Extracting prog: 24.367433237s
Minimizing prog: 11m17.115329616s
Simplifying prog options: 0s
Extracting C: 35.430481102s
Simplifying C: 5m41.39826131s


extracting reproducer from 86 programs
first checking the prog from the crash report
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}}): socket$pppl2tp-socket$inet_udp-ioctl$ifreq_SIOCGIFINDEX_vcan-socket$inet-openat$vcsu-bpf$MAP_CREATE-bpf$BPF_GET_PROG_INFO-connect$pppl2tp-getpeername$packet-sendmmsg-ioctl$SIOCSIFMTU
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet_udp(0x2, 0x2, 0x0)
ioctl$ifreq_SIOCGIFINDEX_vcan(r0, 0x8933, &(0x7f0000000040)={'vcan0\x00', <r2=>0x0})
socket$inet(0x2, 0xa, 0x9)
r3 = openat$vcsu(0xffffffffffffff9c, &(0x7f0000000080), 0x10000, 0x0)
r4 = bpf$MAP_CREATE(0x0, &(0x7f00000000c0)=@base={0x20, 0x7e, 0x43, 0x1fffffd, 0x0, 0xffffffffffffffff, 0x0, '\x00', r2}, 0x50)
bpf$BPF_GET_PROG_INFO(0x4, &(0x7f0000000140)={r4, 0x0, 0x0}, 0x10)
connect$pppl2tp(r0, &(0x7f0000000240)=@pppol2tpin6={0x18, 0x1, {0x0, r1, 0x2, 0x0, 0x0, 0x0, {0xa, 0x4e22, 0x2, @rand_addr=' \x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02'}}}, 0x32)
getpeername$packet(r3, &(0x7f0000000180)={0x11, 0x0, 0x0, 0x1, 0x0, 0x6, @link_local}, &(0x7f00000001c0)=0x14)
sendmmsg(r0, &(0x7f0000004380)=[{{0x0, 0x0, 0x0}}], 0x34000, 0x0)
ioctl$SIOCSIFMTU(r0, 0x8922, &(0x7f0000000000)={'veth0_virt_wifi\x00', 0xe})

program crashed: KASAN: use-after-free Write in pppol2tp_release
single: successfully extracted reproducer
found reproducer with 11 syscalls
minimizing guilty program
testing program (duration=32.408959939s, {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}}): socket$pppl2tp-socket$inet_udp-ioctl$ifreq_SIOCGIFINDEX_vcan-socket$inet-openat$vcsu-bpf$MAP_CREATE-bpf$BPF_GET_PROG_INFO-connect$pppl2tp-getpeername$packet-sendmmsg
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet_udp(0x2, 0x2, 0x0)
ioctl$ifreq_SIOCGIFINDEX_vcan(r0, 0x8933, &(0x7f0000000040)={'vcan0\x00', <r2=>0x0})
socket$inet(0x2, 0xa, 0x9)
r3 = openat$vcsu(0xffffffffffffff9c, &(0x7f0000000080), 0x10000, 0x0)
r4 = bpf$MAP_CREATE(0x0, &(0x7f00000000c0)=@base={0x20, 0x7e, 0x43, 0x1fffffd, 0x0, 0xffffffffffffffff, 0x0, '\x00', r2}, 0x50)
bpf$BPF_GET_PROG_INFO(0x4, &(0x7f0000000140)={r4, 0x0, 0x0}, 0x10)
connect$pppl2tp(r0, &(0x7f0000000240)=@pppol2tpin6={0x18, 0x1, {0x0, r1, 0x2, 0x0, 0x0, 0x0, {0xa, 0x4e22, 0x2, @rand_addr=' \x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02'}}}, 0x32)
getpeername$packet(r3, &(0x7f0000000180)={0x11, 0x0, 0x0, 0x1, 0x0, 0x6, @link_local}, &(0x7f00000001c0)=0x14)
sendmmsg(r0, &(0x7f0000004380)=[{{0x0, 0x0, 0x0}}], 0x34000, 0x0)

