Re: [syzbot] [input?] [usb?] KASAN: slab-use-after-free Read in report_descriptor_read

[syzbot]

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 '10.128.0.41' (ED25519) to the list of known hosts.
2026/10/09 09:34:35 parsed 1 programs
2026/10/09 09:34:35 serving rpc on tcp://43817
[  102.876825][  T925] cfg80211: failed to load regulatory.db
[  106.327252][ T5632] cgroup: Unknown subsys name 'net'
[  106.439832][ T5632] cgroup: Unknown subsys name 'cpuset'
[  106.443439][ T5632] cgroup: Unknown subsys name 'rlimit'
Setting up swapspace version 1, size = 127995904 bytes
[  108.162061][ T5632] Adding 124996k swap on ./swap-file.  Priority:0 extents:1 across:124996k 
[  111.819814][ T5652] 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@xxxxxxxxx if you depend on this functionality.
[  111.895801][ T5652] ebtables: xtables 32bit compat interface no longer supported in namespaces and will be removed soon.
[  111.896346][ T5652] arp_tables: xtables 32bit compat interface no longer supported in namespaces and will be removed soon.
[  111.896898][ T5652] ip_tables: xtables 32bit compat interface no longer supported in namespaces and will be removed soon.
[  111.902540][ T5652] ip6_tables: xtables 32bit compat interface no longer supported in namespaces and will be removed soon.
[  114.332029][   T52] Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
[  114.341885][   T52] Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
[  114.343656][   T52] Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
[  114.361467][   T52] Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
[  114.362876][   T52] Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
[  115.050524][ T5660] bridge0: port 1(bridge_slave_0) entered blocking state
[  115.050711][ T5660] bridge0: port 1(bridge_slave_0) entered disabled state
[  115.050850][ T5660] bridge_slave_0: entered allmulticast mode
[  115.052750][ T5660] bridge_slave_0: entered promiscuous mode
[  115.066100][ T5660] bridge0: port 2(bridge_slave_1) entered blocking state
[  115.066473][ T5660] bridge0: port 2(bridge_slave_1) entered disabled state
[  115.067077][ T5660] bridge_slave_1: entered allmulticast mode
[  115.073434][ T5660] bridge_slave_1: entered promiscuous mode
[  115.203238][ T5660] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link
[  115.237612][ T5660] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link
[  115.351254][ T5660] team0: Port device team_slave_0 added
[  115.367447][ T3373] wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[  115.367473][ T3373] wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
[  115.367963][ T5660] team0: Port device team_slave_1 added
[  115.589878][ T5660] batman_adv: batadv0: Adding interface: batadv_slave_0
[  115.589899][ T5660] 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.
[  115.589927][ T5660] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active
[  115.680889][ T5660] batman_adv: batadv0: Adding interface: batadv_slave_1
[  115.680911][ T5660] 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.
[  115.680940][ T5660] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
[  115.793147][   T38] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[  115.793171][   T38] wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
[  115.967068][ T5660] hsr_slave_0: entered promiscuous mode
[  115.969950][ T5660] hsr_slave_1: entered promiscuous mode
[  116.396134][   T52] Bluetooth: hci0: command tx timeout
[  116.512868][ T5660] netdevsim netdevsim3 netdevsim0: renamed from eth0
[  116.529158][ T5660] 8021q: adding VLAN 0 to HW filter on device netdevsim0
[  116.530373][ T5660] netdevsim netdevsim3 netdevsim1: renamed from eth1
[  116.539523][ T5660] 8021q: adding VLAN 0 to HW filter on device netdevsim1
[  116.550138][ T5660] netdevsim netdevsim3 netdevsim2: renamed from eth2
[  116.566932][ T5660] 8021q: adding VLAN 0 to HW filter on device netdevsim2
[  116.567879][ T5660] netdevsim netdevsim3 netdevsim3: renamed from eth3
[  116.571472][ T5660] 8021q: adding VLAN 0 to HW filter on device netdevsim3
[  116.680185][ T5660] 8021q: adding VLAN 0 to HW filter on device bond0
[  116.709742][ T5660] 8021q: adding VLAN 0 to HW filter on device team0
[  116.726696][   T13] bridge0: port 1(bridge_slave_0) entered blocking state
[  116.726857][   T13] bridge0: port 1(bridge_slave_0) entered forwarding state
[  116.753165][   T13] bridge0: port 2(bridge_slave_1) entered blocking state
