Extracting prog: 29.768610501s
Minimizing prog: 10m30.840232931s
Simplifying prog options: 0s
Extracting C: 1m7.213803806s
Simplifying C: 3m17.421688752s


extracting reproducer from 70 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$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$PPPIOCGL2TPSTATS-socket$pppl2tp-connect$pppl2tp-madvise-mprotect-getsockopt-bpf$MAP_CREATE_CONST_STR-socket$inet6_icmp_raw-bpf$MAP_LOOKUP_ELEM
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r0, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r1, {0x2, 0x4e24, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e) (async)
ioctl$PPPIOCGL2TPSTATS(r0, 0x80487436, &(0x7f00000001c0)="848d2dea7aaf30375b40a0585d6fb3bc53bdfa9b9aca49fd5ae075feec1f864e4113583a1836115b8d43abd18185f424eb0f911b8387832285de7ce9584ff43eae8b085c7d6f3c8595edd757e5c58ea2edf42072d568ef87279f9b76e99da8292c3be19ad0799fdc952402315182d7d426f8df51cbcd04738c4eb811398d7a234504b9b464a68d780ccf1b92b103087ce58e523d7e87a277f2ba2c7771130a3f25084b8019ab8242f77129940526e91241fe0ca9089afecdb8b130af6b308192ed431fa75047d34b77650e1ef2dd724cef36eb4076bdcf3bbb9b")
r2 = socket$pppl2tp(0x18, 0x1, 0x1)
connect$pppl2tp(r2, &(0x7f0000000480)=@pppol2tpv3={0x18, 0x1, {0x0, 0xffffffffffffffff, {0x2, 0x0, @broadcast}, 0x2, 0x1}}, 0x2e)
madvise(&(0x7f0000000000/0x3000)=nil, 0x7fffffffffffffff, 0x15) (async)
mprotect(&(0x7f0000000000/0x3000)=nil, 0x3000, 0x1) (async)
getsockopt(r2, 0x111, 0x1, 0x0, &(0x7f0000000180)) (async)
r3 = bpf$MAP_CREATE_CONST_STR(0x0, &(0x7f0000010000)=ANY=[@ANYBLOB="0200000004000000080000000100000080000000", @ANYRES32, @ANYBLOB="0400"/20, @ANYRES32=0x0, @ANYRES32, @ANYBLOB="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"], 0x50)
socket$inet6_icmp_raw(0xa, 0x3, 0x3a) (async)
bpf$MAP_LOOKUP_ELEM(0x5, &(0x7f00000000c0)={r3, 0x0, &(0x7f0000000040)=""/73}, 0x20)

program crashed: KASAN: use-after-free Write in pppol2tp_release
single: successfully extracted reproducer
found reproducer with 12 syscalls
minimizing guilty program
testing program (duration=35.523296952s, {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$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$PPPIOCGL2TPSTATS-socket$pppl2tp-connect$pppl2tp-madvise-mprotect-getsockopt-bpf$MAP_CREATE_CONST_STR-socket$inet6_icmp_raw
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r0, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r1, {0x2, 0x4e24, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e) (async)
ioctl$PPPIOCGL2TPSTATS(r0, 0x80487436, &(0x7f00000001c0)="848d2dea7aaf30375b40a0585d6fb3bc53bdfa9b9aca49fd5ae075feec1f864e4113583a1836115b8d43abd18185f424eb0f911b8387832285de7ce9584ff43eae8b085c7d6f3c8595edd757e5c58ea2edf42072d568ef87279f9b76e99da8292c3be19ad0799fdc952402315182d7d426f8df51cbcd04738c4eb811398d7a234504b9b464a68d780ccf1b92b103087ce58e523d7e87a277f2ba2c7771130a3f25084b8019ab8242f77129940526e91241fe0ca9089afecdb8b130af6b308192ed431fa75047d34b77650e1ef2dd724cef36eb4076bdcf3bbb9b")
r2 = socket$pppl2tp(0x18, 0x1, 0x1)
connect$pppl2tp(r2, &(0x7f0000000480)=@pppol2tpv3={0x18, 0x1, {0x0, 0xffffffffffffffff, {0x2, 0x0, @broadcast}, 0x2, 0x1}}, 0x2e)
madvise(&(0x7f0000000000/0x3000)=nil, 0x7fffffffffffffff, 0x15) (async)
mprotect(&(0x7f0000000000/0x3000)=nil, 0x3000, 0x1) (async)
getsockopt(r2, 0x111, 0x1, 0x0, &(0x7f0000000180)) (async)
bpf$MAP_CREATE_CONST_STR(0x0, &(0x7f0000010000)=ANY=[@ANYBLOB="0200000004000000080000000100000080000000", @ANYRES32, @ANYBLOB="0400"/20, @ANYRES32=0x0, @ANYRES32, @ANYBLOB="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"], 0x50)
socket$inet6_icmp_raw(0xa, 0x3, 0x3a) (async)