program did not crash
testing program (duration=32.408959939s, {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}}): socket$pppl2tp-socket$inet_udp-ioctl$ifreq_SIOCGIFINDEX_vcan-socket$inet-openat$vcsu-bpf$MAP_CREATE-bpf$BPF_GET_PROG_INFO-connect$pppl2tp-getpeername$packet-ioctl$SIOCSIFMTU
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet_udp(0x2, 0x2, 0x0)
ioctl$ifreq_SIOCGIFINDEX_vcan(r0, 0x8933, &(0x7f0000000040)={'vcan0\x00', <r2=>0x0})
socket$inet(0x2, 0xa, 0x9)
r3 = openat$vcsu(0xffffffffffffff9c, &(0x7f0000000080), 0x10000, 0x0)
r4 = bpf$MAP_CREATE(0x0, &(0x7f00000000c0)=@base={0x20, 0x7e, 0x43, 0x1fffffd, 0x0, 0xffffffffffffffff, 0x0, '\x00', r2}, 0x50)
bpf$BPF_GET_PROG_INFO(0x4, &(0x7f0000000140)={r4, 0x0, 0x0}, 0x10)
connect$pppl2tp(r0, &(0x7f0000000240)=@pppol2tpin6={0x18, 0x1, {0x0, r1, 0x2, 0x0, 0x0, 0x0, {0xa, 0x4e22, 0x2, @rand_addr=' \x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02'}}}, 0x32)
getpeername$packet(r3, &(0x7f0000000180)={0x11, 0x0, 0x0, 0x1, 0x0, 0x6, @link_local}, &(0x7f00000001c0)=0x14)
ioctl$SIOCSIFMTU(r0, 0x8922, &(0x7f0000000000)={'veth0_virt_wifi\x00', 0xe})

program crashed: KASAN: use-after-free Write in pppol2tp_release
testing program (duration=32.408959939s, {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}}): socket$pppl2tp-socket$inet_udp-ioctl$ifreq_SIOCGIFINDEX_vcan-socket$inet-openat$vcsu-bpf$MAP_CREATE-bpf$BPF_GET_PROG_INFO-connect$pppl2tp-ioctl$SIOCSIFMTU
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet_udp(0x2, 0x2, 0x0)
ioctl$ifreq_SIOCGIFINDEX_vcan(r0, 0x8933, &(0x7f0000000040)={'vcan0\x00', <r2=>0x0})
socket$inet(0x2, 0xa, 0x9)
openat$vcsu(0xffffffffffffff9c, &(0x7f0000000080), 0x10000, 0x0)
r3 = bpf$MAP_CREATE(0x0, &(0x7f00000000c0)=@base={0x20, 0x7e, 0x43, 0x1fffffd, 0x0, 0xffffffffffffffff, 0x0, '\x00', r2}, 0x50)
bpf$BPF_GET_PROG_INFO(0x4, &(0x7f0000000140)={r3, 0x0, 0x0}, 0x10)
connect$pppl2tp(r0, &(0x7f0000000240)=@pppol2tpin6={0x18, 0x1, {0x0, r1, 0x2, 0x0, 0x0, 0x0, {0xa, 0x4e22, 0x2, @rand_addr=' \x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02'}}}, 0x32)
ioctl$SIOCSIFMTU(r0, 0x8922, &(0x7f0000000000)={'veth0_virt_wifi\x00', 0xe})

program crashed: KASAN: use-after-free Write in pppol2tp_release
testing program (duration=32.408959939s, {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}}): socket$pppl2tp-socket$inet_udp-ioctl$ifreq_SIOCGIFINDEX_vcan-socket$inet-openat$vcsu-bpf$MAP_CREATE-bpf$BPF_GET_PROG_INFO-ioctl$SIOCSIFMTU
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
socket$inet_udp(0x2, 0x2, 0x0)
ioctl$ifreq_SIOCGIFINDEX_vcan(r0, 0x8933, &(0x7f0000000040)={'vcan0\x00', <r1=>0x0})
socket$inet(0x2, 0xa, 0x9)
openat$vcsu(0xffffffffffffff9c, &(0x7f0000000080), 0x10000, 0x0)
r2 = bpf$MAP_CREATE(0x0, &(0x7f00000000c0)=@base={0x20, 0x7e, 0x43, 0x1fffffd, 0x0, 0xffffffffffffffff, 0x0, '\x00', r1}, 0x50)
bpf$BPF_GET_PROG_INFO(0x4, &(0x7f0000000140)={r2, 0x0, 0x0}, 0x10)
ioctl$SIOCSIFMTU(r0, 0x8922, &(0x7f0000000000)={'veth0_virt_wifi\x00', 0xe})

program did not crash
testing program (duration=32.408959939s, {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}}): socket$pppl2tp-socket$inet_udp-ioctl$ifreq_SIOCGIFINDEX_vcan-socket$inet-openat$vcsu-bpf$MAP_CREATE-connect$pppl2tp-ioctl$SIOCSIFMTU
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet_udp(0x2, 0x2, 0x0)
ioctl$ifreq_SIOCGIFINDEX_vcan(r0, 0x8933, &(0x7f0000000040)={'vcan0\x00', <r2=>0x0})
socket$inet(0x2, 0xa, 0x9)
openat$vcsu(0xffffffffffffff9c, &(0x7f0000000080), 0x10000, 0x0)
bpf$MAP_CREATE(0x0, &(0x7f00000000c0)=@base={0x20, 0x7e, 0x43, 0x1fffffd, 0x0, 0xffffffffffffffff, 0x0, '\x00', r2}, 0x50)
connect$pppl2tp(r0, &(0x7f0000000240)=@pppol2tpin6={0x18, 0x1, {0x0, r1, 0x2, 0x0, 0x0, 0x0, {0xa, 0x4e22, 0x2, @rand_addr=' \x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02'}}}, 0x32)
ioctl$SIOCSIFMTU(r0, 0x8922, &(0x7f0000000000)={'veth0_virt_wifi\x00', 0xe})

