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

Daniel Vetter
2014-09-23T08:34:50Z

On Mon, Sep 22, 2014 at 08:25:21AM -0700, bradley.d.volkin@intel.com wrote:
> From: Brad Volkin <bradley.d.volkin@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@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.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org

> ---
>
> According to the report in bugzilla, this happens in linux-next-20140919 as
> well. I'm not sure what the path is for getting the fix there in addition to
> nightly.
>
> drivers/gpu/drm/i915/i915_cmd_parser.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_cmd_parser.c b/drivers/gpu/drm/i915/i915_cmd_parser.c
> index 4c35e2a..86b3ae0 100644
> --- a/drivers/gpu/drm/i915/i915_cmd_parser.c
> +++ b/drivers/gpu/drm/i915/i915_cmd_parser.c
> @@ -709,11 +709,13 @@ int i915_cmd_parser_init_ring(struct intel_engine_cs *ring)
> BUG_ON(!validate_cmds_sorted(ring, cmd_tables, cmd_table_count));
> BUG_ON(!validate_regs_sorted(ring));
>
> - ret = init_hash_table(ring, cmd_tables, cmd_table_count);
> - if (ret) {
> - DRM_ERROR("CMD: cmd_parser_init failed!\n");
> - fini_hash_table(ring);
> - return ret;
> + if (hash_empty(ring->cmd_hash)) {
> + ret = init_hash_table(ring, cmd_tables, cmd_table_count);
> + if (ret) {
> + DRM_ERROR("CMD: cmd_parser_init failed!\n");
> + fini_hash_table(ring);
> + return ret;
> + }
> }
>
> ring->needs_cmd_parser = true;
> --
> 1.8.3.2
>
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--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch