From: Russell King <rmk@arm.linux.org.uk>
To: duanev@interactivesi.com (duane voth)
Cc: linux-kernel@vger.kernel.org
Subject: Re: obscure bug in vmalloc
Date: Thu, 1 Feb 2001 23:19:22 +0000 (GMT) [thread overview]
Message-ID: <200102012319.f11NJM813793@flint.arm.linux.org.uk> (raw)
In-Reply-To: <3A79EC64.2060502@interactivesi.com> from "duane voth" at Feb 01, 2001 05:08:20 PM
duane voth writes:
> duane voth wrote:
> > ... I've attached a patch that
> > can be used to watch for the problem. The following is a 2.2 patch (2.4
> > will follow in a few minutes). If you see "vmalloc error" you might want
> > to uncomment the look_for_dangling_pgds function to get a better feel for
> > the pgds that cause the probem.
>
> Here is the 2.4.1 version.
> +int
> +duanev_ensure_pgds_same(unsigned long addr, unsigned long size)
>...
> + for_each_task(p) {
> + for (va = addr; va < addr + size; va = (va + PGDIR_SIZE) & PGDIR_MASK) {
> + pgd_t kpgd = *pgd_offset_k(va);
> + if (pgd_val(*pgd_offset(p->mm, va)) != pgd_val(kpgd)) {
>...
In 2.4 kernels, it is legal for a processes pgds in the vmalloc area to be
different from those of the init task in so much as they may be entries
that will cause a fault. The page fault handler will then fill in the
pgd entry for us.
--
Russell King (rmk@arm.linux.org.uk) The developer of ARM Linux
http://www.arm.linux.org.uk/personal/aboutme.html
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prev parent reply other threads:[~2001-02-01 23:24 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-02-01 23:04 obscure bug in vmalloc duane voth
2001-02-01 23:08 ` duane voth
2001-02-01 23:19 ` Russell King [this message]
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