program crashed: KASAN: use-after-free Write in pppol2tp_release
testing program (duration=32.408959939s, {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}}): socket$pppl2tp-socket$inet_udp-ioctl$ifreq_SIOCGIFINDEX_vcan-socket$inet-openat$vcsu-connect$pppl2tp-ioctl$SIOCSIFMTU
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet_udp(0x2, 0x2, 0x0)
ioctl$ifreq_SIOCGIFINDEX_vcan(r0, 0x8933, &(0x7f0000000040)={'vcan0\x00'})
socket$inet(0x2, 0xa, 0x9)
openat$vcsu(0xffffffffffffff9c, &(0x7f0000000080), 0x10000, 0x0)
connect$pppl2tp(r0, &(0x7f0000000240)=@pppol2tpin6={0x18, 0x1, {0x0, r1, 0x2, 0x0, 0x0, 0x0, {0xa, 0x4e22, 0x2, @rand_addr=' \x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02'}}}, 0x32)
ioctl$SIOCSIFMTU(r0, 0x8922, &(0x7f0000000000)={'veth0_virt_wifi\x00', 0xe})

program crashed: KASAN: use-after-free Write in pppol2tp_release
testing program (duration=32.408959939s, {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}}): socket$pppl2tp-socket$inet_udp-ioctl$ifreq_SIOCGIFINDEX_vcan-socket$inet-connect$pppl2tp-ioctl$SIOCSIFMTU
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet_udp(0x2, 0x2, 0x0)
ioctl$ifreq_SIOCGIFINDEX_vcan(r0, 0x8933, &(0x7f0000000040)={'vcan0\x00'})
socket$inet(0x2, 0xa, 0x9)
connect$pppl2tp(r0, &(0x7f0000000240)=@pppol2tpin6={0x18, 0x1, {0x0, r1, 0x2, 0x0, 0x0, 0x0, {0xa, 0x4e22, 0x2, @rand_addr=' \x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02'}}}, 0x32)
ioctl$SIOCSIFMTU(r0, 0x8922, &(0x7f0000000000)={'veth0_virt_wifi\x00', 0xe})

program crashed: KASAN: use-after-free Write in pppol2tp_release
testing program (duration=32.408959939s, {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}}): socket$pppl2tp-socket$inet_udp-ioctl$ifreq_SIOCGIFINDEX_vcan-connect$pppl2tp-ioctl$SIOCSIFMTU
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet_udp(0x2, 0x2, 0x0)
ioctl$ifreq_SIOCGIFINDEX_vcan(r0, 0x8933, &(0x7f0000000040)={'vcan0\x00'})
connect$pppl2tp(r0, &(0x7f0000000240)=@pppol2tpin6={0x18, 0x1, {0x0, r1, 0x2, 0x0, 0x0, 0x0, {0xa, 0x4e22, 0x2, @rand_addr=' \x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02'}}}, 0x32)
ioctl$SIOCSIFMTU(r0, 0x8922, &(0x7f0000000000)={'veth0_virt_wifi\x00', 0xe})

program crashed: KASAN: use-after-free Write in pppol2tp_release
testing program (duration=32.408959939s, {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}}): socket$pppl2tp-socket$inet_udp-connect$pppl2tp-ioctl$SIOCSIFMTU
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet_udp(0x2, 0x2, 0x0)
connect$pppl2tp(r0, &(0x7f0000000240)=@pppol2tpin6={0x18, 0x1, {0x0, r1, 0x2, 0x0, 0x0, 0x0, {0xa, 0x4e22, 0x2, @rand_addr=' \x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02'}}}, 0x32)
ioctl$SIOCSIFMTU(r0, 0x8922, &(0x7f0000000000)={'veth0_virt_wifi\x00', 0xe})

program crashed: KASAN: use-after-free Write in pppol2tp_release
testing program (duration=32.408959939s, {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}}): socket$pppl2tp-connect$pppl2tp-ioctl$SIOCSIFMTU
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
connect$pppl2tp(r0, &(0x7f0000000240)=@pppol2tpin6={0x18, 0x1, {0x0, 0xffffffffffffffff, 0x2, 0x0, 0x0, 0x0, {0xa, 0x4e22, 0x2, @rand_addr=' \x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02'}}}, 0x32)
ioctl$SIOCSIFMTU(r0, 0x8922, &(0x7f0000000000)={'veth0_virt_wifi\x00', 0xe})

