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Diffstat (limited to 'drivers/gpu/drm')
-rw-r--r--drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c6
-rw-r--r--drivers/gpu/drm/drm_auth.c3
-rw-r--r--drivers/gpu/drm/drm_debugfs.c10
-rw-r--r--drivers/gpu/drm/drm_file.c40
-rw-r--r--drivers/gpu/drm/drm_ioctl.c3
-rw-r--r--drivers/gpu/drm/nouveau/nouveau_drm.c5
-rw-r--r--drivers/gpu/drm/vmwgfx/vmwgfx_gem.c6
7 files changed, 60 insertions, 13 deletions
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
index 7da871972a8e..c1ee440a06fe 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
@@ -958,6 +958,7 @@ static int amdgpu_debugfs_gem_info_show(struct seq_file *m, void *unused)
list_for_each_entry(file, &dev->filelist, lhead) {
struct task_struct *task;
struct drm_gem_object *gobj;
+ struct pid *pid;
int id;
/*
@@ -967,8 +968,9 @@ static int amdgpu_debugfs_gem_info_show(struct seq_file *m, void *unused)
* Therefore, we need to protect this ->comm access using RCU.
*/
rcu_read_lock();
- task = pid_task(file->pid, PIDTYPE_TGID);
- seq_printf(m, "pid %8d command %s:\n", pid_nr(file->pid),
+ pid = rcu_dereference(file->pid);
+ task = pid_task(pid, PIDTYPE_TGID);
+ seq_printf(m, "pid %8d command %s:\n", pid_nr(pid),
task ? task->comm : "<unknown>");
rcu_read_unlock();
diff --git a/drivers/gpu/drm/drm_auth.c b/drivers/gpu/drm/drm_auth.c
index cf92a9ae8034..2ed2585ded37 100644
--- a/drivers/gpu/drm/drm_auth.c
+++ b/drivers/gpu/drm/drm_auth.c
@@ -235,7 +235,8 @@ static int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv)
static int
drm_master_check_perm(struct drm_device *dev, struct drm_file *file_priv)
{
- if (file_priv->pid == task_pid(current) && file_priv->was_master)
+ if (file_priv->was_master &&
+ rcu_access_pointer(file_priv->pid) == task_pid(current))
return 0;
if (!capable(CAP_SYS_ADMIN))
diff --git a/drivers/gpu/drm/drm_debugfs.c b/drivers/gpu/drm/drm_debugfs.c
index 34c7d1a580e3..44ecd7d0daac 100644
--- a/drivers/gpu/drm/drm_debugfs.c
+++ b/drivers/gpu/drm/drm_debugfs.c
@@ -92,15 +92,17 @@ static int drm_clients_info(struct seq_file *m, void *data)
*/
mutex_lock(&dev->filelist_mutex);
list_for_each_entry_reverse(priv, &dev->filelist, lhead) {
- struct task_struct *task;
bool is_current_master = drm_is_current_master(priv);
+ struct task_struct *task;
+ struct pid *pid;
- rcu_read_lock(); /* locks pid_task()->comm */
- task = pid_task(priv->pid, PIDTYPE_TGID);
+ rcu_read_lock(); /* Locks priv->pid and pid_task()->comm! */
+ pid = rcu_dereference(priv->pid);
+ task = pid_task(pid, PIDTYPE_TGID);
uid = task ? __task_cred(task)->euid : GLOBAL_ROOT_UID;
seq_printf(m, "%20s %5d %3d %c %c %5d %10u\n",
task ? task->comm : "<unknown>",
- pid_vnr(priv->pid),
+ pid_vnr(pid),
priv->minor->index,
is_current_master ? 'y' : 'n',
priv->authenticated ? 'y' : 'n',
diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
index 883d83bc0e3d..e692770ef6d3 100644
--- a/drivers/gpu/drm/drm_file.c
+++ b/drivers/gpu/drm/drm_file.c
@@ -160,7 +160,7 @@ struct drm_file *drm_file_alloc(struct drm_minor *minor)
/* Get a unique identifier for fdinfo: */
file->client_id = atomic64_inc_return(&ident);
- file->pid = get_pid(task_tgid(current));
+ rcu_assign_pointer(file->pid, get_pid(task_tgid(current)));
file->minor = minor;
/* for compatibility root is always authenticated */
@@ -200,7 +200,7 @@ out_prime_destroy:
drm_syncobj_release(file);
if (drm_core_check_feature(dev, DRIVER_GEM))
drm_gem_release(dev, file);
- put_pid(file->pid);
+ put_pid(rcu_access_pointer(file->pid));
kfree(file);
return ERR_PTR(ret);
@@ -291,7 +291,7 @@ void drm_file_free(struct drm_file *file)
WARN_ON(!list_empty(&file->event_list));
- put_pid(file->pid);
+ put_pid(rcu_access_pointer(file->pid));
kfree(file);
}
@@ -505,6 +505,40 @@ int drm_release(struct inode *inode, struct file *filp)
}
EXPORT_SYMBOL(drm_release);
+void drm_file_update_pid(struct drm_file *filp)
+{
+ struct drm_device *dev;
+ struct pid *pid, *old;
+
+ /*
+ * Master nodes need to keep the original ownership in order for
+ * drm_master_check_perm to keep working correctly. (See comment in
+ * drm_auth.c.)
