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SubjectRe: [PATCH 00/11] Add compression support to pstore
From
On Mon, Aug 5, 2013 at 2:20 PM, Tony Luck <tony.luck@gmail.com> 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 "||"?
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);
kfree(buf);
kfree(stream.workspace);
kfree(big_buf);
buf = NULL;
stream.workspace = NULL;
big_buf = NULL;
if (rc && (rc != -EEXIST || !quiet))
failed++;
}


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

-Tony
[unhandled content-type:application/octet-stream]
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