program did not crash
testing program (duration=32.408959939s, {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}}): socket$inet_udp-connect$pppl2tp-ioctl$SIOCSIFMTU
detailed listing:
executing program 0:
r0 = socket$inet_udp(0x2, 0x2, 0x0)
connect$pppl2tp(0xffffffffffffffff, &(0x7f0000000240)=@pppol2tpin6={0x18, 0x1, {0x0, r0, 0x2, 0x0, 0x0, 0x0, {0xa, 0x4e22, 0x2, @rand_addr=' \x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02'}}}, 0x32)
ioctl$SIOCSIFMTU(0xffffffffffffffff, 0x8922, &(0x7f0000000000)={'veth0_virt_wifi\x00', 0xe})

program did not crash
testing program (duration=32.408959939s, {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}}): socket$pppl2tp-socket$inet_udp-connect$pppl2tp-ioctl$SIOCSIFMTU
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
socket$inet_udp(0x2, 0x2, 0x0)
connect$pppl2tp(r0, 0x0, 0x0)
ioctl$SIOCSIFMTU(r0, 0x8922, &(0x7f0000000000)={'veth0_virt_wifi\x00', 0xe})

program did not crash
testing program (duration=32.408959939s, {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}}): socket$pppl2tp-socket$inet_udp-connect$pppl2tp-ioctl$SIOCSIFMTU
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet_udp(0x2, 0x2, 0x0)
connect$pppl2tp(r0, &(0x7f0000000240)=@pppol2tpin6={0x18, 0x1, {0x0, r1, 0x2, 0x0, 0x0, 0x0, {0xa, 0x4e22, 0x2, @rand_addr=' \x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02'}}}, 0x32)
ioctl$SIOCSIFMTU(r0, 0x8922, 0x0)

program crashed: KASAN: use-after-free Write in pppol2tp_release
extracting C reproducer
testing compiled C program (duration=32.408959939s, {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}}): socket$pppl2tp-socket$inet_udp-connect$pppl2tp-ioctl$SIOCSIFMTU
program crashed: KASAN: use-after-free Write in pppol2tp_release
simplifying C reproducer
testing compiled C program (duration=32.408959939s, {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}}): socket$pppl2tp-socket$inet_udp-connect$pppl2tp-ioctl$SIOCSIFMTU
program crashed: KASAN: use-after-free Write in pppol2tp_release
testing compiled C program (duration=32.408959939s, {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}}): socket$pppl2tp-socket$inet_udp-connect$pppl2tp-ioctl$SIOCSIFMTU
program crashed: KASAN: use-after-free Write in pppol2tp_release
testing compiled C program (duration=32.408959939s, {Threaded:false Repeat:false 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}}): socket$pppl2tp-socket$inet_udp-connect$pppl2tp-ioctl$SIOCSIFMTU
program crashed: KASAN: use-after-free Read in pppol2tp_sock_to_session
a never seen crash title: KASAN: use-after-free Read in pppol2tp_sock_to_session, ignore
testing compiled C program (duration=32.408959939s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:false 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}}): socket$pppl2tp-socket$inet_udp-connect$pppl2tp-ioctl$SIOCSIFMTU
program crashed: KASAN: use-after-free Write in pppol2tp_release
testing compiled C program (duration=32.408959939s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:false NetDevices:false 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}}): socket$pppl2tp-socket$inet_udp-connect$pppl2tp-ioctl$SIOCSIFMTU
program crashed: KASAN: use-after-free Write in pppol2tp_release
testing compiled C program (duration=32.408959939s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false 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}}): socket$pppl2tp-socket$inet_udp-connect$pppl2tp-ioctl$SIOCSIFMTU
program crashed: KASAN: use-after-free Write in pppol2tp_release
testing compiled C program (duration=32.408959939s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:false 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}}): socket$pppl2tp-socket$inet_udp-connect$pppl2tp-ioctl$SIOCSIFMTU
program crashed: KASAN: use-after-free Read in pppol2tp_sock_to_session
a never seen crash title: KASAN: use-after-free Read in pppol2tp_sock_to_session, ignore
testing compiled C program (duration=32.408959939s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:false 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}}): socket$pppl2tp-socket$inet_udp-connect$pppl2tp-ioctl$SIOCSIFMTU
program crashed: KASAN: use-after-free Write in pppol2tp_release
testing compiled C program (duration=32.408959939s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:false HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$pppl2tp-socket$inet_udp-connect$pppl2tp-ioctl$SIOCSIFMTU
program crashed: KASAN: use-after-free Write in pppol2tp_release
testing compiled C program (duration=32.408959939s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:true Swap:true UseTmpDir:false HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$pppl2tp-socket$inet_udp-connect$pppl2tp-ioctl$SIOCSIFMTU
program crashed: KASAN: use-after-free Write in pppol2tp_release
testing compiled C program (duration=32.408959939s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:true UseTmpDir:false HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$pppl2tp-socket$inet_udp-connect$pppl2tp-ioctl$SIOCSIFMTU
program crashed: KASAN: use-after-free Write in pppol2tp_release
testing compiled C program (duration=32.408959939s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:false HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$pppl2tp-socket$inet_udp-connect$pppl2tp-ioctl$SIOCSIFMTU
program crashed: KASAN: use-after-free Write in pppol2tp_release
testing program (duration=32.408959939s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:false HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$pppl2tp-socket$inet_udp-connect$pppl2tp-ioctl$SIOCSIFMTU
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet_udp(0x2, 0x2, 0x0)
connect$pppl2tp(r0, &(0x7f0000000240)=@pppol2tpin6={0x18, 0x1, {0x0, r1, 0x2, 0x0, 0x0, 0x0, {0xa, 0x4e22, 0x2, @rand_addr=' \x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02'}}}, 0x32)
ioctl$SIOCSIFMTU(r0, 0x8922, 0x0)

