• Geert Uytterhoeven's avatar
    xfs: Fix undefined behavior of shift into sign bit · 4320f346
    Geert Uytterhoeven authored
    With gcc-5:
    
        In file included from ./include/trace/define_trace.h:102:0,
    		     from ./fs/xfs/scrub/trace.h:988,
    		     from fs/xfs/scrub/trace.c:40:
        ./fs/xfs/./scrub/trace.h: In function ‘trace_raw_output_xchk_fsgate_class’:
        ./fs/xfs/scrub/scrub.h:111:28: error: initializer element is not constant
         #define XREP_ALREADY_FIXED (1 << 31) /* checking our repair work */
    				^
    
    Shifting the (signed) value 1 into the sign bit is undefined behavior.
    
    Fix this for all definitions in the file by shifting "1U" instead of
    "1".
    
    This was exposed by the first user added in commit 466c525d
    ("xfs: minimize overhead of drain wakeups by using jump labels").
    
    Fixes: 160b5a78 ("xfs: hoist the already_fixed variable to the scrub context")
    Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
    Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
    Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
    4320f346
scrub.h 5.9 KB