Re: [PATCH v7 1/4] spinlock: A new lockref structure for locklessupdate of refcount

[Theodore Ts'o]

Speaking of bool (and I'm not a fan of it either), is this warning
just noise (which is bad enough since it masks real warnings), or is
this going to cause serious problems?

  CHECK   /usr/projects/linux/ext4/kernel/trace/trace.c
/usr/projects/linux/ext4/kernel/trace/trace.c:559:6: warning: symbol 'free_snapshot' was not declared. Should it be static?
/usr/projects/linux/ext4/kernel/trace/trace.c:1489:14: warning: expression using sizeof bool
/usr/projects/linux/ext4/kernel/trace/trace.c:1489:14: warning: expression using sizeof bool
/usr/projects/linux/ext4/kernel/trace/trace.c:1489:14: warning: expression using sizeof bool
/usr/projects/linux/ext4/kernel/trace/trace.c:1489:14: warning: expression using sizeof bool
/usr/projects/linux/ext4/kernel/trace/trace.c:1492:9: warning: expression using sizeof bool
/usr/projects/linux/ext4/kernel/trace/trace.c:1492:9: warning: expression using sizeof bool
/usr/projects/linux/ext4/kernel/trace/trace.c:1492:9: warning: expression using sizeof bool
/usr/projects/linux/ext4/kernel/trace/trace.c:1492:9: warning: expression using sizeof bool
/usr/projects/linux/ext4/kernel/trace/trace.c:1539:9: warning: expression using sizeof bool
/usr/projects/linux/ext4/kernel/trace/trace.c:1539:9: warning: expression using sizeof bool
/usr/projects/linux/ext4/kernel/trace/trace.c:1539:9: warning: expression using sizeof bool
/usr/projects/linux/ext4/kernel/trace/trace.c:1539:9: warning: expression using sizeof bool

(i.e., is a C compiler allowed to pack multiple bools stored in a data
structure into a single byte, with potentially hilarious results for C
code trying to do magic utilizing sizeof and offsetof (which some of
our kernel macros do use, IIRC)?

				- Ted

P.S.  BTW, this is not the only set of sparse warnings that are
emitted by files in kernel/trace/*; maybe it would be good if the
ftrace maintianers worked on nuking them all?  There are also a bunch
of warnings like which I've only recently learned indicated potential
RCU bugs:

/usr/projects/linux/ext4/kernel/trace/trace.c:1885:17: warning: incorrect type in assignment (different address spaces)
/usr/projects/linux/ext4/kernel/trace/trace.c:1885:17:    expected struct trace_buffer_struct *buffers
/usr/projects/linux/ext4/kernel/trace/trace.c:1885:17:    got struct trace_buffer_struct [noderef] <asn:3>*<noident>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/