Message-ID: <695f7522.050a0220.1c677c.0390.GAE@google.com>
Date: Thu, 08 Jan 2026 01:13:06 -0800
From: syzbot <syzbot+6e76aa21aaf2d8be6034@...kaller.appspotmail.com>
To: kartikey406@...il.com, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [batman?] [bluetooth?] memory leak in skb_clone (3)

Hello,

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

SYZFAIL: failed to recv rpc

SYZFAIL: failed to recv rpc
fd=3 want=4 recv=0 n=0 (errno 9: Bad file descriptor)


Warning: Permanently added '10.128.1.206' (ED25519) to the list of known hosts.
2026/01/08 09:12:03 parsed 1 programs
[   39.446388][ T5812] cgroup: Unknown subsys name 'net'
[   39.605314][ T5812] cgroup: Unknown subsys name 'cpuset'
[   39.611595][ T5812] cgroup: Unknown subsys name 'rlimit'
Setting up swapspace version 1, size = 127995904 bytes
[   47.470840][ T5812] Adding 124996k swap on ./swap-file.  Priority:0 extents:1 across:124996k 
[   48.689659][ T5825] soft_limit_in_bytes is deprecated and will be removed. Please report your usecase to linux-mm@...ck.org if you depend on this functionality.
[   48.766059][ T3516] wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   48.773877][ T3516] wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
[   48.807776][ T1319] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   48.815738][ T1319] wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
[   48.963021][ T5846] chnl_net:caif_netlink_parms(): no params data found
[   48.982991][ T5846] bridge0: port 1(bridge_slave_0) entered blocking state
[   48.990106][ T5846] bridge0: port 1(bridge_slave_0) entered disabled state
[   48.997249][ T5846] bridge_slave_0: entered allmulticast mode
[   49.003380][ T5846] bridge_slave_0: entered promiscuous mode
[   49.009804][ T5846] bridge0: port 2(bridge_slave_1) entered blocking state
[   49.017040][ T5846] bridge0: port 2(bridge_slave_1) entered disabled state
[   49.024422][ T5846] bridge_slave_1: entered allmulticast mode
[   49.030550][ T5846] bridge_slave_1: entered promiscuous mode
[   49.042940][ T5846] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link
[   49.052596][ T5846] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link
[   49.066555][ T5846] team0: Port device team_slave_0 added
[   49.073712][ T5846] team0: Port device team_slave_1 added
[   49.083130][ T5846] batman_adv: batadv0: Adding interface: batadv_slave_0
[   49.090176][ 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.
[   49.116048][ T5846] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active
[   49.127131][ T5846] batman_adv: batadv0: Adding interface: batadv_slave_1
[   49.134057][ 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.
[   49.159984][ T5846] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
[   49.178347][ T5846] hsr_slave_0: entered promiscuous mode
[   49.184058][ T5846] hsr_slave_1: entered promiscuous mode
[   49.213013][ T5846] netdevsim netdevsim0 netdevsim0: renamed from eth0
[   49.220688][ T5846] netdevsim netdevsim0 netdevsim1: renamed from eth1
[   49.228231][ T5846] netdevsim netdevsim0 netdevsim2: renamed from eth2
[   49.236272][ T5846] netdevsim netdevsim0 netdevsim3: renamed from eth3
[   49.247812][ T5846] bridge0: port 2(bridge_slave_1) entered blocking state
[   49.254847][ T5846] bridge0: port 2(bridge_slave_1) entered forwarding state
[   49.262104][ T5846] bridge0: port 1(bridge_slave_0) entered blocking state
[   49.269145][ T5846] bridge0: port 1(bridge_slave_0) entered forwarding state
[   49.286316][ T5846] 8021q: adding VLAN 0 to HW filter on device bond0
[   49.295647][ T1319] bridge0: port 1(bridge_slave_0) entered disabled state
[   49.302995][ T1319] bridge0: port 2(bridge_slave_1) entered disabled state
[   49.312485][ T5846] 8021q: adding VLAN 0 to HW filter on device team0
[   49.320726][   T12] bridge0: port 1(bridge_slave_0) entered blocking state
[   49.327779][   T12] bridge0: port 1(bridge_slave_0) entered forwarding state
[   49.336884][ T1319] bridge0: port 2(bridge_slave_1) entered blocking state
