linux-kernel - [tip:x86/urgent] x86/dumpstack: Prevent KASAN false positive warnings

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Message-ID: <tip-91e08ab0c8515450258d7ad9033bfe69bebad25a@git.kernel.org>
Date:   Fri, 18 Nov 2016 01:04:54 -0800
From:   tip-bot for Josh Poimboeuf <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     eranian@...il.com, bp@...en8.de, acme@...nel.org,
        peterz@...radead.org, dvlasenk@...hat.com, luto@...nel.org,
        brgerst@...il.com, tglx@...utronix.de,
        linux-kernel@...r.kernel.org, torvalds@...ux-foundation.org,
        hpa@...or.com, vincent.weaver@...ne.edu, jpoimboe@...hat.com,
        mingo@...nel.org
Subject: [tip:x86/urgent] x86/dumpstack: Prevent KASAN false positive
 warnings

Commit-ID:  91e08ab0c8515450258d7ad9033bfe69bebad25a
Gitweb:     http://git.kernel.org/tip/91e08ab0c8515450258d7ad9033bfe69bebad25a
Author:     Josh Poimboeuf <jpoimboe@...hat.com>
AuthorDate: Thu, 17 Nov 2016 09:57:24 -0600
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Fri, 18 Nov 2016 09:38:00 +0100

x86/dumpstack: Prevent KASAN false positive warnings

The oops stack dump code scans the entire stack, which can cause KASAN
"stack-out-of-bounds" false positive warnings.  Tell KASAN to ignore it.

Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Stephane Eranian <eranian@...il.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Vince Weaver <vincent.weaver@...ne.edu>
Cc: davej@...emonkey.org.uk
Cc: dvyukov@...gle.com
Link: http://lkml.kernel.org/r/5f6e80c4b0c7f7f0b6211900847a247cdaad753c.1479398226.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/kernel/dumpstack.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index 9b7cf5c..85f854b 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -112,7 +112,7 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
 		for (; stack < stack_info.end; stack++) {
 			unsigned long real_addr;
 			int reliable = 0;
-			unsigned long addr = *stack;
+			unsigned long addr = READ_ONCE_NOCHECK(*stack);
 			unsigned long *ret_addr_p =
 				unwind_get_return_address_ptr(&state);