Extracting prog: 1m20.835782991s
Minimizing prog: 11m52.478620631s
Simplifying prog options: 0s
Extracting C: 24.541724472s
Simplifying C: 4m31.369976486s


extracting reproducer from 1 programs
testing a last program of every proc
single: executing 1 programs separately with timeout 30s
testing program (duration=30s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mmap-bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-close-socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$EVIOCGMASK
detailed listing:
executing program 0:
mmap(&(0x7f0000000000/0x200000)=nil, 0x200000, 0x300000b, 0x204031, 0xffffffffffffffff, 0x42791000)
r0 = bpf$BPF_PROG_WITH_BTFID_LOAD(0x5, &(0x7f0000000280)=@bpf_lsm={0x6, 0x3, &(0x7f00000003c0)=ANY=[@ANYBLOB="18000000003f000000000000000000f195"], &(0x7f0000000140)='GPL\x00'}, 0x80)
r1 = bpf$ITER_CREATE(0xb, &(0x7f00000004c0)={r0}, 0x8)
close(r1)
r2 = socket$pppl2tp(0x18, 0x1, 0x1)
r3 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r2, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r3, {0x2, 0x4e23, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e)
ioctl$EVIOCGMASK(r1, 0x80104592, 0x0)

program crashed: KASAN: use-after-free Write in pppol2tp_release
single: successfully extracted reproducer
found reproducer with 8 syscalls
minimizing guilty program
testing program (duration=37.948859826s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mmap-bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-close-socket$pppl2tp-socket$inet6_udp-connect$pppl2tp
detailed listing:
executing program 0:
mmap(&(0x7f0000000000/0x200000)=nil, 0x200000, 0x300000b, 0x204031, 0xffffffffffffffff, 0x42791000)
r0 = bpf$BPF_PROG_WITH_BTFID_LOAD(0x5, &(0x7f0000000280)=@bpf_lsm={0x6, 0x3, &(0x7f00000003c0)=ANY=[@ANYBLOB="18000000003f000000000000000000f195"], &(0x7f0000000140)='GPL\x00'}, 0x80)
r1 = bpf$ITER_CREATE(0xb, &(0x7f00000004c0)={r0}, 0x8)
close(r1)
r2 = socket$pppl2tp(0x18, 0x1, 0x1)
r3 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r2, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r3, {0x2, 0x4e23, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e)

program did not crash
testing program (duration=37.948859826s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mmap-bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-close-socket$pppl2tp-socket$inet6_udp-ioctl$EVIOCGMASK
detailed listing:
executing program 0:
mmap(&(0x7f0000000000/0x200000)=nil, 0x200000, 0x300000b, 0x204031, 0xffffffffffffffff, 0x42791000)
r0 = bpf$BPF_PROG_WITH_BTFID_LOAD(0x5, &(0x7f0000000280)=@bpf_lsm={0x6, 0x3, &(0x7f00000003c0)=ANY=[@ANYBLOB="18000000003f000000000000000000f195"], &(0x7f0000000140)='GPL\x00'}, 0x80)
r1 = bpf$ITER_CREATE(0xb, &(0x7f00000004c0)={r0}, 0x8)
close(r1)
socket$pppl2tp(0x18, 0x1, 0x1)
socket$inet6_udp(0xa, 0x2, 0x0)
ioctl$EVIOCGMASK(r1, 0x80104592, 0x0)

program did not crash
testing program (duration=37.948859826s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mmap-bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-close-socket$pppl2tp-connect$pppl2tp-ioctl$EVIOCGMASK
detailed listing:
executing program 0:
mmap(&(0x7f0000000000/0x200000)=nil, 0x200000, 0x300000b, 0x204031, 0xffffffffffffffff, 0x42791000)
r0 = bpf$BPF_PROG_WITH_BTFID_LOAD(0x5, &(0x7f0000000280)=@bpf_lsm={0x6, 0x3, &(0x7f00000003c0)=ANY=[@ANYBLOB="18000000003f000000000000000000f195"], &(0x7f0000000140)='GPL\x00'}, 0x80)
r1 = bpf$ITER_CREATE(0xb, &(0x7f00000004c0)={r0}, 0x8)
close(r1)
r2 = socket$pppl2tp(0x18, 0x1, 0x1)
connect$pppl2tp(r2, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, 0xffffffffffffffff, {0x2, 0x4e23, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e)
ioctl$EVIOCGMASK(r1, 0x80104592, 0x0)

