[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <e6d2a3c778d9850714ff4b8084a74143d8f3dd5a.1466192946.git.luto@kernel.org>
Date: Fri, 17 Jun 2016 13:00:46 -0700
From: Andy Lutomirski <luto@...nel.org>
To: x86@...nel.org,
linux-kernel@...r.kernel.org
Cc: linux-arch@...r.kernel.org,
Borislav Petkov <bp@...en8.de>,
Nadav Amit <nadav.amit@...il.com>,
Kees Cook <keescook@...omium.org>,
Brian Gerst <brgerst@...il.com>,
"kernel-hardening@...ts.openwall.com" <kernel-hardening@...ts.openwall.com>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Josh Poimboeuf <jpoimboe@...hat.com>,
Jann Horn <jann@...jh.net>,
Heiko Carstens <heiko.carstens@...ibm.com>,
Andy Lutomirski <luto@...nel.org>
Subject: [PATCH v2 10/13] x86/dumpstack: Try harder to get a call trace on stack overflow
If we overflow the stack, print_context_stack will abort. Detect
this case and rewind back into the valid part of the stack so that
we can trace it.
Signed-off-by: Andy Lutomirski <luto@...nel.org>
---
arch/x86/kernel/dumpstack.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index d4d085e27d04..9cdf05d768cf 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -89,7 +89,7 @@ static inline int valid_stack_ptr(struct thread_info *tinfo,
else
return 0;
}
- return p > t && p < t + THREAD_SIZE - size;
+ return p >= t && p < t + THREAD_SIZE - size;
}
unsigned long
@@ -100,6 +100,13 @@ print_context_stack(struct thread_info *tinfo,
{
struct stack_frame *frame = (struct stack_frame *)bp;
+ /*
+ * If we overflowed the stack into a guard page, jump back to the
+ * bottom of the usable stack.
+ */
+ if ((unsigned long)tinfo - (unsigned long)stack < PAGE_SIZE)
+ stack = (unsigned long *)tinfo;
+
while (valid_stack_ptr(tinfo, stack, sizeof(*stack), end)) {
unsigned long addr;
--
2.5.5
Powered by blists - more mailing lists
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
