On Tue, 5 Mar 2024 at 15:51, Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote: > > fs/coredump.c: In function 'dump_user_range': > fs/coredump.c:923:40: warning: left-hand operand of comma expression has no effect [-Wunused-value] > 923 | #define dump_page_copy(src, dst) ((dst), (src)) > | ^ > fs/coredump.c:948:58: note: in expansion of macro 'dump_page_copy' > 948 | int stop = !dump_emit_page(cprm, dump_page_copy(page, dump_page)); > | ^~~~~~~~~~~~~~ > > Introduced by commit > > 4630f2caafcd ("coredump: get machine check errors early rather than during iov_iter") Bah. If comes from that #define dump_page_copy(src,dst) ((dst),(src)) and I did it that way because I wanted to avoid *another* warning, namely the "dst not used" thing. But it would have probably been better to either make it an inline function, or maybe an explicit cast, eg #define dump_page_copy(src,dst) ((void)(dst),(src)) or whatever. Linus