program did not crash
testing program (duration=37.948859826s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mmap-bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-close-socket$inet6_udp-connect$pppl2tp-ioctl$EVIOCGMASK
detailed listing:
executing program 0:
mmap(&(0x7f0000000000/0x200000)=nil, 0x200000, 0x300000b, 0x204031, 0xffffffffffffffff, 0x42791000)
r0 = bpf$BPF_PROG_WITH_BTFID_LOAD(0x5, &(0x7f0000000280)=@bpf_lsm={0x6, 0x3, &(0x7f00000003c0)=ANY=[@ANYBLOB="18000000003f000000000000000000f195"], &(0x7f0000000140)='GPL\x00'}, 0x80)
r1 = bpf$ITER_CREATE(0xb, &(0x7f00000004c0)={r0}, 0x8)
close(r1)
r2 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(0xffffffffffffffff, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r2, {0x2, 0x4e23, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e)
ioctl$EVIOCGMASK(r1, 0x80104592, 0x0)

program did not crash
testing program (duration=37.948859826s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mmap-bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$EVIOCGMASK
detailed listing:
executing program 0:
mmap(&(0x7f0000000000/0x200000)=nil, 0x200000, 0x300000b, 0x204031, 0xffffffffffffffff, 0x42791000)
r0 = bpf$BPF_PROG_WITH_BTFID_LOAD(0x5, &(0x7f0000000280)=@bpf_lsm={0x6, 0x3, &(0x7f00000003c0)=ANY=[@ANYBLOB="18000000003f000000000000000000f195"], &(0x7f0000000140)='GPL\x00'}, 0x80)
r1 = bpf$ITER_CREATE(0xb, &(0x7f00000004c0)={r0}, 0x8)
r2 = socket$pppl2tp(0x18, 0x1, 0x1)
r3 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r2, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r3, {0x2, 0x4e23, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e)
ioctl$EVIOCGMASK(r1, 0x80104592, 0x0)

program did not crash
testing program (duration=37.948859826s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mmap-bpf$BPF_PROG_WITH_BTFID_LOAD-close-socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$EVIOCGMASK
detailed listing:
executing program 0:
mmap(&(0x7f0000000000/0x200000)=nil, 0x200000, 0x300000b, 0x204031, 0xffffffffffffffff, 0x42791000)
bpf$BPF_PROG_WITH_BTFID_LOAD(0x5, &(0x7f0000000280)=@bpf_lsm={0x6, 0x3, &(0x7f00000003c0)=ANY=[@ANYBLOB="18000000003f000000000000000000f195"], &(0x7f0000000140)='GPL\x00'}, 0x80)
close(0xffffffffffffffff)
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r0, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r1, {0x2, 0x4e23, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e)
ioctl$EVIOCGMASK(0xffffffffffffffff, 0x80104592, 0x0)

program did not crash
testing program (duration=37.948859826s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): mmap-bpf$ITER_CREATE-close-socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$EVIOCGMASK
detailed listing:
executing program 0:
mmap(&(0x7f0000000000/0x200000)=nil, 0x200000, 0x300000b, 0x204031, 0xffffffffffffffff, 0x42791000)
r0 = bpf$ITER_CREATE(0xb, &(0x7f00000004c0), 0x8)
close(r0)
r1 = socket$pppl2tp(0x18, 0x1, 0x1)
r2 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r1, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r2, {0x2, 0x4e23, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e)
ioctl$EVIOCGMASK(r0, 0x80104592, 0x0)

program did not crash
testing program (duration=37.948859826s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-close-socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$EVIOCGMASK
detailed listing:
executing program 0:
r0 = bpf$BPF_PROG_WITH_BTFID_LOAD(0x5, &(0x7f0000000280)=@bpf_lsm={0x6, 0x3, &(0x7f00000003c0)=ANY=[@ANYBLOB="18000000003f000000000000000000f195"], &(0x7f0000000140)='GPL\x00'}, 0x80)
r1 = bpf$ITER_CREATE(0xb, &(0x7f00000004c0)={r0}, 0x8)
close(r1)
r2 = socket$pppl2tp(0x18, 0x1, 0x1)
r3 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r2, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r3, {0x2, 0x4e23, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e)
ioctl$EVIOCGMASK(r1, 0x80104592, 0x0)

