On 3/7/2017 12:56 PM, Punit Agrawal wrote:
Punit Agrawal <[email protected]> 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 <[email protected]>
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 <[email protected]>
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;
--
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