[Intel-gfx] [PATCH] drm/i915: Don't leak command parser tables on suspend/resume

[Chris Wilson]

On Tue, Sep 23, 2014 at 10:34:46AM +0200, Daniel Vetter wrote:
> On Mon, Sep 22, 2014 at 08:25:21AM -0700, bradley.d.volkin at intel.com wrote:
> > From: Brad Volkin <bradley.d.volkin at intel.com>
> > 
> > Ring init and cleanup are not balanced because we re-init the rings on
> > resume without having cleaned them up on suspend. This leads to the
> > driver leaking the parser's hash tables with a kmemleak signature such
> > as this:
> > 
> > unreferenced object 0xffff880405960980 (size 32):
> >   comm "systemd-udevd", pid 516, jiffies 4294896961 (age 10202.044s)
> >   hex dump (first 32 bytes):
> >     d0 85 46 c0 ff ff ff ff 00 00 00 00 00 00 00 00  ..F.............
> >     98 60 28 04 04 88 ff ff 00 00 00 00 00 00 00 00  .`(.............
> >   backtrace:
> >     [<ffffffff81816f9e>] kmemleak_alloc+0x4e/0xb0
> >     [<ffffffff811fa678>] kmem_cache_alloc_trace+0x168/0x2f0
> >     [<ffffffffc03e20a5>] i915_cmd_parser_init_ring+0x2a5/0x3e0 [i915]
> >     [<ffffffffc04088a2>] intel_init_ring_buffer+0x202/0x470 [i915]
> >     [<ffffffffc040c998>] intel_init_vebox_ring_buffer+0x1e8/0x2b0 [i915]
> >     [<ffffffffc03eff59>] i915_gem_init_hw+0x2f9/0x3a0 [i915]
> >     [<ffffffffc03f0057>] i915_gem_init+0x57/0x1d0 [i915]
> >     [<ffffffffc045e26a>] i915_driver_load+0xc0a/0x10e0 [i915]
> >     [<ffffffffc02e0d5d>] drm_dev_register+0xad/0x100 [drm]
> >     [<ffffffffc02e3b9f>] drm_get_pci_dev+0x8f/0x200 [drm]
> >     [<ffffffffc03c934b>] i915_pci_probe+0x3b/0x60 [i915]
> >     [<ffffffff81436725>] local_pci_probe+0x45/0xa0
> >     [<ffffffff81437a69>] pci_device_probe+0xd9/0x130
> >     [<ffffffff81524f4d>] driver_probe_device+0x12d/0x3e0
> >     [<ffffffff815252d3>] __driver_attach+0x93/0xa0
> >     [<ffffffff81522e1b>] bus_for_each_dev+0x6b/0xb0
> > 
> > This patch extends the current convention of checking whether a
> > resource is already allocated before allocating it during ring init.
> > Longer term it might make sense to only init the rings once.
> > 
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=83794
> > Signed-off-by: Brad Volkin <bradley.d.volkin at intel.com>
> 
> We should finally get around to split the ring init code properly into
> software init in _init functions (done once) and _init_hw functions for
> rpm/resume ... Anyway, this looks sane.

Maybe someone already sent patches to do so.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre