bisecting fixing commit since 5b7a52cd2eef952cee8a72512ef370bcdef46636 building syzkaller on f24824d3d54060a7d878eeb35c47f85dab84966a testing commit 5b7a52cd2eef952cee8a72512ef370bcdef46636 with gcc (GCC) 8.1.0 kernel signature: 0e6d51f04faaa469ba71b08e8bd9fe6ebc91494e7f7254cb481c97699c998c57 run #0: crashed: general protection fault in __tcf_idr_release run #1: crashed: general protection fault in __tcf_idr_release run #2: crashed: general protection fault in __tcf_idr_release run #3: crashed: BUG: unable to handle kernel paging request in tcf_action_destroy run #4: crashed: general protection fault in __tcf_idr_release run #5: crashed: general protection fault in __tcf_idr_release run #6: crashed: BUG: unable to handle kernel paging request in tcf_action_destroy run #7: crashed: general protection fault in __tcf_idr_release run #8: crashed: KASAN: out-of-bounds Read in tcf_action_destroy run #9: crashed: KASAN: stack-out-of-bounds Read in tcf_action_destroy testing current HEAD 3f2ecb86cb909da0b9157fd2952ad79924cbe5ae testing commit 3f2ecb86cb909da0b9157fd2952ad79924cbe5ae with gcc (GCC) 8.1.0 kernel signature: 5b784951482b42636a3b8bd905d3e88598f9b26c78f72f24fd08245be388c2f2 run #0: crashed: general protection fault in __tcf_idr_release run #1: crashed: general protection fault in __tcf_idr_release run #2: crashed: general protection fault in __tcf_idr_release run #3: crashed: general protection fault in __tcf_idr_release run #4: crashed: general protection fault in __tcf_idr_release run #5: crashed: general protection fault in __tcf_idr_release run #6: crashed: general protection fault in __tcf_idr_release run #7: crashed: BUG: unable to handle kernel paging request in tcf_action_destroy run #8: crashed: general protection fault in __tcf_idr_release run #9: crashed: general protection fault in __tcf_idr_release revisions tested: 2, total time: 23m34.30322094s (build: 16m57.668489339s, test: 5m52.525806196s) the crash still happens on HEAD commit msg: Linux 4.14.212 crash: general protection fault in __tcf_idr_release wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50 wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50 IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready 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: 0 PID: 10542 Comm: syz-executor.3 Not tainted 4.14.212-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8881d0b94140 task.stack: ffff8881cc848000 RIP: 0010:__tcf_idr_release+0xeb/0x1c0 net/sched/act_api.c:99 RSP: 0000:ffff8881cc84f3e0 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: ffff8881cd267680 RCX: ffff8881cd267680 RDX: 03fffe22073499e5 RSI: 0000000000000000 RDI: 1ffff11039a4cf2a RBP: ffff8881cc84f400 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: ffff8881d0b94140 R12: 0000000000000000 R13: 1ffff11039a4cee2 R14: 0000000000000001 R15: 0000000000000000 FS: 00007f0b75c5e700(0000) GS:ffff8881f6400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000050ca70 CR3: 00000001e91f6001 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: tcf_action_destroy+0xbf/0x160 net/sched/act_api.c:527 tcf_action_init+0x335/0x460 net/sched/act_api.c:769 tcf_action_add net/sched/act_api.c:1079 [inline] tc_ctl_action+0x3c4/0x573 net/sched/act_api.c:1131 rtnetlink_rcv_msg+0x34c/0x9e0 net/core/rtnetlink.c:4316 netlink_rcv_skb+0x12f/0x3b0 net/netlink/af_netlink.c:2433 rtnetlink_rcv+0x10/0x20 net/core/rtnetlink.c:4328 netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline] netlink_unicast+0x40b/0x610 net/netlink/af_netlink.c:1313 netlink_sendmsg+0x657/0xc60 net/netlink/af_netlink.c:1878 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xac/0xf0 net/socket.c:656 ___sys_sendmsg+0x625/0x920 net/socket.c:2062 __sys_sendmsg+0xc1/0x140 net/socket.c:2096 SYSC_sendmsg net/socket.c:2107 [inline] SyS_sendmsg+0xd/0x20 net/socket.c:2103 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45deb9 RSP: 002b:00007f0b75c5dc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000000002e680 RCX: 000000000045deb9 RDX: 0000000000000000 RSI: 0000000020002980 RDI: 0000000000000003 RBP: 000000000118bf60 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bf2c R13: 00007ffee11f2f5f R14: 00007f0b75c5e9c0 R15: 000000000118bf2c Code: ff df 48 89 da 48 c1 ea 03 80 3c 02 00 0f 85 de 00 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 2b 49 8d 7d 48 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 b2 00 00 00 49 8b 45 48 48 85 c0 74 09 41 0f RIP: __tcf_idr_release+0xeb/0x1c0 net/sched/act_api.c:99 RSP: ffff8881cc84f3e0 ---[ end trace ca7366b98f7822b7 ]---