Message-ID: <6901b4e2.a70a0220.5b2ed.0011.GAE@google.com>
Date: Tue, 28 Oct 2025 23:32:02 -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:

 67.405772][  T138] bridge0: port 1(bridge_slave_0) entered forwarding state
[   67.422310][  T138] IPv6: ADDRCONF(NETDEV_CHANGE): bridge0: link becomes ready
[   67.428814][  T138] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready
[   67.436709][  T138] IPv6: ADDRCONF(NETDEV_CHANGE): bridge_slave_1: link becomes ready
[   67.444616][  T138] bridge0: port 2(bridge_slave_1) entered blocking state
[   67.450434][  T138] bridge0: port 2(bridge_slave_1) entered forwarding state
[   67.457539][  T138] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bond: link becomes ready
[   67.464951][  T138] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bond: link becomes ready
[   67.472504][  T138] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_team: link becomes ready
[   67.479592][  T138] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready
[   67.486473][  T138] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_team: link becomes ready
[   67.495730][  T138] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready
[   67.506916][ T5650] hsr0: Slave A (hsr_slave_0) is not up; please bring it up to get a fully working HSR network
[   67.515281][ T5650] hsr0: Slave B (hsr_slave_1) is not up; please bring it up to get a fully working HSR network
[   67.528862][  T138] IPv6: ADDRCONF(NETDEV_CHANGE): team0: link becomes ready
[   67.536372][  T138] IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_0: link becomes ready
[   67.542979][  T138] IPv6: ADDRCONF(NETDEV_CHANGE): hsr_slave_1: link becomes ready
[   67.557870][  T138] IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready
[   67.610902][   T18] IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready
[   67.617048][   T18] IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: link becomes ready
[   67.627882][ T5650] 8021q: adding VLAN 0 to HW filter on device batadv0
[   67.640213][   T18] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_virt_wifi: link becomes ready
[   67.654490][   T18] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_vlan: link becomes ready
[   67.662159][   T18] IPv6: ADDRCONF(NETDEV_CHANGE): vlan0: link becomes ready
[   67.668580][   T18] IPv6: ADDRCONF(NETDEV_CHANGE): vlan1: link becomes ready
[   67.677187][ T5650] device veth0_vlan entered promiscuous mode
[   67.691806][ T5650] device veth1_vlan entered promiscuous mode
[   67.706055][   T18] IPv6: ADDRCONF(NETDEV_CHANGE): macvlan0: link becomes ready
[   67.713533][   T18] IPv6: ADDRCONF(NETDEV_CHANGE): macvlan1: link becomes ready
[   67.720200][   T18] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_macvtap: link becomes ready
[   67.729527][ T5650] device veth0_macvtap entered promiscuous mode
[   67.749810][ T5650] device veth1_macvtap entered promiscuous mode
[   67.761853][ T5650] batman_adv: batadv0: Interface activated: batadv_slave_0
[   67.767891][   T18] IPv6: ADDRCONF(NETDEV_CHANGE): macvtap0: link becomes ready
[   67.776673][   T18] IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_0: link becomes ready
[   67.784850][   T18] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_batadv: link becomes ready
[   67.793939][ T5650] batman_adv: batadv0: Interface activated: batadv_slave_1
[   67.801258][   T18] IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_1: link becomes ready
[   67.808485][   T18] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready
[   67.817996][ T5650] netdevsim netdevsim0 netdevsim0: set [1, 0] type 2 family 0 port 6081 - 0
[   67.828026][ T5650] netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
[   67.835828][ T5650] netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
[   67.843642][ T5650] netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
[   67.857737][   T18] ================================================================================
[   67.865522][   T18] UBSAN: signed-integer-overflow in ./arch/x86/include/asm/atomic.h:165:11
[   67.872603][   T18] 995543531 + 1319321246 cannot be represented in type 'int'
[   67.879702][   T18] CPU: 0 PID: 18 Comm: kworker/u2:1 Not tainted syzkaller #0
[   67.886045][   T18] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
[   67.895362][   T18] Workqueue: wg-kex-wg0 wg_packet_handshake_send_worker
[   67.901364][   T18] Call Trace:
[   67.904328][   T18]  dump_stack+0xfd/0x16e
[   67.908005][   T18]  ubsan_epilogue+0xa/0x30
[   67.911778][   T18]  handle_overflow+0x192/0x1b0
[   67.915876][   T18]  ? prandom_u32+0x217/0x260
[   67.919849][   T18]  ip_idents_reserve+0x14a/0x170
[   67.924126][   T18]  __ip_select_ident+0xe4/0x1c0
[   67.928256][   T18]  iptunnel_xmit+0x468/0x850
[   67.932244][   T18]  udp_tunnel_xmit_skb+0x1ba/0x290
[   67.936638][   T18]  send4+0x5d4/0xaf0
[   67.939990][   T18]  wg_socket_send_skb_to_peer+0xcd/0x1c0
[   67.944630][   T18]  wg_packet_handshake_send_worker+0x16b/0x280
[   67.949906][   T18]  process_one_work+0x85e/0xff0
[   67.954046][   T18]  worker_thread+0xa9b/0x1430
[   67.958082][   T18]  ? rcu_lock_release+0x20/0x20
[   67.962220][   T18]  kthread+0x386/0x410
[   67.965686][   T18]  ? rcu_lock_release+0x20/0x20
[   67.969859][   T18]  ? kthread_blkcg+0xd0/0xd0
[   67.973836][   T18]  ret_from_fork+0x1f/0x30
[   67.977674][   T18] ================================================================================
[   67.985359][   T18] Kernel panic - not syncing: UBSAN: panic_on_warn set ...
[   67.991361][   T18] CPU: 0 PID: 18 Comm: kworker/u2:1 Not tainted syzkaller #0
[   67.997465][   T18] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
[   68.006318][   T18] Workqueue: wg-kex-wg0 wg_packet_handshake_send_worker
[   68.012069][   T18] Call Trace:
[   68.014829][   T18]  dump_stack+0xfd/0x16e
[   68.018379][   T18]  panic+0x2f0/0x9c0
[   68.021631][   T18]  check_panic_on_warn+0x95/0xe0
[   68.025741][   T18]  handle_overflow+0x192/0x1b0
[   68.029775][   T18]  ? prandom_u32+0x217/0x260
[   68.033699][   T18]  ip_idents_reserve+0x14a/0x170
[   68.037834][   T18]  __ip_select_ident+0xe4/0x1c0
[   68.042016][   T18]  iptunnel_xmit+0x468/0x850
[   68.045881][   T18]  udp_tunnel_xmit_skb+0x1ba/0x290
[   68.050153][   T18]  send4+0x5d4/0xaf0
[   68.053501][   T18]  wg_socket_send_skb_to_peer+0xcd/0x1c0
[   68.058253][   T18]  wg_packet_handshake_send_worker+0x16b/0x280
[   68.063426][   T18]  process_one_work+0x85e/0xff0
[   68.067469][   T18]  worker_thread+0xa9b/0x1430
[   68.071345][   T18]  ? rcu_lock_release+0x20/0x20
[   68.075396][   T18]  kthread+0x386/0x410
[   68.078889][   T18]  ? rcu_lock_release+0x20/0x20
[   68.083007][   T18]  ? kthread_blkcg+0xd0/0xd0
[   68.086908][   T18]  ret_from_fork+0x1f/0x30
[   68.090956][   T18] Kernel Offset: disabled
[   68.094683][   T18] Rebooting in 86400 seconds..