program crashed: KASAN: use-after-free Read in rcu_cblist_dequeue
testing program (duration=35.523296952s, {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$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$PPPIOCGL2TPSTATS-socket$pppl2tp-connect$pppl2tp-madvise-mprotect-getsockopt-bpf$MAP_CREATE_CONST_STR
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r0, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r1, {0x2, 0x4e24, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e) (async)
ioctl$PPPIOCGL2TPSTATS(r0, 0x80487436, &(0x7f00000001c0)="848d2dea7aaf30375b40a0585d6fb3bc53bdfa9b9aca49fd5ae075feec1f864e4113583a1836115b8d43abd18185f424eb0f911b8387832285de7ce9584ff43eae8b085c7d6f3c8595edd757e5c58ea2edf42072d568ef87279f9b76e99da8292c3be19ad0799fdc952402315182d7d426f8df51cbcd04738c4eb811398d7a234504b9b464a68d780ccf1b92b103087ce58e523d7e87a277f2ba2c7771130a3f25084b8019ab8242f77129940526e91241fe0ca9089afecdb8b130af6b308192ed431fa75047d34b77650e1ef2dd724cef36eb4076bdcf3bbb9b")
r2 = socket$pppl2tp(0x18, 0x1, 0x1)
connect$pppl2tp(r2, &(0x7f0000000480)=@pppol2tpv3={0x18, 0x1, {0x0, 0xffffffffffffffff, {0x2, 0x0, @broadcast}, 0x2, 0x1}}, 0x2e)
madvise(&(0x7f0000000000/0x3000)=nil, 0x7fffffffffffffff, 0x15) (async)
mprotect(&(0x7f0000000000/0x3000)=nil, 0x3000, 0x1) (async)
getsockopt(r2, 0x111, 0x1, 0x0, &(0x7f0000000180)) (async)
bpf$MAP_CREATE_CONST_STR(0x0, &(0x7f0000010000)=ANY=[@ANYBLOB="0200000004000000080000000100000080000000", @ANYRES32, @ANYBLOB="0400"/20, @ANYRES32=0x0, @ANYRES32, @ANYBLOB="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"], 0x50)

program crashed: KASAN: use-after-free Write in pppol2tp_release
testing program (duration=35.523296952s, {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$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$PPPIOCGL2TPSTATS-socket$pppl2tp-connect$pppl2tp-madvise-mprotect-getsockopt
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r0, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r1, {0x2, 0x4e24, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e) (async)
ioctl$PPPIOCGL2TPSTATS(r0, 0x80487436, &(0x7f00000001c0)="848d2dea7aaf30375b40a0585d6fb3bc53bdfa9b9aca49fd5ae075feec1f864e4113583a1836115b8d43abd18185f424eb0f911b8387832285de7ce9584ff43eae8b085c7d6f3c8595edd757e5c58ea2edf42072d568ef87279f9b76e99da8292c3be19ad0799fdc952402315182d7d426f8df51cbcd04738c4eb811398d7a234504b9b464a68d780ccf1b92b103087ce58e523d7e87a277f2ba2c7771130a3f25084b8019ab8242f77129940526e91241fe0ca9089afecdb8b130af6b308192ed431fa75047d34b77650e1ef2dd724cef36eb4076bdcf3bbb9b")
r2 = socket$pppl2tp(0x18, 0x1, 0x1)
connect$pppl2tp(r2, &(0x7f0000000480)=@pppol2tpv3={0x18, 0x1, {0x0, 0xffffffffffffffff, {0x2, 0x0, @broadcast}, 0x2, 0x1}}, 0x2e)
madvise(&(0x7f0000000000/0x3000)=nil, 0x7fffffffffffffff, 0x15) (async)
mprotect(&(0x7f0000000000/0x3000)=nil, 0x3000, 0x1) (async)
getsockopt(r2, 0x111, 0x1, 0x0, &(0x7f0000000180)) (async)

