Messages in this thread Patch in this message |  | | Subject | Re: [PATCH] kernel BUG at sched.c:944! only with CONFIG_PREEMPT=y] | From | Robert Love <> | Date | 13 Sep 2002 03:36:34 -0400 |
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On Fri, 2002-09-13 at 03:19, Ingo Molnar wrote:
> of course. And your point in making it in_interrupt() had what purpose - > hiding that tons of code breaks preemption? [and tons of code breaks on > SMP.] Your patch was removing precisely the tool that can be used to > improve SMP quality on UP boxes as well.
Ingo, Attached is the latest patch I sent Linus. I never doubted the usefulness, just the practicality of having endusers parse so much information.
At any rate, the approach in Linus's BK is wrong because (a) the debug is hit way too often to just BUG() and (b) we have to take into account PREEMPT_ACTIVE.
> yes. And we also need kallsyms and kksymoops in the kernel, so that people > can send in meaningful traces.
Agree 100% here.
Robert Love
iff -urN linux-2.5.34/kernel/sched.c linux/kernel/sched.c --- linux-2.5.34/kernel/sched.c Thu Sep 12 16:26:23 2002 +++ linux/kernel/sched.c Thu Sep 12 16:42:59 2002 @@ -940,8 +940,10 @@ struct list_head *queue; int idx; - if (unlikely(in_atomic())) - BUG(); + if (unlikely(in_atomic() && preempt_count() != PREEMPT_ACTIVE)) { + printk(KERN_ERROR "schedule() called while non-atomic!\n"); + show_stack(NULL); + } #if CONFIG_DEBUG_HIGHMEM check_highmem_ptes(); @@ -959,7 +961,7 @@ * if entering off of a kernel preemption go straight * to picking the next task. */ - if (unlikely(preempt_count() & PREEMPT_ACTIVE)) + if (unlikely(preempt_count() == PREEMPT_ACTIVE)) goto pick_next_task; switch (prev->state) { - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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