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commit6a0c7cd330upstream. I have received a report about the BUG_ON() in free_basic_memory_bitmaps() triggering mysteriously during an aborted s2disk hibernation attempt. The only way I can explain that is that /dev/snapshot was first opened for writing (resume mode), then closed and then opened again for reading and closed again without freezing tasks. In that case the first invocation of snapshot_open() would set the free_bitmaps flag in snapshot_state, which is a static variable. That flag wouldn't be cleared later and the second invocation of snapshot_open() would just leave it like that, so the subsequent snapshot_release() would see data->frozen set and free_basic_memory_bitmaps() would be called unnecessarily. To prevent that from happening clear data->free_bitmaps in snapshot_open() when the file is being opened for reading (hibernate mode). In addition to that, replace the BUG_ON() in free_basic_memory_bitmaps() with a WARN_ON() as the kernel can continue just fine if the condition checked by that macro occurs. Fixes:aab1728915(PM / hibernate: Fix user space driven resume regression) Reported-by: Oliver Lorenz <olli@olorenz.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>