Re: [syzbot] [gfs2?] KASAN: slab-use-after-free Write in gfs2_qd_dealloc (3)

[syzbot <syzbot+42a37bf8045847d8f9d2@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 '10.128.1.172' (ED25519) to the list of known hosts.
2026/04/30 12:49:26 parsed 1 programs
[   78.581168][ T5617] cgroup: Unknown subsys name 'net'
[   78.678493][ T5617] cgroup: Unknown subsys name 'cpuset'
[   78.687690][ T5617] cgroup: Unknown subsys name 'rlimit'
Setting up swapspace version 1, size = 127995904 bytes
[   80.032556][ T5617] Adding 124996k swap on ./swap-file.  Priority:0 extents:1 across:124996k 
[   82.943242][ T5630] 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.
[   83.062281][   T50] Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
[   83.076191][   T50] Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
[   83.085325][   T50] Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
[   83.094576][   T50] Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
[   83.104084][   T50] Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
[   84.199482][ T5654] bridge0: port 1(bridge_slave_0) entered blocking state
[   84.207733][ T5654] bridge0: port 1(bridge_slave_0) entered disabled state
[   84.216747][ T5654] bridge_slave_0: entered allmulticast mode
[   84.223809][ T5654] bridge_slave_0: entered promiscuous mode
[   84.233002][ T5654] bridge0: port 2(bridge_slave_1) entered blocking state
[   84.240220][ T5654] bridge0: port 2(bridge_slave_1) entered disabled state
[   84.247416][ T5654] bridge_slave_1: entered allmulticast mode
[   84.254439][ T5654] bridge_slave_1: entered promiscuous mode
[   84.282622][ T5654] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link
[   84.294237][ T5654] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link
[   84.323883][ T5654] team0: Port device team_slave_0 added
[   84.332696][ T5654] team0: Port device team_slave_1 added
[   84.359292][ T5654] batman_adv: batadv0: Adding interface: batadv_slave_0
[   84.366295][ T5654] 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.
[   84.392330][ T5654] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active
[   84.404754][ T5654] batman_adv: batadv0: Adding interface: batadv_slave_1
[   84.411770][ T5654] 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.
[   84.438023][ T5654] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
[   84.478401][ T5654] hsr_slave_0: entered promiscuous mode
[   84.484735][ T5654] hsr_slave_1: entered promiscuous mode
[   84.608498][ T5654] netdevsim netdevsim0 netdevsim0: renamed from eth0
[   84.620785][ T5654] 8021q: adding VLAN 0 to HW filter on device netdevsim0
[   84.628610][ T5654] netdevsim netdevsim0 netdevsim1: renamed from eth1
[   84.639884][ T5654] 8021q: adding VLAN 0 to HW filter on device netdevsim1
[   84.647927][ T5654] netdevsim netdevsim0 netdevsim2: renamed from eth2
[   84.659025][ T5654] 8021q: adding VLAN 0 to HW filter on device netdevsim2
[   84.666877][ T5654] netdevsim netdevsim0 netdevsim3: renamed from eth3
[   84.678430][ T5654] 8021q: adding VLAN 0 to HW filter on device netdevsim3
[   84.708761][ T5654] bridge0: port 2(bridge_slave_1) entered blocking state
[   84.716402][ T5654] bridge0: port 2(bridge_slave_1) entered forwarding state
[   84.724347][ T5654] bridge0: port 1(bridge_slave_0) entered blocking state
[   84.731895][ T5654] bridge0: port 1(bridge_slave_0) entered forwarding state
[   84.784036][ T5654] 8021q: adding VLAN 0 to HW filter on device bond0
[   84.804490][   T58] bridge0: port 1(bridge_slave_0) entered disabled state
[   84.813934][   T58] bridge0: port 2(bridge_slave_1) entered disabled state
[   84.831679][ T5654] 8021q: adding VLAN 0 to HW filter on device team0
[   84.844859][  T519] bridge0: port 1(bridge_slave_0) entered blocking state
[   84.852286][  T519] bridge0: port 1(bridge_slave_0) entered forwarding state
[   84.866396][   T79] bridge0: port 2(bridge_slave_1) entered blocking state
[   84.873572][   T79] bridge0: port 2(bridge_slave_1) entered forwarding state
[   85.154771][ T5654] 8021q: adding VLAN 0 to HW filter on device batadv0
[   85.198499][ T5654] veth0_vlan: entered promiscuous mode
[   85.210385][ T5654] veth1_vlan: entered promiscuous mode
[   85.244602][ T5654] veth0_macvtap: entered promiscuous mode
[   85.254209][ T5654] veth1_macvtap: entered promiscuous mode
[   85.273388][ T5654] batman_adv: batadv0: Interface activated: batadv_slave_0
