From mboxrd@z Thu Jan 1 00:00:00 1970 From: tbaicar@codeaurora.org (Baicar, Tyler) Date: Tue, 7 Mar 2017 13:28:01 -0700 Subject: [PATCH V2] arm64: hwpoison: add VM_FAULT_HWPOISON[_LARGE] handling In-Reply-To: <874lz4oo80.fsf@e105922-lin.cambridge.arm.com> References: <1487720205-14594-1-git-send-email-tbaicar@codeaurora.org> <87wpc7o7mo.fsf@e105922-lin.cambridge.arm.com> <874lz4oo80.fsf@e105922-lin.cambridge.arm.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 3/7/2017 12:56 PM, Punit Agrawal wrote: > Punit Agrawal writes: > > [...] > >> The code looks good but I ran into some failures while running the >> hugepages hwpoison tests from mce-tests suite[0]. I get a bad pmd error >> in dmesg - >> >> [ 344.165544] mm/pgtable-generic.c:33: bad pmd 000000083af00074. >> >> I suspect that this is due to the huge pte accessors not correctly >> dealing with poisoned entries (which are represented as swap entries). > I think I've got to the bottom of the issue - the problem is due to > huge_pte_at() returning NULL for poisoned pmd entries (which in turn is > due to pmd_present() not handling poisoned pmd entries correctly) > > The following is the call chain for the failure case. > > do_munmap > unmap_region > unmap_vmas > unmap_single_vma > __unmap_hugepage_range_final # The test case uses hugepages > __unmap_hugepage_range > huge_pte_offset # Returns NULL for a poisoned pmd > > Reverting 5bb1cc0ff9a6 ("arm64: Ensure pmd_present() returns false after > pmd_mknotpresent()") fixes the problem for me but I don't think that is > the right fix. > > While I work on a proper fix, it would be great if you can confirm that > reverting 5bb1cc0ff9a6 makes the problem go away at your end. Thanks Punit! I haven't got a chance to do this yet, but I will let you know once I get it tested :) > >> I am investigating the failure but could you try running the tests at >> your end as well. >> >> To run the tests, I cloned the repository[0]. It test needs a simple fix >> at the end of this mail to run correctly. With that applied and running >> as root - >> >> # cd mce-test/cases/function/hwpoison >> # ./run_hugepage.sh >> >> >> [0] https://git.kernel.org/cgit/utils/cpu/mce/mce-test.git/ >> >> --------->8-------------- >> commit cb5c61f18dd86baf01b90404d4ecf51dd3d176c7 >> Author: Punit Agrawal >> Date: Thu Mar 2 18:24:40 2017 +0000 >> >> Use correct return type for getopt_long >> >> getopt_long returns an int. Fix the return type to avoid issues when >> checking for negative error codes on architectures with unsigned char, >> e.g., arm. >> >> Signed-off-by: Punit Agrawal >> >> diff --git a/cases/function/hwpoison/thugetlb.c b/cases/function/hwpoison/thugetlb.c >> index 92dc7d2..fbcf426 100644 >> --- a/cases/function/hwpoison/thugetlb.c >> +++ b/cases/function/hwpoison/thugetlb.c >> @@ -125,7 +125,7 @@ int main(int argc, char *argv[]) >> int forkflag = 0; >> int privateflag = 0; >> int cowflag = 0; >> - char c; >> + int c; >> pid_t pid = 0; >> void *expected_addr = NULL; >> struct sembuf sembuffer; -- Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.