Messages in this thread | | | From | Shakeel Butt <> | Date | Mon, 31 Aug 2020 07:41:05 -0700 | Subject | Re: [PATCH 3/5] shmem: shmem_writepage() split unlikely i915 THP |
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On Sun, Aug 30, 2020 at 2:04 PM Hugh Dickins <hughd@google.com> wrote: > > drivers/gpu/drm/i915/gem/i915_gem_shmem.c contains a shmem_writeback() > which calls shmem_writepage() from a shrinker: that usually works well > enough; but if /sys/kernel/mm/transparent_hugepage/shmem_enabled has > been set to "force" (documented as "Force the huge option on for all - > very useful for testing"), shmem_writepage() is surprised to be called > with a huge page, and crashes on the VM_BUG_ON_PAGE(PageCompound) (I > did not find out where the crash happens when CONFIG_DEBUG_VM is off). > > LRU page reclaim always splits the shmem huge page first: I'd prefer not > to demand that of i915, so check and split compound in shmem_writepage(). > > Fixes: 2d6692e642e7 ("drm/i915: Start writeback from the shrinker") > Signed-off-by: Hugh Dickins <hughd@google.com> > Cc: stable@vger.kernel.org # v5.3+
Reviewed-by: Shakeel Butt <shakeelb@google.com>
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