[Intel-gfx] [PATCH] drm/i915: Remove the failed context from the fpriv->context_idr

[Chris Wilson]

If we encounter an allocation failure during ppggt creation (trivial
even with 16Gib+ RAM!), we need to remove the dead context from the
fpriv->context_idr along with the references.

gem_exec_ctx: page allocation failure: order:0, mode:0x8004
CPU: 3 PID: 27272 Comm: gem_exec_ctx Tainted: G        W       4.2.0-rc5+ #37
 0000000000000000 ffff880086ff7a78 ffffffff816b947a ffff88041ed90038
 0000000000008004 ffff880086ff7b08 ffffffff8114b1a5 ffff880086ff7ac8
 ffffffff8108d848 0000000000000000 ffffffff81ce84b8 0000000000000000
Call Trace:
 [<ffffffff816b947a>] dump_stack+0x45/0x57
 [<ffffffff8114b1a5>] warn_alloc_failed+0xd5/0x120
 [<ffffffff8108d848>] ? __wake_up+0x48/0x60
 [<ffffffff8114e0ed>] __alloc_pages_nodemask+0x73d/0x8e0
 [<ffffffffc0472238>] ? i915_gem_execbuffer2+0x148/0x240 [i915]
 [<ffffffffc0474240>] __setup_page_dma+0x30/0x110 [i915]
 [<ffffffffc0477f61>] gen8_ppgtt_init+0x31/0x2f0 [i915]
 [<ffffffffc04785e0>] i915_ppgtt_init+0x30/0x80 [i915]
 [<ffffffffc0478928>] i915_ppgtt_create+0x48/0xc0 [i915]
 [<ffffffffc046c9c2>] i915_gem_create_context+0x1c2/0x390 [i915]
 [<ffffffffc046d9cb>] i915_gem_context_create_ioctl+0x5b/0xa0 [i915]

leading to an oops in i915_gem_context_close. Also note that this
benchmark should not be running out of memory in the first place...

Testcase: igt/benchmark/gem_exec_ctx -b create # ppgtt >= 2
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem_context.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index d0f6d90f6d0e..d87e422228a5 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -420,6 +420,7 @@ err_unpin:
 	if (vma)
 		i915_vma_unpin(vma);
 err_destroy:
+	idr_remove(&file_priv->context_idr, ctx->user_handle);
 	i915_gem_context_unreference(ctx);
 	return ERR_PTR(ret);
 }
-- 
2.5.0