Re: DM Regression in 4.16-rc1 - read() returns data when it shouldn't

From: Thorsten Leemhuis
Date: Mon Feb 26 2018 - 12:31:49 EST


On 26.02.2018 12:01, NeilBrown wrote:
> On Mon, Feb 26 2018, Thorsten Leemhuis wrote:
>> Hi Mike! On 19.02.2018 18:15, Mike Snitzer wrote:
>>> On Mon, Feb 19 2018 at 8:44am -0500,
>>> Thorsten Leemhuis <regressions@xxxxxxxxxxxxx> wrote:
>>>> JFYI: This issues is tracked in the regression reports for Linux 4.16
>>>> (http://bit.ly/lnxregrep416 ) with this id:
>>>> Linux-Regression-ID: lr#9e195f
>>>> Please include this line in the comment section of patches that are
>>> [â]
>>> The fix was already merged by Linus on Friday, see:
>>> git.kernel.org/linus/8dd601fa8317243be887458c49f6c29c2f3d719f
>> Ohh, thx for the pointer. Could you please next time add a tag like
>> Fixes: 18a25da84354 ("dm: ensure bio submission follows a depth-first
>> tree walk")
>
> The thing is... it didn't fix that commit. That commit was fine.
> If fixed something else much further back, which that commit just made
> more problematic.
> That is why I added the Cc: stable with the earliest version that needed
> fixing.
>
> Unfortunately, reality isn't always neat and tidy :-( when it is, I do
> use Fixes:

Ha, okay, sorry for the noise then.

Side note: At the same time this is might be a reason why a
"Linux-Regression-ID" or something like that might make sense, because
it shows that even a bisected commit sometimes isn't enough to build a
obvious connection between a regression report and the commit with the
fix...
Ciao, Thorsten