Message-ID: <695f6ff8.050a0220.1c677c.038d.GAE@google.com>
Date: Thu, 08 Jan 2026 00:51:04 -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 '10.128.1.244' (ED25519) to the list of known hosts.
2026/01/08 08:50:22 parsed 1 programs
[   44.412272][ T5812] cgroup: Unknown subsys name 'net'
[   44.552213][ T5812] cgroup: Unknown subsys name 'cpuset'
[   44.558758][ T5812] cgroup: Unknown subsys name 'rlimit'
Setting up swapspace version 1, size = 127995904 bytes
[   53.102607][ T5812] Adding 124996k swap on ./swap-file.  Priority:0 extents:1 across:124996k 
[   54.610733][ T5820] 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.
[   54.970990][ T4540] wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   54.979079][ T4540] wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
[   54.989620][ T4540] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   54.998662][ T4540] wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
[   55.095104][ T5854] chnl_net:caif_netlink_parms(): no params data found
[   55.116031][ T5854] bridge0: port 1(bridge_slave_0) entered blocking state
[   55.123620][ T5854] bridge0: port 1(bridge_slave_0) entered disabled state
[   55.130804][ T5854] bridge_slave_0: entered allmulticast mode
[   55.137513][ T5854] bridge_slave_0: entered promiscuous mode
[   55.144864][ T5854] bridge0: port 2(bridge_slave_1) entered blocking state
[   55.152202][ T5854] bridge0: port 2(bridge_slave_1) entered disabled state
[   55.159726][ T5854] bridge_slave_1: entered allmulticast mode
[   55.166034][ T5854] bridge_slave_1: entered promiscuous mode
[   55.181476][ T5854] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link
[   55.191700][ T5854] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link
[   55.206168][ T5854] team0: Port device team_slave_0 added
[   55.212408][ T5854] team0: Port device team_slave_1 added
[   55.222377][ T5854] batman_adv: batadv0: Adding interface: batadv_slave_0
[   55.229456][ T5854] 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.
[   55.255645][ T5854] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active
[   55.266796][ T5854] batman_adv: batadv0: Adding interface: batadv_slave_1
[   55.274160][ T5854] 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.
[   55.300431][ T5854] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
[   55.319448][ T5854] hsr_slave_0: entered promiscuous mode
[   55.325770][ T5854] hsr_slave_1: entered promiscuous mode
[   55.362408][ T5854] netdevsim netdevsim0 netdevsim0: renamed from eth0
[   55.370244][ T5854] netdevsim netdevsim0 netdevsim1: renamed from eth1
[   55.378970][ T5854] netdevsim netdevsim0 netdevsim2: renamed from eth2
[   55.388147][ T5854] netdevsim netdevsim0 netdevsim3: renamed from eth3
[   55.401593][ T5854] bridge0: port 2(bridge_slave_1) entered blocking state
[   55.408842][ T5854] bridge0: port 2(bridge_slave_1) entered forwarding state
[   55.416647][ T5854] bridge0: port 1(bridge_slave_0) entered blocking state
[   55.423865][ T5854] bridge0: port 1(bridge_slave_0) entered forwarding state
[   55.442923][ T5854] 8021q: adding VLAN 0 to HW filter on device bond0
[   55.453099][  T616] bridge0: port 1(bridge_slave_0) entered disabled state
[   55.460774][  T616] bridge0: port 2(bridge_slave_1) entered disabled state
[   55.471115][ T5854] 8021q: adding VLAN 0 to HW filter on device team0
[   55.480096][   T67] bridge0: port 1(bridge_slave_0) entered blocking state
[   55.487260][   T67] bridge0: port 1(bridge_slave_0) entered forwarding state
[   55.496479][  T616] bridge0: port 2(bridge_slave_1) entered blocking state
[   55.503846][  T616] bridge0: port 2(bridge_slave_1) entered forwarding state
[   55.550208][ T5854] 8021q: adding VLAN 0 to HW filter on device batadv0
[   55.565686][ T5854] veth0_vlan: entered promiscuous mode
[   55.573327][ T5854] veth1_vlan: entered promiscuous mode
[   55.585138][ T5854] veth0_macvtap: entered promiscuous mode
[   55.592480][ T5854] veth1_macvtap: entered promiscuous mode
[   55.601527][ T5854] batman_adv: batadv0: Interface activated: batadv_slave_0
[   55.610880][ T5854] batman_adv: batadv0: Interface activated: batadv_slave_1
[   55.620306][  T616] netdevsim netdevsim0 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
[   55.629467][  T616] netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[   55.638355][  T616] netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[   55.648753][  T616] netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
[   55.703784][   T35] netdevsim netdevsim0 netdevsim3 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[   55.723557][   T35] netdevsim netdevsim0 netdevsim2 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[   55.763184][   T35] netdevsim netdevsim0 netdevsim1 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[   55.823220][   T35] netdevsim netdevsim0 netdevsim0 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[   56.020250][   T50] Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
[   56.027724][   T50] Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
[   56.034988][   T50] Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
[   56.042645][   T50] Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
[   56.050572][   T50] Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
2026/01/08 08:50:36 executed programs: 0
[   59.032883][   T35] bridge_slave_1: left allmulticast mode
[   59.038658][   T35] bridge_slave_1: left promiscuous mode
[   59.045176][   T35] bridge0: port 2(bridge_slave_1) entered disabled state
[   59.052922][   T35] bridge_slave_0: left allmulticast mode
[   59.058648][   T35] bridge_slave_0: left promiscuous mode
[   59.064629][   T35] bridge0: port 1(bridge_slave_0) entered disabled state