program crashed: KASAN: use-after-free Read in pppol2tp_sock_to_session
testing program (duration=37.948859826s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-close-socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$EVIOCGMASK
detailed listing:
executing program 0:
r0 = bpf$BPF_PROG_WITH_BTFID_LOAD(0x5, 0x0, 0x0)
r1 = bpf$ITER_CREATE(0xb, &(0x7f00000004c0)={r0}, 0x8)
close(r1)
r2 = socket$pppl2tp(0x18, 0x1, 0x1)
r3 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r2, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r3, {0x2, 0x4e23, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e)
ioctl$EVIOCGMASK(r1, 0x80104592, 0x0)

program did not crash
testing program (duration=37.948859826s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-close-socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$EVIOCGMASK
detailed listing:
executing program 0:
r0 = bpf$BPF_PROG_WITH_BTFID_LOAD(0x5, &(0x7f0000000280)=@bpf_lsm={0x6, 0x3, 0x0, &(0x7f0000000140)='GPL\x00'}, 0x94)
r1 = bpf$ITER_CREATE(0xb, &(0x7f00000004c0)={r0}, 0x8)
close(r1)
r2 = socket$pppl2tp(0x18, 0x1, 0x1)
r3 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r2, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r3, {0x2, 0x4e23, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e)
ioctl$EVIOCGMASK(r1, 0x80104592, 0x0)

program did not crash
testing program (duration=37.948859826s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-close-socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$EVIOCGMASK
detailed listing:
executing program 0:
r0 = bpf$BPF_PROG_WITH_BTFID_LOAD(0x5, &(0x7f0000000280)=@bpf_lsm={0x6, 0x3, &(0x7f00000003c0)=ANY=[@ANYBLOB], &(0x7f0000000140)='GPL\x00'}, 0x94)
r1 = bpf$ITER_CREATE(0xb, &(0x7f00000004c0)={r0}, 0x8)
close(r1)
r2 = socket$pppl2tp(0x18, 0x1, 0x1)
r3 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r2, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r3, {0x2, 0x4e23, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e)
ioctl$EVIOCGMASK(r1, 0x80104592, 0x0)

program did not crash
testing program (duration=37.948859826s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-close-socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$EVIOCGMASK
detailed listing:
executing program 0:
r0 = bpf$BPF_PROG_WITH_BTFID_LOAD(0x5, &(0x7f0000000280)=@bpf_lsm={0x6, 0x3, &(0x7f00000003c0)=ANY=[@ANYBLOB="18000000003f000000000000000000f195"], 0x0}, 0x94)
r1 = bpf$ITER_CREATE(0xb, &(0x7f00000004c0)={r0}, 0x8)
close(r1)
r2 = socket$pppl2tp(0x18, 0x1, 0x1)
r3 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r2, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r3, {0x2, 0x4e23, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e)
ioctl$EVIOCGMASK(r1, 0x80104592, 0x0)

program did not crash
testing program (duration=37.948859826s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-close-socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$EVIOCGMASK
detailed listing:
executing program 0:
bpf$BPF_PROG_WITH_BTFID_LOAD(0x5, &(0x7f0000000280)=@bpf_lsm={0x6, 0x3, &(0x7f00000003c0)=ANY=[@ANYBLOB="18000000003f000000000000000000f195"], &(0x7f0000000140)='GPL\x00'}, 0x80)
r0 = bpf$ITER_CREATE(0xb, 0x0, 0x0)
close(r0)
r1 = socket$pppl2tp(0x18, 0x1, 0x1)
r2 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r1, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r2, {0x2, 0x4e23, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e)
ioctl$EVIOCGMASK(r0, 0x80104592, 0x0)

program did not crash
testing program (duration=37.948859826s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-close-socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$EVIOCGMASK
detailed listing:
executing program 0:
r0 = bpf$BPF_PROG_WITH_BTFID_LOAD(0x5, &(0x7f0000000280)=@bpf_lsm={0x6, 0x3, &(0x7f00000003c0)=ANY=[@ANYBLOB="18000000003f000000000000000000f195"], &(0x7f0000000140)='GPL\x00'}, 0x80)
r1 = bpf$ITER_CREATE(0xb, &(0x7f00000004c0)={r0}, 0x8)
close(r1)
r2 = socket$pppl2tp(0x18, 0x1, 0x1)
socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r2, 0x0, 0x0)
ioctl$EVIOCGMASK(r1, 0x80104592, 0x0)

