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drm/xe: Fix fault on fd close after unbind

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If userspace holds an fd open, unbinds the device and then closes it,
the driver shouldn't try to access the hardware. Protect it by using
drm_dev_enter()/drm_dev_exit(). This fixes the following page fault:

<6> [IGT] xe_wedged: exiting, ret=98
<1> BUG: unable to handle page fault for address: ffffc901bc5e508c
<1> #PF: supervisor read access in kernel mode
<1> #PF: error_code(0x0000) - not-present page
...
<4>   xe_lrc_update_timestamp+0x1c/0xd0 [xe]
<4>   xe_exec_queue_update_run_ticks+0x50/0xb0 [xe]
<4>   xe_exec_queue_fini+0x16/0xb0 [xe]
<4>   __guc_exec_queue_fini_async+0xc4/0x190 [xe]
<4>   guc_exec_queue_fini_async+0xa0/0xe0 [xe]
<4>   guc_exec_queue_fini+0x23/0x40 [xe]
<4>   xe_exec_queue_destroy+0xb3/0xf0 [xe]
<4>   xe_file_close+0xd4/0x1a0 [xe]
<4>   drm_file_free+0x210/0x280 [drm]
<4>   drm_close_helper.isra.0+0x6d/0x80 [drm]
<4>   drm_release_noglobal+0x20/0x90 [drm]

Fixes: 83db047d94 ("drm/xe: Stop accumulating LRC timestamp on job_free")
Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/3421
Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241218053122.2730195-1-lucas.demarchi@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
This commit is contained in:
Lucas De Marchi 2024-12-17 21:31:21 -08:00
parent 2f12e9c029
commit 4ca1fd4183
1 changed files with 9 additions and 0 deletions
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9
drivers/gpu/drm/xe/xe_exec_queue.c
View File

@ -8,6 +8,7 @@
#include <linux/nospec.h>
#include <drm/drm_device.h>
#include <drm/drm_drv.h>
#include <drm/drm_file.h>
#include <uapi/drm/xe_drm.h>
@ -768,9 +769,11 @@ bool xe_exec_queue_is_idle(struct xe_exec_queue *q)
*/
void xe_exec_queue_update_run_ticks(struct xe_exec_queue *q)
{
struct xe_device *xe = gt_to_xe(q->gt);
struct xe_file *xef;
struct xe_lrc *lrc;
u32 old_ts, new_ts;
int idx;
/*
* Jobs that are run during driver load may use an exec_queue, but are
@ -780,6 +783,10 @@ void xe_exec_queue_update_run_ticks(struct xe_exec_queue *q)
if (!q->vm || !q->vm->xef)
return;
/* Synchronize with unbind while holding the xe file open */
if (!drm_dev_enter(&xe->drm, &idx))
return;
xef = q->vm->xef;
/*
@ -793,6 +800,8 @@ void xe_exec_queue_update_run_ticks(struct xe_exec_queue *q)
lrc = q->lrc[0];
new_ts = xe_lrc_update_timestamp(lrc, &old_ts);
xef->run_ticks[q->class] += (new_ts - old_ts) * q->width;
drm_dev_exit(idx);
}
/**