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[PATCH] Fix potential interrupts during alternative patching

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Interrupts must be disabled during alternative instruction patching.  On
systems with high timer IRQ rates, or when running in an emulator, timing
differences can result in random kernel panics because of running partially
patched instructions.  This doesn't yet fix NMIs, which requires extricating
the patch code from the late bug checking and is logically separate (and also
less likely to cause problems).

Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Zachary Amsden 2006-10-19 23:29:04 -07:00 committed by Linus Torvalds
parent a90b061c0b
commit e51959faa6
1 changed files with 4 additions and 0 deletions
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4
arch/i386/kernel/alternative.c
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@ -344,6 +344,7 @@ void alternatives_smp_switch(int smp)
void __init alternative_instructions(void)
{
unsigned long flags;
if (no_replacement) {
printk(KERN_INFO "(SMP-)alternatives turned off\n");
free_init_pages("SMP alternatives",
@ -351,6 +352,8 @@ void __init alternative_instructions(void)
(unsigned long)__smp_alt_end);
return;
}
local_irq_save(flags);
apply_alternatives(__alt_instructions, __alt_instructions_end);
/* switch to patch-once-at-boottime-only mode and free the
@ -386,4 +389,5 @@ void __init alternative_instructions(void)
alternatives_smp_switch(0);
}
#endif
local_irq_restore(flags);
}