program did not crash
extracting C reproducer
testing compiled C program (duration=37.948859826s, {Threaded:true Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-close-socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$EVIOCGMASK
program crashed: KASAN: use-after-free Write in pppol2tp_release
simplifying C reproducer
testing compiled C program (duration=37.948859826s, {Threaded:false Repeat:true RepeatTimes:0 Procs:5 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-close-socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$EVIOCGMASK
program crashed: KASAN: use-after-free Read in pppol2tp_sock_to_session
testing compiled C program (duration=37.948859826s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:false Cgroups:false BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-close-socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$EVIOCGMASK
program did not crash
testing compiled C program (duration=37.948859826s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:true NetDevices:true NetReset:true Cgroups:true BinfmtMisc:true CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:true VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-close-socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$EVIOCGMASK
program crashed: KASAN: use-after-free Read in pppol2tp_sock_to_session
testing compiled C program (duration=37.948859826s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:false UseTmpDir:true HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-close-socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$EVIOCGMASK
program crashed: KASAN: use-after-free Read in pppol2tp_sock_to_session
testing compiled C program (duration=37.948859826s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:false UseTmpDir:false HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-close-socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$EVIOCGMASK
program crashed: KASAN: use-after-free Read in pppol2tp_sock_to_session
testing compiled C program (duration=37.948859826s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:false UseTmpDir:false HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-close-socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$EVIOCGMASK
program crashed: KASAN: use-after-free Write in rcu_segcblist_enqueue
a never seen crash title: KASAN: use-after-free Write in rcu_segcblist_enqueue, ignore
testing compiled C program (duration=37.948859826s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:false HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-close-socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$EVIOCGMASK
program crashed: KASAN: use-after-free Read in pppol2tp_sock_to_session
testing program (duration=37.948859826s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:false HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-close-socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$EVIOCGMASK
detailed listing:
executing program 0:
r0 = bpf$BPF_PROG_WITH_BTFID_LOAD(0x5, &(0x7f0000000280)=@bpf_lsm={0x6, 0x3, &(0x7f00000003c0)=ANY=[@ANYBLOB="18000000003f000000000000000000f195"], &(0x7f0000000140)='GPL\x00'}, 0x80)
r1 = bpf$ITER_CREATE(0xb, &(0x7f00000004c0)={r0}, 0x8)
close(r1)
r2 = socket$pppl2tp(0x18, 0x1, 0x1)
r3 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r2, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r3, {0x2, 0x4e23, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e)
ioctl$EVIOCGMASK(r1, 0x80104592, 0x0)

program crashed: KASAN: use-after-free Read in pppol2tp_sock_to_session
validation run: crashed=true
testing program (duration=37.948859826s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:false HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-close-socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$EVIOCGMASK
detailed listing:
executing program 0:
r0 = bpf$BPF_PROG_WITH_BTFID_LOAD(0x5, &(0x7f0000000280)=@bpf_lsm={0x6, 0x3, &(0x7f00000003c0)=ANY=[@ANYBLOB="18000000003f000000000000000000f195"], &(0x7f0000000140)='GPL\x00'}, 0x80)
r1 = bpf$ITER_CREATE(0xb, &(0x7f00000004c0)={r0}, 0x8)
close(r1)
r2 = socket$pppl2tp(0x18, 0x1, 0x1)
r3 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r2, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r3, {0x2, 0x4e23, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e)
ioctl$EVIOCGMASK(r1, 0x80104592, 0x0)

program crashed: KASAN: use-after-free Read in pppol2tp_sock_to_session
validation run: crashed=true
testing program (duration=37.948859826s, {Threaded:false Repeat:true RepeatTimes:0 Procs:1 Slowdown:1 Sandbox: SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:false HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): bpf$BPF_PROG_WITH_BTFID_LOAD-bpf$ITER_CREATE-close-socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$EVIOCGMASK
detailed listing:
executing program 0:
r0 = bpf$BPF_PROG_WITH_BTFID_LOAD(0x5, &(0x7f0000000280)=@bpf_lsm={0x6, 0x3, &(0x7f00000003c0)=ANY=[@ANYBLOB="18000000003f000000000000000000f195"], &(0x7f0000000140)='GPL\x00'}, 0x80)
r1 = bpf$ITER_CREATE(0xb, &(0x7f00000004c0)={r0}, 0x8)
close(r1)
r2 = socket$pppl2tp(0x18, 0x1, 0x1)
r3 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r2, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r3, {0x2, 0x4e23, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e)
ioctl$EVIOCGMASK(r1, 0x80104592, 0x0)

program crashed: KASAN: use-after-free Read in pppol2tp_sock_to_session
validation run: crashed=true
reproducing took 20m4.546224953s
repro crashed as (corrupted=false):
==================================================================
BUG: KASAN: use-after-free in pppol2tp_sock_to_session+0x1a0/0x1b0 net/l2tp/l2tp_ppp.c:156
Read of size 4 at addr ffff888110192000 by task syz.2.20/376

