linux-kernel - [PATCH] fgraph: Separate size of ret_stack from PAGE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20241019152951.053f9646@rorschach.local.home>
Date: Sat, 19 Oct 2024 15:29:51 -0400
From: Steven Rostedt <rostedt@...dmis.org>
To: LKML <linux-kernel@...r.kernel.org>, Linux trace kernel
 <linux-trace-kernel@...r.kernel.org>
Cc: Masami Hiramatsu <mhiramat@...nel.org>, Mark Rutland
 <mark.rutland@....com>, Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
 Ryan Roberts <ryan.roberts@....com>
Subject: [PATCH] fgraph: Separate size of ret_stack from PAGE_SIZE

From: Steven Rostedt <rostedt@...dmis.org>

The ret_stack (shadow stack used by function graph infrastructure) is
currently defined as PAGE_SIZE. But some architectures which have 64K
PAGE_SIZE, this is way overkill. Also there's an effort to allow the
PAGE_SIZE to be defined at boot up.

Hard code it for now to 4096. In the future, this size may change and even
be dependent on specific architectures.

Link: https://lore.kernel.org/all/e5067bb8-0fcd-4739-9bca-0e872037d5a1@arm.com/

Suggested-by: Ryan Roberts <ryan.roberts@....com>
Signed-off-by: Steven Rostedt (Google) <rostedt@...dmis.org>
---
 kernel/trace/fgraph.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index ee829d65f301..51e81b299a0d 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -153,7 +153,7 @@ enum {
  * SHADOW_STACK_OFFSET:	The size in long words of the shadow stack
  * SHADOW_STACK_MAX_OFFSET: The max offset of the stack for a new frame to be added
  */
-#define SHADOW_STACK_SIZE	(PAGE_SIZE)
+#define SHADOW_STACK_SIZE	(4096)
 #define SHADOW_STACK_OFFSET	(SHADOW_STACK_SIZE / sizeof(long))
 /* Leave on a buffer at the end */
 #define SHADOW_STACK_MAX_OFFSET				\
-- 
2.45.2