On Thu, Aug 23, 2007 at 02:50:38PM -0700, Andrew Morton wrote: > On Wed, 22 Aug 2007 22:25:51 +0200 > Frederik Deweerdt <[EMAIL PROTECTED]> 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? That means that even when you specify noreplace_smp, some replacing takes place anyway. One of the consequences, besides noreplace_smp not working as expected, is that lguest crashes when you feed it an SMP kernel (I suspect that you can not replace alternatives for smp _and_ paravirt). > > > 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 <[EMAIL PROTECTED]> > > > > 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? > Hmm yes, my bad.
Regards, Frederik - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
