Messages in this thread | | | Date | Thu, 12 Sep 2019 18:50:43 -0400 | From | Sasha Levin <> | Subject | Re: [PATCH AUTOSEL 5.2 13/23] drm/i915/userptr: Acquire the page lock around set_page_dirty() |
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On Thu, Sep 12, 2019 at 11:51:33PM +0300, Thomas Backlund wrote: >Den 03-09-2019 kl. 19:24, skrev Sasha Levin: >>From: Chris Wilson <chris@chris-wilson.co.uk> >> >>[ Upstream commit aa56a292ce623734ddd30f52d73f527d1f3529b5 ] >> >>set_page_dirty says: >> >> For pages with a mapping this should be done under the page lock >> for the benefit of asynchronous memory errors who prefer a >> consistent dirty state. This rule can be broken in some special >> cases, but should be better not to. >> >>Under those rules, it is only safe for us to use the plain set_page_dirty >>calls for shmemfs/anonymous memory. Userptr may be used with real >>mappings and so needs to use the locked version (set_page_dirty_lock). >> >>Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203317 >>Fixes: 5cc9ed4b9a7a ("drm/i915: Introduce mapping of user pages into video memory (userptr) ioctl") >>References: 6dcc693bc57f ("ext4: warn when page is dirtied without buffers") >>Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> >>Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> >>Cc: stable@vger.kernel.org >>Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> >>Link: https://patchwork.freedesktop.org/patch/msgid/20190708140327.26825-1-chris@chris-wilson.co.uk >>(cherry picked from commit cb6d7c7dc7ff8cace666ddec66334117a6068ce2) >>Signed-off-by: Jani Nikula <jani.nikula@intel.com> >>Signed-off-by: Sasha Levin <sashal@kernel.org> >>--- >> drivers/gpu/drm/i915/i915_gem_userptr.c | 10 +++++++++- >> 1 file changed, 9 insertions(+), 1 deletion(-) >> >>diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c >>index 8079ea3af1039..b1fc15c7f5997 100644 >>--- a/drivers/gpu/drm/i915/i915_gem_userptr.c >>+++ b/drivers/gpu/drm/i915/i915_gem_userptr.c >>@@ -678,7 +678,15 @@ i915_gem_userptr_put_pages(struct drm_i915_gem_object *obj, >> for_each_sgt_page(page, sgt_iter, pages) { >> if (obj->mm.dirty) >>- set_page_dirty(page); >>+ /* >>+ * As this may not be anonymous memory (e.g. shmem) >>+ * but exist on a real mapping, we have to lock >>+ * the page in order to dirty it -- holding >>+ * the page reference is not sufficient to >>+ * prevent the inode from being truncated. >>+ * Play safe and take the lock. >>+ */ >>+ set_page_dirty_lock(page); >> mark_page_accessed(page); >> put_page(page); >> > > >Please drop this one from all 5.2 and 4.19 stable queues > >It has now been reverted in Linus tree: >https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=505a8ec7e11ae5236c4a154a1e24ef49a8349600
Now dropped, thank you.
-- Thanks, Sasha
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