VM DIAGNOSIS:
06:30:55  Registers:
info registers vcpu 0

CPU#0
RAX=0000000000000039 RBX=0000000000000039 RCX=0000000000000000 RDX=00000000000003f8
RSI=0000000000000000 RDI=0000000000000020 RBP=00000000000003f8 RSP=ffffc900004474e0
R8 =dffffc0000000000 R9 =fffff52000088e9e R10=fffff52000088e9e R11=ffffffff83f6a690
R12=dffffc0000000000 R13=1ffffffff2ad0463 R14=ffffffff9616bde0 R15=0000000000000000
RIP=ffffffff83f6a708 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=00005649c4ac8168 CR3=000000003cee0000 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 34c0e75a57eedab6 df075a43b3530442
ZMM01=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 cd93e3d1997b1ad0 ac02d2502393cada
ZMM02=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 739bb957f0df0046 e893118a65186997
ZMM03=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 dcce5dad54d123ff 05ce08a3fac4eb3e
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 0ad426484b0072e0 3ee4763b2d2ad138
ZMM07=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 542de23f41d7d499 0000000000000000
ZMM08=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 64f818e79afcdfd0 39f02c83a206bdbb
ZMM09=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 3caa366800000000 8c2d7c3421c3af63
ZMM10=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 2a1a2c77e3ec1418 ef53c166bcfc26d7
ZMM11=0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 5689bc5aba259e21 eb51e68077b68e8f
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-build1854730157=/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/ccDmF0ws.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=11583e7c580000


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=145b6fe2580000

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