Message-ID: <68fb291a.050a0220.346f24.00ab.GAE@google.com>
Date: Fri, 24 Oct 2025 00:22:02 -0700
From: syzbot <syzbot+30b53487d00b4f7f0922@...kaller.appspotmail.com>
To: dmantipov@...dex.ru, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [ocfs2?] KASAN: use-after-free Read in ocfs2_dx_dir_lookup_rec

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

 T5709] bridge0: port 1(bridge_slave_0) entered forwarding state
[   68.240298][ T5709] 8021q: adding VLAN 0 to HW filter on device bond0
[   68.252314][ T3052] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
[   68.259280][ T3052] bridge0: port 1(bridge_slave_0) entered disabled state
[   68.266321][ T3052] bridge0: port 2(bridge_slave_1) entered disabled state
[   68.273111][ T3052] IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready
[   68.283113][ T5709] 8021q: adding VLAN 0 to HW filter on device team0
[   68.292693][ T3052] IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_0: link becomes ready
[   68.299864][ T3052] bridge0: port 1(bridge_slave_0) entered blocking state
[   68.306738][ T3052] bridge0: port 1(bridge_slave_0) entered forwarding state
[   68.323464][ T3052] IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_1: link becomes ready
[   68.330362][ T3052] bridge0: port 2(bridge_slave_1) entered blocking state
[   68.336215][ T3052] bridge0: port 2(bridge_slave_1) entered forwarding state
[   68.345510][ T3052] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready
[   68.360723][ T5709] hsr0: Slave A (hsr_slave_0) is not up; please bring it up to get a fully working HSR network
[   68.370569][ T5709] hsr0: Slave B (hsr_slave_1) is not up; please bring it up to get a fully working HSR network
[   68.383585][ T3052] IPv6: ADDRCONF(NETDEV_CHANGE): team0: link becomes ready
[   68.390265][ T3052] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready
[   68.397595][ T3052] IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_0: link becomes ready
[   68.404843][ T3052] IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_1: link becomes ready
[   68.419136][ T3052] IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready
[   68.475464][ T3020] IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: link becomes ready
[   68.482714][ T3020] IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready
[   68.492279][ T5709] 8021q: adding VLAN 0 to HW filter on device batadv0
[   68.504284][ T3020] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_virt_wifi: link becomes ready
[   68.518322][ T5709] device veth0_vlan entered promiscuous mode
[   68.524533][ T3020] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_vlan: link becomes ready
[   68.532452][ T3020] IPv6: ADDRCONF(NETDEV_CHANGE): vlan0: link becomes ready
[   68.538937][ T3020] IPv6: ADDRCONF(NETDEV_CHANGE): vlan1: link becomes ready
[   68.548991][ T5709] device veth1_vlan entered promiscuous mode
[   68.561923][ T3020] IPv6: ADDRCONF(NETDEV_CHANGE): macvlan0: link becomes ready
[   68.577076][ T3020] IPv6: ADDRCONF(NETDEV_CHANGE): macvlan1: link becomes ready
[   68.584768][ T3020] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_macvtap: link becomes ready
[   68.593467][ T5709] device veth0_macvtap entered promiscuous mode
[   68.600185][ T5709] device veth1_macvtap entered promiscuous mode
[   68.612225][ T5709] batman_adv: batadv0: Interface activated: batadv_slave_0
[   68.618206][ T3020] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_batadv: link becomes ready
[   68.627196][ T3020] IPv6: ADDRCONF(NETDEV_CHANGE): macvtap0: link becomes ready
