From: Zachary Amsden Date: Fri, 20 Oct 2006 06:29:04 +0000 (-0700) Subject: [PATCH] Fix potential interrupts during alternative patching X-Git-Tag: v2.6.19-rc3~57 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e51959faa61278c762389802faf8ba1a40676628;p=linux-2.6 [PATCH] Fix potential interrupts during alternative patching 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/arch/i386/kernel/alternative.c b/arch/i386/kernel/alternative.c index 28ab806497..583c238e17 100644 --- a/arch/i386/kernel/alternative.c +++ b/arch/i386/kernel/alternative.c @@ -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); }