[Crash-utility] crash-5.0: zero-size memory-allocation

[ville.mattila at stonesoft.com]

Hello,

We have a custom kernel based on 2.6.27.39. This kernel
has 2/2 memory split. Now we have one crash dump that can be
successfully be opened with crash 4.0-8.8 but not with crash 5.0.
This crashdump happens because double free of memory block, so there
might be some memory corruption in cache data area.

Unfortunately I cannot pinpoint the exact version where this
starts to happen because I could not find older crash releases.

Here is some debug info.

The tail of crash -d 10 output
...
NOTE: page_hash_table does not exist in this kernel
please wait... (gathering kmem slab cache data)<readmem: 8075801c, KVADDR,
"cache_chain", 4, (FOE), ffb944f8>
    addr: 8075801c  paddr: 75801c  cnt: 4
GETBUF(128 -> 0)
FREEBUF(0)
GETBUF(204 -> 0)
<readmem: 8067f1c0, KVADDR, "kmem_cache buffer", 204, (FOE), 8520f00>
    addr: 8067f1c0  paddr: 67f1c0  cnt: 204
  GETBUF(128 -> 1)
  FREEBUF(1)
  GETBUF(128 -> 1)
  FREEBUF(1)

kmem_cache_downsize: SIZE(kmem_cache_s): 204 cache_cache.buffer_size: 0
kmem_cache_downsize: nr_node_ids: 1
FREEBUF(0)

crash: zero-size memory allocation! (called from 80b7b7b)
>
addr2line -e crash 80b7b7b
/workarea/build/packages/crash/crash-5.0.0-32bit/memory.c:7439

I'm happy to test patches.