FAILED: patch "[PATCH] drm/i915: Fix syncmap memory leak" failed to apply to 5.4-stable tree

The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From a63bcf08f0efb5348105bb8e0e1e8c6671077753 Mon Sep 17 00:00:00 2001
From: Matthew Brost <[email protected]>
Date: Fri, 30 Jul 2021 12:53:42 -0700
Subject: [PATCH] drm/i915: Fix syncmap memory leak

A small race exists between intel_gt_retire_requests_timeout and intel_timeline_exit which could result in the syncmap not getting free'd. Rather than work to hard to seal this race, simply cleanup the syncmap on fini.

unreferenced object 0xffff88813bc53b18 (size 96):
comm "gem_close_race", pid 5410, jiffies 4294917818 (age 1105.600s) hex dump (first 32 bytes):

    01 00 00 00 00 00 00 00 00 00 00 00 0a 00 00 00  ................
    00 00 00 00 00 00 00 00 6b 6b 6b 6b 06 00 00 00  ........kkkk....
  backtrace:
    [<00000000120b863a>] __sync_alloc_leaf+0x1e/0x40 [i915]
    [<00000000042f6959>] __sync_set+0x1bb/0x240 [i915]
    [<0000000090f0e90f>] i915_request_await_dma_fence+0x1c7/0x400 [i915]
    [<0000000056a48219>] i915_request_await_object+0x222/0x360 [i915]
    [<00000000aaac4ee3>] i915_gem_do_execbuffer+0x1bd0/0x2250 [i915]
    [<000000003c9d830f>] i915_gem_execbuffer2_ioctl+0x405/0xce0 [i915]
    [<00000000fd7a8e68>] drm_ioctl_kernel+0xb0/0xf0 [drm]
    [<00000000e721ee87>] drm_ioctl+0x305/0x3c0 [drm]
    [<000000008b0d8986>] __x64_sys_ioctl+0x71/0xb0
    [<0000000076c362a4>] do_syscall_64+0x33/0x80
    [<00000000eb7a4831>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

index c4a126c8caef..1257f4f11e66 100644
@@ -127,6 +127,15 @@ static void intel_timeline_fini(struct rcu_head *rcu)
 
 	i915_vma_put(timeline->hwsp_ggtt);
 	i915_active_fini(&timeline->active);
+
+	/*
+	 * A small race exists between intel_gt_retire_requests_timeout and
+	 * intel_timeline_exit which could result in the syncmap not getting
+	 * free'd. Rather than work to hard to seal this race, simply cleanup
+	 * the syncmap on fini.
+	 */
+	i915_syncmap_free(&timeline->sync);
+
 	kfree(timeline);
 }