id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	field_blocks	field_dependson	field_seealso
459	Failed assertion on cpu.timeoutlock spinlock	Vojtech Horky	Jakub Jermář	"When trying to reproduce bugs #396 and #458, following assertion was hit (see attached picture for full log):
{{{
######> Kernel panic on cpu3 due to a failed assertion: <######
irq_spinlock_trylock() at generic/src/synch/spinlock.c:262:
!lock->guard, cpu.timeoutlock

THE=...
...
...: generic/src/debug/panic.o:panic_common()
...: generic/src/synch/spinlock.o:irq_spinlock_trylock()
...: generic/src/time/timeout.o:timeout_unregister()
...: generic/src/synch/waitq.o:waitq_unsleep()
...: generic/src/ipc/sysipc.o:sys_ipc_poke()
...: generic/src/syscall/syscall.o:syscall_handler()
...: arch/amd64/src/asm.o:syscall_entry()
...
cpu2: looping on spinlock ...:timeout_t_lock, \
    caller=... (generic/src/time/timeout.o:timeout_register)
}}}

'''Steps to reproduce'''
1. Compile default `ia32` or `amd64` from [changeset:mainline,1486 current mainline (1486)] or from [https://code.launchpad.net/~jakub/helenos/mm lp:~jakub/helenos/mm (985)].
2. Run in QEMU:
{{{
qemu -cdrom image.iso -smp 4 -m 1024 -net user \
  -device e1000,vlan=0 -redir tcp:2223::2223
}}}
3. Configure networking in HelenOS
{{{
inetcfg create 10.0.2.15/24 net/eth1 addr
}}}
4. Connect to HelenOS from the host via
{{{
telnet localhost 2223
}}}
5. Start typing something in the telnet session, such as `tester malloc1`
6. HelenOS will panic typically when typing the word `malloc1` or soon after the `tester` is started

'''Notes'''
This problem might be related to the mentioned bugs but as I can see no clear connection, I opened a new ticket.

I have tried the described steps several times and hit the assertion always. The problem appears regardless of the amount of the memory the guest machine has.

It looks that if the kernel thread balancing thread `kcpulb` is disabled (e.g. by adding `return` after thread_detach(THREAD) in [source:mainline/kernel/generic/src/proc/scheduler.c@mainline,1486#L562 scheduler.c]), the problem is reproducible on 2 CPUs only. Otherwise, 4-SMP machine is needed.

"	defect	closed	major	0.5.0	helenos/kernel/amd64	mainline	fixed	spinlock