linux-kernel - Re: [patch] procfs: provide stack information for threads

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

Date:	Fri, 02 Oct 2009 23:17:14 +0200
From:	Andreas Schwab <schwab@...ux-m68k.org>
To:	Stefani Seibold <stefani@...bold.net>
Cc:	linux-kernel <linux-kernel@...r.kernel.org>,
	linux-mm <linux-mm@...ck.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [patch] procfs: provide stack information for threads

Stefani Seibold <stefani@...bold.net> writes:

> This is the newest version of the formaly named "detailed stack info"
> patch which give you a better overview of the userland application stack
> usage, especially for embedded linux.
>
> Currently you are only able to dump the main process/thread stack usage
> which is showed in /proc/pid/status by the "VmStk" Value. But you get no
> information about the consumed stack memory of the the threads.
>
> There is an enhancement in the /proc/<pid>/{task/*,}/*maps and which
> marks the vm mapping where the thread stack pointer reside with "[thread
> stack xxxxxxxx]". xxxxxxxx is the start address of the stack.
>
> Also there is a new entry "stack usage" in /proc/<pid>/{task/*,}/status
> which will you give the current stack usage in kb.
>
> I also fixed stack base address in /proc/<pid>/task/*/stat to the base
> address of the associated thread stack and not the one of the main
> process. This makes more sense.

That does not work right.  I sometimes get meaningless values printed
for the stack usage in /proc/*/status (like 18014398509480456 kB), and
the stack start in /proc/*/stat is wrong.  Apparently task->stack_start
contains the stack start of the _parent_ process.

$ awk '{printf "%x\n", $28}' /proc/self/stat; grep stack /proc/self/maps /proc/$$/maps
ffd34990
/proc/self/maps:ffa9c000-ffab1000 rw-p 00000000 00:00 0                                  [stack]
/proc/4054/maps:ffd22000-ffd37000 rw-p 00000000 00:00 0                                  [stack]

Andreas.

-- 
Andreas Schwab, schwab@...ux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."
--
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/