[   49.343946][ T1319] bridge0: port 2(bridge_slave_1) entered forwarding state
[   49.383078][ T5846] 8021q: adding VLAN 0 to HW filter on device batadv0
[   49.397071][ T5846] veth0_vlan: entered promiscuous mode
[   49.403780][ T5846] veth1_vlan: entered promiscuous mode
[   49.414196][ T5846] veth0_macvtap: entered promiscuous mode
[   49.420989][ T5846] veth1_macvtap: entered promiscuous mode
[   49.429785][ T5846] batman_adv: batadv0: Interface activated: batadv_slave_0
[   49.438714][ T5846] batman_adv: batadv0: Interface activated: batadv_slave_1
[   49.447616][   T12] netdevsim netdevsim0 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
[   49.456376][   T12] netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[   49.465324][   T12] netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[   49.474002][   T12] netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
[   49.537965][ T3516] netdevsim netdevsim0 netdevsim3 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[   49.575587][ T3516] netdevsim netdevsim0 netdevsim2 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[   49.625524][ T3516] netdevsim netdevsim0 netdevsim1 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[   49.676203][ T3516] netdevsim netdevsim0 netdevsim0 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[   49.717152][ T5134] Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
[   49.724228][ T5134] Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
[   49.731484][ T5134] Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
[   49.740040][ T5134] Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
[   49.747339][ T5134] Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
2026/01/08 09:12:15 executed programs: 0
[   52.728523][ T3516] bridge_slave_1: left allmulticast mode
[   52.734180][ T3516] bridge_slave_1: left promiscuous mode
[   52.740446][ T3516] bridge0: port 2(bridge_slave_1) entered disabled state
[   52.748078][ T3516] bridge_slave_0: left allmulticast mode
[   52.753702][ T3516] bridge_slave_0: left promiscuous mode
[   52.759611][ T3516] bridge0: port 1(bridge_slave_0) entered disabled state
[   52.826783][ T3516] bond0 (unregistering): (slave bond_slave_0): Releasing backup interface
[   52.836559][ T3516] bond0 (unregistering): (slave bond_slave_1): Releasing backup interface
[   52.845690][ T3516] bond0 (unregistering): Released all slaves
[   52.946650][ T3516] hsr_slave_0: left promiscuous mode
[   52.953380][ T3516] hsr_slave_1: left promiscuous mode
[   52.959024][ T3516] batman_adv: batadv0: Interface deactivated: batadv_slave_0
[   52.966522][ T3516] batman_adv: batadv0: Removing interface: batadv_slave_0
[   52.973866][ T3516] batman_adv: batadv0: Interface deactivated: batadv_slave_1
[   52.981792][ T3516] batman_adv: batadv0: Removing interface: batadv_slave_1
[   52.995844][ T3516] veth1_macvtap: left promiscuous mode
[   53.001322][ T3516] veth0_macvtap: left promiscuous mode
[   53.006881][ T3516] veth1_vlan: left promiscuous mode
[   53.012105][ T3516] veth0_vlan: left promiscuous mode
[   53.035995][ T3516] team0 (unregistering): Port device team_slave_1 removed
[   53.044002][ T3516] team0 (unregistering): Port device team_slave_0 removed
[   55.432868][   T50] Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
[   55.439938][   T50] Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
[   55.446972][   T50] Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
[   55.454519][   T50] Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
[   55.461754][   T50] Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
[   55.495653][ T5988] chnl_net:caif_netlink_parms(): no params data found
[   55.513339][ T5988] bridge0: port 1(bridge_slave_0) entered blocking state
[   55.520538][ T5988] bridge0: port 1(bridge_slave_0) entered disabled state
[   55.527732][ T5988] bridge_slave_0: entered allmulticast mode
[   55.533952][ T5988] bridge_slave_0: entered promiscuous mode
[   55.540831][ T5988] bridge0: port 2(bridge_slave_1) entered blocking state
