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@gmail.com wrote:
From: João Paulo Gonçalves joao.goncalves@toradex.com
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@vger.kernel.org Fixes: 517985ebc531 ("iio: trigger: Add simple trigger_validation helper") Signed-off-by: João Paulo Gonçalves joao.goncalves@toradex.com
Reviewed-by: Francesco Dolcini francesco.dolcini@toradex.com
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.
Francesco