Re: [syzbot] [mm?] [cgroups?] kernel BUG in swap_cgroup_record (2)

[syzbot <syzbot+d97580a8cceb9b03c13e@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


Warning: Permanently added '10.128.1.115' (ED25519) to the list of known hosts.
2026/01/12 17:22:39 parsed 1 programs
[   82.355124][ T5825] cgroup: Unknown subsys name 'net'
[   82.462751][ T5825] cgroup: Unknown subsys name 'cpuset'
[   82.472202][ T5825] cgroup: Unknown subsys name 'rlimit'
Setting up swapspace version 1, size = 127995904 bytes
[   83.906410][ T5825] Adding 124996k swap on ./swap-file.  Priority:0 extents:1 across:124996k 
[   86.975545][ T5843] 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.
[   87.202360][  T981] cfg80211: failed to load regulatory.db
[   87.362862][ T5143] Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
[   87.373407][ T5143] Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
[   87.381143][ T5143] Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
[   87.390171][ T5143] Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
[   87.439616][ T5143] Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
[   88.365680][   T67] wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   88.399392][   T67] wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
[   88.589212][   T67] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   88.597071][   T67] wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
[   89.835852][ T5889] chnl_net:caif_netlink_parms(): no params data found
[   90.228347][ T5889] bridge0: port 1(bridge_slave_0) entered blocking state
[   90.239581][ T5889] bridge0: port 1(bridge_slave_0) entered disabled state
[   90.246917][ T5889] bridge_slave_0: entered allmulticast mode
[   90.256371][ T5889] bridge_slave_0: entered promiscuous mode
[   90.265733][ T5889] bridge0: port 2(bridge_slave_1) entered blocking state
[   90.273158][ T5889] bridge0: port 2(bridge_slave_1) entered disabled state
[   90.281856][ T5889] bridge_slave_1: entered allmulticast mode
[   90.290137][ T5889] bridge_slave_1: entered promiscuous mode
[   90.413855][ T5889] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link
[   90.425935][ T5889] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link
[   90.501838][ T5889] team0: Port device team_slave_0 added
[   90.510759][ T5889] team0: Port device team_slave_1 added
[   90.555934][ T5889] batman_adv: batadv0: Adding interface: batadv_slave_0
[   90.564110][ T5889] 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.
[   90.590902][ T5889] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active
[   90.616343][ T5889] batman_adv: batadv0: Adding interface: batadv_slave_1
[   90.623556][ T5889] 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.
[   90.649772][ T5889] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
[   90.705764][ T5889] hsr_slave_0: entered promiscuous mode
[   90.713531][ T5889] hsr_slave_1: entered promiscuous mode
[   90.916005][ T5889] netdevsim netdevsim3 netdevsim0: renamed from eth0
[   90.929511][ T5889] netdevsim netdevsim3 netdevsim1: renamed from eth1
[   90.941154][ T5889] netdevsim netdevsim3 netdevsim2: renamed from eth2
[   90.952423][ T5889] netdevsim netdevsim3 netdevsim3: renamed from eth3
[   91.033645][ T5889] 8021q: adding VLAN 0 to HW filter on device bond0
[   91.060124][ T5889] 8021q: adding VLAN 0 to HW filter on device team0
[   91.074550][ T3448] bridge0: port 1(bridge_slave_0) entered blocking state
[   91.081980][ T3448] bridge0: port 1(bridge_slave_0) entered forwarding state
[   91.101431][  T146] bridge0: port 2(bridge_slave_1) entered blocking state
[   91.108582][  T146] bridge0: port 2(bridge_slave_1) entered forwarding state
[   91.283990][ T5889] 8021q: adding VLAN 0 to HW filter on device batadv0
[   91.326572][ T5889] veth0_vlan: entered promiscuous mode
[   91.339642][ T5889] veth1_vlan: entered promiscuous mode
[   91.372247][ T5889] veth0_macvtap: entered promiscuous mode
[   91.382836][ T5889] veth1_macvtap: entered promiscuous mode
[   91.403819][ T5889] batman_adv: batadv0: Interface activated: batadv_slave_0
[   91.419341][ T5889] batman_adv: batadv0: Interface activated: batadv_slave_1
[   91.435991][  T146] netdevsim netdevsim3 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
[   91.447488][  T146] netdevsim netdevsim3 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[   91.458151][  T146] netdevsim netdevsim3 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[   91.468162][  T146] netdevsim netdevsim3 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
2026/01/12 17:22:51 executed programs: 0
[   91.617871][   T51] Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
[   91.627315][   T51] Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
[   91.636293][   T51] Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
[   91.650415][   T51] Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
[   91.658087][   T51] Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
[   91.867766][ T5933] chnl_net:caif_netlink_parms(): no params data found
[   91.947831][ T5933] bridge0: port 1(bridge_slave_0) entered blocking state
[   91.955090][ T5933] bridge0: port 1(bridge_slave_0) entered disabled state
[   91.962571][ T5933] bridge_slave_0: entered allmulticast mode
[   91.970169][ T5933] bridge_slave_0: entered promiscuous mode
[   91.981276][ T5933] bridge0: port 2(bridge_slave_1) entered blocking state
[   91.988502][ T5933] bridge0: port 2(bridge_slave_1) entered disabled state
[   91.996341][ T5933] bridge_slave_1: entered allmulticast mode
[   92.004890][ T5933] bridge_slave_1: entered promiscuous mode
[   92.040822][ T5933] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link
[   92.052807][ T5933] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link
[   92.087150][ T5933] team0: Port device team_slave_0 added
[   92.096317][ T5933] team0: Port device team_slave_1 added
[   92.125800][ T5933] batman_adv: batadv0: Adding interface: batadv_slave_0
[   92.132843][ T5933] 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.
[   92.160391][ T5933] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active
[   92.175276][ T5933] batman_adv: batadv0: Adding interface: batadv_slave_1
[   92.182369][ T5933] 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.
[   92.208618][ T5933] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
[   92.262268][ T5933] hsr_slave_0: entered promiscuous mode
[   92.268793][ T5933] hsr_slave_1: entered promiscuous mode
[   92.275370][ T5933] debugfs: 'hsr0' already exists in 'hsr'
[   92.281260][ T5933] Cannot create hsr debugfs directory
[   92.454270][ T5933] netdevsim netdevsim0 netdevsim0: renamed from eth0
[   92.464921][ T5933] netdevsim netdevsim0 netdevsim1: renamed from eth1
[   92.476743][ T5933] netdevsim netdevsim0 netdevsim2: renamed from eth2
[   92.487822][ T5933] netdevsim netdevsim0 netdevsim3: renamed from eth3
[   92.521997][ T5933] bridge0: port 2(bridge_slave_1) entered blocking state
[   92.529373][ T5933] bridge0: port 2(bridge_slave_1) entered forwarding state
[   92.537501][ T5933] bridge0: port 1(bridge_slave_0) entered blocking state
[   92.545011][ T5933] bridge0: port 1(bridge_slave_0) entered forwarding state
[   92.611103][ T5933] 8021q: adding VLAN 0 to HW filter on device bond0
[   92.628121][   T12] bridge0: port 1(bridge_slave_0) entered disabled state
[   92.638874][   T12] bridge0: port 2(bridge_slave_1) entered disabled state
[   92.655069][ T5933] 8021q: adding VLAN 0 to HW filter on device team0
[   92.670870][ T3448] bridge0: port 1(bridge_slave_0) entered blocking state
[   92.678028][ T3448] bridge0: port 1(bridge_slave_0) entered forwarding state
[   92.692502][   T12] bridge0: port 2(bridge_slave_1) entered blocking state
[   92.699727][   T12] bridge0: port 2(bridge_slave_1) entered forwarding state
[   92.881583][ T5933] 8021q: adding VLAN 0 to HW filter on device batadv0
[   92.922279][ T5933] veth0_vlan: entered promiscuous mode
[   92.936672][ T5933] veth1_vlan: entered promiscuous mode
[   92.971137][ T5933] veth0_macvtap: entered promiscuous mode
[   92.981189][ T5933] veth1_macvtap: entered promiscuous mode
[   93.001283][ T5933] batman_adv: batadv0: Interface activated: batadv_slave_0
[   93.017932][ T5933] batman_adv: batadv0: Interface activated: batadv_slave_1
[   93.036848][ T3013] netdevsim netdevsim0 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
[   93.047100][ T3013] netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[   93.057457][ T3013] netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[   93.066673][ T3013] netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
[   93.136251][   T67] wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   93.144412][   T67] wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
[   93.184930][   T12] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   93.193952][   T12] wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
SYZFAIL: failed to recv rpc
[   93.751896][   T12] netdevsim netdevsim3 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-build2122481591=/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/ccWbF51D.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:         f417b7ff Add linux-next specific files for 20260109
git tree:       linux-next
kernel config:  https://syzkaller.appspot.com/x/.config?x=63a1fc1b4011ac76
dashboard link: https://syzkaller.appspot.com/bug?extid=d97580a8cceb9b03c13e
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=13ab299a580000