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[v6,01/10,hack] silence ttm fini WARNING

Message ID 20210204145712.1531203-2-kraxel@redhat.com (mailing list archive)
State New, archived
Headers show
Series drm/qxl: fix driver shutdown issues. | expand

Commit Message

Gerd Hoffmann Feb. 4, 2021, 2:57 p.m. UTC 
kobject: '(null)' ((____ptrval____)): is not initialized, yet kobject_put() is being called.
WARNING: CPU: 0 PID: 209 at lib/kobject.c:750 kobject_put+0x3a/0x60
[ ... ]
Call Trace:
 ttm_device_fini+0x133/0x1b0 [ttm]
 qxl_ttm_fini+0x2f/0x40 [qxl]
---
 drivers/gpu/drm/ttm/ttm_device.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Christian König Feb. 4, 2021, 2:58 p.m. UTC | #1 
?

What's the background here?

Christian.

Am 04.02.21 um 15:57 schrieb Gerd Hoffmann:
> kobject: '(null)' ((____ptrval____)): is not initialized, yet kobject_put() is being called.
> WARNING: CPU: 0 PID: 209 at lib/kobject.c:750 kobject_put+0x3a/0x60
> [ ... ]
> Call Trace:
>   ttm_device_fini+0x133/0x1b0 [ttm]
>   qxl_ttm_fini+0x2f/0x40 [qxl]
> ---
>   drivers/gpu/drm/ttm/ttm_device.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/ttm/ttm_device.c b/drivers/gpu/drm/ttm/ttm_device.c
> index ac0903c9e60a..b638cbb0bd45 100644
> --- a/drivers/gpu/drm/ttm/ttm_device.c
> +++ b/drivers/gpu/drm/ttm/ttm_device.c
> @@ -50,7 +50,7 @@ static void ttm_global_release(void)
>   		goto out;
>   
>   	kobject_del(&glob->kobj);
> -	kobject_put(&glob->kobj);
> +//	kobject_put(&glob->kobj);
>   	ttm_mem_global_release(&ttm_mem_glob);
>   	__free_page(glob->dummy_read_page);
>   	memset(glob, 0, sizeof(*glob));
Gerd Hoffmann Feb. 5, 2021, 7:39 a.m. UTC | #2 
On Thu, Feb 04, 2021 at 03:58:33PM +0100, Christian König wrote:
> ?
> 
> What's the background here?
> 
> Christian.
> 
> Am 04.02.21 um 15:57 schrieb Gerd Hoffmann:
> > kobject: '(null)' ((____ptrval____)): is not initialized, yet kobject_put() is being called.
> > WARNING: CPU: 0 PID: 209 at lib/kobject.c:750 kobject_put+0x3a/0x60
> > [ ... ]
> > Call Trace:
> >   ttm_device_fini+0x133/0x1b0 [ttm]
> >   qxl_ttm_fini+0x2f/0x40 [qxl]

Happens on driver removal.  Seen with both qxl and bochs (the later
using vram helpers).

Testcase: "drmtest --unbind" (https://git.kraxel.org/cgit/drminfo/).

static int try_unbind(int card)
{
    char path[256];
    char *device, *name;
    int fd;

    snprintf(path, sizeof(path), "/sys/class/drm/card%d/device", card);
    device = realpath(path, NULL);
    if (device == NULL) {
        fprintf(stderr, "%s: can't resolve sysfs device path\n", __func__);
        return -1;
    }

    snprintf(path, sizeof(path), "%s/driver/unbind", device);
    fd = open(path, O_WRONLY);
    if (fd < 0) {
        fprintf(stderr, "open %s: %s\n", path, strerror(errno));
        return -1;
    }

    name = strrchr(device, '/') + 1;
    write(fd, name, strlen(name));
    close(fd);
    return 0;
}

take care,
  Gerd
diff mbox series

Patch

diff --git a/drivers/gpu/drm/ttm/ttm_device.c b/drivers/gpu/drm/ttm/ttm_device.c
index ac0903c9e60a..b638cbb0bd45 100644
--- a/drivers/gpu/drm/ttm/ttm_device.c
+++ b/drivers/gpu/drm/ttm/ttm_device.c
@@ -50,7 +50,7 @@  static void ttm_global_release(void)
 		goto out;
 
 	kobject_del(&glob->kobj);
-	kobject_put(&glob->kobj);
+//	kobject_put(&glob->kobj);
 	ttm_mem_global_release(&ttm_mem_glob);
 	__free_page(glob->dummy_read_page);
 	memset(glob, 0, sizeof(*glob));