From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Nathan Chancellor <natechancellor@gmail.com>
Subject: [for-linus][PATCH 2/5] tracing: Fix clang -Wint-in-bool-context warnings in IF_ASSIGN macro
Date: Sun, 29 Sep 2019 16:06:44 -0400 [thread overview]
Message-ID: <20190929200748.397303700@goodmis.org> (raw)
In-Reply-To: 20190929200642.036511084@goodmis.org
From: Nathan Chancellor <natechancellor@gmail.com>
After r372664 in clang, the IF_ASSIGN macro causes a couple hundred
warnings along the lines of:
kernel/trace/trace_output.c:1331:2: warning: converting the enum
constant to a boolean [-Wint-in-bool-context]
kernel/trace/trace.h:409:3: note: expanded from macro
'trace_assign_type'
IF_ASSIGN(var, ent, struct ftrace_graph_ret_entry,
^
kernel/trace/trace.h:371:14: note: expanded from macro 'IF_ASSIGN'
WARN_ON(id && (entry)->type != id); \
^
264 warnings generated.
This warning can catch issues with constructs like:
if (state == A || B)
where the developer really meant:
if (state == A || state == B)
This is currently the only occurrence of the warning in the kernel
tree across defconfig, allyesconfig, allmodconfig for arm32, arm64,
and x86_64. Add the implicit '!= 0' to the WARN_ON statement to fix
the warnings and find potential issues in the future.
Link: https://github.com/llvm/llvm-project/commit/28b38c277a2941e9e891b2db30652cfd962f070b
Link: https://github.com/ClangBuiltLinux/linux/issues/686
Link: http://lkml.kernel.org/r/20190926162258.466321-1-natechancellor@gmail.com
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
kernel/trace/trace.h | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 26b0a08f3c7d..f801d154ff6a 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -365,11 +365,11 @@ static inline struct trace_array *top_trace_array(void)
__builtin_types_compatible_p(typeof(var), type *)
#undef IF_ASSIGN
-#define IF_ASSIGN(var, entry, etype, id) \
- if (FTRACE_CMP_TYPE(var, etype)) { \
- var = (typeof(var))(entry); \
- WARN_ON(id && (entry)->type != id); \
- break; \
+#define IF_ASSIGN(var, entry, etype, id) \
+ if (FTRACE_CMP_TYPE(var, etype)) { \
+ var = (typeof(var))(entry); \
+ WARN_ON(id != 0 && (entry)->type != id); \
+ break; \
}
/* Will cause compile errors if type is not found. */
--
2.20.1
next prev parent reply other threads:[~2019-09-29 20:07 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-29 20:06 [for-linus][PATCH 0/5] tracing: Minor fixes for the last pull request Steven Rostedt
2019-09-29 20:06 ` [for-linus][PATCH 1/5] tracing/probe: Fix to check the difference of nr_args before adding probe Steven Rostedt
2019-09-29 20:06 ` Steven Rostedt [this message]
2019-09-29 20:06 ` [for-linus][PATCH 3/5] tracing: Have error path in predicate_parse() free its allocated memory Steven Rostedt
2019-09-29 20:06 ` [for-linus][PATCH 4/5] mm, tracing: Print symbol name for call_site in trace events Steven Rostedt
2019-09-29 20:06 ` [for-linus][PATCH 5/5] selftests/ftrace: Fix same probe error test Steven Rostedt
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