Re: [syzbot] [hams?] memory leak in nr_add_node

[syzbot <syzbot+3f2d46b6e62b8dd546d3@syzkaller.appspotmail.com>]

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 '10.128.0.254' (ED25519) to the list of known hosts.
2026/01/16 08:02:17 parsed 1 programs
[   41.087441][ T5820] cgroup: Unknown subsys name 'net'
[   41.206631][ T5820] cgroup: Unknown subsys name 'cpuset'
[   41.213349][ T5820] cgroup: Unknown subsys name 'rlimit'
Setting up swapspace version 1, size = 127995904 bytes
[   49.319220][ T5820] Adding 124996k swap on ./swap-file.  Priority:0 extents:1 across:124996k 
[   50.551457][ T5832] 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.
[   50.743054][ T5851] Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
[   50.750655][ T5851] Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
[   50.757962][ T5851] Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
[   50.765365][ T5851] Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
[   50.772807][ T5851] Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
[   50.866434][   T71] wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   50.874785][   T71] wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
[   50.890522][ T3978] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   50.898625][ T3978] wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
[   51.236484][ T5900] chnl_net:caif_netlink_parms(): no params data found
[   51.258827][ T5900] bridge0: port 1(bridge_slave_0) entered blocking state
[   51.266070][ T5900] bridge0: port 1(bridge_slave_0) entered disabled state
[   51.273249][ T5900] bridge_slave_0: entered allmulticast mode
[   51.279886][ T5900] bridge_slave_0: entered promiscuous mode
[   51.288425][ T5900] bridge0: port 2(bridge_slave_1) entered blocking state
[   51.295600][ T5900] bridge0: port 2(bridge_slave_1) entered disabled state
[   51.302727][ T5900] bridge_slave_1: entered allmulticast mode
[   51.308934][ T5900] bridge_slave_1: entered promiscuous mode
[   51.319403][ T5900] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link
[   51.329487][ T5900] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link
[   51.343436][ T5900] team0: Port device team_slave_0 added
[   51.350119][ T5900] team0: Port device team_slave_1 added
[   51.364030][ T5900] batman_adv: batadv0: Adding interface: batadv_slave_0
[   51.371293][ T5900] 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.
[   51.398014][ T5900] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active
[   51.409050][ T5900] batman_adv: batadv0: Adding interface: batadv_slave_1
[   51.416003][ T5900] 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.
[   51.443416][ T5900] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
[   51.460967][ T5900] hsr_slave_0: entered promiscuous mode
[   51.467467][ T5900] hsr_slave_1: entered promiscuous mode
[   51.495110][ T5900] netdevsim netdevsim0 netdevsim0: renamed from eth0
[   51.503248][ T5900] netdevsim netdevsim0 netdevsim1: renamed from eth1
[   51.511129][ T5900] netdevsim netdevsim0 netdevsim2: renamed from eth2
[   51.518843][ T5900] netdevsim netdevsim0 netdevsim3: renamed from eth3
[   51.530290][ T5900] bridge0: port 2(bridge_slave_1) entered blocking state
[   51.537440][ T5900] bridge0: port 2(bridge_slave_1) entered forwarding state
[   51.544696][ T5900] bridge0: port 1(bridge_slave_0) entered blocking state
[   51.551853][ T5900] bridge0: port 1(bridge_slave_0) entered forwarding state
[   51.568410][ T5900] 8021q: adding VLAN 0 to HW filter on device bond0
[   51.577765][ T4464] bridge0: port 1(bridge_slave_0) entered disabled state
[   51.585068][ T4464] bridge0: port 2(bridge_slave_1) entered disabled state
[   51.594301][ T5900] 8021q: adding VLAN 0 to HW filter on device team0
[   51.602757][ T3190] bridge0: port 1(bridge_slave_0) entered blocking state
[   51.609832][ T3190] bridge0: port 1(bridge_slave_0) entered forwarding state
[   51.618795][ T4464] bridge0: port 2(bridge_slave_1) entered blocking state
[   51.626034][ T4464] bridge0: port 2(bridge_slave_1) entered forwarding state
[   51.666181][ T5900] 8021q: adding VLAN 0 to HW filter on device batadv0
[   51.681447][ T5900] veth0_vlan: entered promiscuous mode
[   51.688371][ T5900] veth1_vlan: entered promiscuous mode
[   51.699293][ T5900] veth0_macvtap: entered promiscuous mode
[   51.706838][ T5900] veth1_macvtap: entered promiscuous mode
[   51.715608][ T5900] batman_adv: batadv0: Interface activated: batadv_slave_0
[   51.724956][ T5900] batman_adv: batadv0: Interface activated: batadv_slave_1
[   51.733920][ T3190] netdevsim netdevsim0 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
[   51.743349][ T3190] netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[   51.752924][ T3190] netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[   51.762992][ T3190] netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
[   51.808219][   T71] netdevsim netdevsim0 netdevsim3 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[   51.856276][   T71] netdevsim netdevsim0 netdevsim2 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
2026/01/16 08:02:29 executed programs: 0
[   51.896248][   T71] netdevsim netdevsim0 netdevsim1 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[   51.946260][   T71] netdevsim netdevsim0 netdevsim0 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[   54.910747][   T71] bridge_slave_1: left allmulticast mode
[   54.917591][   T71] bridge_slave_1: left promiscuous mode
[   54.923218][   T71] bridge0: port 2(bridge_slave_1) entered disabled state
[   54.931147][   T71] bridge_slave_0: left allmulticast mode
[   54.937176][   T71] bridge_slave_0: left promiscuous mode
[   54.942989][   T71] bridge0: port 1(bridge_slave_0) entered disabled state