[   85.287887][ T5654] batman_adv: batadv0: Interface activated: batadv_slave_1
[   85.303085][  T519] netdevsim netdevsim0 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
[   85.313495][  T519] netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[   85.324141][  T519] netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[   85.334774][  T519] netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
[   85.490249][   T79] netdevsim netdevsim0 netdevsim3 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[   85.573851][   T79] netdevsim netdevsim0 netdevsim2 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[   85.676103][   T79] netdevsim netdevsim0 netdevsim1 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[   85.771539][   T79] netdevsim netdevsim0 netdevsim0 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
[   86.835963][   T10] cfg80211: failed to load regulatory.db
[   87.316370][ T3344] wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   87.324743][ T3344] wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
[   87.350286][   T58] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   87.359386][   T58] wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
[   87.851968][   T79] bridge_slave_1: left allmulticast mode
[   87.865300][   T79] bridge_slave_1: left promiscuous mode
[   87.886744][   T79] bridge0: port 2(bridge_slave_1) entered disabled state
[   87.900702][   T79] bridge_slave_0: left allmulticast mode
[   87.908697][   T79] bridge_slave_0: left promiscuous mode
[   87.915377][   T79] bridge0: port 1(bridge_slave_0) entered disabled state
2026/04/30 12:49:38 executed programs: 0
[   88.103597][ T4938] Bluetooth: hci0: unexpected cc 0x0c03 length: 249 > 1
[   88.114089][ T4938] Bluetooth: hci0: unexpected cc 0x1003 length: 249 > 9
[   88.122041][ T4938] Bluetooth: hci0: unexpected cc 0x1001 length: 249 > 9
[   88.130307][ T4938] Bluetooth: hci0: unexpected cc 0x0c23 length: 249 > 4
[   88.139480][ T4938] Bluetooth: hci0: unexpected cc 0x0c38 length: 249 > 2
[   88.153169][   T79] bond0 (unregistering): (slave bond_slave_0): Releasing backup interface
[   88.167922][   T79] bond0 (unregistering): (slave bond_slave_1): Releasing backup interface
[   88.178737][   T79] bond0 (unregistering): Released all slaves
[   88.321105][   T79] hsr_slave_0: left promiscuous mode
[   88.338092][   T79] hsr_slave_1: left promiscuous mode
[   88.355972][   T79] batman_adv: batadv0: Interface deactivated: batadv_slave_0
[   88.375542][   T79] batman_adv: batadv0: Removing interface: batadv_slave_0
[   88.393217][   T79] batman_adv: batadv0: Interface deactivated: batadv_slave_1
[   88.401729][   T79] batman_adv: batadv0: Removing interface: batadv_slave_1
[   88.424969][   T79] veth1_macvtap: left promiscuous mode
[   88.431510][   T79] veth0_macvtap: left promiscuous mode
[   88.437686][   T79] veth1_vlan: left promiscuous mode
[   88.443055][   T79] veth0_vlan: left promiscuous mode
[   88.712941][   T79] team0 (unregistering): Port device team_slave_1 removed
[   88.734406][   T79] team0 (unregistering): Port device team_slave_0 removed
[   88.823217][ T5283] 8021q: adding VLAN 0 to HW filter on device eth1
[   89.417167][ T5283] 8021q: adding VLAN 0 to HW filter on device eth2
[   89.784159][ T5744] bridge0: port 1(bridge_slave_0) entered blocking state
[   89.792012][ T5744] bridge0: port 1(bridge_slave_0) entered disabled state
[   89.799424][ T5744] bridge_slave_0: entered allmulticast mode
[   89.807280][ T5744] bridge_slave_0: entered promiscuous mode
[   89.819396][ T5744] bridge0: port 2(bridge_slave_1) entered blocking state
[   89.827997][ T5744] bridge0: port 2(bridge_slave_1) entered disabled state
[   89.835690][ T5744] bridge_slave_1: entered allmulticast mode
[   89.848008][ T5744] bridge_slave_1: entered promiscuous mode
[   89.940194][ T5744] bond0: (slave bond_slave_0): Enslaving as an active interface with an up link
[   90.048674][ T5744] bond0: (slave bond_slave_1): Enslaving as an active interface with an up link
[   90.099125][ T5744] team0: Port device team_slave_0 added
[   90.108074][ T5744] team0: Port device team_slave_1 added
[   90.186048][   T50] Bluetooth: hci0: command tx timeout
[   90.213279][ T5744] batman_adv: batadv0: Adding interface: batadv_slave_0
[   90.220519][ T5744] 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.