[   68.636160][ T5709] batman_adv: batadv0: Interface activated: batadv_slave_1
[   68.642694][ T3020] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready
[   68.650882][ T5709] netdevsim netdevsim0 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
[   68.658395][ T5709] netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[   68.666616][ T5709] netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[   68.674870][ T5709] netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
[   68.687772][ T3020] ================================================================================
[   68.695596][ T3020] UBSAN: signed-integer-overflow in ./arch/x86/include/asm/atomic.h:165:11
[   68.703028][ T3020] 1496745227 + 1827093953 cannot be represented in type 'int'
[   68.710244][ T3020] CPU: 0 PID: 3020 Comm: kworker/u2:4 Not tainted syzkaller #0
[   68.716579][ T3020] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
[   68.725798][ T3020] Workqueue: wg-kex-wg0 wg_packet_handshake_send_worker
[   68.731523][ T3020] Call Trace:
[   68.734230][ T3020]  dump_stack+0xfd/0x16e
[   68.737665][ T3020]  ubsan_epilogue+0xa/0x30
[   68.741273][ T3020]  handle_overflow+0x192/0x1b0
[   68.745235][ T3020]  ? prandom_u32+0x217/0x260
[   68.748968][ T3020]  ip_idents_reserve+0x14a/0x170
[   68.753042][ T3020]  __ip_select_ident+0xe4/0x1c0
[   68.757100][ T3020]  iptunnel_xmit+0x468/0x850
[   68.760939][ T3020]  udp_tunnel_xmit_skb+0x1ba/0x290
[   68.765181][ T3020]  send4+0x5d4/0xaf0
[   68.768350][ T3020]  wg_socket_send_skb_to_peer+0xcd/0x1c0
[   68.772983][ T3020]  wg_packet_handshake_send_worker+0x16b/0x280
[   68.778059][ T3020]  process_one_work+0x85e/0xff0
[   68.782159][ T3020]  worker_thread+0xa9b/0x1430
[   68.786018][ T3020]  ? rcu_lock_release+0x20/0x20
[   68.790096][ T3020]  kthread+0x386/0x410
[   68.793572][ T3020]  ? rcu_lock_release+0x20/0x20
[   68.797547][ T3020]  ? kthread_blkcg+0xd0/0xd0
[   68.801233][ T3020]  ret_from_fork+0x1f/0x30
[   68.805017][ T3020] ================================================================================
[   68.812880][ T3020] Kernel panic - not syncing: UBSAN: panic_on_warn set ...
[   68.818697][ T3020] CPU: 0 PID: 3020 Comm: kworker/u2:4 Not tainted syzkaller #0
[   68.824803][ T3020] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
[   68.833531][ T3020] Workqueue: wg-kex-wg0 wg_packet_handshake_send_worker
[   68.839263][ T3020] Call Trace:
[   68.841987][ T3020]  dump_stack+0xfd/0x16e
[   68.845483][ T3020]  panic+0x2f0/0x9c0
[   68.848723][ T3020]  check_panic_on_warn+0x95/0xe0
[   68.852928][ T3020]  handle_overflow+0x192/0x1b0
[   68.856879][ T3020]  ? prandom_u32+0x217/0x260
[   68.860645][ T3020]  ip_idents_reserve+0x14a/0x170
[   68.864734][ T3020]  __ip_select_ident+0xe4/0x1c0
[   68.868721][ T3020]  iptunnel_xmit+0x468/0x850
[   68.872545][ T3020]  udp_tunnel_xmit_skb+0x1ba/0x290
[   68.876778][ T3020]  send4+0x5d4/0xaf0
[   68.879994][ T3020]  wg_socket_send_skb_to_peer+0xcd/0x1c0
[   68.884597][ T3020]  wg_packet_handshake_send_worker+0x16b/0x280
[   68.889687][ T3020]  process_one_work+0x85e/0xff0
[   68.893658][ T3020]  worker_thread+0xa9b/0x1430
[   68.897487][ T3020]  ? rcu_lock_release+0x20/0x20
[   68.901443][ T3020]  kthread+0x386/0x410
[   68.904823][ T3020]  ? rcu_lock_release+0x20/0x20
[   68.908761][ T3020]  ? kthread_blkcg+0xd0/0xd0
[   68.912531][ T3020]  ret_from_fork+0x1f/0x30
[   68.916474][ T3020] Kernel Offset: disabled
[   68.920027][ T3020] Rebooting in 86400 seconds..