program crashed: KASAN: use-after-free Write in pppol2tp_release
testing program (duration=35.523296952s, {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$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$PPPIOCGL2TPSTATS-socket$pppl2tp-connect$pppl2tp-madvise-mprotect
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r0, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r1, {0x2, 0x4e24, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e) (async)
ioctl$PPPIOCGL2TPSTATS(r0, 0x80487436, &(0x7f00000001c0)="848d2dea7aaf30375b40a0585d6fb3bc53bdfa9b9aca49fd5ae075feec1f864e4113583a1836115b8d43abd18185f424eb0f911b8387832285de7ce9584ff43eae8b085c7d6f3c8595edd757e5c58ea2edf42072d568ef87279f9b76e99da8292c3be19ad0799fdc952402315182d7d426f8df51cbcd04738c4eb811398d7a234504b9b464a68d780ccf1b92b103087ce58e523d7e87a277f2ba2c7771130a3f25084b8019ab8242f77129940526e91241fe0ca9089afecdb8b130af6b308192ed431fa75047d34b77650e1ef2dd724cef36eb4076bdcf3bbb9b")
r2 = socket$pppl2tp(0x18, 0x1, 0x1)
connect$pppl2tp(r2, &(0x7f0000000480)=@pppol2tpv3={0x18, 0x1, {0x0, 0xffffffffffffffff, {0x2, 0x0, @broadcast}, 0x2, 0x1}}, 0x2e)
madvise(&(0x7f0000000000/0x3000)=nil, 0x7fffffffffffffff, 0x15) (async)
mprotect(&(0x7f0000000000/0x3000)=nil, 0x3000, 0x1) (async)

program crashed: KASAN: use-after-free Read in pppol2tp_sock_to_session
testing program (duration=35.523296952s, {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$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$PPPIOCGL2TPSTATS-socket$pppl2tp-connect$pppl2tp-madvise
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r0, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r1, {0x2, 0x4e24, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e) (async)
ioctl$PPPIOCGL2TPSTATS(r0, 0x80487436, &(0x7f00000001c0)="848d2dea7aaf30375b40a0585d6fb3bc53bdfa9b9aca49fd5ae075feec1f864e4113583a1836115b8d43abd18185f424eb0f911b8387832285de7ce9584ff43eae8b085c7d6f3c8595edd757e5c58ea2edf42072d568ef87279f9b76e99da8292c3be19ad0799fdc952402315182d7d426f8df51cbcd04738c4eb811398d7a234504b9b464a68d780ccf1b92b103087ce58e523d7e87a277f2ba2c7771130a3f25084b8019ab8242f77129940526e91241fe0ca9089afecdb8b130af6b308192ed431fa75047d34b77650e1ef2dd724cef36eb4076bdcf3bbb9b")
r2 = socket$pppl2tp(0x18, 0x1, 0x1)
connect$pppl2tp(r2, &(0x7f0000000480)=@pppol2tpv3={0x18, 0x1, {0x0, 0xffffffffffffffff, {0x2, 0x0, @broadcast}, 0x2, 0x1}}, 0x2e)
madvise(&(0x7f0000000000/0x3000)=nil, 0x7fffffffffffffff, 0x15) (async)

