Re: + proc-dont-lock-task_structs-indefinitely-cpuset-fix-2.patch added to -mm tree

Andrew Morton
2006-03-02T21:50:29Z

Paul Jackson <pj@sgi.com> wrote:
>
> ...
>
> The initial failure is in the file:
>
> arch/ia64/kernel/topology.c
>
> function:
>
> topology_init
>
> line:
>
> sysfs_cpus = kzalloc(sizeof(struct ia64_cpu) * NR_CPUS, GFP_KERNEL);
>
> With our large NR_CPUS of 1024, and the additional cost of
> the CONFIG_DEBUG_SPINLOCK* debug stuff, and the little bit of
> additional data added by this patch, that kzalloc() fails.
>

Oh. Maybe we should put a big fat printk in slab for that.

> I should stare at the code between this point of initial failure and
> the point that the house of cards finally collapsed and see if
> something should have squeaked sooner.

Probably a panic() in your topology_init().

Also the below patch should have been done ages ago.

> I suspect that the short term solution is to proceed without
> prejudice to the patch that triggered this:
>
> gregkh-driver-allow-sysfs-attribute-files-to-be-pollable.patch

Well yeah, except I find that patch to be independently malodorous ;)

> while I look at some way, if just a stop gap measure, to complain
> earlier in the boot, closer to the scene of the original crime,
> so that others hitting this won't waste more time.

See below.

> Perhaps failing that first kzalloc should cause a complaint,
> if not a panic. It would seem that the system is beyond repair
> if that kzalloc fails. And since the system hasn't even finished
> booting yet, and is for sure trying to boot some larger than tried
> before configuration, might just as well announce ones death boldly.

Yeah, it's dead.

From: Andrew Morton <akpm@osdl.org>

We presently ignore the return values from initcalls. But that can carry
useful debugging information. So print it out if it's non-zero.

Also make that warning message more friendly by printing the name of the
initcall function.

Signed-off-by: Andrew Morton <akpm@osdl.org>
---

init/main.c | 20 ++++++++++++++------
1 files changed, 14 insertions(+), 6 deletions(-)

diff -puN init/main.c~initcall-failure-reporting init/main.c
--- 25/init/main.c~initcall-failure-reporting Thu Mar 2 13:41:02 2006
+++ 25-akpm/init/main.c Thu Mar 2 13:50:53 2006
@@ -565,17 +565,23 @@ static void __init do_initcalls(void)
int count = preempt_count();

for (call = __initcall_start; call < __initcall_end; call++) {
- char *msg;
+ char *msg = NULL;
+ char msgbuf[40];
+ int result;

if (initcall_debug) {
printk(KERN_DEBUG "Calling initcall 0x%p", *call);
- print_fn_descriptor_symbol(": %s()", (unsigned long) *call);
+ print_fn_descriptor_symbol(": %s()",
+ (unsigned long) *call);
printk("\n");
}

- (*call)();
+ result = (*call)();

- msg = NULL;
+ if (result) {
+ sprintf(msgbuf, "error code %d", result);
+ msg = msgbuf;
+ }
if (preempt_count() != count) {
msg = "preemption imbalance";
preempt_count() = count;
@@ -585,8 +591,10 @@ static void __init do_initcalls(void)
local_irq_enable();
}
if (msg) {
- printk(KERN_WARNING "error in initcall at 0x%p: "
- "returned with %s\n", *call, msg);
+ printk(KERN_WARNING "initcall at 0x%p", *call);
+ print_fn_descriptor_symbol(": %s()",
+ (unsigned long) *call);
+ printk(": returned with %s\n", msg);
}
}

_