Commit-ID: d594aa0277e541bb997aef0bc0a55172d8138340 Gitweb: http://git.kernel.org/tip/d594aa0277e541bb997aef0bc0a55172d8138340 Author: Ashish Kalra <ashish@xxxxxxxxxxxxxx> AuthorDate: Wed, 19 Apr 2017 20:50:15 +0530 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Thu, 20 Apr 2017 10:05:23 +0200 x86/boot: Fix BSS corruption/overwrite bug in early x86 kernel startup The minimum size for a new stack (512 bytes) setup for arch/x86/boot components when the bootloader does not setup/provide a stack for the early boot components is not "enough". The setup code executing as part of early kernel startup code, uses the stack beyond 512 bytes and accidentally overwrites and corrupts part of the BSS section. This is exposed mostly in the early video setup code, where it was corrupting BSS variables like force_x, force_y, which in-turn affected kernel parameters such as screen_info (screen_info.orig_video_cols) and later caused an exception/panic in console_init(). Most recent boot loaders setup the stack for early boot components, so this stack overwriting into BSS section issue has not been exposed. Signed-off-by: Ashish Kalra <ashish@xxxxxxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: Brian Gerst <brgerst@xxxxxxxxx> Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx> Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/20170419152015.10011-1-ashishkalra@Ashishs-MacBook-Pro.local Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/boot/boot.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/boot/boot.h b/arch/x86/boot/boot.h index 9b42b6d..ef5a9cc 100644 --- a/arch/x86/boot/boot.h +++ b/arch/x86/boot/boot.h @@ -16,7 +16,7 @@ #ifndef BOOT_BOOT_H #define BOOT_BOOT_H -#define STACK_SIZE 512 /* Minimum number of bytes for stack */ +#define STACK_SIZE 1024 /* Minimum number of bytes for stack */ #ifndef __ASSEMBLY__ -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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