program crashed: KASAN: use-after-free Read in rcu_cblist_dequeue
testing program (duration=35.523296952s, {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$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$PPPIOCGL2TPSTATS-socket$pppl2tp-connect$pppl2tp
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r0, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r1, {0x2, 0x4e24, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e) (async)
ioctl$PPPIOCGL2TPSTATS(r0, 0x80487436, &(0x7f00000001c0)="848d2dea7aaf30375b40a0585d6fb3bc53bdfa9b9aca49fd5ae075feec1f864e4113583a1836115b8d43abd18185f424eb0f911b8387832285de7ce9584ff43eae8b085c7d6f3c8595edd757e5c58ea2edf42072d568ef87279f9b76e99da8292c3be19ad0799fdc952402315182d7d426f8df51cbcd04738c4eb811398d7a234504b9b464a68d780ccf1b92b103087ce58e523d7e87a277f2ba2c7771130a3f25084b8019ab8242f77129940526e91241fe0ca9089afecdb8b130af6b308192ed431fa75047d34b77650e1ef2dd724cef36eb4076bdcf3bbb9b")
r2 = socket$pppl2tp(0x18, 0x1, 0x1)
connect$pppl2tp(r2, &(0x7f0000000480)=@pppol2tpv3={0x18, 0x1, {0x0, 0xffffffffffffffff, {0x2, 0x0, @broadcast}, 0x2, 0x1}}, 0x2e)

program crashed: KASAN: use-after-free Read in pppol2tp_sock_to_session
testing program (duration=35.523296952s, {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$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$PPPIOCGL2TPSTATS-socket$pppl2tp
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r0, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r1, {0x2, 0x4e24, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e) (async)
ioctl$PPPIOCGL2TPSTATS(r0, 0x80487436, &(0x7f00000001c0)="848d2dea7aaf30375b40a0585d6fb3bc53bdfa9b9aca49fd5ae075feec1f864e4113583a1836115b8d43abd18185f424eb0f911b8387832285de7ce9584ff43eae8b085c7d6f3c8595edd757e5c58ea2edf42072d568ef87279f9b76e99da8292c3be19ad0799fdc952402315182d7d426f8df51cbcd04738c4eb811398d7a234504b9b464a68d780ccf1b92b103087ce58e523d7e87a277f2ba2c7771130a3f25084b8019ab8242f77129940526e91241fe0ca9089afecdb8b130af6b308192ed431fa75047d34b77650e1ef2dd724cef36eb4076bdcf3bbb9b")
socket$pppl2tp(0x18, 0x1, 0x1)

program crashed: KASAN: use-after-free Write in pppol2tp_release
testing program (duration=35.523296952s, {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$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$PPPIOCGL2TPSTATS
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r0, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r1, {0x2, 0x4e24, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e) (async)
ioctl$PPPIOCGL2TPSTATS(r0, 0x80487436, &(0x7f00000001c0)="848d2dea7aaf30375b40a0585d6fb3bc53bdfa9b9aca49fd5ae075feec1f864e4113583a1836115b8d43abd18185f424eb0f911b8387832285de7ce9584ff43eae8b085c7d6f3c8595edd757e5c58ea2edf42072d568ef87279f9b76e99da8292c3be19ad0799fdc952402315182d7d426f8df51cbcd04738c4eb811398d7a234504b9b464a68d780ccf1b92b103087ce58e523d7e87a277f2ba2c7771130a3f25084b8019ab8242f77129940526e91241fe0ca9089afecdb8b130af6b308192ed431fa75047d34b77650e1ef2dd724cef36eb4076bdcf3bbb9b")

program crashed: KASAN: use-after-free Write in pppol2tp_release
testing program (duration=35.523296952s, {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$pppl2tp-socket$inet6_udp-connect$pppl2tp
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r0, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r1, {0x2, 0x4e24, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e) (async)

