Hi,
You probably know that sparse produces a ton of errors & warnings when
run on the Linux kernel tree (a little over 1 MB in my latest 'make C=1'
on x86_64 arch.).
I'm wondering if all of these are valid.
Examples:
1. Use of the BUILD_BUG_ON() macro causes this error from sparse:
arch/x86/kernel/paravirt.c:101:9: error: invalid bitfield width, -1.
include/linux/kernel.h:
/* Force a compilation error if condition is true */
#define BUILD_BUG_ON(condition) ((void)BUILD_BUG_ON_ZERO(condition))
/* Force a compilation error if condition is true, but also produce a
result (of value 0 and type size_t), so the expression can be used
e.g. in a structure initializer (or where-ever else comma expressions
aren't permitted). */
#define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
2. drivers/block/drbd/drbd_int.h uses __protected_by(var);
this seems to be unknown to sparse.
#ifdef __CHECKER__
# define __protected_by(x) __attribute__((require_context(x,1,999,"rdwr")))
sparse says many times:
drivers/block/drbd/drbd_int.h:887:39: error: attribute 'require_context': unknown attribute
3. I don't see the problem here -- maybe it's simple (or maybe it's
related to BUILD_BUG_ON stuff):
drivers/char/ipmi/ipmi_watchdog.c:291:1: error: cannot dereference this type
referring to:
module_param_call(action, set_param_str, get_param_str, action_op, 0644);
which comes from include/linux/moduleparam.h
4. from include/linux/swab.h:
include/linux/swab.h:51:16: warning: unreplaced symbol 'val'
include/linux/swab.h:51:16: warning: unreplaced symbol 'val'
include/linux/swab.h:51:9: warning: unreplaced symbol 'return'
referring to:
static inline __attribute_const__ __u16 __fswab16(__u16 val)
{
#ifdef __arch_swab16
return __arch_swab16(val);
#else
return ___constant_swab16(val);
#endif
}
5. sparse reports (maybe correctly?):
include/linux/skbuff.h:357:41: error: invalid bitfield specifier for type restricted __be16.
on struct sk_buff, this line:
__be16 protocol:16;
6. sparse reports:
drivers/usb/gadget/zero.c:166:9: warning: advancing past deep designator
on
static struct usb_string strings_dev[] = {
[STRING_MANUFACTURER_IDX].s = manufacturer,
[STRING_PRODUCT_IDX].s = longname,
[STRING_SERIAL_IDX].s = serial,
{ } /* end of list */
};
Is that an improper initializer? The sparse warning doesn't mean much to me.
Thanks for listening, insights, etc.
---
~Randy
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