From: Linus Torvalds Date: Mon, 20 May 2013 18:36:03 +0000 (-0700) Subject: x86: Fix bit corruption at CPU resume time X-Git-Tag: firefly_0821_release~3680^2~447 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=5e427ec2d066b48a5c27b3a5a3315f7e4e729077;p=firefly-linux-kernel-4.4.55.git x86: Fix bit corruption at CPU resume time In commit 78d77df71510 ("x86-64, init: Do not set NX bits on non-NX capable hardware") we added the early_pmd_flags that gets the NX bit set when a CPU supports NX. However, the new variable was marked __initdata, because the main _use_ of this is in an __init routine. However, the bit setting happens from secondary_startup_64(), which is called not only at bootup, but on every secondary CPU start. Including resuming from STR and at CPU hotplug time. So the value cannot be __initdata. Reported-bisected-and-tested-by: Michal Hocko Cc: stable@vger.kernel.org # v3.9 Acked-by: Peter Anvin Cc: Fernando Luis Vázquez Cao Signed-off-by: Linus Torvalds --- diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index dab95a85f7f8..55b67614ed94 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -34,7 +34,7 @@ extern pgd_t early_level4_pgt[PTRS_PER_PGD]; extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD]; static unsigned int __initdata next_early_pgt = 2; -pmdval_t __initdata early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX); +pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX); /* Wipe all early page tables except for the kernel symbol map */ static void __init reset_early_page_tables(void)