program did not crash
testing program (duration=35.523296952s, {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$pppl2tp-socket$inet6_udp-ioctl$PPPIOCGL2TPSTATS
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
socket$inet6_udp(0xa, 0x2, 0x0)
ioctl$PPPIOCGL2TPSTATS(r0, 0x80487436, &(0x7f00000001c0)="848d2dea7aaf30375b40a0585d6fb3bc53bdfa9b9aca49fd5ae075feec1f864e4113583a1836115b8d43abd18185f424eb0f911b8387832285de7ce9584ff43eae8b085c7d6f3c8595edd757e5c58ea2edf42072d568ef87279f9b76e99da8292c3be19ad0799fdc952402315182d7d426f8df51cbcd04738c4eb811398d7a234504b9b464a68d780ccf1b92b103087ce58e523d7e87a277f2ba2c7771130a3f25084b8019ab8242f77129940526e91241fe0ca9089afecdb8b130af6b308192ed431fa75047d34b77650e1ef2dd724cef36eb4076bdcf3bbb9b")

program did not crash
testing program (duration=35.523296952s, {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$PPPIOCGL2TPSTATS
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
connect$pppl2tp(r0, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, 0xffffffffffffffff, {0x2, 0x4e24, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e) (async)
ioctl$PPPIOCGL2TPSTATS(r0, 0x80487436, &(0x7f00000001c0)="848d2dea7aaf30375b40a0585d6fb3bc53bdfa9b9aca49fd5ae075feec1f864e4113583a1836115b8d43abd18185f424eb0f911b8387832285de7ce9584ff43eae8b085c7d6f3c8595edd757e5c58ea2edf42072d568ef87279f9b76e99da8292c3be19ad0799fdc952402315182d7d426f8df51cbcd04738c4eb811398d7a234504b9b464a68d780ccf1b92b103087ce58e523d7e87a277f2ba2c7771130a3f25084b8019ab8242f77129940526e91241fe0ca9089afecdb8b130af6b308192ed431fa75047d34b77650e1ef2dd724cef36eb4076bdcf3bbb9b")

program did not crash
testing program (duration=35.523296952s, {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$inet6_udp-connect$pppl2tp-ioctl$PPPIOCGL2TPSTATS
detailed listing:
executing program 0:
r0 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(0xffffffffffffffff, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r0, {0x2, 0x4e24, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e) (async)
ioctl$PPPIOCGL2TPSTATS(0xffffffffffffffff, 0x80487436, &(0x7f00000001c0)="848d2dea7aaf30375b40a0585d6fb3bc53bdfa9b9aca49fd5ae075feec1f864e4113583a1836115b8d43abd18185f424eb0f911b8387832285de7ce9584ff43eae8b085c7d6f3c8595edd757e5c58ea2edf42072d568ef87279f9b76e99da8292c3be19ad0799fdc952402315182d7d426f8df51cbcd04738c4eb811398d7a234504b9b464a68d780ccf1b92b103087ce58e523d7e87a277f2ba2c7771130a3f25084b8019ab8242f77129940526e91241fe0ca9089afecdb8b130af6b308192ed431fa75047d34b77650e1ef2dd724cef36eb4076bdcf3bbb9b")

program did not crash
testing program (duration=35.523296952s, {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$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$PPPIOCGL2TPSTATS
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r0, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r1, {0x2, 0x4e24, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e)
ioctl$PPPIOCGL2TPSTATS(r0, 0x80487436, &(0x7f00000001c0)="848d2dea7aaf30375b40a0585d6fb3bc53bdfa9b9aca49fd5ae075feec1f864e4113583a1836115b8d43abd18185f424eb0f911b8387832285de7ce9584ff43eae8b085c7d6f3c8595edd757e5c58ea2edf42072d568ef87279f9b76e99da8292c3be19ad0799fdc952402315182d7d426f8df51cbcd04738c4eb811398d7a234504b9b464a68d780ccf1b92b103087ce58e523d7e87a277f2ba2c7771130a3f25084b8019ab8242f77129940526e91241fe0ca9089afecdb8b130af6b308192ed431fa75047d34b77650e1ef2dd724cef36eb4076bdcf3bbb9b")

