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    Subject[PATCH AUTOSEL 5.4 183/330] tracing: Use address-of operator on section symbols
    Date
    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 9007f5edbb207..db8162b34ef64 100644
    --- a/kernel/trace/trace.c
    +++ b/kernel/trace/trace.c
    @@ -9146,7 +9146,7 @@ __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();

    --
    2.25.1
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