Message-ID: <6953df19.050a0220.a1b6.02fc.GAE@google.com>
Date: Tue, 30 Dec 2025 06:18:01 -0800
From: syzbot <syzbot+05f9cecd28e356241aba@...kaller.appspotmail.com>
To: linux-kernel@...r.kernel.org, penguin-kernel@...ove.sakura.ne.jp, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [net?] INFO: task hung in new_device_store (5)

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 '10.128.10.21' (ED25519) to the list of known hosts.
1970/01/01 00:00:33 parsed 1 programs
[   34.595053][ T6574] cgroup: Unknown subsys name 'net'
[   34.745068][ T6574] cgroup: Unknown subsys name 'cpuset'
[   34.746978][ T6574] cgroup: Unknown subsys name 'rlimit'
Setting up swapspace version 1, size = 127995904 bytes
[   34.917455][ T6574] Adding 124996k swap on ./swap-file.  Priority:0 extents:1 across:124996k SS
[   42.237282][   T53] Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
[   42.239113][   T53] Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
[   42.240666][   T53] Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
[   42.242510][   T53] Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
[   42.244658][   T53] Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
[   42.318133][ T6589] 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.
[   42.330851][   T41] wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   42.330883][   T41] wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
[   42.358127][   T41] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   42.359482][   T41] wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
[   42.936079][ T6631] chnl_net:caif_netlink_parms(): no params data found
[   43.065956][ T6631] bridge0: port 1(bridge_slave_0) entered blocking state
[   43.067590][ T6631] bridge0: port 1(bridge_slave_0) entered disabled state
[   43.069087][ T6631] bridge_slave_0: entered allmulticast mode
[   43.070758][ T6631] bridge_slave_0: entered promiscuous mode
[   43.105741][ T6631] bridge0: port 2(bridge_slave_1) entered blocking state
[   43.107034][ T6631] bridge0: port 2(bridge_slave_1) entered disabled state
[   43.108357][ T6631] bridge_slave_1: entered allmulticast mode
[   43.109850][ T6631] bridge_slave_1: entered promiscuous mode
[   43.130851][ T6631] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link
[   43.138345][ T6631] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link
[   43.198443][ T6631] team0: Port device team_slave_0 added
[   43.200373][ T6631] team0: Port device team_slave_1 added
[   43.230111][ T6631] batman_adv: batadv0: Adding interface: batadv_slave_0
[   43.231292][ T6631] 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.
[   43.237324][ T6631] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active
[   43.255103][ T6631] batman_adv: batadv0: Adding interface: batadv_slave_1
[   43.259539][ T6631] 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.
[   43.264470][ T6631] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
[   43.307858][ T6631] hsr_slave_0: entered promiscuous mode
[   43.309501][ T6631] hsr_slave_1: entered promiscuous mode
[   43.528843][ T6631] netdevsim netdevsim3 netdevsim0: renamed from eth0
[   43.533089][ T6631] netdevsim netdevsim3 netdevsim1: renamed from eth1
[   43.538635][ T6631] netdevsim netdevsim3 netdevsim2: renamed from eth2
[   43.541207][ T6631] netdevsim netdevsim3 netdevsim3: renamed from eth3
[   43.567146][ T6631] 8021q: adding VLAN 0 to HW filter on device bond0
[   43.572525][ T6631] 8021q: adding VLAN 0 to HW filter on device team0
[   43.578588][ T5188] bridge0: port 1(bridge_slave_0) entered blocking state
[   43.578639][ T5188] bridge0: port 1(bridge_slave_0) entered forwarding state
[   43.581070][   T41] bridge0: port 2(bridge_slave_1) entered blocking state
[   43.581088][   T41] bridge0: port 2(bridge_slave_1) entered forwarding state
[   43.710104][ T6631] 8021q: adding VLAN 0 to HW filter on device batadv0
[   43.730903][ T6631] veth0_vlan: entered promiscuous mode
[   43.734344][ T6631] veth1_vlan: entered promiscuous mode
[   43.741716][ T6631] veth0_macvtap: entered promiscuous mode
[   43.744783][ T6631] veth1_macvtap: entered promiscuous mode
[   43.749309][ T6631] batman_adv: batadv0: Interface activated: batadv_slave_0
[   43.752345][ T6631] batman_adv: batadv0: Interface activated: batadv_slave_1
[   43.824087][  T825] netdevsim netdevsim3 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
[   43.883955][  T825] netdevsim netdevsim3 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[   43.885487][  T825] netdevsim netdevsim3 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[   43.903861][  T825] netdevsim netdevsim3 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
1970/01/01 00:00:43 executed programs: 0
[   43.991539][ T6162] Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
[   43.993239][ T6162] Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
[   43.995049][ T6162] Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
[   43.996597][ T6162] Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
[   43.998242][ T6162] Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
[   44.063365][ T6685] chnl_net:caif_netlink_parms(): no params data found