CPU: 1 PID: 376 Comm: syz.2.20 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:88
 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:427 [inline]
 kasan_report+0x10f/0x150 mm/kasan/report.c:444
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308
 pppol2tp_sock_to_session+0x1a0/0x1b0 net/l2tp/l2tp_ppp.c:156
 pppol2tp_release+0x150/0x2b0 net/l2tp/l2tp_ppp.c:435
 __sock_release net/socket.c:649 [inline]
 sock_close+0xb8/0x200 net/socket.c:1335
 __fput+0x22b/0x900 fs/file_table.c:311
 ____fput+0x15/0x20 fs/file_table.c:339
 task_work_run+0x127/0x190 kernel/task_work.c:188
 exit_task_work include/linux/task_work.h:33 [inline]
 do_exit+0xb70/0x29a0 kernel/exit.c:890
 do_group_exit+0x149/0x310 kernel/exit.c:1004
 __do_sys_exit_group kernel/exit.c:1015 [inline]
 __se_sys_exit_group kernel/exit.c:1013 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1013
 x64_sys_call+0x832/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f2ed78c5e59
Code: Unable to access opcode bytes at RIP 0x7f2ed78c5e2f.
RSP: 002b:00007ffefa1eed08 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f2ed78c5e59
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffefa1eed6c R08: 0000000000000000 R09: 00000000000927c0
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000003
R13: 00000000000927c0 R14: 0000000000006e08 R15: 00007ffefa1eedc0
 </TASK>

Allocated by task 376:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:433 [inline]
 ____kasan_kmalloc mm/kasan/common.c:512 [inline]
 __kasan_kmalloc+0xd4/0x100 mm/kasan/common.c:521
 kasan_kmalloc include/linux/kasan.h:227 [inline]
 __kmalloc+0x13d/0x2c0 mm/slub.c:4436
 kmalloc include/linux/slab.h:624 [inline]
 kzalloc include/linux/slab.h:750 [inline]
 l2tp_session_create+0x39/0xb60 net/l2tp/l2tp_core.c:1616
 pppol2tp_connect+0xbf5/0x1640 net/l2tp/l2tp_ppp.c:772
 __sys_connect_file net/socket.c:1922 [inline]
 __sys_connect+0x3cb/0x450 net/socket.c:1939
 __do_sys_connect net/socket.c:1949 [inline]
 __se_sys_connect net/socket.c:1946 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:1946
 x64_sys_call+0x7c/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:43
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Freed by task 8:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4a/0x70 mm/kasan/common.c:45
 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370
 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:365
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:373
 kasan_slab_free include/linux/kasan.h:193 [inline]
 slab_free_hook mm/slub.c:1728 [inline]
 slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1754
 slab_free mm/slub.c:3526 [inline]
 kfree+0xc4/0x270 mm/slub.c:4588
 l2tp_session_free net/l2tp/l2tp_core.c:168 [inline]
 l2tp_session_put+0xaf/0x1a0 net/l2tp/l2tp_core.c:193
 l2tp_session_delete+0x3a9/0x4a0 net/l2tp/l2tp_core.c:1589
 l2tp_tunnel_closeall net/l2tp/l2tp_core.c:1235 [inline]
 l2tp_tunnel_del_work+0x180/0x3d0 net/l2tp/l2tp_core.c:1273
 process_one_work+0x6c8/0xbb0 kernel/workqueue.c:2328
 worker_thread+0xaa0/0x1250 kernel/workqueue.c:2475
 kthread+0x3f5/0x4f0 kernel/kthread.c:337
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