program crashed: KASAN: use-after-free Write in pppol2tp_release
validation run: crashed=true
testing program (duration=32.408959939s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:false HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$pppl2tp-socket$inet_udp-connect$pppl2tp-ioctl$SIOCSIFMTU
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet_udp(0x2, 0x2, 0x0)
connect$pppl2tp(r0, &(0x7f0000000240)=@pppol2tpin6={0x18, 0x1, {0x0, r1, 0x2, 0x0, 0x0, 0x0, {0xa, 0x4e22, 0x2, @rand_addr=' \x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02'}}}, 0x32)
ioctl$SIOCSIFMTU(r0, 0x8922, 0x0)

program crashed: KASAN: use-after-free Write in pppol2tp_release
validation run: crashed=true
testing program (duration=32.408959939s, {Threaded:false Repeat:false RepeatTimes:0 Procs:1 Slowdown:1 Sandbox:none SandboxArg:0 Leak:false NetInjection:false NetDevices:false NetReset:false Cgroups:false BinfmtMisc:false CloseFDs:true KCSAN:false DevlinkPCI:false NicVF:false USB:false VhciInjection:false Wifi:false IEEE802154:false Sysctl:false Swap:false UseTmpDir:false HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$pppl2tp-socket$inet_udp-connect$pppl2tp-ioctl$SIOCSIFMTU
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet_udp(0x2, 0x2, 0x0)
connect$pppl2tp(r0, &(0x7f0000000240)=@pppol2tpin6={0x18, 0x1, {0x0, r1, 0x2, 0x0, 0x0, 0x0, {0xa, 0x4e22, 0x2, @rand_addr=' \x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02'}}}, 0x32)
ioctl$SIOCSIFMTU(r0, 0x8922, 0x0)

program crashed: KASAN: use-after-free Write in pppol2tp_release
validation run: crashed=true
reproducing took 19m10.458765178s
repro crashed as (corrupted=false):
==================================================================
BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:102 [inline]
BUG: KASAN: use-after-free in atomic_long_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1779 [inline]
BUG: KASAN: use-after-free in __mutex_trylock_fast kernel/locking/mutex.c:176 [inline]
BUG: KASAN: use-after-free in mutex_lock+0x86/0x1b0 kernel/locking/mutex.c:295
Write of size 8 at addr ffff88812de8f950 by task syz.2.17/375

CPU: 1 PID: 375 Comm: syz.2.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x24 lib/dump_stack.c:88
 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
 print_address_description+0x71/0x200 mm/kasan/report.c:316
 print_report+0x4a/0x60 mm/kasan/report.c:420
 kasan_report+0x122/0x150 mm/kasan/report.c:524
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x249/0x2a0 mm/kasan/generic.c:189
 __kasan_check_write+0x14/0x20 mm/kasan/shadow.c:37
 instrument_atomic_read_write include/linux/instrumented.h:102 [inline]
 atomic_long_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1779 [inline]
 __mutex_trylock_fast kernel/locking/mutex.c:176 [inline]
 mutex_lock+0x86/0x1b0 kernel/locking/mutex.c:295
 pppol2tp_release+0x178/0x2b0 net/l2tp/l2tp_ppp.c:441
 __sock_release net/socket.c:652 [inline]
 sock_close+0xc9/0x220 net/socket.c:1389
 __fput+0x1fd/0x8f0 fs/file_table.c:320
 ____fput+0x15/0x20 fs/file_table.c:348
 task_work_run+0x1e1/0x250 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0x9b/0xb0 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f026099ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffca693628 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fffca693710 RCX: 00007f026099ce59
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 000000000000655d R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b33120000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0260c15fac R14: 00007f0260c15fa8 R15: 00007f0260c15fa0
 </TASK>

