From f92ff8f5dca2acfa475842c71212657b0703c3be Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 15 Sep 2022 13:10:40 +0200 Subject: [PATCH] x86/paravirt: Ensure proper alignment The entries in the .parainstructions sections are 8 byte aligned and the corresponding C struct paravirt_patch_site makes the array offset 16 bytes. Though the pushed entries are only using 12 bytes, __parainstructions_end is therefore 4 bytes short. That works by chance because it's only used in a loop: for (p = start; p < end; p++) But this falls flat when calculating the number of elements: n = end - start That's obviously off by one. Ensure that the gap is filled and the last entry is occupying 16 bytes. [ bp: Add the proper struct and section names. ] Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov Reviewed-by: Juergen Gross Link: https://lore.kernel.org/r/20220915111142.992398801@infradead.org --- arch/x86/include/asm/paravirt.h | 1 + arch/x86/include/asm/paravirt_types.h | 1 + 2 files changed, 2 insertions(+) diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h index 964442b99245..2a0b8dd4ec33 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -743,6 +743,7 @@ extern void default_banner(void); word 771b; \ .byte ptype; \ .byte 772b-771b; \ + _ASM_ALIGN; \ .popsection diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h index 89df6c6617f5..27b036a15f70 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -294,6 +294,7 @@ extern struct paravirt_patch_template pv_ops; " .byte " type "\n" \ " .byte 772b-771b\n" \ " .short " clobber "\n" \ + _ASM_ALIGN "\n" \ ".popsection\n" /* Generate patchable code, with the default asm parameters. */