Messages in this thread Patch in this message | | | Date | Thu, 11 Dec 2008 21:36:04 +0100 | From | Ingo Molnar <> | Subject | Re: Linux 2.6.28-rc8 |
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* Linus Torvalds <torvalds@linux-foundation.org> wrote:
> On Thu, 11 Dec 2008, Ingo Molnar wrote: > > > > hm, the warning caught a couple of real bugs already. (one in some > > cpq driver, another was in some networking driver iirc) > > Well, one thing that does irritate me is that it scares people who > can't do anything about it, and probably _shouldn't_ do anything about > it.
yeah - and false positives also tend to create apathy and resistence against kernel warnings - thus drawing tester resources away from more important bugs.
> I wonder if we should just change the "Warning" message to > "Informational" or something. Yes, they are often real bugs. But no, > they're not _automatically_ bugs. Almost all the time when a warning > triggers, it's really just a developer who wants to know about it, it's > not something that a user should really care/worry about.
ok. In this case i'd suggest we should just remove the warning. People do get scared by needless kernel stack dumps - no matter whether it's marked informational or not.
So how about the patch below, queued up in tip/x86/debug? Arjan, what do you think?
Ingo
---------------> From 2dcae81e819fa5cc0e9310ef8b0c079940df3bf3 Mon Sep 17 00:00:00 2001 From: Ingo Molnar <mingo@elte.hu> Date: Thu, 11 Dec 2008 21:29:51 +0100 Subject: [PATCH] IO resources, x86: remove multi-BAR mapping sanity check
Impact: remove a debug warning
The ioremap() time multi-BAR map warning has been causing false positives:
http://lkml.org/lkml/2008/12/10/432 http://lkml.org/lkml/2008/12/11/136
So remove it for now.
Signed-off-by: Ingo Molnar <mingo@elte.hu> --- arch/x86/mm/ioremap.c | 6 ------ include/linux/ioport.h | 1 - kernel/resource.c | 38 -------------------------------------- 3 files changed, 0 insertions(+), 45 deletions(-)
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index d4c4307..421b92d 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -220,12 +220,6 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr, return (__force void __iomem *)phys_to_virt(phys_addr); /* - * Check if the request spans more than any BAR in the iomem resource - * tree. - */ - WARN_ON(iomem_map_sanity_check(phys_addr, size)); - - /* * Don't allow anybody to remap normal RAM that we're using.. */ for (pfn = phys_addr >> PAGE_SHIFT; diff --git a/include/linux/ioport.h b/include/linux/ioport.h index 041e95a..0dde772 100644 --- a/include/linux/ioport.h +++ b/include/linux/ioport.h @@ -174,7 +174,6 @@ extern struct resource * __devm_request_region(struct device *dev, extern void __devm_release_region(struct device *dev, struct resource *parent, resource_size_t start, resource_size_t n); -extern int iomem_map_sanity_check(resource_size_t addr, unsigned long size); #endif /* __ASSEMBLY__ */ #endif /* _LINUX_IOPORT_H */ diff --git a/kernel/resource.c b/kernel/resource.c index 4337063..4b0bc70 100644 --- a/kernel/resource.c +++ b/kernel/resource.c @@ -829,41 +829,3 @@ static int __init reserve_setup(char *str) } __setup("reserve=", reserve_setup); - -/* - * Check if the requested addr and size spans more than any slot in the - * iomem resource tree. - */ -int iomem_map_sanity_check(resource_size_t addr, unsigned long size) -{ - struct resource *p = &iomem_resource; - int err = 0; - loff_t l; - - read_lock(&resource_lock); - for (p = p->child; p ; p = r_next(NULL, p, &l)) { - /* - * We can probably skip the resources without - * IORESOURCE_IO attribute? - */ - if (p->start >= addr + size) - continue; - if (p->end < addr) - continue; - if (PFN_DOWN(p->start) <= PFN_DOWN(addr) && - PFN_DOWN(p->end) >= PFN_DOWN(addr + size - 1)) - continue; - printk(KERN_WARNING "resource map sanity check conflict: " - "0x%llx 0x%llx 0x%llx 0x%llx %s\n", - (unsigned long long)addr, - (unsigned long long)(addr + size - 1), - (unsigned long long)p->start, - (unsigned long long)p->end, - p->name); - err = -1; - break; - } - read_unlock(&resource_lock); - - return err; -}
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