+ */
+ if (filp->was_master)
+ return;
+
+ pid = task_tgid(current);
+
+ /*
+ * Quick unlocked check since the model is a single handover followed by
+ * exclusive repeated use.
+ */
+ if (pid == rcu_access_pointer(filp->pid))
+ return;
+
+ dev = filp->minor->dev;
+ mutex_lock(&dev->filelist_mutex);
+ old = rcu_replace_pointer(filp->pid, pid, 1);
+ mutex_unlock(&dev->filelist_mutex);
+
+ if (pid != old) {
+ get_pid(pid);
+ synchronize_rcu();
+ put_pid(old);
+ }
+}
+
/**
* drm_release_noglobal - release method for DRM file
* @inode: device inode
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index f03ffbacfe9b..77590b0f38fa 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -776,6 +776,9 @@ long drm_ioctl_kernel(struct file *file, drm_ioctl_t *func, void *kdata,
struct drm_device *dev = file_priv->minor->dev;
int retcode;
+ /* Update drm_file owner if fd was passed along. */
+ drm_file_update_pid(file_priv);
+
if (drm_dev_is_unplugged(dev))
return -ENODEV;
diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
index 4396f501b16a..50589f982d1a 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
@@ -1133,7 +1133,10 @@ nouveau_drm_open(struct drm_device *dev, struct drm_file *fpriv)
}
get_task_comm(tmpname, current);
- snprintf(name, sizeof(name), "%s[%d]", tmpname, pid_nr(fpriv->pid));
+ rcu_read_lock();
+ snprintf(name, sizeof(name), "%s[%d]",
+ tmpname, pid_nr(rcu_dereference(fpriv->pid)));
+ rcu_read_unlock();
if (!(cli = kzalloc(sizeof(*cli), GFP_KERNEL))) {
ret = -ENOMEM;
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c b/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c
index c0da89e16e6f..a07e5b7e2f2f 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c
@@ -232,6 +232,7 @@ static int vmw_debugfs_gem_info_show(struct seq_file *m, void *unused)
list_for_each_entry(file, &dev->filelist, lhead) {
struct task_struct *task;
struct drm_gem_object *gobj;
+ struct pid *pid;
int id;
/*
@@ -241,8 +242,9 @@ static int vmw_debugfs_gem_info_show(struct seq_file *m, void *unused)
* Therefore, we need to protect this ->comm access using RCU.
*/
rcu_read_lock();
- task = pid_task(file->pid, PIDTYPE_TGID);
- seq_printf(m, "pid %8d command %s:\n", pid_nr(file->pid),
+ pid = rcu_dereference(file->pid);
+ task = pid_task(pid, PIDTYPE_TGID);
+ seq_printf(m, "pid %8d command %s:\n", pid_nr(pid),
task ? task->comm : "<unknown>");
rcu_read_unlock();
generated by cgit v1.2.3 (git 2.25.1) at 2025-07-25 10:47:32 +0000