770447][ T5945] batman_adv: batadv0: Adding interface: batadv_slave_0
[ 88.778982][ T5945] 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.
[ 88.806119][ T5945] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active
[ 88.819400][ T5945] batman_adv: batadv0: Adding interface: batadv_slave_1
[ 88.826898][ T5945] 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.
[ 88.854775][ T5945] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
[ 88.906117][ T5945] hsr_slave_0: entered promiscuous mode
[ 88.913653][ T5945] hsr_slave_1: entered promiscuous mode
[ 88.920136][ T5945] debugfs: 'hsr0' already exists in 'hsr'
[ 88.926073][ T5945] Cannot create hsr debugfs directory
[ 89.100742][ T5945] netdevsim netdevsim0 netdevsim0: renamed from eth0
[ 89.113003][ T5945] netdevsim netdevsim0 netdevsim1: renamed from eth1
[ 89.123282][ T5945] netdevsim netdevsim0 netdevsim2: renamed from eth2
[ 89.134611][ T5945] netdevsim netdevsim0 netdevsim3: renamed from eth3
[ 89.164880][ T5945] bridge0: port 2(bridge_slave_1) entered blocking state
[ 89.172220][ T5945] bridge0: port 2(bridge_slave_1) entered forwarding state
[ 89.180595][ T5945] bridge0: port 1(bridge_slave_0) entered blocking state
[ 89.188151][ T5945] bridge0: port 1(bridge_slave_0) entered forwarding state
[ 89.201467][ T13] bridge0: port 1(bridge_slave_0) entered disabled state
[ 89.210194][ T13] bridge0: port 2(bridge_slave_1) entered disabled state
[ 89.271133][ T5945] 8021q: adding VLAN 0 to HW filter on device bond0
[ 89.292385][ T5945] 8021q: adding VLAN 0 to HW filter on device team0
[ 89.304472][ T13] bridge0: port 1(bridge_slave_0) entered blocking state
[ 89.311731][ T13] bridge0: port 1(bridge_slave_0) entered forwarding state
[ 89.328520][ T1303] bridge0: port 2(bridge_slave_1) entered blocking state
[ 89.336026][ T1303] bridge0: port 2(bridge_slave_1) entered forwarding state
[ 89.510299][ T5945] 8021q: adding VLAN 0 to HW filter on device batadv0
[ 89.555268][ T5945] veth0_vlan: entered promiscuous mode
[ 89.567506][ T5945] veth1_vlan: entered promiscuous mode
[ 89.602029][ T5945] veth0_macvtap: entered promiscuous mode
[ 89.611643][ T5945] veth1_macvtap: entered promiscuous mode
[ 89.630992][ T5945] batman_adv: batadv0: Interface activated: batadv_slave_0
[ 89.645744][ T5945] batman_adv: batadv0: Interface activated: batadv_slave_1
[ 89.661459][ T13] netdevsim netdevsim0 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
[ 89.675047][ T13] netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[ 89.685863][ T13] netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[ 89.695952][ T13] netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
[ 89.763899][ T3460] wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[ 89.773242][ T3460] wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
[ 89.806188][ T13] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[ 89.814827][ T13] wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
SYZFAIL: failed to recv rpc
[ 90.239026][ T13] netdevsim netdevsim2 netdevsim3 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0

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-build2089224975=/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 d6526ea3e
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=d6526ea3e6ad9081c902859bbb80f9f840377cb4 -X github.com/google/syzkaller/prog.gitRevisionDate=20251126-113115" ./sys/syz-sysgen | grep -q false || go install -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=d6526ea3e6ad9081c902859bbb80f9f840377cb4 -X github.com/google/syzkaller/prog.gitRevisionDate=20251126-113115" ./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=d6526ea3e6ad9081c902859bbb80f9f840377cb4 -X github.com/google/syzkaller/prog.gitRevisionDate=20251126-113115" -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=\"d6526ea3e6ad9081c902859bbb80f9f840377cb4\"
/usr/bin/ld: /tmp/cc9mWJPn.o: in function `Connection::Connect(char const*, char const*)':
executor.cc:(.text._ZN10Connection7ConnectEPKcS1_[_ZN10Connection7ConnectEPKcS1_]+0x104): 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

Tested on:

commit: bc04acf4 Add linux-next specific files for 20251204
git tree: linux-next
kernel config: https://syzkaller.appspot.com/x/.config?x=a94030c847137a18
dashboard link: https://syzkaller.appspot.com/bug?extid=d222f4b7129379c3d5bc
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
patch: https://syzkaller.appspot.com/x/patch.diff?x=1731d01a580000