program crashed: KASAN: use-after-free Write in pppol2tp_release
testing program (duration=35.523296952s, {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$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$PPPIOCGL2TPSTATS
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r0, 0x0, 0x0)
ioctl$PPPIOCGL2TPSTATS(r0, 0x80487436, &(0x7f00000001c0)="848d2dea7aaf30375b40a0585d6fb3bc53bdfa9b9aca49fd5ae075feec1f864e4113583a1836115b8d43abd18185f424eb0f911b8387832285de7ce9584ff43eae8b085c7d6f3c8595edd757e5c58ea2edf42072d568ef87279f9b76e99da8292c3be19ad0799fdc952402315182d7d426f8df51cbcd04738c4eb811398d7a234504b9b464a68d780ccf1b92b103087ce58e523d7e87a277f2ba2c7771130a3f25084b8019ab8242f77129940526e91241fe0ca9089afecdb8b130af6b308192ed431fa75047d34b77650e1ef2dd724cef36eb4076bdcf3bbb9b")

program did not crash
testing program (duration=35.523296952s, {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$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$PPPIOCGL2TPSTATS
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r0, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r1, {0x2, 0x4e24, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e)
ioctl$PPPIOCGL2TPSTATS(r0, 0x80487436, 0x0)

program crashed: KASAN: use-after-free Read in pppol2tp_sock_to_session
extracting C reproducer
testing compiled C program (duration=35.523296952s, {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$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$PPPIOCGL2TPSTATS
program crashed: KASAN: use-after-free Write in pppol2tp_release
simplifying C reproducer
testing compiled C program (duration=35.523296952s, {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$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$PPPIOCGL2TPSTATS
program crashed: KASAN: use-after-free Write in pppol2tp_release
testing compiled C program (duration=35.523296952s, {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$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$PPPIOCGL2TPSTATS
program crashed: KASAN: use-after-free Write in pppol2tp_release
testing compiled C program (duration=35.523296952s, {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$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$PPPIOCGL2TPSTATS
program crashed: KASAN: use-after-free Read in pppol2tp_sock_to_session
testing compiled C program (duration=35.523296952s, {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:false HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$PPPIOCGL2TPSTATS
program crashed: KASAN: use-after-free Read in pppol2tp_sock_to_session
testing compiled C program (duration=35.523296952s, {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:false HandleSegv:false Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$PPPIOCGL2TPSTATS
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=35.523296952s, {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:false Swap:false UseTmpDir:false HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$PPPIOCGL2TPSTATS
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 program (duration=35.523296952s, {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:false HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$PPPIOCGL2TPSTATS
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r0, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r1, {0x2, 0x4e24, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e)
ioctl$PPPIOCGL2TPSTATS(r0, 0x80487436, 0x0)

program crashed: KASAN: use-after-free Read in pppol2tp_sock_to_session
validation run: crashed=true
testing program (duration=35.523296952s, {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:false HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$PPPIOCGL2TPSTATS
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r0, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r1, {0x2, 0x4e24, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e)
ioctl$PPPIOCGL2TPSTATS(r0, 0x80487436, 0x0)

program crashed: KASAN: use-after-free Write in pppol2tp_release
validation run: crashed=true
testing program (duration=35.523296952s, {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:false HandleSegv:true Trace:false CallComments:true LegacyOptions:{Collide:false Fault:false FaultCall:0 FaultNth:0}}): socket$pppl2tp-socket$inet6_udp-connect$pppl2tp-ioctl$PPPIOCGL2TPSTATS
detailed listing:
executing program 0:
r0 = socket$pppl2tp(0x18, 0x1, 0x1)
r1 = socket$inet6_udp(0xa, 0x2, 0x0)
connect$pppl2tp(r0, &(0x7f0000000740)=@pppol2tpv3={0x18, 0x1, {0x3, r1, {0x2, 0x4e24, @broadcast}, 0x2, 0x0, 0x4}}, 0x2e)
ioctl$PPPIOCGL2TPSTATS(r0, 0x80487436, 0x0)

program crashed: KASAN: use-after-free Read in pppol2tp_sock_to_session
validation run: crashed=true
reproducing took 17m47.885665361s
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 ffff8881218bd000 by task syz.2.17/373

CPU: 0 PID: 373 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+0x21/0x30 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
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0xd0/0xe0 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f9fcac88e59
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:00007ffc3d948ba8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffc3d948c90 RCX: 00007f9fcac88e59
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00000000000070b7 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b33020000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9fcaf01fac R14: 00007f9fcaf01fa8 R15: 00007f9fcaf01fa0
 </TASK>

