Re: [PATCH 00/11] Add compression support to pstore

From: Tony Luck
Date: Fri Aug 02 2013 - 17:40:01 EST

On Thu, Aug 1, 2013 at 4:42 PM, Luck, Tony <tony.luck@xxxxxxxxx> wrote:
> when I rebuilt a plain 3.11-rc3 it didn't log anything via pstore either :-(

Well this turned out to be operator error on my part. 3.11-rc3 does in fact
log errors to pstore and allows them to be retrieved and cleared.

So then I start testing with your 11 patches in place.

First boot was fine - ERST had no records, and pstore mounted OK
(and showed no files).

Then I panic'd the machine and rebooted. The boot hung when some
rc script printed"

Mounting other filesystems:

I guess something went wrong when pstore found a non-empty ERST.

I added some debug traces and booted again. This time the boot succeeded
but I saw a GP fault reported from pstore_mkfile(). Possibly in this code:

spin_lock_irqsave(&allpstore_lock, flags);
list_for_each_entry(pos, &allpstore, list) {
if (pos->type == type &&
pos->id == id &&
pos->psi == psi) {
rc = -EEXIST;
spin_unlock_irqrestore(&allpstore_lock, flags);

My other tracing showed that we'd already found two compressed entries in
ERST and were working on a third when this error happened (implying that
my hang had been a panic that failed to print anything to console)

I've attached one of the compressed files that v3.11-rc3 shows in pstore
now. The "openssl zlib -d" trick you mentioned back in June mostly works
to decode ... but it seems to dump some trailing garbage at the end of
the file.


Attachment: unknown-erst-5907623178007478273
Description: Binary data