Re: Misleading messages from match 0.6.1-rc1
Toomas Soome <[email protected]>
| Newsgroups | org.kernel.vger.smatch |
|---|---|
| Message-ID | <[email protected]> |
> On 5. Feb 2020, at 09:05, Dan Carpenter <[email protected]> wrote: > > On Wed, Feb 05, 2020 at 08:51:11AM +0200, Toomas Soome wrote: >> >> Hi! >> >> While checking illumos soource, smatch is reporting: >> >> /code/illumos-gate/usr/src/tools/proto/root_sparc-nd/opt/onbld/bin/sparc/smatch: ../../common/fs/ufs/ufs_vnops.c:737 wrip() warn: subtract is higher precedence than shift >> >> The code is: >> >> http://src.illumos.org/source/xref/illumos-gate/usr/src/uts/common/fs/ufs/ufs_vnops.c#737 >> >> limit = MIN(UFS_MAXOFFSET_T, limit); >> >> Where MIN is defined: >> >> #define MIN(a, b) ((a) < (b) ? (a) : (b)) >> >> As seen from those facts, we have no subtraction nor shift. In code above, limit is unsigned 64-bit, UFS_MAXOFFSET_T is signed. >> > > It's complaining about UFS_MAXOFFSET_T. > > #define UFS_MAXOFFSET_T ((1LL << NBBY * sizeof (daddr32_t) + DEV_BSHIFT - 1) \ > - 1) > > I assume the code is correct but adding parenthese around the > (DEV_BSHIFT - 1) doesn't help explain where the minus one comes from. > > regards, > dan carpenter Oh, it is my oversight, totally missed the alternate define. That case is actually (1 << 40) - 1 and indeed, the warning is to tell us that we might use () around the right side of << operator. Thanks, Toomas