[ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.165' (ECDSA) to the list of known hosts. 2020/07/02 04:06:31 fuzzer started 2020/07/02 04:06:31 dialing manager at 10.128.0.105:43447 2020/07/02 04:06:33 syscalls: 3106 2020/07/02 04:06:33 code coverage: enabled 2020/07/02 04:06:33 comparison tracing: enabled 2020/07/02 04:06:33 extra coverage: enabled 2020/07/02 04:06:33 setuid sandbox: enabled 2020/07/02 04:06:33 namespace sandbox: enabled 2020/07/02 04:06:33 Android sandbox: /sys/fs/selinux/policy does not exist 2020/07/02 04:06:33 fault injection: enabled 2020/07/02 04:06:33 leak checking: CONFIG_DEBUG_KMEMLEAK is not enabled 2020/07/02 04:06:33 net packet injection: enabled 2020/07/02 04:06:33 net device setup: enabled 2020/07/02 04:06:33 concurrency sanitizer: enabled 2020/07/02 04:06:33 devlink PCI setup: PCI device 0000:00:10.0 is not available 2020/07/02 04:06:33 USB emulation: enabled 2020/07/02 04:06:34 suppressing KCSAN reports in functions: 'alloc_pid' 'do_nanosleep' '__send_signal' 'blk_mq_dispatch_rq_list' 'copy_process' 'ext4_free_inode' '__ext4_new_inode' 'do_epoll_wait' 'pcpu_alloc' 'generic_write_end' 'dd_has_work' '__xa_clear_mark' syzkaller login: [ 45.756434][ T8661] ================================================================== [ 45.764558][ T8661] BUG: KCSAN: data-race in __mod_timer / timer_clear_idle [ 45.771628][ T8661] [ 45.773971][ T8661] write to 0xffff88812c11cb24 of 1 bytes by task 0 on cpu 1: [ 45.781309][ T8661] timer_clear_idle+0x2e/0x40 [ 45.785954][ T8661] tick_nohz_idle_retain_tick+0x3e/0x40 [ 45.791467][ T8661] do_idle+0x287/0x310 [ 45.795521][ T8661] cpu_startup_entry+0x15/0x20 [ 45.800255][ T8661] start_secondary+0xe3/0x110 [ 45.804918][ T8661] secondary_startup_64+0xa4/0xb0 [ 45.809906][ T8661] [ 45.812207][ T8661] read to 0xffff88812c11cb24 of 1 bytes by task 8661 on cpu 0: [ 45.819718][ T8661] __mod_timer+0xb87/0xf00 [ 45.824116][ T8661] mod_timer+0x1b/0x20 [ 45.828169][ T8661] sk_reset_timer+0x1f/0xa0 [ 45.832641][ T8661] tcp_rearm_rto+0x204/0x210 [ 45.837206][ T8661] tcp_write_xmit+0x1bee/0x3f40 [ 45.842027][ T8661] __tcp_push_pending_frames+0x68/0x1c0 [ 45.847542][ T8661] tcp_push+0x2da/0x2f0 [ 45.851667][ T8661] tcp_sendmsg_locked+0x1bf9/0x2200 [ 45.856833][ T8661] tcp_sendmsg+0x2c/0x40 [ 45.861063][ T8661] inet_sendmsg+0x5f/0x80 [ 45.865368][ T8661] sock_write_iter+0x1a1/0x200 [ 45.870112][ T8661] __vfs_write+0x2d8/0x340 [ 45.874499][ T8661] vfs_write+0x19b/0x350 [ 45.878723][ T8661] ksys_write+0xce/0x180 [ 45.882936][ T8661] __x64_sys_write+0x3e/0x50 [ 45.887494][ T8661] do_syscall_64+0x51/0xb0 [ 45.891892][ T8661] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 45.897747][ T8661] [ 45.900047][ T8661] Reported by Kernel Concurrency Sanitizer on: [ 45.906179][ T8661] CPU: 0 PID: 8661 Comm: syz-fuzzer Not tainted 5.8.0-rc3-syzkaller #0 [ 45.914392][ T8661] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 45.924417][ T8661] ================================================================== [ 45.932468][ T8661] Kernel panic - not syncing: panic_on_warn set ... [ 45.939042][ T8661] CPU: 0 PID: 8661 Comm: syz-fuzzer Not tainted 5.8.0-rc3-syzkaller #0 [ 45.947257][ T8661] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 45.957284][ T8661] Call Trace: [ 45.960547][ T8661] dump_stack+0x10f/0x19d [ 45.964848][ T8661] panic+0x207/0x64a [ 45.968713][ T8661] ? vprintk_emit+0x44a/0x4f0 [ 45.973360][ T8661] kcsan_report+0x684/0x690 [ 45.977834][ T8661] ? kcsan_setup_watchpoint+0x453/0x4d0 [ 45.983349][ T8661] ? __mod_timer+0xb87/0xf00 [ 45.987908][ T8661] ? mod_timer+0x1b/0x20 [ 45.992122][ T8661] ? sk_reset_timer+0x1f/0xa0 [ 45.996784][ T8661] ? tcp_rearm_rto+0x204/0x210 [ 46.001526][ T8661] ? tcp_write_xmit+0x1bee/0x3f40 [ 46.006519][ T8661] ? __tcp_push_pending_frames+0x68/0x1c0 [ 46.012231][ T8661] ? tcp_push+0x2da/0x2f0 [ 46.016532][ T8661] ? tcp_sendmsg_locked+0x1bf9/0x2200 [ 46.021874][ T8661] ? tcp_sendmsg+0x2c/0x40 [ 46.026255][ T8661] ? inet_sendmsg+0x5f/0x80 [ 46.030730][ T8661] ? sock_write_iter+0x1a1/0x200 [ 46.035639][ T8661] ? __vfs_write+0x2d8/0x340 [ 46.040210][ T8661] ? vfs_write+0x19b/0x350 [ 46.044594][ T8661] ? ksys_write+0xce/0x180 [ 46.048994][ T8661] ? __x64_sys_write+0x3e/0x50 [ 46.053727][ T8661] ? do_syscall_64+0x51/0xb0 [ 46.058288][ T8661] ? entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 46.064337][ T8661] ? __ip_queue_xmit+0x9ba/0x9e0 [ 46.069243][ T8661] ? __copy_skb_header+0x228/0x270 [ 46.074325][ T8661] kcsan_setup_watchpoint+0x453/0x4d0 [ 46.079680][ T8661] __mod_timer+0xb87/0xf00 [ 46.084065][ T8661] mod_timer+0x1b/0x20 [ 46.088117][ T8661] sk_reset_timer+0x1f/0xa0 [ 46.092589][ T8661] tcp_rearm_rto+0x204/0x210 [ 46.097152][ T8661] tcp_write_xmit+0x1bee/0x3f40 [ 46.101982][ T8661] ? check_preemption_disabled+0x51/0x140 [ 46.107668][ T8661] ? iov_iter_advance+0x1e0/0x890 [ 46.113620][ T8661] ? _copy_from_iter_full+0x1d9/0x6d0 [ 46.118977][ T8661] __tcp_push_pending_frames+0x68/0x1c0 [ 46.124505][ T8661] tcp_push+0x2da/0x2f0 [ 46.128632][ T8661] tcp_sendmsg_locked+0x1bf9/0x2200 [ 46.133806][ T8661] tcp_sendmsg+0x2c/0x40 [ 46.138017][ T8661] inet_sendmsg+0x5f/0x80 [ 46.142328][ T8661] sock_write_iter+0x1a1/0x200 [ 46.147064][ T8661] __vfs_write+0x2d8/0x340 [ 46.151465][ T8661] vfs_write+0x19b/0x350 [ 46.155691][ T8661] ksys_write+0xce/0x180 [ 46.159913][ T8661] __x64_sys_write+0x3e/0x50 [ 46.164471][ T8661] do_syscall_64+0x51/0xb0 [ 46.168858][ T8661] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 46.174720][ T8661] RIP: 0033:0x4b3cdb [ 46.178589][ T8661] Code: Bad RIP value. [ 46.182628][ T8661] RSP: 002b:000000c00397b540 EFLAGS: 00000202 ORIG_RAX: 0000000000000001 [ 46.191043][ T8661] RAX: ffffffffffffffda RBX: 000000c00002c000 RCX: 00000000004b3cdb [ 46.198991][ T8661] RDX: 0000000000000007 RSI: 000000c00000a200 RDI: 0000000000000006 [ 46.206946][ T8661] RBP: 000000c00397b590 R08: 000000c00000a201 R09: 0000000000000007 [ 46.214899][ T8661] R10: 000000c000114000 R11: 0000000000000202 R12: 000000000000011e [ 46.222850][ T8661] R13: 000000c000484000 R14: 0000000000000007 R15: 0000000000001c78 [ 47.293669][ T8661] Shutting down cpus with NMI [ 47.299416][ T8661] Kernel Offset: disabled [ 47.303725][ T8661] Rebooting in 86400 seconds..