[   55.548069][ T5988] bridge0: port 2(bridge_slave_1) entered disabled state
[   55.555238][ T5988] bridge_slave_1: entered allmulticast mode
[   55.561388][ T5988] bridge_slave_1: entered promiscuous mode
[   55.571735][ T5988] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link
[   55.581491][ T5988] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link
[   55.594719][ T5988] team0: Port device team_slave_0 added
[   55.600867][ T5988] team0: Port device team_slave_1 added
[   55.611085][ T5988] batman_adv: batadv0: Adding interface: batadv_slave_0
[   55.618166][ T5988] 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.
[   55.644127][ T5988] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active
[   55.655387][ T5988] batman_adv: batadv0: Adding interface: batadv_slave_1
[   55.662325][ T5988] 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.
[   55.688309][ T5988] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
[   55.704682][ T5988] hsr_slave_0: entered promiscuous mode
[   55.710387][ T5988] hsr_slave_1: entered promiscuous mode
[   55.896676][ T5988] netdevsim netdevsim0 netdevsim0: renamed from eth0
[   55.904652][ T5988] netdevsim netdevsim0 netdevsim1: renamed from eth1
[   55.912369][ T5988] netdevsim netdevsim0 netdevsim2: renamed from eth2
[   55.921723][ T5988] netdevsim netdevsim0 netdevsim3: renamed from eth3
[   55.936770][ T5988] bridge0: port 2(bridge_slave_1) entered blocking state
[   55.943837][ T5988] bridge0: port 2(bridge_slave_1) entered forwarding state
[   55.951469][ T5988] bridge0: port 1(bridge_slave_0) entered blocking state
[   55.958535][ T5988] bridge0: port 1(bridge_slave_0) entered forwarding state
[   55.978522][ T5988] 8021q: adding VLAN 0 to HW filter on device bond0
[   55.987742][   T12] bridge0: port 1(bridge_slave_0) entered disabled state
[   55.998188][   T12] bridge0: port 2(bridge_slave_1) entered disabled state
[   56.007799][ T5988] 8021q: adding VLAN 0 to HW filter on device team0
[   56.017320][  T178] bridge0: port 1(bridge_slave_0) entered blocking state
[   56.024383][  T178] bridge0: port 1(bridge_slave_0) entered forwarding state
[   56.034662][   T12] bridge0: port 2(bridge_slave_1) entered blocking state
[   56.041783][   T12] bridge0: port 2(bridge_slave_1) entered forwarding state
[   56.092099][ T5988] 8021q: adding VLAN 0 to HW filter on device batadv0
[   56.109092][ T5988] veth0_vlan: entered promiscuous mode
[   56.116470][ T5988] veth1_vlan: entered promiscuous mode
[   56.128642][ T5988] veth0_macvtap: entered promiscuous mode
[   56.136702][ T5988] veth1_macvtap: entered promiscuous mode
[   56.146283][ T5988] batman_adv: batadv0: Interface activated: batadv_slave_0
[   56.159235][ T5988] batman_adv: batadv0: Interface activated: batadv_slave_1
[   56.172406][   T12] netdevsim netdevsim0 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
[   56.181580][   T12] netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[   56.190576][   T12] netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[   56.202027][   T12] netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
[   56.221912][   T12] wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   56.236285][   T12] wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
SYZFAIL: failed to recv rpc
fd=3 want=4 recv=0 n=0 (errno 9: Bad file descriptor)
[   56.247653][ T3516] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   56.255571][ T3516] wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50


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-build3005886320=/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/ccZuE7Pn.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:         f0b9d8eb Merge tag 'nfsd-6.19-3' of git://git.kernel.o..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=d60836e327fd6756
dashboard link: https://syzkaller.appspot.com/bug?extid=6e76aa21aaf2d8be6034
compiler:       gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1157a922580000

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