[   44.087212][ T6685] bridge0: port 1(bridge_slave_0) entered blocking state
[   44.087293][ T6685] bridge0: port 1(bridge_slave_0) entered disabled state
[   44.087344][ T6685] bridge_slave_0: entered allmulticast mode
[   44.087767][ T6685] bridge_slave_0: entered promiscuous mode
[   44.088930][ T6685] bridge0: port 2(bridge_slave_1) entered blocking state
[   44.088978][ T6685] bridge0: port 2(bridge_slave_1) entered disabled state
[   44.089023][ T6685] bridge_slave_1: entered allmulticast mode
[   44.089448][ T6685] bridge_slave_1: entered promiscuous mode
[   44.102408][ T6685] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link
[   44.103304][ T6685] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link
[   44.128118][ T6685] team0: Port device team_slave_0 added
[   44.129165][ T6685] team0: Port device team_slave_1 added
[   44.135876][ T6685] batman_adv: batadv0: Adding interface: batadv_slave_0
[   44.135901][ T6685] 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.
[   44.135918][ T6685] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active
[   44.136432][ T6685] batman_adv: batadv0: Adding interface: batadv_slave_1
[   44.136438][ T6685] 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.
[   44.136448][ T6685] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
[   44.159247][ T6685] hsr_slave_0: entered promiscuous mode
[   44.160734][ T6685] hsr_slave_1: entered promiscuous mode
[   44.162193][ T6685] debugfs: 'hsr0' already exists in 'hsr'
[   44.163441][ T6685] Cannot create hsr debugfs directory
[   44.204803][ T6685] netdevsim netdevsim0 netdevsim0: renamed from eth0
[   44.207252][ T6685] netdevsim netdevsim0 netdevsim1: renamed from eth1
[   44.209729][ T6685] netdevsim netdevsim0 netdevsim2: renamed from eth2
[   44.211719][ T6685] netdevsim netdevsim0 netdevsim3: renamed from eth3
[   44.220229][ T6685] bridge0: port 2(bridge_slave_1) entered blocking state
[   44.220269][ T6685] bridge0: port 2(bridge_slave_1) entered forwarding state
[   44.220414][ T6685] bridge0: port 1(bridge_slave_0) entered blocking state
[   44.220438][ T6685] bridge0: port 1(bridge_slave_0) entered forwarding state
[   44.233479][ T6685] 8021q: adding VLAN 0 to HW filter on device bond0
[   44.236569][ T5188] bridge0: port 1(bridge_slave_0) entered disabled state
[   44.237964][ T5188] bridge0: port 2(bridge_slave_1) entered disabled state
[   44.241410][ T6685] 8021q: adding VLAN 0 to HW filter on device team0
[   44.245743][ T2746] bridge0: port 1(bridge_slave_0) entered blocking state
[   44.245790][ T2746] bridge0: port 1(bridge_slave_0) entered forwarding state
[   44.248261][ T2746] bridge0: port 2(bridge_slave_1) entered blocking state
[   44.248276][ T2746] bridge0: port 2(bridge_slave_1) entered forwarding state
[   44.299372][ T6685] 8021q: adding VLAN 0 to HW filter on device batadv0
[   44.309235][ T6685] veth0_vlan: entered promiscuous mode
[   44.311035][ T6685] veth1_vlan: entered promiscuous mode
[   44.319349][ T6685] veth0_macvtap: entered promiscuous mode
[   44.320292][ T6685] veth1_macvtap: entered promiscuous mode
[   44.323850][ T6685] batman_adv: batadv0: Interface activated: batadv_slave_0
[   44.325162][ T6685] batman_adv: batadv0: Interface activated: batadv_slave_1
[   44.327601][ T2746] netdevsim netdevsim0 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
[   44.327691][ T2746] netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[   44.327709][ T2746] netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[   44.327725][ T2746] netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
[   44.352754][  T825] wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   44.352779][  T825] wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
[   44.365715][  T825] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   44.365742][  T825] wlan1: 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)


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-build1018672540=/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=arm64 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_arm64/syz-execprog github.com/google/syzkaller/tools/syz-execprog
mkdir -p ./bin/linux_arm64
aarch64-linux-gnu-g++ -o ./bin/linux_arm64/syz-executor executor/executor.cc \
	-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_arm64=1 \
	-DHOSTGOOS_linux=1 -DGIT_REVISION=\"d6526ea3e6ad9081c902859bbb80f9f840377cb4\"
/usr/lib/gcc-cross/aarch64-linux-gnu/12/../../../../aarch64-linux-gnu/bin/ld: /tmp/ccCZ6pDV.o: in function `Connection::Connect(char const*, char const*)':
executor.cc:(.text._ZN10Connection7ConnectEPKcS1_[_ZN10Connection7ConnectEPKcS1_]+0xd8): 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:         8640b745 Merge tag 'kbuild-fixes-6.19-1' of git://git...
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=8a8594efdc14f07a
dashboard link: https://syzkaller.appspot.com/bug?extid=05f9cecd28e356241aba
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
userspace arch: arm64
patch:          https://syzkaller.appspot.com/x/patch.diff?x=11ed749a580000

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