[   90.247468][ T5744] batman_adv: batadv0: Not using interface batadv_slave_0 (retrying later): interface not active
[   90.265774][ T5744] batman_adv: batadv0: Adding interface: batadv_slave_1
[   90.276621][ T5744] 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.
[   90.303922][ T5744] batman_adv: batadv0: Not using interface batadv_slave_1 (retrying later): interface not active
[   90.469408][ T5744] hsr_slave_0: entered promiscuous mode
[   90.481812][ T5744] hsr_slave_1: entered promiscuous mode
[   90.681880][ T5283] 8021q: adding VLAN 0 to HW filter on device eth3
[   91.138311][ T5744] netdevsim netdevsim0 netdevsim0: renamed from eth0
[   91.152779][ T5744] 8021q: adding VLAN 0 to HW filter on device netdevsim0
[   91.162541][ T5744] netdevsim netdevsim0 netdevsim1: renamed from eth1
[   91.182054][ T5744] 8021q: adding VLAN 0 to HW filter on device netdevsim1
[   91.193977][ T5744] netdevsim netdevsim0 netdevsim2: renamed from eth2
[   91.208510][ T5744] 8021q: adding VLAN 0 to HW filter on device netdevsim2
[   91.218476][ T5744] netdevsim netdevsim0 netdevsim3: renamed from eth3
[   91.231736][ T5744] 8021q: adding VLAN 0 to HW filter on device netdevsim3
[   91.336798][ T5744] 8021q: adding VLAN 0 to HW filter on device bond0
[   91.369870][ T5744] 8021q: adding VLAN 0 to HW filter on device team0
[   91.386212][  T519] bridge0: port 1(bridge_slave_0) entered blocking state
[   91.393493][  T519] bridge0: port 1(bridge_slave_0) entered forwarding state
[   91.411832][  T519] bridge0: port 2(bridge_slave_1) entered blocking state
[   91.419160][  T519] bridge0: port 2(bridge_slave_1) entered forwarding state
[   91.908716][ T5744] 8021q: adding VLAN 0 to HW filter on device batadv0
[   91.978101][ T5744] veth0_vlan: entered promiscuous mode
[   91.994318][ T5744] veth1_vlan: entered promiscuous mode
[   92.035783][ T5744] veth0_macvtap: entered promiscuous mode
[   92.047946][ T5744] veth1_macvtap: entered promiscuous mode
[   92.079050][ T5744] batman_adv: batadv0: Interface activated: batadv_slave_0
[   92.097856][ T5744] batman_adv: batadv0: Interface activated: batadv_slave_1
[   92.121401][   T58] netdevsim netdevsim0 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
[   92.141194][   T58] netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[   92.162525][   T58] netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[   92.198589][  T519] netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
[   92.251556][  T519] wlan0: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   92.260991][   T50] Bluetooth: hci0: command tx timeout
[   92.267206][  T519] wlan0: Creating new IBSS network, BSSID 50:50:50:50:50:50
[   92.301651][   T13] wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
[   92.309879][   T13] 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-build2958903999=/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 d6526ea3e6a
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/cceLaIYh.o: in function `Connection::Connect(char const*, char const*)':
executor.cc:(.text._ZN10Connection7ConnectEPKcS1_[_ZN10Connection7ConnectEPKcS1_]+0x386): 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:         e75a43c7 Merge tag 'trace-v7.1-rc1' of git://git.kerne..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=39862773faeb52a2
dashboard link: https://syzkaller.appspot.com/bug?extid=42a37bf8045847d8f9d2
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=15365348580000