Commit 8f924c0a authored by Chris Wilson's avatar Chris Wilson Committed by Greg Kroah-Hartman
Browse files

drm/i915/gem: Serialise debugfs i915_gem_objects with ctx->mutex



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: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: CQ Tang <cq.tang@intel.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: stable@vger.kernel.org
Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200723172119.17649-3-chris@chris-wilson.co.uk


(cherry picked from commit 102f5aa491f262c818e607fc4fee08a724a76c69)
Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 241bd102
......@@ -323,6 +323,7 @@ static void print_context_stats(struct seq_file *m,
}
i915_gem_context_unlock_engines(ctx);
mutex_lock(&ctx->mutex);
if (!IS_ERR_OR_NULL(ctx->file_priv)) {
struct file_stats stats = {
.vm = rcu_access_pointer(ctx->vm),
......@@ -343,6 +344,7 @@ static void print_context_stats(struct seq_file *m,
print_file_stats(m, name, stats);
}
mutex_unlock(&ctx->mutex);
spin_lock(&i915->gem.contexts.lock);
list_safe_reset_next(ctx, cn, link);
......
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment