Re: [syzbot] [media?] KASAN: slab-use-after-free Read in __dynamic_dev_dbg

[syzbot <syzbot+9bfac891bdd42eb708fc@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)
execution of simple program fails: NOTFAIL: arptable checkpoint: getsockopt(ARPT_SO_GET_ENTRIES) failed. table=filter (errno 22: Invalid argument).


Warning: Permanently added '[localhost]:54685' (ED25519) to the list of known hosts.
2026/09/18 05:30:02 parsed 1 programs
2026/09/18 05:30:02 serving rpc on tcp://32951
[   47.745155][ T5743] cgroup: Unknown subsys name 'net'
[   47.852384][ T5743] cgroup: Unknown subsys name 'cpuset'
[   47.856459][ T5743] cgroup: Unknown subsys name 'rlimit'
Setting up swapspace version 1, size = 127995904 bytes
[   48.886846][ T5743] Adding 124996k swap on ./swap-file.  Priority:0 extents:1 across:124996k 
[   51.358683][ T5755] soft_limit_in_bytes is deprecated and will be removed. Writing any value to this file has no effect. Please report your usecase to linux-mm@kvack.org if you depend on this functionality.
[   51.365586][ T5755] ebtables: xtables 32bit compat interface no longer supported in namespaces and will be removed soon.
[   51.375529][ T5755] arp_tables: xtables 32bit compat interface no longer supported in namespaces and will be removed soon.
[   51.379024][   T37] wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   51.379041][   T37] wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
[   51.518286][  T228] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   51.518311][  T228] wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
[   52.518770][   T66] Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
[   52.526974][   T66] Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
[   52.535189][   T66] Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
[   52.539813][   T66] Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
[   52.540335][   T66] Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
[   52.541643][ T5769] bridge0: port 1(bridge_slave_0) entered blocking state
[   52.542691][ T5769] bridge0: port 1(bridge_slave_0) entered disabled state
[   52.542775][ T5769] bridge_slave_0: entered allmulticast mode
[   52.545963][ T5769] bridge_slave_0: entered promiscuous mode
[   52.558325][ T5769] bridge0: port 2(bridge_slave_1) entered blocking state
[   52.558372][ T5769] bridge0: port 2(bridge_slave_1) entered disabled state
[   52.558428][ T5769] bridge_slave_1: entered allmulticast mode
[   52.560598][ T5769] bridge_slave_1: entered promiscuous mode
[   52.584378][ T5769] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link
[   52.611029][ T5769] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link
[   52.648950][ T5769] team0: Port device team_slave_0 added
[   52.660980][ T5769] team0: Port device team_slave_1 added
[   52.719483][ T5769] batman_adv: batadv0: Adding interface: batadv_slave_0
[   52.719500][ T5769] 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.
[   52.719521][ T5769] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active
[   52.737518][ T5769] batman_adv: batadv0: Adding interface: batadv_slave_1
[   52.737533][ T5769] 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.
[   52.737551][ T5769] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
[   52.909782][ T5809] ip_tables: xtables 32bit compat interface no longer supported in namespaces and will be removed soon.
[   52.910132][ T5809] ip6_tables: xtables 32bit compat interface no longer supported in namespaces and will be removed soon.
[   52.936259][ T5769] hsr_slave_0: entered promiscuous mode
[   52.942371][ T5769] hsr_slave_1: entered promiscuous mode
[   53.428872][ T5769] netdevsim netdevsim4 netdevsim0: renamed from eth0
[   53.436610][ T5769] 8021q: adding VLAN 0 to HW filter on device netdevsim0
[   53.437232][ T5769] netdevsim netdevsim4 netdevsim1: renamed from eth1
[   53.441662][ T5769] 8021q: adding VLAN 0 to HW filter on device netdevsim1
[   53.442889][ T5769] netdevsim netdevsim4 netdevsim2: renamed from eth2
[   53.457545][ T5769] 8021q: adding VLAN 0 to HW filter on device netdevsim2
[   53.468017][ T5769] netdevsim netdevsim4 netdevsim3: renamed from eth3
[   53.472353][ T5769] 8021q: adding VLAN 0 to HW filter on device netdevsim3
[   53.554786][ T5769] 8021q: adding VLAN 0 to HW filter on device bond0
[   53.574890][ T5769] 8021q: adding VLAN 0 to HW filter on device team0
[   53.583923][   T37] bridge0: port 1(bridge_slave_0) entered blocking state
[   53.584039][   T37] bridge0: port 1(bridge_slave_0) entered forwarding state
[   53.592421][   T37] bridge0: port 2(bridge_slave_1) entered blocking state
[   53.592552][   T37] bridge0: port 2(bridge_slave_1) entered forwarding state
[   53.917390][ T5769] 8021q: adding VLAN 0 to HW filter on device batadv0
[   54.072213][ T5769] veth0_vlan: entered promiscuous mode
[   54.077626][ T5769] veth1_vlan: entered promiscuous mode
[   54.092533][ T5769] veth0_macvtap: entered promiscuous mode
[   54.094902][ T5769] veth1_macvtap: entered promiscuous mode
[   54.106231][ T5769] batman_adv: batadv0: Interface activated: batadv_slave_0
[   54.111897][ T5769] batman_adv: batadv0: Interface activated: batadv_slave_1
[   54.141095][   T12] netdevsim netdevsim4 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
[   54.141137][   T12] netdevsim netdevsim4 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[   54.141165][   T12] netdevsim netdevsim4 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[   54.141194][   T12] netdevsim netdevsim4 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
[   54.184771][   T12] netdevsim netdevsim4 netdevsim3 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
SYZFAIL: failed to recv rpc
fd=3 want=4 recv=0 n=0 (errno 9: Bad file descriptor)
execution of simple program fails: NOTFAIL: arptable checkpoint: getsockopt(ARPT_SO_GET_ENTRIES) failed. table=filter (errno 22: Invalid argument).
[   54.261521][   T12] netdevsim netdevsim4 netdevsim2 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[   54.340989][   T12] netdevsim netdevsim4 netdevsim1 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[   54.428677][   T12] netdevsim netdevsim4 netdevsim0 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[   55.676684][   T12] bridge_slave_1: left allmulticast mode
[   55.676720][   T12] bridge_slave_1: left promiscuous mode
[   55.679098][   T12] bridge0: port 2(bridge_slave_1) entered disabled state
[   55.685646][   T12] bridge_slave_0: left allmulticast mode
[   55.685669][   T12] bridge_slave_0: left promiscuous mode
[   55.685832][   T12] bridge0: port 1(bridge_slave_0) entered disabled state
[   55.793840][   T12] bond0 (unregistering): (slave bond_slave_0): Releasing backup interface
[   55.796673][   T12] bond0 (unregistering): (slave bond_slave_1): Releasing backup interface
[   55.798080][   T12] bond0 (unregistering): Released all slaves
[   55.875181][ T5450] 8021q: adding VLAN 0 to HW filter on device eth2
[   55.907074][   T12] hsr_slave_0: left promiscuous mode
[   55.907494][   T12] hsr_slave_1: left promiscuous mode
[   55.907913][   T12] batman_adv: batadv0: Interface deactivated: batadv_slave_0
[   55.907928][   T12] batman_adv: batadv0: Removing interface: batadv_slave_0
[   55.908530][   T12] batman_adv: batadv0: Interface deactivated: batadv_slave_1
[   55.908540][   T12] batman_adv: batadv0: Removing interface: batadv_slave_1
[   55.917255][   T12] veth1_macvtap: left promiscuous mode
[   55.917296][   T12] veth0_macvtap: left promiscuous mode
[   55.917345][   T12] veth1_vlan: left promiscuous mode
[   55.917401][   T12] veth0_vlan: left promiscuous mode
[   56.037674][   T12] team0 (unregistering): Port device team_slave_1 removed
[   56.054457][   T12] team0 (unregistering): Port device team_slave_0 removed
[   56.103005][ T5450] 8021q: adding VLAN 0 to HW filter on device eth3
[   56.289426][ T5450] 8021q: adding VLAN 0 to HW filter on device eth4
[   56.450317][ T5450] 8021q: adding VLAN 0 to HW filter on device eth5


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-build3502523694=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/syzkaller/jobs/linux/gopath/src/github.com/google/syzkaller/go.mod'
GOMODCACHE='/syzkaller/jobs/linux/gopath/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/syzkaller/jobs/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='go1.26.0'
GOWORK=''
PKG_CONFIG='pkg-config'

git status (err=<nil>)
HEAD detached at f41e228a2e7
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=f41e228a2e7b883d75a56aa602070c9893ccb54c -X github.com/google/syzkaller/prog.gitRevisionDate=20260915-092900"  ./sys/syz-sysgen | grep -q false || go install -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=f41e228a2e7b883d75a56aa602070c9893ccb54c -X github.com/google/syzkaller/prog.gitRevisionDate=20260915-092900"  ./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=f41e228a2e7b883d75a56aa602070c9893ccb54c -X github.com/google/syzkaller/prog.gitRevisionDate=20260915-092900"  -o ./bin/linux_amd64/syz-execprog github.com/google/syzkaller/tools/syz-execprog
mkdir -p ./bin/linux_386
x86_64-linux-gnu-g++ -o ./bin/linux_386/syz-executor executor/executor.cc \
	-m32 -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_386=1 \
	-DHOSTGOOS_linux=1 -DGIT_REVISION=\"f41e228a2e7b883d75a56aa602070c9893ccb54c\"
/usr/bin/ld: /tmp/ccyeqg4J.o: in function `Connection::Connect(char const*, char const*)':
executor.cc:(.text._ZN10Connection7ConnectEPKcS1_[_ZN10Connection7ConnectEPKcS1_]+0x145): 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
[INFO] Unsupported architecture '386', skipping check.



Tested on:

commit:         5dd1818b Merge tag 'for-next-keys-v7.3-rc4' of git://g..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=d61c584072d6137
dashboard link: https://syzkaller.appspot.com/bug?extid=9bfac891bdd42eb708fc
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
userspace arch: i386
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1741b8c9580000