bisecting fixing commit since 2b79150141611d3c6e1b55d4e70f49602482f0b8 building syzkaller on 8bc4594f832068a30c0eff44d468311780057d1f testing commit 2b79150141611d3c6e1b55d4e70f49602482f0b8 with gcc (GCC) 8.4.1 20210217 kernel signature: 2bfeb7cbbeb0dfe33970c95ecaf3a5597495155770ab58c1d285c595a5fdfe93 run #0: crashed: KASAN: out-of-bounds Read in __tcf_idr_release run #1: crashed: general protection fault in __tcf_idr_release run #2: crashed: BUG: unable to handle kernel paging request in tcf_action_destroy 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: BUG: unable to handle kernel paging request in tcf_action_destroy run #6: crashed: general protection fault in __tcf_idr_release run #7: crashed: general protection fault in __tcf_idr_release run #8: crashed: general protection fault in __tcf_idr_release run #9: crashed: BUG: unable to handle kernel paging request in tcf_action_destroy run #10: crashed: general protection fault in __tcf_idr_release run #11: crashed: general protection fault in __tcf_idr_release run #12: crashed: general protection fault in __tcf_idr_release run #13: crashed: BUG: unable to handle kernel paging request in tcf_action_destroy run #14: crashed: general protection fault in __tcf_idr_release run #15: crashed: general protection fault in __tcf_idr_release run #16: crashed: general protection fault in __tcf_idr_release run #17: crashed: general protection fault in __tcf_idr_release run #18: crashed: general protection fault in __tcf_idr_release run #19: crashed: general protection fault in __tcf_idr_release testing current HEAD cf256fbcbe347b7d0ff58fe2dfa382a156bd3694 testing commit cf256fbcbe347b7d0ff58fe2dfa382a156bd3694 with gcc (GCC) 8.4.1 20210217 kernel signature: d2ec831b0ff1fad56f4135478d0caa8c764e05f644398056ab6410a0d5668b17 run #0: crashed: general protection fault in __tcf_idr_release run #1: crashed: general protection fault in __tcf_idr_release run #2: crashed: BUG: spinlock bad magic in __tcf_idr_release run #3: crashed: KASAN: use-after-free Read 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: general protection fault in __tcf_idr_release run #9: crashed: general protection fault in __tcf_idr_release revisions tested: 2, total time: 21m55.173361589s (build: 14m47.180614805s, test: 6m46.180803378s) the crash still happens on HEAD commit msg: Linux 4.14.231 crash: general protection fault in __tcf_idr_release netlink: 32 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 32 bytes leftover after parsing attributes in process `syz-executor.2'. netlink: 32 bytes leftover after parsing attributes in process `syz-executor.5'. 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: 10404 Comm: syz-executor.2 Not tainted 4.14.231-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8881e7d26080 task.stack: ffff8881d0340000 RIP: 0010:atomic_inc arch/x86/include/asm/atomic.h:92 [inline] RIP: 0010:__lock_acquire+0x262/0x42d0 kernel/locking/lockdep.c:3382 RSP: 0018:ffff8881d0347160 EFLAGS: 00010002 RAX: 0040414000000002 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 1ffff1103d117c6c RSI: 0000000000000000 RDI: ffff8881e88be360 RBP: ffff8881d0347330 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: ffff8881e7d26080 R12: ffff8881e88be358 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000 FS: 00007f06facd0700(0000) GS:ffff8881f6500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000055c000 CR3: 00000001f37cb005 CR4: 00000000001606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x17e/0x3e0 kernel/locking/lockdep.c:3998 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:176 spin_lock_bh include/linux/spinlock.h:322 [inline] tcf_idr_remove net/sched/act_api.c:78 [inline] __tcf_idr_release net/sched/act_api.c:101 [inline] __tcf_idr_release+0x12e/0x1c0 net/sched/act_api.c:85 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+0x3c4/0x580 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+0x639/0xbe0 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: 0033:0x465889 RSP: 002b:00007f06facd0188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000000055bf00 RCX: 0000000000465889 RDX: 0000000000000000 RSI: 0000000020002980 RDI: 0000000000000003 RBP: 00000000004af68d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000055bf00 R13: 00007ffe636622ef R14: 00007f06facd0300 R15: 0000000000022000 Code: 00 00 fc ff df 89 f3 49 8d 7c dc 08 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 cd 2e 00 00 49 8b 44 dc 08 48 85 c0 0f 84 03 ff ff ff ff 80 38 01 00 00 49 8d 9b 80 08 00 00 48 ba 00 00 00 00 00 RIP: atomic_inc arch/x86/include/asm/atomic.h:92 [inline] RSP: ffff8881d0347160 RIP: __lock_acquire+0x262/0x42d0 kernel/locking/lockdep.c:3382 RSP: ffff8881d0347160 ---[ end trace 79b878192f304d43 ]---