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

From: Aruna Balakrishnaiah
Date: Tue Aug 06 2013 - 21:59:03 EST

On Wednesday 07 August 2013 05:06 AM, Tony Luck wrote:
On Mon, Aug 5, 2013 at 2:20 PM, Tony Luck <tony.luck@xxxxxxxxx> wrote:
Still have problems booting if there are any compressed images in ERST
to be inflated.
So I took another look at this part of the code ... and saw a couple of issues:

while ((size = psi->read(&id, &type, &count, &time, &buf, &compressed,
psi)) > 0) {
if (compressed && (type == PSTORE_TYPE_DMESG)) {
big_buf_sz = (psinfo->bufsize * 100) / 45;
big_buf = allocate_buf_for_decompression(big_buf_sz);

if (big_buf || stream.workspace)
Did you mean "&&" here rather that "||"?

Yes right, it should be &&.

unzipped_len = pstore_decompress(buf, big_buf,
size, big_buf_sz);
Need an "else" here to set unzipped_len to -1 (or set it to -1 down
at the bottom of the loop ready for next time around.
if (unzipped_len > 0) {
buf = big_buf;
This sets us up for problems. First, you just overwrote the address
of the buffer that psi->read allocated - so we have a memory leak. But
worse than that we now double free the same buffer below when we
kfree(buf) and then kfree(big_buf)
size = unzipped_len;
compressed = false;
} else {
pr_err("pstore: decompression failed;"
"returned %d\n", unzipped_len);
compressed = true;
rc = pstore_mkfile(type, psi->name, id, count, buf,
compressed, (size_t)size, time, psi);
buf = NULL;
stream.workspace = NULL;
big_buf = NULL;
if (rc && (rc != -EEXIST || !quiet))

See attached patch that fixes these - but the code still looks like it
could be cleaned up a bit more.

The patch looks right. I will clean it up. Does the issue still persist after this?


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