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To: Tejun Heo <tj@kernel.org>, "David Airlie" <airlied@linux.ie>
From: Chris Wilson <chris@chris-wilson.co.uk>
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Subject: Re: [next-20170609] WARNING: CPU: 3 PID: 71167 at lib/idr.c:157 idr_replace
Date: Thu, 22 Jun 2017 00:31:35 +0100
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Quoting Tejun Heo (2017-06-13 14:58:49)
> Cc'ing David Airlie.
> 
> This is from drm driver calling in idr_replace() w/ a negative id.
> Probably a silly bug in error handling path?

No, this is the validation of an invalid userspace handle. The drm ABI
for handles is supposed to be a full u32 range with 0 reserved for an
invalid handle (constrained by the idr_alloc ofc). The WARN was
introduced by 0a835c4f090a.
-Chris