From: Kees Cook <keescook@chromium.org>
To: kernel-hardening@lists.openwall.com
Cc: Alexander Popov <alex.popov@linux.com>,
Emese Revfy <re.emese@gmail.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH] gcc-plugins/stackleak: Avoid assignment for unused macro argument
Date: Thu, 2 Apr 2020 01:10:47 -0700 [thread overview]
Message-ID: <202004020103.731F201@keescook> (raw)
With GCC version >= 8, the cgraph_create_edge() macro argument using
"frequency" goes unused. Instead of assigning a temporary variable for
the argument, pass the compute_call_stmt_bb_frequency() call directly
as the macro argument so that it will just not be uncalled when it is
not wanted by the macros.
Silences the warning:
scripts/gcc-plugins/stackleak_plugin.c:54:6: warning: variable ‘frequency’ set but not used [-Wunused-but-set-variable]
Now builds cleanly with gcc-7 and gcc-9. Both boot and pass
STACKLEAK_ERASING LKDTM test.
Signed-off-by: Kees Cook <keescook@chromium.org>
---
scripts/gcc-plugins/stackleak_plugin.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/scripts/gcc-plugins/stackleak_plugin.c b/scripts/gcc-plugins/stackleak_plugin.c
index dbd37460c573..cc75eeba0be1 100644
--- a/scripts/gcc-plugins/stackleak_plugin.c
+++ b/scripts/gcc-plugins/stackleak_plugin.c
@@ -51,7 +51,6 @@ static void stackleak_add_track_stack(gimple_stmt_iterator *gsi, bool after)
gimple stmt;
gcall *stackleak_track_stack;
cgraph_node_ptr node;
- int frequency;
basic_block bb;
/* Insert call to void stackleak_track_stack(void) */
@@ -68,9 +67,9 @@ static void stackleak_add_track_stack(gimple_stmt_iterator *gsi, bool after)
bb = gimple_bb(stackleak_track_stack);
node = cgraph_get_create_node(track_function_decl);
gcc_assert(node);
- frequency = compute_call_stmt_bb_frequency(current_function_decl, bb);
cgraph_create_edge(cgraph_get_node(current_function_decl), node,
- stackleak_track_stack, bb->count, frequency);
+ stackleak_track_stack, bb->count,
+ compute_call_stmt_bb_frequency(current_function_decl, bb));
}
static bool is_alloca(gimple stmt)
--
2.20.1
--
Kees Cook
next reply other threads:[~2020-04-02 8:10 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-02 8:10 Kees Cook [this message]
2020-04-07 15:30 ` [PATCH] gcc-plugins/stackleak: Avoid assignment for unused macro argument Alexander Popov
2020-04-07 16:33 ` Kees Cook
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=202004020103.731F201@keescook \
--to=keescook@chromium.org \
--cc=alex.popov@linux.com \
--cc=kernel-hardening@lists.openwall.com \
--cc=linux-kernel@vger.kernel.org \
--cc=re.emese@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).