On 07/09/14 15:03, Buland Kumar Singh
wrote:
Hello Everyone,
I am analysing a kernel crash dump (vmcore) captured from
RHEL-5
kernel version (2.6.18-371.4.1.el5) and found that the value
of
"NR_WRITEBACK" counter is negative (-126).
As we're
running a 64 bit kernel and the counters are signed long,
so this is very unlikely to be a counter overflow. I need
pointers
and suggestions to determine the *cause* of negative counter
from
vmcore.
Additional Information:
$ git show ce866b34ae1b7f1ce60234cf65855886ac7e7d30
[..]
diff --git a/drivers/base/node.c b/drivers/base/node.c
index 6fed520..a7b3dcb 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -49,9 +49,6 @@ static ssize_t node_read_meminfo(struct
sys_device * dev, char * buf)
get_page_state_node(&ps, nid);
__get_zone_counts(&active, &inactive,
&free, NODE_DATA(nid));
- /* Check for negative values in these approximate
counters */
- if ((long)ps.nr_writeback < 0)
- ps.nr_writeback = 0;
Not that I know anything about this. But based on the comment that
you are
deleting, it is stated that this is an approximate
counter. I.E. to me that says
that this counter is allowed to be incorrect. Negative is just
part of the incorrect values.
The code you are deleting looks to be a fixup because the caller
of node_read_meminfo()
(or later in this function) will not "do the right thing" if the
number is negative. So removing
this correction is bad.
-Don Slutz
n = sprintf(buf, "\n"
"Node %d MemTotal: %8lu kB\n"
[..]
Thank you !
--
BKS
--
Crash-utility mailing list
Crash-utility@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/crash-utility
|
--
Crash-utility mailing list
Crash-utility@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/crash-utility