Re: Glibc recvmsg from kernel netlink socket hangs forever

From: Guenter Roeck
Date: Fri Sep 25 2015 - 23:46:08 EST


On 09/25/2015 08:55 AM, Herbert Xu wrote:
On Thu, Sep 24, 2015 at 10:34:10PM -0700, Guenter Roeck wrote:

Any idea what may be needed for 4.1 ?
I am currently trying,

This patch should not make any difference on 4.1 and later because
4.1 is where I rewrote rhashtable resizing and it should work (or
if it is broken then the latest kernel should be broken too).

but I have no idea if that will help with the problem we are seeing there.

Having looked at your message agin I don't think the issue I
alluded to is relevant since the symptom there ought to be a
straight kernel lock-up as opposed to just a user-space one because
you will end up with the kernel sending a message to itself.

And the fact that 4.2 works is more indicative as the bug is
present in both 4.1 and 4.2.

I'll try to reproduce this in 4.1 as time permits but no promises.

After applying your two patches, I don't see the problem in 4.1 anymore.
We'll run the system through regression; the complete cycle may take
a couple of weeks. I'll let you know if we find any further problems.

If you submit additional patches in that area, it would be great if you
can Cc: me.


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