Allocated by task 373:
 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 ffff8881218bd000
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 0 bytes inside of
 512-byte region [ffff8881218bd000, ffff8881218bd200)
The buggy address belongs to the page:
page:ffffea0004862f00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1218bc
head:ffffea0004862f00 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 369, ts 28878372138, free_ts 26615748817
 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]
 netlink_alloc_large_skb net/netlink/af_netlink.c:1186 [inline]
 netlink_sendmsg+0x611/0xb80 net/netlink/af_netlink.c:1897
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 __sys_sendto+0x46d/0x620 net/socket.c:2062
 __do_sys_sendto net/socket.c:2074 [inline]
 __se_sys_sendto net/socket.c:2070 [inline]
 __x64_sys_sendto+0xe5/0x100 net/socket.c:2070
 x64_sys_call+0x178/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:45
 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
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1474 [inline]
 free_pcp_prepare mm/page_alloc.c:1546 [inline]
 free_unref_page_prepare+0x5fa/0x600 mm/page_alloc.c:3536
 free_unref_page+0xae/0x540 mm/page_alloc.c:3618
 free_the_page mm/page_alloc.c:805 [inline]
 __free_pages+0x6c/0x100 mm/page_alloc.c:5900
 __vunmap+0x801/0x980 mm/vmalloc.c:2660
 __vfree mm/vmalloc.c:2709 [inline]
 vfree+0x8b/0xc0 mm/vmalloc.c:2740
 kcov_mmap+0x8f/0x130 kernel/kcov.c:498
 call_mmap include/linux/fs.h:2217 [inline]
 mmap_file+0x60/0xb0 mm/util.c:1099
 __mmap_region mm/mmap.c:1808 [inline]
 mmap_region+0xe42/0x1700 mm/mmap.c:2959
 do_mmap+0x812/0xf10 mm/mmap.c:1598
 vm_mmap_pgoff+0x1d6/0x410 mm/util.c:555
 ksys_mmap_pgoff+0x161/0x1d0 mm/mmap.c:1647
 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:93 [inline]
 __se_sys_mmap arch/x86/kernel/sys_x86_64.c:86 [inline]
 __x64_sys_mmap+0xfa/0x110 arch/x86/kernel/sys_x86_64.c:86
 x64_sys_call+0x83/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:10
 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

Memory state around the buggy address:
 ffff8881218bcf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881218bcf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8881218bd000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff8881218bd080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881218bd100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
------------[ cut here ]------------
WARNING: CPU: 1 PID: 373 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: 373 Comm: syz.2.17 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 cc f2 0b fd be 02 00 00 00 eb 0a e8 c0 f2 0b fd be 01 00 00 00 4c 89 f7 e8 13 62 f2 fd e9 0f ff ff ff e8 a9 f2 0b fd <0f> 0b 48 89 df e8 ef 00 00 00 eb bd e8 98 f2 0b fd 4c 89 f7 be 03
RSP: 0018:ffffc90000b37d10 EFLAGS: 00010293
RAX: ffffffff845db907 RBX: ffff888111644000 RCX: ffff88810dcd0000
RDX: 0000000000000000 RSI: 000000000c9f97c0 RDI: 000000000c04eb7d
RBP: ffffc90000b37d30 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff0e18c4c R12: dffffc0000000000
R13: dffffc0000000000 R14: 000000000c9f97c0 R15: ffff8881218bd000
FS:  0000555567bd7500(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000012e11b000 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
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0xd0/0xe0 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f9fcac88e59
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:00007ffc3d948ba8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffc3d948c90 RCX: 00007f9fcac88e59
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00000000000070b7 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b33020000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9fcaf01fac R14: 00007f9fcaf01fa8 R15: 00007f9fcaf01fa0
 </TASK>
---[ end trace 433422ed8632ea93 ]---

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 ffff8881218bd000 by task syz.2.17/373

