On 05/20/2017 05:01 AM, zhong jiang wrote: > On 2017/5/20 10:40, Hugh Dickins wrote: >> On Sat, 20 May 2017, Xishi Qiu wrote: >>> Here is a bug report form redhat: https://bugzilla.redhat.com/show_bug.cgi?id=1305620 >>> And I meet the bug too. However it is hard to reproduce, and >>> 624483f3ea82598("mm: rmap: fix use-after-free in __put_anon_vma") is not help. >>> >>> From the vmcore, it seems that the page is still mapped(_mapcount=0 and _count=2), >>> and the value of mapping is a valid address(mapping = 0xffff8801b3e2a101), >>> but anon_vma has been corrupted. >>> >>> Any ideas? >> Sorry, no. I assume that _mapcount has been misaccounted, for example >> a pte mapped in on top of another pte; but cannot begin tell you where >> in Red Hat's kernel-3.10.0-229.4.2.el7 that might happen. >> >> Hugh >> >> . >> > Hi, Hugh > > I find the following message from the dmesg. > > [26068.316592] BUG: Bad rss-counter state mm:ffff8800a7de2d80 idx:1 val:1 > > I can prove that the __mapcount is misaccount. when task is exited. the rmap > still exist. Check if the kernel in question contains this commit: ad33bb04b2a6 ("mm: thp: fix SMP race condition between THP page fault and MADV_DONTNEED") > Thanks > zhongjiang > > -- > 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> > -- 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>
