[Crash-utility] vt->kmem_cache_len_nodes not set
Hello Dave,
I have a s390x dump of a Linux-3.1 kernel where I get the error message:
crash: zero-size memory allocation! (called from 8009f504)
The error comes from max_cpudata_limit() where GETBUF fails:
/*
* Check the shared list of all the nodes.
*/
start_address = (ulong *)GETBUF(sizeof(ulong) * vt->kmem_cache_len_nodes);
--> vt->kmem_cache_len_nodes = 0
I debugged the problem a bit and found out that the reason is
that crash does not set vt->kmem_cache_len_nodes for that dump.
This attribute seem to be only set in kmem_cache_downsize():
if (buffer_size < SIZE(kmem_cache_s)) {
if (kernel_symbol_exists("nr_node_ids")) {
get_symbol_data("nr_node_ids", sizeof(int),
&nr_node_ids);
vt->kmem_cache_len_nodes = nr_node_ids;
} else {
fprintf(fp, "XXX kernel_symbol_exists(\n");
vt->kmem_cache_len_nodes = 1;
}
In my dump the "if" condition returns false (buffer_size = 768,
SIZE(kmem_cache_s = 624) therefore vt->kmem_cache_len_nodes is
not set. Perhaps the content of "cache_cache" is useful to understand
what is going on:
print cache_cache
$7 = {
batchcount = 27,
limit = 54,
shared = 8,
buffer_size = 768, <<-----
reciprocal_buffer_size = 5592406,
flags = 0,
num = 5,
gfporder = 0,
gfpflags = 0,
colour = 0,
colour_off = 256,
slabp_cache = 0x0,
slab_size = 256,
dflags = 0,
ctor = 0,
name = 0x667b8e "kmem_cache",
next = {
next = 0x93b528,
prev = 0xff04158
},
nodelists = 0x93b538,
array = {0xff23e00, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
0x0, 0x0, 0x0,
0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
0x0, 0x0, 0x
0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
0x0, 0x0, 0x0,
0x0, 0x0, 0x0, 0x0, 0x0, 0x0}
}
Any idea what's wrong here?
Best Regards
Michael