Allocated by task 375:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_alloc_info+0x1f/0x30 mm/kasan/generic.c:505
 ____kasan_kmalloc mm/kasan/common.c:380 [inline]
 __kasan_kmalloc+0x95/0xb0 mm/kasan/common.c:389
 kasan_kmalloc include/linux/kasan.h:212 [inline]
 __do_kmalloc_node mm/slab_common.c:938 [inline]
 __kmalloc+0xb4/0x1e0 mm/slab_common.c:951
 kmalloc include/linux/slab.h:568 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 l2tp_session_create+0x38/0xbd0 net/l2tp/l2tp_core.c:1609
 pppol2tp_connect+0xbf5/0x1640 net/l2tp/l2tp_ppp.c:771
 __sys_connect_file net/socket.c:2000 [inline]
 __sys_connect+0x3da/0x460 net/socket.c:2017
 __do_sys_connect net/socket.c:2027 [inline]
 __se_sys_connect net/socket.c:2024 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:2024
 x64_sys_call+0x88d/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:43
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Freed by task 375:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:516
 ____kasan_slab_free+0x132/0x180 mm/kasan/common.c:242
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:250
 kasan_slab_free include/linux/kasan.h:178 [inline]
 slab_free_hook mm/slub.c:1750 [inline]
 slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1776
 slab_free mm/slub.c:3712 [inline]
 __kmem_cache_free+0xb7/0x1b0 mm/slub.c:3728
 kfree+0x6f/0xf0 mm/slab_common.c:990
 l2tp_session_free net/l2tp/l2tp_core.c:168 [inline]
 l2tp_session_put+0xaf/0x1a0 net/l2tp/l2tp_core.c:193
 l2tp_session_delete+0x3df/0x4d0 net/l2tp/l2tp_core.c:1582
 pppol2tp_release+0x169/0x2b0 net/l2tp/l2tp_ppp.c:438
 __sock_release net/socket.c:652 [inline]
 sock_close+0xc9/0x220 net/socket.c:1389
 __fput+0x1fd/0x8f0 fs/file_table.c:320
 ____fput+0x15/0x20 fs/file_table.c:348
 task_work_run+0x1e1/0x250 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0x9b/0xb0 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

The buggy address belongs to the object at ffff88812de8f800
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 336 bytes inside of
 512-byte region [ffff88812de8f800, ffff88812de8fa00)

The buggy address belongs to the physical page:
page:ffffea0004b7a300 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12de8c
head:ffffea0004b7a300 order:2 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=1)
raw: 4000000000010200 0000000000000000 dead000000000122 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 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 370, tgid 370 (syz-executor), ts 25960965973, free_ts 25959966254
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2672
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2679
 get_page_from_freelist+0x2ca9/0x2d20 mm/page_alloc.c:4586
 __alloc_pages+0x1fa/0x610 mm/page_alloc.c:5930
 alloc_slab_page+0x6e/0xf0 include/linux/gfp.h:-1
 allocate_slab mm/slub.c:1967 [inline]
 new_slab+0x98/0x3e0 mm/slub.c:2020
 ___slab_alloc+0x70f/0xb70 mm/slub.c:3177
 __slab_alloc+0x5e/0xa0 mm/slub.c:3263
 slab_alloc_node mm/slub.c:3348 [inline]
 __kmem_cache_alloc_node+0x204/0x2d0 mm/slub.c:3423
 __do_kmalloc_node mm/slab_common.c:937 [inline]
 __kmalloc+0xa4/0x1e0 mm/slab_common.c:951
 kmalloc include/linux/slab.h:568 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 fib6_info_alloc+0x34/0xe0 net/ipv6/ip6_fib.c:156
 ip6_route_info_create+0x51b/0x14d0 net/ipv6/route.c:3796
 ip6_route_add+0x27/0x130 net/ipv6/route.c:3892
 addrconf_prefix_route+0x233/0x310 net/ipv6/addrconf.c:2466
 inet6_addr_add+0x527/0x9c0 net/ipv6/addrconf.c:3042
 inet6_rtm_newaddr+0x74a/0xa10 net/ipv6/addrconf.c:4999
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1580 [inline]
 free_pcp_prepare mm/page_alloc.c:1654 [inline]
 free_unref_page_prepare+0x80c/0x820 mm/page_alloc.c:3621
 free_unref_page+0x93/0x530 mm/page_alloc.c:3719
 free_the_page mm/page_alloc.c:863 [inline]
 __free_pages+0x67/0x100 mm/page_alloc.c:6020
 free_pages+0x82/0x90 mm/page_alloc.c:6031
 __stack_depot_save+0x45f/0x490 lib/stackdepot.c:506
 stack_depot_save+0x13/0x20 lib/stackdepot.c:533
 ref_tracker_free+0x129/0x800 lib/ref_tracker.c:122
 netdev_tracker_free include/linux/netdevice.h:4105 [inline]
 netdev_put include/linux/netdevice.h:4122 [inline]
 __qdisc_destroy+0x128/0x290 net/sched/sch_generic.c:1079
 qdisc_put net/sched/sch_generic.c:1103 [inline]
 dev_shutdown+0x459/0x580 net/sched/sch_generic.c:1464
 unregister_netdevice_many+0x9a0/0x1910 net/core/dev.c:10996
 ip6_tnl_exit_batch_net+0x3ee/0x440 net/ipv6/ip6_tunnel.c:2302
 ops_exit_list net/core/net_namespace.c:177 [inline]
 cleanup_net+0x630/0xb10 net/core/net_namespace.c:604
 process_one_work+0x717/0xc30 kernel/workqueue.c:2302
 worker_thread+0xa4d/0x11d0 kernel/workqueue.c:2449
 kthread+0x281/0x320 kernel/kthread.c:386
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Memory state around the buggy address:
 ffff88812de8f800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88812de8f880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88812de8f900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff88812de8f980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88812de8fa00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

