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

bradley.d.volkin
2014-09-22T15:25:49Z

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>
---

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