On Sat, 7 Jun 2014, Sasha Levin wrote: > On 04/11/2014 08:50 AM, Sasha Levin wrote: > > Hi all, > > > > While fuzzing with trinity inside a KVM tools guest running the latest -next > > kernel I've stumbled on the following: > > Ping? Still happening (rarely on -next): > > [ 5818.038245] WARNING: CPU: 4 PID: 22726 at arch/x86/mm/pat.c:781 untrack_pfn+0x65/0xb0() > [ 5818.044203] Modules linked in: > [ 5818.045172] CPU: 4 PID: 22726 Comm: trinity-c239 Tainted: G W 3.15.0-rc8-next-20140606-sasha-00021-ga9d3a0b-dirty #596 > [ 5818.048317] 0000000000000009 ffff8800024d3be8 ffffffff9e50fe6b 0000000000000001 > [ 5818.050516] 0000000000000000 ffff8800024d3c28 ffffffff9b15f96c ffff8800024d3c38 > [ 5818.052567] ffff88000203f400 0000000000000000 ffff8800024d3d68 ffff8800024d3d68 > [ 5818.053785] Call Trace: > [ 5818.054483] dump_stack (lib/dump_stack.c:52) > [ 5818.055586] warn_slowpath_common (kernel/panic.c:430) > [ 5818.056763] warn_slowpath_null (kernel/panic.c:465) > [ 5818.057789] untrack_pfn (arch/x86/mm/pat.c:781 (discriminator 3)) > [ 5818.059412] unmap_single_vma (mm/memory.c:1327) > [ 5818.061530] ? pagevec_lru_move_fn (include/linux/pagevec.h:44 mm/swap.c:435) > [ 5818.063412] unmap_vmas (mm/memory.c:1377 (discriminator 1)) > [ 5818.064610] unmap_region (mm/mmap.c:2363 (discriminator 3)) > [ 5818.065453] ? validate_mm_rb (mm/mmap.c:404) > [ 5818.066422] ? vma_rb_erase (mm/mmap.c:449 include/linux/rbtree_augmented.h:219 include/linux/rbtree_augmented.h:227 mm/mmap.c:488) > [ 5818.067316] do_munmap (mm/mmap.c:3359 mm/mmap.c:2561) > [ 5818.068126] move_vma (mm/mremap.c:313) > [ 5818.069000] SyS_mremap (mm/mremap.c:446 mm/mremap.c:508 mm/mremap.c:477) > [ 5818.069839] tracesys (arch/x86/kernel/entry_64.S:542) I could easily be wrong, but I think of this one as another manifestation of the filemap.c:202 BUG_ON(page_mapped(page)) bug, whatever that is. In each case, we have a BUG or WARNING at the point where we detect that there should have been a pte in a page table, but it somehow disappeared. VM_PFNMAP in this case, an ordinary file mapping in the other case; and nothing to show in the anonymous case, there the page would just leak. Hugh -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>