[   59.113036][   T35] bond0 (unregistering): (slave bond_slave_0): Releasing backup interface
[   59.122429][   T35] bond0 (unregistering): (slave bond_slave_1): Releasing backup interface
[   59.132012][   T35] bond0 (unregistering): Released all slaves
[   59.203982][   T35] hsr_slave_0: left promiscuous mode
[   59.209616][   T35] hsr_slave_1: left promiscuous mode
[   59.215254][   T35] batman_adv: batadv0: Interface deactivated: batadv_slave_0
[   59.222841][   T35] batman_adv: batadv0: Removing interface: batadv_slave_0
[   59.230239][   T35] batman_adv: batadv0: Interface deactivated: batadv_slave_1
[   59.237951][   T35] batman_adv: batadv0: Removing interface: batadv_slave_1
[   59.246416][   T35] veth1_macvtap: left promiscuous mode
[   59.252390][   T35] veth0_macvtap: left promiscuous mode
[   59.257961][   T35] veth1_vlan: left promiscuous mode
[   59.263367][   T35] veth0_vlan: left promiscuous mode
[   59.288522][   T35] team0 (unregistering): Port device team_slave_1 removed
[   59.296801][   T35] team0 (unregistering): Port device team_slave_0 removed
[   61.956988][ T5134] Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
[   61.964164][ T5134] Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
[   61.971580][ T5134] Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
[   61.978935][ T5134] Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
[   61.986248][ T5134] Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
[   62.024970][ T5987] chnl_net:caif_netlink_parms(): no params data found
[   62.044720][ T5987] bridge0: port 1(bridge_slave_0) entered blocking state
[   62.051850][ T5987] bridge0: port 1(bridge_slave_0) entered disabled state
[   62.059088][ T5987] bridge_slave_0: entered allmulticast mode
[   62.065458][ T5987] bridge_slave_0: entered promiscuous mode
[   62.071899][ T5987] bridge0: port 2(bridge_slave_1) entered blocking state
[   62.078959][ T5987] bridge0: port 2(bridge_slave_1) entered disabled state
[   62.086298][ T5987] bridge_slave_1: entered allmulticast mode
[   62.093018][ T5987] bridge_slave_1: entered promiscuous mode
[   62.104620][ T5987] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link
[   62.114765][ T5987] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link
[   62.128762][ T5987] team0: Port device team_slave_0 added
[   62.135127][ T5987] team0: Port device team_slave_1 added
[   62.145113][ T5987] batman_adv: batadv0: Adding interface: batadv_slave_0
[   62.152247][ T5987] 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.
[   62.179221][ T5987] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active
[   62.190316][ T5987] batman_adv: batadv0: Adding interface: batadv_slave_1
[   62.197395][ T5987] 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.
[   62.223735][ T5987] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
[   62.240965][ T5987] hsr_slave_0: entered promiscuous mode
[   62.246931][ T5987] hsr_slave_1: entered promiscuous mode
[   62.415056][ T5987] netdevsim netdevsim0 netdevsim0: renamed from eth0
[   62.423232][ T5987] netdevsim netdevsim0 netdevsim1: renamed from eth1
[   62.431634][ T5987] netdevsim netdevsim0 netdevsim2: renamed from eth2
[   62.440024][ T5987] netdevsim netdevsim0 netdevsim3: renamed from eth3
[   62.459073][ T5987] bridge0: port 2(bridge_slave_1) entered blocking state
[   62.466378][ T5987] bridge0: port 2(bridge_slave_1) entered forwarding state
[   62.473702][ T5987] bridge0: port 1(bridge_slave_0) entered blocking state
[   62.480879][ T5987] bridge0: port 1(bridge_slave_0) entered forwarding state
[   62.502486][ T5987] 8021q: adding VLAN 0 to HW filter on device bond0
[   62.512598][ T1099] bridge0: port 1(bridge_slave_0) entered disabled state
[   62.520129][ T1099] bridge0: port 2(bridge_slave_1) entered disabled state
[   62.530248][ T5987] 8021q: adding VLAN 0 to HW filter on device team0
[   62.540199][ T1099] bridge0: port 1(bridge_slave_0) entered blocking state
[   62.547315][ T1099] bridge0: port 1(bridge_slave_0) entered forwarding state
[   62.564025][ T5987] hsr0: Slave A (hsr_slave_0) is not up; please bring it up to get a fully working HSR network
[   62.574677][ T5987] hsr0: Slave B (hsr_slave_1) is not up; please bring it up to get a fully working HSR network
[   62.587204][ T1099] bridge0: port 2(bridge_slave_1) entered blocking state
[   62.594310][ T1099] bridge0: port 2(bridge_slave_1) entered forwarding state
[   62.643732][ T5987] 8021q: adding VLAN 0 to HW filter on device batadv0
[   62.662658][ T5987] veth0_vlan: entered promiscuous mode
[   62.670978][ T5987] veth1_vlan: entered promiscuous mode
[   62.685995][ T5987] veth0_macvtap: entered promiscuous mode
[   62.694531][ T5987] veth1_macvtap: entered promiscuous mode
[   62.704853][ T5987] batman_adv: batadv0: Interface activated: batadv_slave_0
[   62.714729][ T5987] batman_adv: batadv0: Interface activated: batadv_slave_1
[   62.724965][ T1099] netdevsim netdevsim0 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
[   62.734666][ T1099] netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[   62.744973][ T1099] netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[   62.756496][ T1099] netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
[   62.781601][ T1099] wlan0: Created IBSS using preconfigured 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)
[   62.789541][ T1099] wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
[   62.806901][   T67] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   62.815348][   T67] 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-build91986741=/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/cci9bR9C.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=176f1f92580000

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