Re: [ckrm-tech] [PATCH 4/13] BC: context handling
From: Paul Menage
Date: Thu Nov 23 2006 - 04:32:36 EST
On 11/23/06, Pavel Emelianov <xemul@xxxxxxxxxx> wrote:
You mean moving is like this:
old_bc = task->real_bc;
task->real_bc = new_bc;
cmpxchg(&tsk->exec_bc, old_bc, new_bc);
? Then this won't work:
Initialisation:
current->exec_bc = init_bc;
current->real_bc = init_bc;
...
IRQ:
current->exec_bc = init_bc;
...
old_bc = tsk->real_bc; /* init_bc */
tsk->real_bc = bc1;
cx(tsk->exec_bc, init_bc, bc1); /* ok */
...
Here at the middle of an interrupt
we have bc1 set as exec_bc on task
which IS wrong!
You could get round that by having a separate "irq_bc" that's never
valid for a task not in an interrupt.
Paul
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