drm/xe: Store process name and pid in xe file

An xe file can outlive the associated process as the GPU cleanup is just
triggered upon file close (process kill) and completes sometime later.
If the file close triggers error conditions (GPU hangs) the process
cannot be safely referenced to retrieve the name and pid for debug
information. Store the process name and pid directly in the xe file to
be safe.

v2:
 - Access file->pid via rcu_access_pointer (Matthew Auld)

Fixes: b10d0c5e9df7 ("drm/xe: Add process name to devcoredump")
Fixes: f6ca930d974e ("drm/xe: Add process name and PID to job timedout message")
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240723151045.1725417-1-matthew.brost@intel.com

diff --git a/drivers/gpu/drm/xe/xe_devcoredump.c b/drivers/gpu/drm/xe/xe_devcoredump.c
index 62c2b10..d8d8ca2 100644 (file)
--- a/drivers/gpu/drm/xe/xe_devcoredump.c
+++ b/drivers/gpu/drm/xe/xe_devcoredump.c
@@ -171,7 +171,6 @@ static void devcoredump_snapshot(struct xe_devcoredump *coredump,
        u32 adj_logical_mask = q->logical_mask;
        u32 width_mask = (0x1 << q->width) - 1;
        const char *process_name = "no process";
-       struct task_struct *task = NULL;
 
        int i;
        bool cookie;
@@ -179,14 +178,9 @@ static void devcoredump_snapshot(struct xe_devcoredump *coredump,
        ss->snapshot_time = ktime_get_real();
        ss->boot_time = ktime_get_boottime();
 
-       if (q->vm && q->vm->xef) {
-               task = get_pid_task(q->vm->xef->drm->pid, PIDTYPE_PID);
-               if (task)
-                       process_name = task->comm;
-       }
+       if (q->vm && q->vm->xef)
+               process_name = q->vm->xef->process_name;
        strscpy(ss->process_name, process_name);
-       if (task)
-               put_task_struct(task);
 
        ss->gt = q->gt;
        INIT_WORK(&ss->work, xe_devcoredump_deferred_snap_work);

diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
index b677608..1aba6f9 100644 (file)
--- a/drivers/gpu/drm/xe/xe_device.c
+++ b/drivers/gpu/drm/xe/xe_device.c
@@ -64,6 +64,7 @@ static int xe_file_open(struct drm_device *dev, struct drm_file *file)
        struct xe_drm_client *client;
        struct xe_file *xef;
        int ret = -ENOMEM;
+       struct task_struct *task = NULL;
 
        xef = kzalloc(sizeof(*xef), GFP_KERNEL);
        if (!xef)
@@ -92,6 +93,13 @@ static int xe_file_open(struct drm_device *dev, struct drm_file *file)
        file->driver_priv = xef;
        kref_init(&xef->refcount);
 
+       task = get_pid_task(rcu_access_pointer(file->pid), PIDTYPE_PID);
+       if (task) {
+               xef->process_name = kstrdup(task->comm, GFP_KERNEL);
+               xef->pid = task->pid;
+               put_task_struct(task);
+       }
+
        return 0;
 }
 
@@ -110,6 +118,7 @@ static void xe_file_destroy(struct kref *ref)
        spin_unlock(&xe->clients.lock);
 
        xe_drm_client_put(xef->client);
+       kfree(xef->process_name);
        kfree(xef);
 }
 

diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
index 36252d5..5b7292a 100644 (file)
--- a/drivers/gpu/drm/xe/xe_device_types.h
+++ b/drivers/gpu/drm/xe/xe_device_types.h
@@ -582,6 +582,18 @@ struct xe_file {
        /** @client: drm client */
        struct xe_drm_client *client;
 
+       /**
+        * @process_name: process name for file handle, used to safely output
+        * during error situations where xe file can outlive process
+        */
+       char *process_name;
+
+       /**
+        * @pid: pid for file handle, used to safely output uring error
+        * situations where xe file can outlive process
+        */
+       pid_t pid;
+
        /** @refcount: ref count of this xe file */
        struct kref refcount;
 };

diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c b/drivers/gpu/drm/xe/xe_guc_submit.c
index da2ead8..a457063 100644 (file)
--- a/drivers/gpu/drm/xe/xe_guc_submit.c
+++ b/drivers/gpu/drm/xe/xe_guc_submit.c
@@ -1072,7 +1072,6 @@ guc_exec_queue_timedout_job(struct drm_sched_job *drm_job)
        struct xe_gpu_scheduler *sched = &q->guc->sched;
        struct xe_guc *guc = exec_queue_to_guc(q);
        const char *process_name = "no process";
-       struct task_struct *task = NULL;
        int err = -ETIME;
        pid_t pid = -1;
        int i = 0;
@@ -1172,17 +1171,12 @@ trigger_reset:
        }
 
        if (q->vm && q->vm->xef) {
-               task = get_pid_task(q->vm->xef->drm->pid, PIDTYPE_PID);
-               if (task) {
-                       process_name = task->comm;
-                       pid = task->pid;
-               }
+               process_name = q->vm->xef->process_name;
+               pid = q->vm->xef->pid;
        }
        xe_gt_notice(guc_to_gt(guc), "Timedout job: seqno=%u, lrc_seqno=%u, guc_id=%d, flags=0x%lx in %s [%d]",
                     xe_sched_job_seqno(job), xe_sched_job_lrc_seqno(job),
                     q->guc->id, q->flags, process_name, pid);
-       if (task)
-               put_task_struct(task);
 
        trace_xe_sched_job_timedout(job);