final repro crashed as (corrupted=false):
==================================================================
BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:102 [inline]
BUG: KASAN: use-after-free in atomic_long_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1779 [inline]
BUG: KASAN: use-after-free in __mutex_trylock_fast kernel/locking/mutex.c:176 [inline]
BUG: KASAN: use-after-free in mutex_lock+0x86/0x1b0 kernel/locking/mutex.c:295
Write of size 8 at addr ffff88812de8f950 by task syz.2.17/375

CPU: 1 PID: 375 Comm: syz.2.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x24 lib/dump_stack.c:88
 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
 print_address_description+0x71/0x200 mm/kasan/report.c:316
 print_report+0x4a/0x60 mm/kasan/report.c:420
 kasan_report+0x122/0x150 mm/kasan/report.c:524
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x249/0x2a0 mm/kasan/generic.c:189
 __kasan_check_write+0x14/0x20 mm/kasan/shadow.c:37
 instrument_atomic_read_write include/linux/instrumented.h:102 [inline]
 atomic_long_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1779 [inline]
 __mutex_trylock_fast kernel/locking/mutex.c:176 [inline]
 mutex_lock+0x86/0x1b0 kernel/locking/mutex.c:295
 pppol2tp_release+0x178/0x2b0 net/l2tp/l2tp_ppp.c:441
 __sock_release net/socket.c:652 [inline]
 sock_close+0xc9/0x220 net/socket.c:1389
 __fput+0x1fd/0x8f0 fs/file_table.c:320
 ____fput+0x15/0x20 fs/file_table.c:348
 task_work_run+0x1e1/0x250 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0x9b/0xb0 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f026099ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffca693628 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fffca693710 RCX: 00007f026099ce59
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 000000000000655d R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b33120000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0260c15fac R14: 00007f0260c15fa8 R15: 00007f0260c15fa0
 </TASK>

Allocated by task 375:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_alloc_info+0x1f/0x30 mm/kasan/generic.c:505
 ____kasan_kmalloc mm/kasan/common.c:380 [inline]
 __kasan_kmalloc+0x95/0xb0 mm/kasan/common.c:389
 kasan_kmalloc include/linux/kasan.h:212 [inline]
 __do_kmalloc_node mm/slab_common.c:938 [inline]
 __kmalloc+0xb4/0x1e0 mm/slab_common.c:951
 kmalloc include/linux/slab.h:568 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 l2tp_session_create+0x38/0xbd0 net/l2tp/l2tp_core.c:1609
 pppol2tp_connect+0xbf5/0x1640 net/l2tp/l2tp_ppp.c:771
 __sys_connect_file net/socket.c:2000 [inline]
 __sys_connect+0x3da/0x460 net/socket.c:2017
 __do_sys_connect net/socket.c:2027 [inline]
 __se_sys_connect net/socket.c:2024 [inline]
 __x64_sys_connect+0x7a/0x90 net/socket.c:2024
 x64_sys_call+0x88d/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:43
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Freed by task 375:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:516
 ____kasan_slab_free+0x132/0x180 mm/kasan/common.c:242
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:250
 kasan_slab_free include/linux/kasan.h:178 [inline]
 slab_free_hook mm/slub.c:1750 [inline]
 slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1776
 slab_free mm/slub.c:3712 [inline]
 __kmem_cache_free+0xb7/0x1b0 mm/slub.c:3728
 kfree+0x6f/0xf0 mm/slab_common.c:990
 l2tp_session_free net/l2tp/l2tp_core.c:168 [inline]
 l2tp_session_put+0xaf/0x1a0 net/l2tp/l2tp_core.c:193
 l2tp_session_delete+0x3df/0x4d0 net/l2tp/l2tp_core.c:1582
 pppol2tp_release+0x169/0x2b0 net/l2tp/l2tp_ppp.c:438
 __sock_release net/socket.c:652 [inline]
 sock_close+0xc9/0x220 net/socket.c:1389
 __fput+0x1fd/0x8f0 fs/file_table.c:320
 ____fput+0x15/0x20 fs/file_table.c:348
 task_work_run+0x1e1/0x250 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0x9b/0xb0 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

