Messages in this thread | | | Date | Sun, 10 Jan 2010 03:09:55 +0100 | From | Andi Kleen <> | Subject | 2.6.33 pagemap endless read loop |
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An LTP run on x86-64/2.6.33-rc3 run right now results in "proc01" hanging
lr-x------ 1 root root 64 2010-01-10 02:28 7 -> /proc/2679/task/2679/pagemap
strace shows an endless loop of
read(7, "\0\0\0\0\0\0\0\6\0\0\0\0\0\0\0\6\0\0\0\0\0\0\0\6\0\0\0"..., 1024) = 1024 read(7, "\0\0\0\0\0\0\0\6\0\0\0\0\0\0\0\6\0\0\0\0\0\0\0\6\0\0\0"..., 1024) = 1024 read(7, "\0\0\0\0\0\0\0\6\0\0\0\0\0\0\0\6\0\0\0\0\0\0\0\6\0\0\0"..., 1024) = 1024 read(7, "\0\0\0\0\0\0\0\6\0\0\0\0\0\0\0\6\0\0\0\0\0\0\0\6\0\0\0"..., 1024) = 1024 read(7, "\0\0\0\0\0\0\0\6\0\0\0\0\0\0\0\6\0\0\0\0\0\0\0\6\0\0\0"..., 1024) = 1024 read(7, "\0\0\0\0\0\0\0\6\0\0\0\0\0\0\0\6\0\0\0\0\0\0\0\6\0\0\0"..., 1024) = 1024 read(7, "\0\0\0\0\0\0\0\6\0\0\0\0\0\0\0\6\0\0\0\0\0\0\0\6\0\0\0"..., 1024) = 10
cat of that file hangs in the same way so it seems like a kernel bug. A cat of /proc/2679/pagemap also hangs, in fact any pagemap cat seems to.
I tried to revert the latest change from Horiguchi-san:
commit 5dc37642cbce34619e4588a9f0bdad1d2f870956 Author: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Date: Mon Dec 14 18:00:01 2009 -0800
mm hugetlb: add hugepage support to pagemap
but that didn't fix it, so it must be something else.
Haven't done further bisect or anything, should be easy to reproduce.
-Andi
-- ak@linux.intel.com -- Speaking for myself only.
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