[  116.753330][   T13] bridge0: port 2(bridge_slave_1) entered forwarding state
[  116.868524][ T5660] 8021q: adding VLAN 0 to HW filter on device batadv0
[  116.940028][ T5660] veth0_vlan: entered promiscuous mode
[  116.952983][ T5660] veth1_vlan: entered promiscuous mode
[  116.991256][ T5660] veth0_macvtap: entered promiscuous mode
[  117.005351][ T5660] veth1_macvtap: entered promiscuous mode
[  117.032181][ T5660] batman_adv: batadv0: Interface activated: batadv_slave_0
[  117.050081][ T5660] batman_adv: batadv0: Interface activated: batadv_slave_1
[  117.124391][   T59] netdevsim netdevsim3 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
[  117.125110][   T59] netdevsim netdevsim3 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[  117.125403][   T59] netdevsim netdevsim3 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[  117.125442][   T59] netdevsim netdevsim3 netdevsim0: set [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).
[  117.799185][   T13] netdevsim netdevsim3 netdevsim3 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[  119.087949][   T13] netdevsim netdevsim3 netdevsim2 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[  120.448211][   T13] netdevsim netdevsim3 netdevsim1 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[  120.500961][   T13] netdevsim netdevsim3 netdevsim0 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[  120.612426][   T13] bridge_slave_1: left allmulticast mode
[  120.612473][   T13] bridge_slave_1: left promiscuous mode
[  120.613994][   T13] bridge0: port 2(bridge_slave_1) entered disabled state
[  120.642935][   T13] bridge_slave_0: left allmulticast mode
[  120.642959][   T13] bridge_slave_0: left promiscuous mode
[  120.643537][   T13] bridge0: port 1(bridge_slave_0) entered disabled state
[  120.800837][   T13] bond0 (unregistering): (slave bond_slave_0): Releasing backup interface
[  120.803647][   T13] bond0 (unregistering): (slave bond_slave_1): Releasing backup interface
[  120.829743][   T13] bond0 (unregistering): Released all slaves
[  121.362267][   T13] hsr_slave_0: left promiscuous mode
[  121.363205][   T13] hsr_slave_1: left promiscuous mode
[  121.364924][   T13] batman_adv: batadv0: Interface deactivated: batadv_slave_0
[  121.365067][   T13] batman_adv: batadv0: Removing interface: batadv_slave_0
[  121.387394][   T13] batman_adv: batadv0: Interface deactivated: batadv_slave_1
[  121.387417][   T13] batman_adv: batadv0: Removing interface: batadv_slave_1
[  121.420376][   T13] veth1_macvtap: left promiscuous mode
[  121.420458][   T13] veth0_macvtap: left promiscuous mode
[  121.420618][   T13] veth1_vlan: left promiscuous mode
[  121.421002][   T13] veth0_vlan: left promiscuous mode
[  121.712487][   T13] team0 (unregistering): Port device team_slave_1 removed
[  121.730041][   T13] team0 (unregistering): Port device team_slave_0 removed
[  121.880288][ T5281] 8021q: adding VLAN 0 to HW filter on device eth1
[  122.378773][ T5281] 8021q: adding VLAN 0 to HW filter on device eth2
[  122.808975][ T5281] 8021q: adding VLAN 0 to HW filter on device eth3
[  123.211497][ T5281] 8021q: adding VLAN 0 to HW filter on device eth4


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-build95449590=/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 1e72964b0
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=1e72964b0111319984575e60f266d1fa0a98abb5 -X github.com/google/syzkaller/prog.gitRevisionDate=20260817-123423"  ./sys/syz-sysgen | grep -q false || go install -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=1e72964b0111319984575e60f266d1fa0a98abb5 -X github.com/google/syzkaller/prog.gitRevisionDate=20260817-123423"  ./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=1e72964b0111319984575e60f266d1fa0a98abb5 -X github.com/google/syzkaller/prog.gitRevisionDate=20260817-123423"  -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=\"1e72964b0111319984575e60f266d1fa0a98abb5\"
/usr/bin/ld: /tmp/cc4sYuge.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:         af32da41 Merge tag 'net-7.3-rc7' of git://git.kernel.o..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=e54cfa0d265a296a
dashboard link: https://syzkaller.appspot.com/bug?extid=bc537ca7a0efe33988eb
compiler:       Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
userspace arch: i386
patch:          https://syzkaller.appspot.com/x/patch.diff?x=108bb9d1580000