linux-kernel - perf PLT hit turns off symbol annotations

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Date:	Sun, 25 Mar 2012 15:53:45 -0400 (EDT)
From:	David Miller <davem@...emloft.net>
To:	acme@...stprotocols.net
CC:	penberg@...helsinki.fi, linux-kernel@...r.kernel.org
Subject: perf PLT hit turns off symbol annotations

PLT entries are anon memory on sparc once they are written to by the
dynamic linker.

But if we take a perf event within such a page, perf thinks it's this
JIT tmp/perf-***.map stuff.

Of course there won't be a real /tmp/perf-***.map file for this
anonymous memory, so dso__load() fails and this turns off symbol
annotation completely.

First of all, this is a very extreme way to handle being unable
to load a DSO.  We should just fail to annotate symbols in that
DSO, rather than everywhere.

Second of all, assuming code execution hits are in anonymous memory
must be JIT code is not correct either.  It can be in the PLT on
several architectures.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/