bisecting fixing commit since e132c8d7b58d8dc2c1888f5768454550d1f3ea7b
building syzkaller on b5268b89c2964733654c89f8322fb155d9fa6799
testing commit e132c8d7b58d8dc2c1888f5768454550d1f3ea7b with gcc (GCC) 8.1.0
kernel signature: 5515d843e090c27f8847fecd999333994e33381b7c15721439453eedca04479b
run #0: crashed: KASAN: use-after-free Write in pppol2tp_connect
run #1: crashed: KASAN: use-after-free Write in pppol2tp_connect
run #2: crashed: KASAN: use-after-free Read in pppol2tp_session_close
run #3: crashed: KASAN: use-after-free Read in l2tp_session_create
run #4: crashed: KASAN: use-after-free Read in l2tp_session_create
run #5: crashed: KASAN: use-after-free Read in lock_sock_nested
run #6: crashed: KASAN: use-after-free Read in pppol2tp_session_close
run #7: crashed: KASAN: use-after-free Write in pppol2tp_connect
run #8: crashed: KASAN: use-after-free Read in pppol2tp_session_close
run #9: crashed: KASAN: use-after-free Read in pppol2tp_session_close
testing current HEAD b850307b279cbd12ab8c654d1a3dfe55319cc475
testing commit b850307b279cbd12ab8c654d1a3dfe55319cc475 with gcc (GCC) 8.1.0
kernel signature: 7afbb6c33ce7d0fa48f0ebca23d932ab0ab50409b727968acb9eafa642067920
all runs: crashed: general protection fault in pppol2tp_session_init
revisions tested: 2, total time: 23m56.123688027s (build: 17m0.105935044s, test: 6m10.309127314s)
the crash still happens on HEAD
commit msg: Linux 4.14.184
crash: general protection fault in pppol2tp_session_init
IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready
8021q: adding VLAN 0 to HW filter on device batadv0
8021q: adding VLAN 0 to HW filter on device batadv0
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 7685 Comm: syz-executor.1 Not tainted 4.14.184-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff888092e16080 task.stack: ffff88808b9f8000
RIP: 0010:__read_once_size include/linux/compiler.h:183 [inline]
RIP: 0010:sk_dst_get include/net/sock.h:1766 [inline]
RIP: 0010:pppol2tp_session_init+0x1c1/0x480 net/l2tp/l2tp_ppp.c:616
RSP: 0018:ffff88808b9ffb88 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff8880850d4480 RCX: 1ffffffff0edabad
RDX: 0000000000000045 RSI: ffffffff86bce1e0 RDI: 0000000000000228
RBP: ffff88808b9ffbb0 R08: ffff888092e16950 R09: 0000000000000000
R10: 0000000000000028 R11: ffff888092e16080 R12: 0000000000000000
R13: 0000000000001e05 R14: ffff88808b9ffd28 R15: ffff8880a6157280
FS:  00007f111b9c7700(0000) GS:ffff8880aef00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000960004 CR3: 000000008c468000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 pppol2tp_connect+0xce4/0x1380 net/l2tp/l2tp_ppp.c:790
 SYSC_connect+0x1e3/0x2a0 net/socket.c:1655
 SyS_connect+0x9/0x10 net/socket.c:1636
 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x459a59
RSP: 002b:00007f111b9c6c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459a59
RDX: 0000000000000026 RSI: 0000000020000180 RDI: 0000000000000005
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f111b9c76d4
R13: 00000000004c0006 R14: 00000000004d2298 R15: 00000000ffffffff
Code: 5a 85 c0 74 0d 80 3d 2c ea 9c 02 00 0f 84 0c 02 00 00 49 8d bc 24 28 02 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 8d 02 00 00 4d 8b b4 24 28 02 00 00 e8 88 01 
RIP: __read_once_size include/linux/compiler.h:183 [inline] RSP: ffff88808b9ffb88
RIP: sk_dst_get include/net/sock.h:1766 [inline] RSP: ffff88808b9ffb88
RIP: pppol2tp_session_init+0x1c1/0x480 net/l2tp/l2tp_ppp.c:616 RSP: ffff88808b9ffb88
---[ end trace a3fb0b68125f7a97 ]---