Le 03/11/2015 00:48, Ian Munsie a écrit :

Excerpts from Michael Ellerman's message of 2015-11-02 11:53:45 +1100:

quoted

On Thu, 2015-10-29 at 13:39 +0100, Frederic Barrat wrote:

quoted

When the cxl driver creates a context, it stores the pid of the
calling task, incrementing the reference count on the struct
pid. Current code mistakenly increments the reference count twice,
once through get_task_pid(), once through get_pid(). The reference
count is only decremented once on detach, thus the struct pid of the
task attaching is never freed. The fix is to simply remove the call to
get_pid().

Signed-off-by: Frederic Barrat <redacted>

What's the symptom?

Everytime a process attached to a capi device it would reduce the total
number of processes that can be running simultaneously by one.

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Broken since when?
Forever?
So should go to stable?
Starting from which release?

Looks like we managed to introduce the same bug twice (d'oh!), so we
should probably split this into two separate patches:

The bug in file.c has existed forever so the fix for that should go to
stable for 3.18+

The bug in api.c will only need to go in for 4.3 since that is the
release where cxlflash was merged and there weren't any users of that
code before that.

So I'm dropping this patch and will resubmit as 2 separate patches.

   Fred