The buggy address belongs to the object at ffff88812de8f800
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 336 bytes inside of
 512-byte region [ffff88812de8f800, ffff88812de8fa00)

The buggy address belongs to the physical page:
page:ffffea0004b7a300 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12de8c
head:ffffea0004b7a300 order:2 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=1)
raw: 4000000000010200 0000000000000000 dead000000000122 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 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 370, tgid 370 (syz-executor), ts 25960965973, free_ts 25959966254
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2672
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2679
 get_page_from_freelist+0x2ca9/0x2d20 mm/page_alloc.c:4586
 __alloc_pages+0x1fa/0x610 mm/page_alloc.c:5930
 alloc_slab_page+0x6e/0xf0 include/linux/gfp.h:-1
 allocate_slab mm/slub.c:1967 [inline]
 new_slab+0x98/0x3e0 mm/slub.c:2020
 ___slab_alloc+0x70f/0xb70 mm/slub.c:3177
 __slab_alloc+0x5e/0xa0 mm/slub.c:3263
 slab_alloc_node mm/slub.c:3348 [inline]
 __kmem_cache_alloc_node+0x204/0x2d0 mm/slub.c:3423
 __do_kmalloc_node mm/slab_common.c:937 [inline]
 __kmalloc+0xa4/0x1e0 mm/slab_common.c:951
 kmalloc include/linux/slab.h:568 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 fib6_info_alloc+0x34/0xe0 net/ipv6/ip6_fib.c:156
 ip6_route_info_create+0x51b/0x14d0 net/ipv6/route.c:3796
 ip6_route_add+0x27/0x130 net/ipv6/route.c:3892
 addrconf_prefix_route+0x233/0x310 net/ipv6/addrconf.c:2466
 inet6_addr_add+0x527/0x9c0 net/ipv6/addrconf.c:3042
 inet6_rtm_newaddr+0x74a/0xa10 net/ipv6/addrconf.c:4999
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1580 [inline]
 free_pcp_prepare mm/page_alloc.c:1654 [inline]
 free_unref_page_prepare+0x80c/0x820 mm/page_alloc.c:3621
 free_unref_page+0x93/0x530 mm/page_alloc.c:3719
 free_the_page mm/page_alloc.c:863 [inline]
 __free_pages+0x67/0x100 mm/page_alloc.c:6020
 free_pages+0x82/0x90 mm/page_alloc.c:6031
 __stack_depot_save+0x45f/0x490 lib/stackdepot.c:506
 stack_depot_save+0x13/0x20 lib/stackdepot.c:533
 ref_tracker_free+0x129/0x800 lib/ref_tracker.c:122
 netdev_tracker_free include/linux/netdevice.h:4105 [inline]
 netdev_put include/linux/netdevice.h:4122 [inline]
 __qdisc_destroy+0x128/0x290 net/sched/sch_generic.c:1079
 qdisc_put net/sched/sch_generic.c:1103 [inline]
 dev_shutdown+0x459/0x580 net/sched/sch_generic.c:1464
 unregister_netdevice_many+0x9a0/0x1910 net/core/dev.c:10996
 ip6_tnl_exit_batch_net+0x3ee/0x440 net/ipv6/ip6_tunnel.c:2302
 ops_exit_list net/core/net_namespace.c:177 [inline]
 cleanup_net+0x630/0xb10 net/core/net_namespace.c:604
 process_one_work+0x717/0xc30 kernel/workqueue.c:2302
 worker_thread+0xa4d/0x11d0 kernel/workqueue.c:2449
 kthread+0x281/0x320 kernel/kthread.c:386
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Memory state around the buggy address:
 ffff88812de8f800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88812de8f880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88812de8f900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff88812de8f980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88812de8fa00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================