Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> writes: > On Tue, 2014-02-11 at 09:31 -0800, Greg KH wrote: >> On Fri, Feb 07, 2014 at 07:21:57PM +0530, Aneesh Kumar K.V wrote: >> > From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx> >> > >> > This patch fix the below crash >> > >> > NIP [c00000000004cee4] .__hash_page_thp+0x2a4/0x440 >> > LR [c0000000000439ac] .hash_page+0x18c/0x5e0 >> > ... >> > Call Trace: >> > [c000000736103c40] [00001ffffb000000] 0x1ffffb000000(unreliable) >> > [437908.479693] [c000000736103d50] [c0000000000439ac] .hash_page+0x18c/0x5e0 >> > [437908.479699] [c000000736103e30] [c00000000000924c] .do_hash_page+0x4c/0x58 >> > >> > On ppc64 we use the pgtable for storing the hpte slot information and >> > store address to the pgtable at a constant offset (PTRS_PER_PMD) from >> > pmd. On mremap, when we switch the pmd, we need to withdraw and deposit >> > the pgtable again, so that we find the pgtable at PTRS_PER_PMD offset >> > from new pmd. >> > >> > We also want to move the withdraw and deposit before the set_pmd so >> > that, when page fault find the pmd as trans huge we can be sure that >> > pgtable can be located at the offset. >> > >> > variant of upstream SHA1: b3084f4db3aeb991c507ca774337c7e7893ed04f >> > for 3.12 stable series >> >> This doesn't look like a "variant", it looks totally different. Why >> can't I just take the b3084f4db3aeb991c507ca774337c7e7893ed04f patch >> (and follow-on fix) for 3.12? >> >> I _REALLY_ dislike patches that are totally different from Linus's tree >> in stable trees, it has caused nothing but problems in the past. > > I don't think it applies... (I tried on an internal tree) but the > affected function changed in 3.13 in various ways. Aneesh, please > provide a more details explanation and whether we should backport those > other changes too or whether this is not necessary Yes the affected function added support for split ptl locks for huge pte. I don't think that is a stable material. . > > BTW. Aneesh, we need a 3.11.x one too > 3.11.x it is already applied. -aneesh -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html