CPU: 0 PID: 373 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+0x21/0x30 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
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0xd0/0xe0 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f9fcac88e59
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:00007ffc3d948ba8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffc3d948c90 RCX: 00007f9fcac88e59
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00000000000070b7 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b33020000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9fcaf01fac R14: 00007f9fcaf01fa8 R15: 00007f9fcaf01fa0
 </TASK>

Allocated by task 373:
 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 ffff8881218bd000
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 0 bytes inside of
 512-byte region [ffff8881218bd000, ffff8881218bd200)
The buggy address belongs to the page:
page:ffffea0004862f00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1218bc
head:ffffea0004862f00 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 369, ts 28878372138, free_ts 26615748817
 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]
 netlink_alloc_large_skb net/netlink/af_netlink.c:1186 [inline]
 netlink_sendmsg+0x611/0xb80 net/netlink/af_netlink.c:1897
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 __sys_sendto+0x46d/0x620 net/socket.c:2062
 __do_sys_sendto net/socket.c:2074 [inline]
 __se_sys_sendto net/socket.c:2070 [inline]
 __x64_sys_sendto+0xe5/0x100 net/socket.c:2070
 x64_sys_call+0x178/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:45
 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
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1474 [inline]
 free_pcp_prepare mm/page_alloc.c:1546 [inline]
 free_unref_page_prepare+0x5fa/0x600 mm/page_alloc.c:3536
 free_unref_page+0xae/0x540 mm/page_alloc.c:3618
 free_the_page mm/page_alloc.c:805 [inline]
 __free_pages+0x6c/0x100 mm/page_alloc.c:5900
 __vunmap+0x801/0x980 mm/vmalloc.c:2660
 __vfree mm/vmalloc.c:2709 [inline]
 vfree+0x8b/0xc0 mm/vmalloc.c:2740
 kcov_mmap+0x8f/0x130 kernel/kcov.c:498
 call_mmap include/linux/fs.h:2217 [inline]
 mmap_file+0x60/0xb0 mm/util.c:1099
 __mmap_region mm/mmap.c:1808 [inline]
 mmap_region+0xe42/0x1700 mm/mmap.c:2959
 do_mmap+0x812/0xf10 mm/mmap.c:1598
 vm_mmap_pgoff+0x1d6/0x410 mm/util.c:555
 ksys_mmap_pgoff+0x161/0x1d0 mm/mmap.c:1647
 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:93 [inline]
 __se_sys_mmap arch/x86/kernel/sys_x86_64.c:86 [inline]
 __x64_sys_mmap+0xfa/0x110 arch/x86/kernel/sys_x86_64.c:86
 x64_sys_call+0x83/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:10
 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

Memory state around the buggy address:
 ffff8881218bcf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881218bcf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8881218bd000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff8881218bd080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881218bd100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
------------[ cut here ]------------
WARNING: CPU: 1 PID: 373 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: 373 Comm: syz.2.17 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 cc f2 0b fd be 02 00 00 00 eb 0a e8 c0 f2 0b fd be 01 00 00 00 4c 89 f7 e8 13 62 f2 fd e9 0f ff ff ff e8 a9 f2 0b fd <0f> 0b 48 89 df e8 ef 00 00 00 eb bd e8 98 f2 0b fd 4c 89 f7 be 03
RSP: 0018:ffffc90000b37d10 EFLAGS: 00010293
RAX: ffffffff845db907 RBX: ffff888111644000 RCX: ffff88810dcd0000
RDX: 0000000000000000 RSI: 000000000c9f97c0 RDI: 000000000c04eb7d
RBP: ffffc90000b37d30 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff0e18c4c R12: dffffc0000000000
R13: dffffc0000000000 R14: 000000000c9f97c0 R15: ffff8881218bd000
FS:  0000555567bd7500(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000012e11b000 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
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0xd0/0xe0 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f9fcac88e59
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:00007ffc3d948ba8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffc3d948c90 RCX: 00007f9fcac88e59
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00000000000070b7 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b33020000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9fcaf01fac R14: 00007f9fcaf01fa8 R15: 00007f9fcaf01fa0
 </TASK>
---[ end trace 433422ed8632ea93 ]---