Re: drivers/md/dm-vdo/data-vio.c:976 vdo_launch_bio() warn: inconsistent returns '&pool->lock'.

[Dan Carpenter]

On Tue, Oct 29, 2024 at 11:07:07AM +0300, Dan Carpenter wrote:
> On Tue, Oct 29, 2024 at 03:15:47PM +0800, Philip Li wrote:
> > On Tue, Oct 29, 2024 at 11:03:07AM +0800, Philip Li wrote:
> > > On Mon, Oct 28, 2024 at 07:00:40PM -0400, Matthew Sakai wrote:
> > > > This should be addressed upstream by commit
> > > > 872564c501b72ae0c84af51084753e8652e4a84b ("dm vdo data-vio: silence sparse
> > > > warnings about locking context imbalances")
> > > > 
> > > > That commit is from February. Would it be possible for these checks to use a
> > > > more up-to-date version of the code before warning us about things that have
> > > > already been addressed?
> > > 
> > > Sorry about this Matt, the bot side will check why this happens and fix
> > > the issue asap to avoid meaningless report.
> > 
> > Hi Matt and Dan, would you mind do a further check of this, per the re-test,
> > smatch warns as below on v6.12-rc3
> > 
> > 	drivers/md/dm-vdo/data-vio.c:982 vdo_launch_bio() warn: inconsistent returns '&pool->lock'.
> > 	  Locked on  : 972,977
> > 	  Unlocked on: 982
> > 
> > The corresponding code of drivers/md/dm-vdo/data-vio.c is below
> > 
> 
> Ah.  Right.
> 
> The cross function DB doesn't scale well enough for the zero day bot to use so
> it didn't detect the fix.  If we had the cross function DB then that silences
> the warning.
> 
> 1) I re-wrote the locking check so it detected this bug where before it didn't.
> 2) The kbuild bot was using the new check on old code because Matthew Sakai
>    did a branch based on 8 month old code.

That's not it, is it...  The branch was based on the latest code, and the
kbuild-bot bisected it back to 8 months ago and it happened to be right.

Anyway, it's a rare coincidence.

regards,
dan carpenter