Re: [syzbot] [net?] KASAN: slab-use-after-free Read in sock_def_readable (2)

[syzbot]

Hello,

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

lost connection to test machine



syzkaller login: qemu-system-x86_64: ahci: PRDT length for NCQ command (0x0) is smaller than the requested size (0x400000)
Warning: Permanently added '[localhost]:61150' (ED25519) to the list of known hosts.
2026/03/09 08:11:07 parsed 1 programs
[  100.778155][ T5308] cgroup: Unknown subsys name 'net'
[  100.824718][ T5308] cgroup: Unknown subsys name 'cpuset'
[  100.835966][ T5308] cgroup: Unknown subsys name 'rlimit'
[  102.495043][    T9] cfg80211: failed to load regulatory.db
[  143.453170][ T1316] ieee802154 phy0 wpan0: encryption failed: -22
[  143.456980][ T1316] ieee802154 phy1 wpan1: encryption failed: -22
[  151.790041][ T1009] ata1.00: exception Emask 0x0 SAct 0x200000 SErr 0x0 action 0x6 frozen
[  151.795444][ T1009] ata1.00: failed command: WRITE FPDMA QUEUED
[  151.798620][ T1009] ata1.00: cmd 61/00:a8:36:c1:04/20:00:00:00:00/40 tag 21 ncq dma 4194304 ou
[  151.798620][ T1009]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[  151.807230][ T1009] ata1.00: status: { DRDY }
[  151.810358][ T1009] ata1: hard resetting link
[  152.133478][ T1009] ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
[  152.138661][ T1009] ata1.00: configured for UDMA/100
[  152.142424][ T1009] ata1: EH complete
qemu-system-x86_64: ahci: PRDT length for NCQ command (0x0) is smaller than the requested size (0x400000)
[  152.180979][ T1009] ata1.00: Read log 0x10 page 0x00 failed, Emask 0x1
[  152.184589][ T1009] ata1: failed to read log page 10h (errno=-5)
[  152.187583][ T1009] ata1.00: exception Emask 0x1 SAct 0x76 SErr 0x0 action 0x0
[  152.200268][ T1009] ata1.00: irq_stat 0x41000000
[  152.202658][ T1009] ata1.00: failed command: WRITE FPDMA QUEUED
[  152.205600][ T1009] ata1.00: cmd 61/00:08:36:c1:04/20:00:00:00:00/40 tag 1 ncq dma 4194304 ou
[  152.205600][ T1009]          res 50/00:00:00:00:00/00:00:00:00:00/00 Emask 0x1 (device error)
[  152.233239][ T1009] ata1.00: status: { DRDY }
[  152.240616][ T1009] ata1.00: failed command: WRITE FPDMA QUEUED
[  152.243710][ T1009] ata1.00: cmd 61/08:10:4e:04:10/00:00:00:00:00/40 tag 2 ncq dma 4096 out
[  152.243710][ T1009]          res 50/00:00:00:00:00/00:00:00:00:00/00 Emask 0x1 (device error)
[  152.257043][ T1009] ata1.00: status: { DRDY }
[  152.260632][ T1009] ata1.00: failed command: WRITE FPDMA QUEUED
[  152.263657][ T1009] ata1.00: cmd 61/00:20:36:01:05/20:00:00:00:00/40 tag 4 ncq dma 4194304 ou
[  152.263657][ T1009]          res 50/00:00:00:00:00/00:00:00:00:00/00 Emask 0x1 (device error)
[  152.272096][ T1009] ata1.00: status: { DRDY }
[  152.274461][ T1009] ata1.00: failed command: WRITE FPDMA QUEUED
[  152.277407][ T1009] ata1.00: cmd 61/00:28:36:21:05/20:00:00:00:00/40 tag 5 ncq dma 4194304 ou
[  152.277407][ T1009]          res 50/00:00:00:00:00/00:00:00:00:00/00 Emask 0x1 (device error)
[  152.286072][ T1009] ata1.00: status: { DRDY }
[  152.288291][ T1009] ata1.00: failed command: WRITE FPDMA QUEUED
[  152.291815][ T1009] ata1.00: cmd 61/f8:30:36:41:05/0b:00:00:00:00/40 tag 6 ncq dma 1568768 ou
[  152.291815][ T1009]          res 50/00:00:00:00:00/00:00:00:00:00/00 Emask 0x1 (device error)
[  152.300643][ T1009] ata1.00: status: { DRDY }
[  152.304040][ T1009] ata1.00: configured for UDMA/100
[  152.307255][ T1009] ata1: EH complete
qemu-system-x86_64: ahci: PRDT length for NCQ command (0x0) is smaller than the requested size (0x400000)
[  152.331089][ T1009] ata1.00: Read log 0x10 page 0x00 failed, Emask 0x1
[  152.334242][ T1009] ata1: failed to read log page 10h (errno=-5)
[  152.337932][ T1009] ata1.00: NCQ disabled due to excessive errors
[  152.341762][ T1009] ata1.00: exception Emask 0x1 SAct 0x800 SErr 0x0 action 0x0
[  152.345331][ T1009] ata1.00: irq_stat 0x41000008
[  152.347892][ T1009] ata1.00: failed command: WRITE FPDMA QUEUED
[  152.351796][ T1009] ata1.00: cmd 61/00:58:36:c1:04/20:00:00:00:00/40 tag 11 ncq dma 4194304 ou
[  152.351796][ T1009]          res 50/04:00:00:00:00/00:00:00:00:00/00 Emask 0x1 (device error)
[  152.361851][ T1009] ata1.00: status: { DRDY }
[  152.364344][ T1009] ata1.00: error: { ABRT }
[  152.367708][ T1009] ata1.00: configured for UDMA/100
[  152.372040][ T1009] ata1: EH complete
Setting up swapspace version 1, size = 127995904 bytes
[  154.342839][ T5308] Adding 124996k swap on ./swap-file.  Priority:0 extents:1 across:124996k 
qemu-system-x86_64: hw/ide/core.c:934: ide_dma_cb: Assertion `prep_size >= 0 && prep_size <= n * 512' failed.
Connection to localhost closed by remote host.


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-build997279610=/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 7c9658af8505
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=7c9658af8505abccd5bf5890cc8a8e6d9826eaa0 -X github.com/google/syzkaller/prog.gitRevisionDate=20260223-092328"  ./sys/syz-sysgen | grep -q false || go install -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=7c9658af8505abccd5bf5890cc8a8e6d9826eaa0 -X github.com/google/syzkaller/prog.gitRevisionDate=20260223-092328"  ./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=7c9658af8505abccd5bf5890cc8a8e6d9826eaa0 -X github.com/google/syzkaller/prog.gitRevisionDate=20260223-092328"  -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=\"7c9658af8505abccd5bf5890cc8a8e6d9826eaa0\"
/usr/bin/ld: /tmp/ccdnCVXi.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:         1f318b96 Linux 7.0-rc3
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=c5c49ee0942d1cdb
dashboard link: https://syzkaller.appspot.com/bug?extid=f50072212ab792c86925
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=108a4806580000