VM DIAGNOSIS:
07:21:42  Registers:
info registers vcpu 0

CPU#0
RAX=1ffffffff2c2d760 RBX=00000000000003fd RCX=0000000000000000 RDX=00000000000003fd
RSI=0000000000000000 RDI=0000000000000020 RBP=0000000000000020 RSP=ffffc900018d7488
R8 =dffffc0000000000 R9 =fffff5200031ae9e R10=fffff5200031ae9e R11=ffffffff83f6a420
R12=dffffc0000000000 R13=1ffffffff2ad0463 R14=ffffffff9616bde0 R15=0000000000000000
RIP=ffffffff83f6a493 RFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0000 0000000000000000 ffffffff 00c00000
CS =0010 0000000000000000 ffffffff 00a09b00 DPL=0 CS64 [-RA]
SS =0018 0000000000000000 ffffffff 00c09300 DPL=0 DS   [-WA]
DS =0000 0000000000000000 ffffffff 00c00000
FS =0000 0000000000000000 ffffffff 00c00000
GS =0000 ffff888020600000 ffffffff 00c00000
LDT=0000 0000000000000000 ffffffff 00c00000
TR =0040 fffffe0000003000 00004087 00008b00 DPL=0 TSS64-busy
GDT=     fffffe0000001000 0000007f
IDT=     fffffe0000000000 00000fff
CR0=80050033 CR2=00007f70fa315e9c CR3=00000000552ec000 CR4=00350ef0
DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000 
DR6=00000000fffe0ff0 DR7=0000000000000400
EFER=0000000000000d01
FCW=037f FSW=0000 [ST=0] FTW=00 MXCSR=00001f80
FPR0=0000000000000000 0000 FPR1=0000000000000000 0000
FPR2=0000000000000000 0000 FPR3=0000000000000000 0000
FPR4=0000000000000000 0000 FPR5=0000000000000000 0000
FPR6=0000000000000000 0000 FPR7=0000000000000000 0000
Opmask00=0000000004222200 Opmask01=0000000000000fff Opmask02=00000000ffffffef Opmask03=0000000000000000
Opmask04=0000000000000000 Opmask05=0000000000000000 Opmask06=0000000000000000 Opmask07=0000000000000000
ZMM00=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 cdbdb4c6f9b3cfa9 ccfdd53f3940cda9
ZMM01=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 61f8e5020c5491fa 26bc4e1f9a76504d
ZMM02=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 d36be18d52e74008 92e0425df8168802
ZMM03=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 646f3db649b453b8 e19fc6320e65a175
ZMM04=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 00000000ffffffff 00000000000000b4
ZMM05=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000034
ZMM06=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 b7184e26892817da 642e11a230cac1df
ZMM07=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 027c24cb4c152817 0000000000000000
ZMM08=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 64b81aac9d6a7288 bca2e73a631a5a4e
ZMM09=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 8e994ecd00000000 f2462c1638d210f8
ZMM10=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 b60ba1988284cefc 87c3fed8a05ffd9a
ZMM11=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 eae31e2d506dbe72 ca832c4f00373649
ZMM12=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000
ZMM13=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000
ZMM14=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 a54ff53a3c6ef372 bb67ae856a09e667
ZMM15=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 5be0cd191f83d9ab 9b05688c510e527f
ZMM16=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000
ZMM17=0000000000000000 0000000000000000 0000000000000000 0000000000000000 2525252525252525 2525252525252525 2525252525252525 2525252525252525
ZMM18=0000000000000000 0000000000000000 0000000000000000 0000000000000000 6c6c255b20642523 00202c0028732520 3e2d205d736d756c 6c255b2064252300
ZMM19=0000000000000000 0000000000000000 0000000000000000 0000000000000000 4949005b05410006 000509000d560005 1b08055d56485049 49005b0541000600
ZMM20=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000
ZMM21=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000
ZMM22=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000
ZMM23=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000
ZMM24=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000
ZMM25=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000
ZMM26=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000
ZMM27=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000
ZMM28=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000
ZMM29=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000
ZMM30=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000
ZMM31=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000


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-build1635881792=/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='go1.24.4'
GOWORK=''
PKG_CONFIG='pkg-config'

git status (err=<nil>)
HEAD detached at 001c90610fb
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=001c90610fb2f2ac7cbbc9cd6af3f547b821a8ad -X github.com/google/syzkaller/prog.gitRevisionDate=20250926-171341"  ./sys/syz-sysgen | grep -q false || go install -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=001c90610fb2f2ac7cbbc9cd6af3f547b821a8ad -X github.com/google/syzkaller/prog.gitRevisionDate=20250926-171341"  ./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=001c90610fb2f2ac7cbbc9cd6af3f547b821a8ad -X github.com/google/syzkaller/prog.gitRevisionDate=20250926-171341"  -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=\"001c90610fb2f2ac7cbbc9cd6af3f547b821a8ad\"
/usr/bin/ld: /tmp/ccZqxKJx.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


Error text is too large and was truncated, full error text is at:
https://syzkaller.appspot.com/x/error.txt?x=11068c92580000


Tested on:

commit:         d3d0b4e2 Linux 5.10.245
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git linux-5.10.y
kernel config:  https://syzkaller.appspot.com/x/.config?x=7c6f4ecbfb251fb
dashboard link: https://syzkaller.appspot.com/bug?extid=30b53487d00b4f7f0922
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=144e63cd980000

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