On Sun, 2 Sep 2007, Jeff Garzik wrote: > > Satyam Sharma wrote: > > drivers/scsi/dc395x.c: In function ‘dc395x_init_one’: > > drivers/scsi/dc395x.c:4272: warning: ‘ptr’ may be used uninitialized in this > > function > > > > has been verified to be a bogus warning. Let's shut it up. > > > > Signed-off-by: Satyam Sharma <satyam@xxxxxxxxxxxxx> > > > > --- > > > > drivers/scsi/dc395x.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > --- linux-2.6.23-rc4-mm1/drivers/scsi/dc395x.c~fix 2007-09-02 > > 20:57:51.000000000 +0530 > > +++ linux-2.6.23-rc4-mm1/drivers/scsi/dc395x.c 2007-09-02 > > 21:10:49.000000000 +0530 > > @@ -4269,7 +4269,7 @@ static int __devinit adapter_sg_tables_a > > const unsigned srbs_per_page = PAGE_SIZE/SEGMENTX_LEN; > > int srb_idx = 0; > > unsigned i = 0; > > - struct SGentry *ptr; > > + struct SGentry * uninitialized_var(ptr); > > For things like this, we need to see (perhaps a separate email in the same > thread) your build details: config, arch, compiler version, etc. I'll post the info as a reply to the first mail in this series. I have fairly recent gcc (4.1.1) and I don't see us dropping support for it in the next few years. > I paid careful attention to my recent set of uninitialized_var() markers (now > upstream), making sure that they persisted across several compiler versions, > ensuring the warning was not a temporary optimizer bug quickly remedied. > > I hope to encourage similar diligence in others :) These markers have the > very-real potential downside of hiding bugs, so they should be used sparingly. Well, uninitialized_var() is definitely more greppable than "= 0" which code all over does all the time :-) Anyway, the point is that the warnings are bogus anyway (hence maintainers Cc:'ed so that they can confirm if I arrived at the conclusion correctly) /and/ that uninitialized_var() stands out sorely, so I don't see bugs getting "hidden" at all -- in fact I did find two bugs during this process, and fixed them accordingly. Thanks, Satyam
