On Wed, 30 Oct 2013, Cowell, Matt (NSN - US/Arlington Heights) wrote:
> Repost to linux-rt-users list, as there has been no response on the linux-kernel list and it missed several rt patch releases. Originally seen on 3.10.10-rt7.
>
>
> There is a deadlock condition with RT spin_locks that may use trylock in
> hardirq context. The main user of this is get_next_timer_interrupt, which
> will deadlock if an IRQ preempts a timer wheel modification.
Errm. No.
> Detected by spinlock lockup debug:
> BUG: spinlock lockup suspected on CPU#1, ncp_nca_0_grp_5/133
> lock: 0xee02a000, .magic: dead4ead, .owner: <none>/-1, .owner_cpu: -1
> CPU: 1 PID: 133 Comm: ncp_nca_0_grp_5 Tainted: G O 3.10.10-rt7 #53
The cpu is in thread context and therefor not idle.
void tick_nohz_irq_exit(void)
{
if (!ts->inidle)
return;
....
}
So you are papering over the real issue:
Why is ts->inidle true, if the CPU is not in idle?
Thanks,
tglx
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