On 12/09/17 18:42, Thomas Hellstrom wrote: > Hi, Colin, > > On 09/12/2017 07:35 PM, Colin King wrote: >> From: Colin Ian King <colin.king@xxxxxxxxxxxxx> >> >> mmap'ing the device multiple times will spam the kernel log with the >> DRM_ERROR message about illegal mmap'ing the old fifo space. > How are you hitting this? Multiple mappings should be fine as long as > mapping offsets are correct, > so hitting this message should indicate that the user-space app is doing > something seriously wrong, and > having it present in the log should probably help more than it hurts. > > /Thomas Good question. I hit similar issues with the drm qxl driver when running some kernel regression tests with stress-ng [1]. I realize this is an artificial test scenario so it is definitely not a typical use-case, however, sync the illegal mmapping will return -EINVAL the application will pick up that this is an error without the need of spotting it in the kernel log. And a user space application can perform many millions of these invalid mmaps causing kernel log spamming. [1] http://kernel.ubuntu.com/~cking/stress-ng/ > > > >> Since >> the mmap'ing will fail with an -EINVAL there is no need to emit this >> message, so just remove it. >> >> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx> >> --- >> drivers/gpu/drm/vmwgfx/vmwgfx_ttm_glue.c | 4 +--- >> 1 file changed, 1 insertion(+), 3 deletions(-) >> >> diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_glue.c >> b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_glue.c >> index e771091d2cd3..1e633c602fb1 100644 >> --- a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_glue.c >> +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_glue.c >> @@ -33,10 +33,8 @@ int vmw_mmap(struct file *filp, struct >> vm_area_struct *vma) >> struct drm_file *file_priv; >> struct vmw_private *dev_priv; >> - if (unlikely(vma->vm_pgoff < VMWGFX_FILE_PAGE_OFFSET)) { >> - DRM_ERROR("Illegal attempt to mmap old fifo space.\n"); >> + if (unlikely(vma->vm_pgoff < VMWGFX_FILE_PAGE_OFFSET)) >> return -EINVAL; >> - } >> file_priv = filp->private_data; >> dev_priv = vmw_priv(file_priv->minor->dev); > > -- To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
