----- Forwarded message from Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> -----
Date: Tue, 24 Dec 2013 20:50:23 +0900
From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
To: chris@xxxxxxxxxxxxxxxxxx, ben@xxxxxxxxxxxx, daniel.vetter@xxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Subject: [PATCH] drm/i915: Fix refcount leak and possible NULL pointer dereference.
Message-Id: <201312242050.CGH78112.JQFOSVMLOFtHOF@xxxxxxxxxxxxxxxxxxx>
>From 482be6384379072eb4c0d45d0ab8a25df4f59ed7 Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Date: Tue, 24 Dec 2013 18:04:14 +0900
Subject: [PATCH] drm/i915: Fix refcount leak and possible NULL pointer dereference.
Since get_pid_task() grabs a reference on the task_struct, we have to drop the
refcount after reading that task's comm name. Also, directly reading like
get_pid_task()->comm can trigger an oops when get_pid_task() returned NULL.
This patch fixes both problems.
Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_debugfs.c | 11 ++++++++++-
1 files changed, 10 insertions(+), 1 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 6ed45a9..d0a8e0a 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -406,11 +406,20 @@ static int i915_gem_object_info(struct seq_file *m, void* data)
seq_putc(m, '\n');
list_for_each_entry_reverse(file, &dev->filelist, lhead) {
struct file_stats stats;
+ struct task_struct *task;
+ char name[TASK_COMM_LEN];
memset(&stats, 0, sizeof(stats));
idr_for_each(&file->object_idr, per_file_stats, &stats);
+ task = get_pid_task(file->pid, PIDTYPE_PID);
+ if (task) {
+ get_task_comm(name, task);
+ put_task_struct(task);
+ } else {
+ strlcpy(name, "<unknown>", sizeof(name));
+ }
seq_printf(m, "%s: %u objects, %zu bytes (%zu active, %zu inactive, %zu unbound)\n",
- get_pid_task(file->pid, PIDTYPE_PID)->comm,
+ name,
stats.count,
stats.total,
stats.active,
--
1.7.1
----- End forwarded message -----
--
Ben Widawsky, Intel Open Source Technology Center
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