The buggy address belongs to the object at ffff888110192000
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 0 bytes inside of
 512-byte region [ffff888110192000, ffff888110192200)
The buggy address belongs to the page:
page:ffffea0004406400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x110190
head:ffffea0004406400 order:2 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=1)
raw: 4000000000010200 ffffea0004450200 0000000400000004 ffff888100042f00
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 103, ts 5596955464, free_ts 0
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2607
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2613
 get_page_from_freelist+0x2c3a/0x2cd0 mm/page_alloc.c:4487
 __alloc_pages+0x1a2/0x460 mm/page_alloc.c:5824
 alloc_slab_page mm/slub.c:-1 [inline]
 allocate_slab mm/slub.c:1937 [inline]
 new_slab+0xa0/0x4d0 mm/slub.c:2000
 ___slab_alloc+0x3ac/0x840 mm/slub.c:3033
 __slab_alloc+0x49/0x90 mm/slub.c:3120
 slab_alloc_node mm/slub.c:3211 [inline]
 slab_alloc mm/slub.c:3255 [inline]
 __kmalloc_track_caller+0x169/0x2c0 mm/slub.c:4954
 kmalloc_reserve net/core/skbuff.c:357 [inline]
 __alloc_skb+0x210/0x730 net/core/skbuff.c:428
 alloc_skb include/linux/skbuff.h:1183 [inline]
 alloc_skb_with_frags+0xa8/0x620 net/core/skbuff.c:6207
 sock_alloc_send_pskb+0x87f/0x9a0 net/core/sock.c:2542
 unix_dgram_sendmsg+0x6f3/0x19b0 net/unix/af_unix.c:1816
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 sock_write_iter+0x2a6/0x3a0 net/socket.c:1079
 call_write_iter include/linux/fs.h:2212 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x831/0xfd0 fs/read_write.c:594
 ksys_write+0x14a/0x260 fs/read_write.c:647
 __do_sys_write fs/read_write.c:659 [inline]
 __se_sys_write fs/read_write.c:656 [inline]
 __x64_sys_write+0x7b/0x90 fs/read_write.c:656
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888110191f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888110191f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888110192000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff888110192080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888110192100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
------------[ cut here ]------------
WARNING: CPU: 1 PID: 376 at net/l2tp/l2tp_ppp.c:156 pppol2tp_sock_to_session+0x167/0x1b0 net/l2tp/l2tp_ppp.c:156
Modules linked in:
CPU: 1 PID: 376 Comm: syz.2.20 Tainted: G    B             syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:pppol2tp_sock_to_session+0x167/0x1b0 net/l2tp/l2tp_ppp.c:156
Code: 5d c3 e8 1c f1 0b fd be 02 00 00 00 eb 0a e8 10 f1 0b fd be 01 00 00 00 4c 89 f7 e8 a3 60 f2 fd e9 0f ff ff ff e8 f9 f0 0b fd <0f> 0b 48 89 df e8 ef 00 00 00 eb bd e8 e8 f0 0b fd 4c 89 f7 be 03
RSP: 0018:ffffc90000aa7b90 EFLAGS: 00010293
RAX: ffffffff845dbbf7 RBX: ffff888111891000 RCX: ffff888110e393c0
RDX: 0000000000000000 RSI: 000000002c8ebbc0 RDI: 000000000c04eb7d
RBP: ffffc90000aa7bb0 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff0e18c4c R12: dffffc0000000000
R13: dffffc0000000000 R14: 000000002c8ebbc0 R15: ffff888110192000
FS:  0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002aa447c59000 CR3: 000000010f854000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 pppol2tp_release+0x150/0x2b0 net/l2tp/l2tp_ppp.c:435
 __sock_release net/socket.c:649 [inline]
 sock_close+0xb8/0x200 net/socket.c:1335
 __fput+0x22b/0x900 fs/file_table.c:311
 ____fput+0x15/0x20 fs/file_table.c:339
 task_work_run+0x127/0x190 kernel/task_work.c:188
 exit_task_work include/linux/task_work.h:33 [inline]
 do_exit+0xb70/0x29a0 kernel/exit.c:890
 do_group_exit+0x149/0x310 kernel/exit.c:1004
 __do_sys_exit_group kernel/exit.c:1015 [inline]
 __se_sys_exit_group kernel/exit.c:1013 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1013
 x64_sys_call+0x832/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f2ed78c5e59
Code: Unable to access opcode bytes at RIP 0x7f2ed78c5e2f.
RSP: 002b:00007ffefa1eed08 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f2ed78c5e59
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffefa1eed6c R08: 0000000000000000 R09: 00000000000927c0
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000003
R13: 00000000000927c0 R14: 0000000000006e08 R15: 00007ffefa1eedc0
 </TASK>
---[ end trace 2cd116f6e4dca291 ]---

final repro crashed as (corrupted=false):
==================================================================
BUG: KASAN: use-after-free in pppol2tp_sock_to_session+0x1a0/0x1b0 net/l2tp/l2tp_ppp.c:156
Read of size 4 at addr ffff888110192000 by task syz.2.20/376

CPU: 1 PID: 376 Comm: syz.2.20 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:88
 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:427 [inline]
 kasan_report+0x10f/0x150 mm/kasan/report.c:444
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:308
 pppol2tp_sock_to_session+0x1a0/0x1b0 net/l2tp/l2tp_ppp.c:156
 pppol2tp_release+0x150/0x2b0 net/l2tp/l2tp_ppp.c:435
 __sock_release net/socket.c:649 [inline]
 sock_close+0xb8/0x200 net/socket.c:1335
 __fput+0x22b/0x900 fs/file_table.c:311
 ____fput+0x15/0x20 fs/file_table.c:339
 task_work_run+0x127/0x190 kernel/task_work.c:188
 exit_task_work include/linux/task_work.h:33 [inline]
 do_exit+0xb70/0x29a0 kernel/exit.c:890
 do_group_exit+0x149/0x310 kernel/exit.c:1004
 __do_sys_exit_group kernel/exit.c:1015 [inline]
 __se_sys_exit_group kernel/exit.c:1013 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1013
 x64_sys_call+0x832/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f2ed78c5e59
Code: Unable to access opcode bytes at RIP 0x7f2ed78c5e2f.
RSP: 002b:00007ffefa1eed08 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f2ed78c5e59
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffefa1eed6c R08: 0000000000000000 R09: 00000000000927c0
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000003
R13: 00000000000927c0 R14: 0000000000006e08 R15: 00007ffefa1eedc0
 </TASK>

Allocated by task 376:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:433 [inline]
 ____kasan_kmalloc mm/kasan/common.c:512 [inline]
 __kasan_kmalloc+0xd4/0x100 mm/kasan/common.c:521
 kasan_kmalloc include/linux/kasan.h:227 [inline]
 __kmalloc+0x13d/0x2c0 mm/slub.c:4436
 kmalloc include/linux/slab.h:624 [inline]
 kzalloc include/linux/slab.h:750 [inline]
 l2tp_session_create+0x39/0xb60 net/l2tp/l2tp_core.c:1616
 pppol2tp_connect+0xbf5/0x1640 net/l2tp/l2tp_ppp.c:772
 __sys_connect_file net/socket.c:1922 [inline]
 __sys_connect+0x3cb/0x450 net/socket.c:1939
 __do_sys_connect net/socket.c:1949 [inline]
 __se_sys_connect net/socket.c:1946 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:1946
 x64_sys_call+0x7c/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:43
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Freed by task 8:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4a/0x70 mm/kasan/common.c:45
 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370
 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:365
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:373
 kasan_slab_free include/linux/kasan.h:193 [inline]
 slab_free_hook mm/slub.c:1728 [inline]
 slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1754
 slab_free mm/slub.c:3526 [inline]
 kfree+0xc4/0x270 mm/slub.c:4588
 l2tp_session_free net/l2tp/l2tp_core.c:168 [inline]
 l2tp_session_put+0xaf/0x1a0 net/l2tp/l2tp_core.c:193
 l2tp_session_delete+0x3a9/0x4a0 net/l2tp/l2tp_core.c:1589
 l2tp_tunnel_closeall net/l2tp/l2tp_core.c:1235 [inline]
 l2tp_tunnel_del_work+0x180/0x3d0 net/l2tp/l2tp_core.c:1273
 process_one_work+0x6c8/0xbb0 kernel/workqueue.c:2328
 worker_thread+0xaa0/0x1250 kernel/workqueue.c:2475
 kthread+0x3f5/0x4f0 kernel/kthread.c:337
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

