Re: WARN_ON noise in 2.5.63's kernel/sched.c:context_switch

[William Lee Irwin III]

On Wed, Mar 05, 2003 at 04:13:48PM +0900, Miles Bader wrote:
> Ok, I think I found the reason; sched.c cleans up some stuff in
> schedule_tail, and in this code (arch/v850/kernel/entry.S):
> C_ENTRY(ret_from_fork):
> #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
> 	mov	r10, r6			// switch_thread returns the prev task.
> 	jarl	CSYM(schedule_tail), lp	// ...which is schedule_tail's arg
> #endif
> 	mov	r0, r10			// Child's fork call should return 0.
> 	br	ret_from_trap		// Do normal trap return.
> ... it only calls that if CONFIG_PREEMPT is turned on.  If I remove the
> #ifdef, then I get no warnings.
> I take it that the call to schedule_tail should now be unconditional?
> [some other archs have the same #ifdef]

Yeah, this is the root problem. You have to go through schedule_tail()
to clean up the mm's etc.

-- wli