This is a note to let you know that I've just added the patch titled
drm/i915/gem: Serialise debugfs i915_gem_objects with ctx->mutex
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-i915-gem-serialise-debugfs-i915_gem_objects-with-ctx-mutex.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 4fe9af8e881d946bf60790eeb37a7c4f96e28382 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Date: Thu, 23 Jul 2020 18:21:19 +0100
Subject: drm/i915/gem: Serialise debugfs i915_gem_objects with ctx->mutex
From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
commit 4fe9af8e881d946bf60790eeb37a7c4f96e28382 upstream.
Since the debugfs may peek into the GEM contexts as the corresponding
client/fd is being closed, we may try and follow a dangling pointer.
However, the context closure itself is serialised with the ctx->mutex,
so if we hold that mutex as we inspect the state coupled in the context,
we know the pointers within the context are stable and will remain valid
as we inspect their tables.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: CQ Tang <cq.tang@xxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20200723172119.17649-3-chris@xxxxxxxxxxxxxxxxxx
(cherry picked from commit 102f5aa491f262c818e607fc4fee08a724a76c69)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_debugfs.c | 2 ++
1 file changed, 2 insertions(+)
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -328,6 +328,7 @@ static void print_context_stats(struct s
}
i915_gem_context_unlock_engines(ctx);
+ mutex_lock(&ctx->mutex);
if (!IS_ERR_OR_NULL(ctx->file_priv)) {
struct file_stats stats = { .vm = ctx->vm, };
struct drm_file *file = ctx->file_priv->file;
@@ -466,6 +467,7 @@ static int i915_interrupt_info(struct se
intel_display_power_put(dev_priv, power_domain, pref);
}
+ mutex_unlock(&ctx->mutex);
pref = intel_display_power_get(dev_priv, POWER_DOMAIN_INIT);
seq_printf(m, "Port hotplug:\t%08x\n",
Patches currently in stable-queue which might be from chris@xxxxxxxxxxxxxxxxxx are
queue-5.4/drm-i915-gem-serialise-debugfs-i915_gem_objects-with-ctx-mutex.patch
