On Thu, Feb 08, 2018 at 02:58:56PM +0100, Julia Lawall wrote: > > > On Thu, 8 Feb 2018, Dan Carpenter wrote: > > > On Thu, Feb 08, 2018 at 01:53:54PM +0100, Julia Lawall wrote: > > > This checks for a comparison using < or > between two constants, > > > considering both explicit constants (1, 2, etc) and macros defined > > > with #define. False positives are possible in the latter case, when > > > a macro may have multiple possible definitions and it is indeed > > > necessary to check the value. There are currently two such false > > > positives, in drivers/net/ethernet/chelsio/cxgb3/sge.c: > > > > > > q->fl.use_pages = FL0_PG_CHUNK_SIZE > 0; > > > q->fl.use_pages = FL1_PG_CHUNK_SIZE > 0; > > > > > > > We could eliminate both these false postives by ignoring >> vs >. Did > > searching for > actually find any bugs? I think you were right that > > right shifting a constant is way less common than left shifting and I > > have some smatch scripts where I ignore right shifting bugs. > > > > On the other hand, two false positives are not a big deal. > > I found no bugs with > at the moment. I figured that the person could > have just as easily written 0 < FL0_PG_CHUNK_SIZE, so it was not worth ^^^^^^^^^^^^^^^^^^^^^ That's a Yoda speak type condition though so it's less common.
Unrelated, but I fixed a Yoda condition today where the test was reversed so I feel like Yoda conditions are more likely to be buggy (because they are hard to read). regards, dan carpenter _______________________________________________ Cocci mailing list Cocci@systeme.lip6.fr https://systeme.lip6.fr/mailman/listinfo/cocci