Commit bf2cbe04 authored Feb 19, 2020 by Nathan Chancellor Committed by Steven Rostedt (VMware) Mar 19, 2020

tracing: Use address-of operator on section symbols

Clang warns:

../kernel/trace/trace.c:9335:33: warning: array comparison always
evaluates to true [-Wtautological-compare]
        if (__stop___trace_bprintk_fmt != __start___trace_bprintk_fmt)
                                       ^
1 warning generated.

These are not true arrays, they are linker defined symbols, which are
just addresses. Using the address of operator silences the warning and
does not change the runtime result of the check (tested with some print
statements compiled in with clang + ld.lld and gcc + ld.bfd in QEMU).

Link: http://lkml.kernel.org/r/20200220051011.26113-1-natechancellor@gmail.com

Link: https://github.com/ClangBuiltLinux/linux/issues/893


Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

parent bbd9d056

kernel/trace/trace.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -9334,7 +9334,7 @@ __init static int tracer_alloc_buffers(void)
	goto out_free_buffer_mask;		goto out_free_buffer_mask;

	/* Only allocate trace_printk buffers if a trace_printk exists */		/* Only allocate trace_printk buffers if a trace_printk exists */
	if (__stop___trace_bprintk_fmt != __start___trace_bprintk_fmt)		if (&__stop___trace_bprintk_fmt != &__start___trace_bprintk_fmt)
	/* Must be called before global_trace.buffer is allocated */		/* Must be called before global_trace.buffer is allocated */
	trace_printk_init_buffers();		trace_printk_init_buffers();

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