Re: crash in kmem_cache_init

On 1/22/08, Olaf Hering [off-list ref] wrote:

On Tue, Jan 22, Mel Gorman wrote:

quoted

http://www.csn.ul.ie/~mel/postings/slab-20080122/partial-revert-slab-changes.patch
.. Can you please check on your machine if it fixes your problem?

It does not fix or change the nature of the crash.

quoted

Olaf, please confirm whether you need the patch below as well as the
revert to make your machine boot.

It crashes now in a different way if the patch below is applied:

Was this with the revert Mel mentioned applied as well? I get the
feeling both patches are needed to fix up the memoryless SLAB issue.

Linux version 2.6.24-rc8-ppc64 (olaf@lingonberry) (gcc version 4.1.2 20070115 (prerelease) (SUSE Linux)) #43 SMP Tue Jan 22 22:39:05 CET 2008

<snip>

early_node_map[1] active PFN ranges
    1:        0 ->   892928

<snip>

Unable to handle kernel paging request for data at address 0x00000058
Faulting instruction address: 0xc0000000000fe018
cpu 0x0: Vector: 300 (Data Access) at [c00000000075bac0]
    pc: c0000000000fe018: .setup_cpu_cache+0x184/0x1f4
    lr: c0000000000fdfa8: .setup_cpu_cache+0x114/0x1f4
    sp: c00000000075bd40
   msr: 8000000000009032
   dar: 58
 dsisr: 42000000
  current = 0xc000000000665a50
  paca    = 0xc000000000666380
    pid   = 0, comm = swapper
enter ? for help
[c00000000075bd40] c0000000000fb368 .kmem_cache_create+0x3c0/0x478 (unreliable)
[c00000000075be20] c0000000005e6780 .kmem_cache_init+0x284/0x4f4
[c00000000075bee0] c0000000005bf8ec .start_kernel+0x2f8/0x3fc
[c00000000075bf90] c000000000008590 .start_here_common+0x60/0xd0
0:mon>

0xc0000000000fe018 is in setup_cpu_cache (/home/olaf/kernel/git/linux-2.6-numa/mm/slab.c:2111).
2106                                    BUG_ON(!cachep->nodelists[node]);
2107                                    kmem_list3_init(cachep->nodelists[node]);

I might be barking up the wrong tree, but this block above is supposed
to set up the cachep->nodeslists[*] that are used immediately below.
But if the loop wasn't changed from N_NORMAL_MEMORY to N_ONLINE or
whatever, you might get a bad access right below for node 0 that has
no memory, if that's the node we're running on...

2108                            }
2109                    }
2110            }
2111            cachep->nodelists[numa_node_id()]->next_reap =
2112                            jiffies + REAPTIMEOUT_LIST3 +
2113                            ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
2114
2115            cpu_cache_get(cachep)->avail = 0;

Thanks,
Nish