On Sun, 16 Jun 2024 11:38:54 +0200 Francesco Dolcini <francesco@xxxxxxxxxx> wrote: > On Sat, Jun 15, 2024 at 11:50:18AM +0100, Jonathan Cameron wrote: > > On Fri, 14 Jun 2024 11:36:58 -0300 > > João Paulo Gonçalves <jpaulo.silvagoncalves@xxxxxxxxx> wrote: > > > > > From: João Paulo Gonçalves <joao.goncalves@xxxxxxxxxxx> > > > > > > The condition for checking if triggers belong to the same IIO device to > > > set attached_own_device is currently inverted, causing > > > iio_trigger_using_own() to return an incorrect value. Fix it by testing > > > for the correct return value of iio_validate_own_trigger(). > > > > > > Cc: stable@xxxxxxxxxxxxxxx > > > Fixes: 517985ebc531 ("iio: trigger: Add simple trigger_validation helper") > > > Signed-off-by: João Paulo Gonçalves <joao.goncalves@xxxxxxxxxxx> > > Reviewed-by: Francesco Dolcini <francesco.dolcini@xxxxxxxxxxx> > > > > > Ouch. Can you give an example of resulting user visible result? That > > will help people decide whether to pick this up for their distro kernels > > etc. In some cases, looks like we'll get garbage timestamps and in others > > may get stale data (or garbage). > > This was noticed while me and Joao were working on the ads1119 driver you > have been recently reviewing. We wanted to use iio_trigger_using_own() > and it was not behaving the right way. We looked into it and found the bug. > > Given that I do not know the exact impact on the drivers that are using this > function. > > > Odd no one has noticed this in the past whilst testing those dependent > > features in particular drivers and I worry a little that we may have bugs > > in the users as a result of iio_trigger_using_own() reporting the inverse > > of the intended. I've take a quick look at the users and 'think' they are > > ok, but would definitely like a few others to confirm. > > All the users of iio_trigger_using_own() are older than the commit that > introduced the bug, it is safe to assume that they need the fix and > are expecting the function to behave the same way is documented and it was > before the bug was introduced. > > The broken commit is not that old and less than 10 IIO drivers are using this > function. Given that I think that is not that odd that it took 1 year to find > the bug. Yes. Long tail of IIO devices that are used on the sort of board that only gets a kernel update once in a while and well behind mainline. So indeed not that surprising :( Applied to the fixes-togreg branch of iio.git Thanks, Jonathan > > Francesco >