[tip: x86/entry] x86/entry: Increase entry_stack size to a full page

tip-bot2 for Peter Zijlstra
2020-06-25T11:53:45Z

The following commit has been merged into the x86/entry branch of tip:

Commit-ID: c7aadc09321d8f9a1d3bd1e6d8a47222ecddf6c5
Gitweb: https://git.kernel.org/tip/c7aadc09321d8f9a1d3bd1e6d8a47222ecddf6c5
Author: Peter Zijlstra <peterz@infradead.org>
AuthorDate: Wed, 17 Jun 2020 18:25:57 +02:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Thu, 25 Jun 2020 13:45:40 +02:00

x86/entry: Increase entry_stack size to a full page

Marco crashed in bad_iret with a Clang11/KCSAN build due to
overflowing the stack. Now that we run C code on it, expand it to a
full page.

Suggested-by: Andy Lutomirski <luto@amacapital.net>
Reported-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
Tested-by: Marco Elver <elver@google.com>
Link: https://lkml.kernel.org/r/20200618144801.819246178@infradead.org
---
arch/x86/include/asm/processor.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 42cd333..03b7c4c 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -370,7 +370,7 @@ struct x86_hw_tss {
#define IO_BITMAP_OFFSET_INVALID (__KERNEL_TSS_LIMIT + 1)

struct entry_stack {
- unsigned long words[64];
+ char stack[PAGE_SIZE];
};

struct entry_stack_page {