bisecting fixing commit since 88d6de67e390b6093f2c11189ad022988a9e2961 building syzkaller on 56cd6c9b80ee424566e3ceaf8a4b042803a130ad testing commit 88d6de67e390b6093f2c11189ad022988a9e2961 with gcc (GCC) 8.1.0 kernel signature: fb52a9208cde3b0a62bd5226fd2b938f6d56c57578f763f811a93620a2f6955f all runs: crashed: KASAN: null-ptr-deref Read in __tcf_idr_release testing current HEAD 43d555d83c3f1fb8168367ca5b47c3a6570ca487 testing commit 43d555d83c3f1fb8168367ca5b47c3a6570ca487 with gcc (GCC) 8.1.0 kernel signature: 1662316dae92a2101058e98616abd37c3fd0005f55f4382054007c17f6142625 all runs: crashed: KASAN: null-ptr-deref Read in __tcf_idr_release revisions tested: 2, total time: 30m5.133706754s (build: 17m39.092315989s, test: 11m25.077689931s) the crash still happens on HEAD commit msg: Linux 4.19.169 crash: KASAN: null-ptr-deref Read in __tcf_idr_release bond0 (unregistering): Releasing backup interface bond_slave_1 bond0 (unregistering): Releasing backup interface bond_slave_0 bond0 (unregistering): Released all slaves ================================================================== BUG: KASAN: null-ptr-deref in atomic_read include/asm-generic/atomic-instrumented.h:21 [inline] BUG: KASAN: null-ptr-deref in __tcf_idr_release+0x30/0x90 net/sched/act_api.c:139 Read of size 4 at addr 0000000000000010 by task syz-executor414/8886 CPU: 0 PID: 8886 Comm: syz-executor414 Not tainted 4.19.169-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x123/0x171 lib/dump_stack.c:118 kasan_report_error mm/kasan/report.c:352 [inline] kasan_report.cold.9+0x6d/0x2fe mm/kasan/report.c:412 check_memory_region_inline mm/kasan/kasan.c:260 [inline] check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267 kasan_check_read+0x11/0x20 mm/kasan/kasan.c:272 atomic_read include/asm-generic/atomic-instrumented.h:21 [inline] __tcf_idr_release+0x30/0x90 net/sched/act_api.c:139 tcf_del_walker net/sched/act_api.c:266 [inline] tcf_generic_walker+0x595/0x930 net/sched/act_api.c:292 tcf_ife_walker+0x113/0x1d0 net/sched/act_ife.c:862 tca_action_flush net/sched/act_api.c:1142 [inline] tca_action_gd+0xd27/0x1480 net/sched/act_api.c:1248 tc_ctl_action+0x1fe/0x3d0 net/sched/act_api.c:1373 rtnetlink_rcv_msg+0x34f/0x8f0 net/core/rtnetlink.c:4778 netlink_rcv_skb+0x13e/0x3d0 net/netlink/af_netlink.c:2455 rtnetlink_rcv+0x10/0x20 net/core/rtnetlink.c:4796 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x443/0x650 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x765/0xc40 net/netlink/af_netlink.c:1909 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xb5/0xf0 net/socket.c:632 ___sys_sendmsg+0x647/0x950 net/socket.c:2115 __sys_sendmsg+0xd9/0x180 net/socket.c:2153 __do_sys_sendmsg net/socket.c:2162 [inline] __se_sys_sendmsg net/socket.c:2160 [inline] __x64_sys_sendmsg+0x73/0xb0 net/socket.c:2160 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4469a9 Code: e8 0c e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 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 0f 83 db 06 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ff42de32da8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00000000006dbc28 RCX: 00000000004469a9 RDX: 0000000000000000 RSI: 0000000020000300 RDI: 0000000000000003 RBP: 00000000006dbc20 R08: 0000000000000008 R09: 0000000000000000 R10: 000000000000000c R11: 0000000000000246 R12: 00000000006dbc2c R13: 0000000020000400 R14: 00000000004ae868 R15: 000000000000002d ==================================================================