(4/3/13 2:35 PM), Naoya Horiguchi wrote: > Currently we fail to include any data on hugepages into coredump, > because VM_DONTDUMP is set on hugetlbfs's vma. This behavior was recently > introduced by commit 314e51b98 "mm: kill vma flag VM_RESERVED and > mm->reserved_vm counter". This looks to me a serious regression, > so let's fix it.
I don't think this is enough explanations. Let's explain the code meaning time to time order. First, we had no madvice(DONTDUMP) nor coredump_filter(HUGETLB). then hugetlb pages were never dumped. Second, I added coredump_filter(HUGETLB). and then vm_dump_size became.. vm_dump_size() { /* Hugetlb memory check */ if (vma->vm_flags & VM_HUGETLB) { .. goto whole; } if (vma->vm_flags & VM_RESERVED) return 0; The point is, hugetlb was checked before VM_RESERVED. i.e. hugetlb core dump ignored VM_RESERVED. At this time, "if (vma->vm_flags & VM_HUGETLB)" statement don't need return 0 because VM_RESERVED prevented to go into the subsequent flag checks. Third, Jason added madvise(DONTDUMP). then vm_dump_size became... vm_dump_size() { if (vma->vm_flags & VM_NODUMP) return 0; /* Hugetlb memory check */ if (vma->vm_flags & VM_HUGETLB) { .. goto whole; } if (vma->vm_flags & VM_RESERVED) return 0; Look, VM_NODUMP and VM_RESERVED had similar and different meanings at this time. Finally, Konstantin removed VM_RESERVED and hugetlb coredump behavior has been changed. Thus, patch [1/3] and [2/3] should be marked [stable for v3.6 or later]. Anyway, this patch is correct. Thank you! Acked-by: KOSAKI Motohiro <kosaki.motoh...@jp.fujitsu.com> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/