From: Eric Anholt Subject: Re: [patch] i915: take struct_mutex in i915_dma_cleanup() Date: Thu, 01 Jul 2010 15:39:57 -0700 Message-ID: <87fx0225du.fsf@pollan.anholt.net> References: <20100623111954.GA16433@bicker> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha1; protocol="application/pgp-signature" Return-path: In-Reply-To: <20100623111954.GA16433@bicker> Sender: linux-kernel-owner@vger.kernel.org To: Dan Carpenter , David Airlie Cc: Jesse Barnes , Chris Wilson , Zhenyu Wang , nanhai.zou@intel.com, Benny Halevy , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org List-Id: dri-devel@lists.freedesktop.org --=-=-= Content-Transfer-Encoding: quoted-printable On Wed, 23 Jun 2010 13:19:55 +0200, Dan Carpenter wrote: > intel_cleanup_ring_buffer() calls drm_gem_object_unreference() (as > opposed to drm_gem_object_unreference_unlocked()) so it needs to be > called with "struct_mutex" held. If we don't hold the lock, it triggers > a BUG_ON(!mutex_is_locked(&dev->struct_mutex)); >=20 > I also audited the other places that call intel_cleanup_ring_buffer() > and they all hold the lock so they're OK. >=20 > This was introduced in: 8187a2b70e3 "drm/i915: introduce > intel_ring_buffer structure (V2)" and it's a regression from v2.6.34. >=20 > Addresses: https://bugzilla.kernel.org/show_bug.cgi?id=3D16247 >=20 > Signed-off-by: Dan Carpenter > Reported-by: Benny Halevy > Tested-by: Benny Halevy Applied to for-linus. Thanks! --=-=-= Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iEYEARECAAYFAkwtGT0ACgkQHUdvYGzw6vfJPgCfentvhj0aYdeqE4E/aVq7yRVB G/AAn3M8Z47jmFAiDN47s9UwKhmv05PU =akqV -----END PGP SIGNATURE----- --=-=-=--