perf: WARNING: CPU: 1 PID: 3691 at kernel/events/core.c:2647 task_ctx_sched_out+0x195/0x1f0()

[Sasha Levin]

Hi all,

While fuzzing with trinity inside a KVM tools guest, running the latest -next
kernel, I've hit the following warning:

[  394.086642] WARNING: CPU: 1 PID: 3691 at kernel/events/core.c:2647 task_ctx_sched_out+0x195/0x1f0()
[  394.087732] Modules linked in:
[  394.088190] CPU: 1 PID: 3691 Comm: trinity-c95 Not tainted 4.4.0-rc8-next-20160108-sasha-00024-gaaecb9a #2780
[  394.089354]  1ffff100387d8f19 0000000036fa75d1 ffff8801c3ec7948 ffffffff8301a182
[  394.090283]  0000000041b58ab3 ffffffff8e1b3838 ffffffff8301a0b7 0000000000000000
[  394.091266]  ffff8801c44fc500 0000000036fa75d1 ffffffff8145d240 0000000000000001
[  394.092247] Call Trace:
[  394.092604] dump_stack (lib/dump_stack.c:52)
[  394.094810] warn_slowpath_common (kernel/panic.c:484)
[  394.095570] ? task_ctx_sched_out (kernel/events/core.c:2647 (discriminator 3))
[  394.096385] warn_slowpath_null (kernel/panic.c:518)
[  394.097134] task_ctx_sched_out (kernel/events/core.c:2647 (discriminator 3))
[  394.097900] perf_event_exit_task (kernel/events/core.c:8756 kernel/events/core.c:8821)
[  394.101501] do_exit (kernel/exit.c:759)
[  394.105344] do_group_exit (kernel/exit.c:862)
[  394.106053] get_signal (kernel/signal.c:2307)
[  394.106740] do_signal (arch/x86/kernel/signal.c:781)
[  394.112553] exit_to_usermode_loop (arch/x86/entry/common.c:249)
[  394.113311] syscall_return_slowpath (./arch/x86/include/asm/jump_label.h:35 include/linux/context_tracking_state.h:30 include/linux/context_tracking.h:24 arch/x86/entry/common.c:284 arch/x86/entry/common.c:344)
[  394.114111] int_ret_from_sys_call (arch/x86/entry/entry_64.S:282)


Thanks,
Sasha