[   54.997555][   T71] bond0 (unregistering): (slave bond_slave_0): Releasing backup interface
[   55.006647][   T71] bond0 (unregistering): (slave bond_slave_1): Releasing backup interface
[   55.016135][   T71] bond0 (unregistering): Released all slaves
[   55.068870][   T71] hsr_slave_0: left promiscuous mode
[   55.079391][   T71] hsr_slave_1: left promiscuous mode
[   55.085080][   T71] batman_adv: batadv0: Interface deactivated: batadv_slave_0
[   55.092634][   T71] batman_adv: batadv0: Removing interface: batadv_slave_0
[   55.100332][   T71] batman_adv: batadv0: Interface deactivated: batadv_slave_1
[   55.108378][   T71] batman_adv: batadv0: Removing interface: batadv_slave_1
[   55.116737][   T71] veth1_macvtap: left promiscuous mode
[   55.122201][   T71] veth0_macvtap: left promiscuous mode
[   55.127711][   T71] veth1_vlan: left promiscuous mode
[   55.132908][   T71] veth0_vlan: left promiscuous mode
[   55.156128][   T71] team0 (unregistering): Port device team_slave_1 removed
[   55.164224][   T71] team0 (unregistering): Port device team_slave_0 removed
[   57.217110][ T5141] Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
[   57.224285][ T5141] Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
[   57.231521][ T5141] Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
[   57.239322][ T5141] Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
[   57.246587][ T5141] Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
[   57.281718][ T5997] chnl_net:caif_netlink_parms(): no params data found
[   57.299895][ T5997] bridge0: port 1(bridge_slave_0) entered blocking state
[   57.307481][ T5997] bridge0: port 1(bridge_slave_0) entered disabled state
[   57.314752][ T5997] bridge_slave_0: entered allmulticast mode
[   57.321146][ T5997] bridge_slave_0: entered promiscuous mode
[   57.327659][ T5997] bridge0: port 2(bridge_slave_1) entered blocking state
[   57.334726][ T5997] bridge0: port 2(bridge_slave_1) entered disabled state
[   57.342049][ T5997] bridge_slave_1: entered allmulticast mode
[   57.348478][ T5997] bridge_slave_1: entered promiscuous mode
[   57.360565][ T5997] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link
[   57.370600][ T5997] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link
[   57.384295][ T5997] team0: Port device team_slave_0 added
[   57.390657][ T5997] team0: Port device team_slave_1 added
[   57.400168][ T5997] batman_adv: batadv0: Adding interface: batadv_slave_0
[   57.407138][ T5997] 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.
[   57.433263][ T5997] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active
[   57.444502][ T5997] batman_adv: batadv0: Adding interface: batadv_slave_1
[   57.451799][ T5997] 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.
[   57.478423][ T5997] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
[   57.495431][ T5997] hsr_slave_0: entered promiscuous mode
[   57.501243][ T5997] hsr_slave_1: entered promiscuous mode
[   57.676135][ T5997] netdevsim netdevsim0 netdevsim0: renamed from eth0
[   57.684062][ T5997] netdevsim netdevsim0 netdevsim1: renamed from eth1
[   57.691985][ T5997] netdevsim netdevsim0 netdevsim2: renamed from eth2
[   57.700149][ T5997] netdevsim netdevsim0 netdevsim3: renamed from eth3
[   57.719190][ T5997] bridge0: port 2(bridge_slave_1) entered blocking state
[   57.726656][ T5997] bridge0: port 2(bridge_slave_1) entered forwarding state
[   57.733929][ T5997] bridge0: port 1(bridge_slave_0) entered blocking state
[   57.741367][ T5997] bridge0: port 1(bridge_slave_0) entered forwarding state
[   57.762688][ T5997] 8021q: adding VLAN 0 to HW filter on device bond0
[   57.773099][   T12] bridge0: port 1(bridge_slave_0) entered disabled state
[   57.781745][   T12] bridge0: port 2(bridge_slave_1) entered disabled state
[   57.793131][ T5997] 8021q: adding VLAN 0 to HW filter on device team0
[   57.801745][   T71] bridge0: port 1(bridge_slave_0) entered blocking state
[   57.808801][   T71] bridge0: port 1(bridge_slave_0) entered forwarding state
[   57.820075][   T12] bridge0: port 2(bridge_slave_1) entered blocking state
[   57.827262][   T12] bridge0: port 2(bridge_slave_1) entered forwarding state
[   57.882027][ T5997] 8021q: adding VLAN 0 to HW filter on device batadv0
[   57.900757][ T5997] veth0_vlan: entered promiscuous mode
[   57.908547][ T5997] veth1_vlan: entered promiscuous mode
[   57.921577][ T5997] veth0_macvtap: entered promiscuous mode
[   57.929031][ T5997] veth1_macvtap: entered promiscuous mode
[   57.939405][ T5997] batman_adv: batadv0: Interface activated: batadv_slave_0
[   57.949374][ T5997] batman_adv: batadv0: Interface activated: batadv_slave_1
[   57.959371][   T71] netdevsim netdevsim0 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
[   57.972648][   T71] netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[   57.985870][   T71] netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[   57.994669][   T71] netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
[   58.016091][   T71] wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   58.024009][   T71] 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)
[   58.041330][   T12] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   58.049530][   T12] 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-build1601059179=/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/ccwG8xGk.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:         983d014a kernel: modules: Add SPDX license identifier ..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=87bc41cae23d2144
dashboard link: https://syzkaller.appspot.com/bug?extid=3f2d46b6e62b8dd546d3
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=12c3e39a580000