| Date | Thu, 23 Aug 2007 14:50:38 -0700 | From | Andrew Morton <> | Subject | Re: [-mm patch] enforce noreplace-smp in alternative_instructions() |
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On Wed, 22 Aug 2007 22:25:51 +0200 Frederik Deweerdt <deweerdt@free.fr> wrote:
> On Wed, Aug 22, 2007 at 02:06:48AM -0700, Andrew Morton wrote: > > > > ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.23-rc3/2.6.23-rc3-mm1/ > > > Hi Jeremy, > > arch/i386/kernel/alternative.c:alternative_instructions() doesn't > check for noreplace-smp before setting capability bits and freeing the > __smp_locks section.
umm, so? What happens then? What bug is being fixed here, and what are its consequences?
> Every call to alternatives_smp_unlock() checks for noreplace-smp > beforehand, so remove the check from there. > > Boot tested on i386 with UP+noreplace-smp (lguest) and SMP (real hardware) > > Regards, > Frederik > > Signed-off-by: Frederik Deweerdt <frederik.deweerdt@gmail.com> > > diff --git a/arch/i386/kernel/alternative.c b/arch/i386/kernel/alternative.c > index 9f4ac8b..7c5af80 100644 > --- a/arch/i386/kernel/alternative.c > +++ b/arch/i386/kernel/alternative.c > @@ -221,9 +221,6 @@ static void alternatives_smp_unlock(u8 **start, u8 **end, u8 *text, u8 *text_end > u8 **ptr; > char insn[1]; > > - if (noreplace_smp) > - return; > - > add_nops(insn, 1); > for (ptr = start; ptr < end; ptr++) { > if (*ptr < text) > @@ -406,7 +403,7 @@ void __init alternative_instructions(void) > #endif > > #ifdef CONFIG_SMP > - if (smp_alt_once) { > + if (smp_alt_once && !noreplace_smp) { > if (1 == num_possible_cpus()) { > printk(KERN_INFO "SMP alternatives: switching to UP code\n"); > set_bit(X86_FEATURE_UP, boot_cpu_data.x86_capability);
You refer to rc3-mm1 and this is described as a "-mm patch" but it seems to also be applicable to mainline? - 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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