The buggy address belongs to the object at ffff888110192000
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 0 bytes inside of
 512-byte region [ffff888110192000, ffff888110192200)
The buggy address belongs to the page:
page:ffffea0004406400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x110190
head:ffffea0004406400 order:2 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=1)
raw: 4000000000010200 ffffea0004450200 0000000400000004 ffff888100042f00
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 103, ts 5596955464, free_ts 0
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2607
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2613
 get_page_from_freelist+0x2c3a/0x2cd0 mm/page_alloc.c:4487
 __alloc_pages+0x1a2/0x460 mm/page_alloc.c:5824
 alloc_slab_page mm/slub.c:-1 [inline]
 allocate_slab mm/slub.c:1937 [inline]
 new_slab+0xa0/0x4d0 mm/slub.c:2000
 ___slab_alloc+0x3ac/0x840 mm/slub.c:3033
 __slab_alloc+0x49/0x90 mm/slub.c:3120
 slab_alloc_node mm/slub.c:3211 [inline]
 slab_alloc mm/slub.c:3255 [inline]
 __kmalloc_track_caller+0x169/0x2c0 mm/slub.c:4954
 kmalloc_reserve net/core/skbuff.c:357 [inline]
 __alloc_skb+0x210/0x730 net/core/skbuff.c:428
 alloc_skb include/linux/skbuff.h:1183 [inline]
 alloc_skb_with_frags+0xa8/0x620 net/core/skbuff.c:6207
 sock_alloc_send_pskb+0x87f/0x9a0 net/core/sock.c:2542
 unix_dgram_sendmsg+0x6f3/0x19b0 net/unix/af_unix.c:1816
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 sock_write_iter+0x2a6/0x3a0 net/socket.c:1079
 call_write_iter include/linux/fs.h:2212 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x831/0xfd0 fs/read_write.c:594
 ksys_write+0x14a/0x260 fs/read_write.c:647
 __do_sys_write fs/read_write.c:659 [inline]
 __se_sys_write fs/read_write.c:656 [inline]
 __x64_sys_write+0x7b/0x90 fs/read_write.c:656
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888110191f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888110191f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888110192000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff888110192080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888110192100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
------------[ cut here ]------------
WARNING: CPU: 1 PID: 376 at net/l2tp/l2tp_ppp.c:156 pppol2tp_sock_to_session+0x167/0x1b0 net/l2tp/l2tp_ppp.c:156
Modules linked in:
CPU: 1 PID: 376 Comm: syz.2.20 Tainted: G    B             syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:pppol2tp_sock_to_session+0x167/0x1b0 net/l2tp/l2tp_ppp.c:156
Code: 5d c3 e8 1c f1 0b fd be 02 00 00 00 eb 0a e8 10 f1 0b fd be 01 00 00 00 4c 89 f7 e8 a3 60 f2 fd e9 0f ff ff ff e8 f9 f0 0b fd <0f> 0b 48 89 df e8 ef 00 00 00 eb bd e8 e8 f0 0b fd 4c 89 f7 be 03
RSP: 0018:ffffc90000aa7b90 EFLAGS: 00010293
RAX: ffffffff845dbbf7 RBX: ffff888111891000 RCX: ffff888110e393c0
RDX: 0000000000000000 RSI: 000000002c8ebbc0 RDI: 000000000c04eb7d
RBP: ffffc90000aa7bb0 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff0e18c4c R12: dffffc0000000000
R13: dffffc0000000000 R14: 000000002c8ebbc0 R15: ffff888110192000
FS:  0000000000000000(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002aa447c59000 CR3: 000000010f854000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 pppol2tp_release+0x150/0x2b0 net/l2tp/l2tp_ppp.c:435
 __sock_release net/socket.c:649 [inline]
 sock_close+0xb8/0x200 net/socket.c:1335
 __fput+0x22b/0x900 fs/file_table.c:311
 ____fput+0x15/0x20 fs/file_table.c:339
 task_work_run+0x127/0x190 kernel/task_work.c:188
 exit_task_work include/linux/task_work.h:33 [inline]
 do_exit+0xb70/0x29a0 kernel/exit.c:890
 do_group_exit+0x149/0x310 kernel/exit.c:1004
 __do_sys_exit_group kernel/exit.c:1015 [inline]
 __se_sys_exit_group kernel/exit.c:1013 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1013
 x64_sys_call+0x832/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f2ed78c5e59
Code: Unable to access opcode bytes at RIP 0x7f2ed78c5e2f.
RSP: 002b:00007ffefa1eed08 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f2ed78c5e59
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffefa1eed6c R08: 0000000000000000 R09: 00000000000927c0
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000003
R13: 00000000000927c0 R14: 0000000000006e08 R15: 00007ffefa1eedc0
 </TASK>
---[ end trace 2cd116f6e4dca291 ]---