From: Nathan Chancellor natechancellor@gmail.com
[ Upstream commit bf2cbe044da275021b2de5917240411a19e5c50d ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/trace/trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 22759f5607192..19526297a5b1c 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -8346,7 +8346,7 @@ __init static int tracer_alloc_buffers(void) goto out_free_buffer_mask;
/* 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 */ trace_printk_init_buffers();