linux-kernel - debugfs_create

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-next>] [day] [month] [year] [list]

Message-ID: <20080718035237.GA7744@localhost>
Date:	Fri, 18 Jul 2008 06:52:37 +0300
From:	Eduard - Gabriel Munteanu <eduard.munteanu@...ux360.ro>
To:	greg@...ah.com
Cc:	torvalds@...ux-foundation.org, Randy Dunlap <rdunlap@...otime.net>,
	linux-kernel@...r.kernel.org, Pekka Enberg <penberg@...helsinki.fi>
Subject: debugfs_create_u*() not SMP-safe

Hi,

I noticed debugfs_create_u*() functions don't allow for any precautions
to be taken while doing r/w to the exported variables. Thus any export of a
variable isn't SMP-safe.

As far as I can tell, this only works safely for constant data. Let me
ask then, what is the purpose of these functions? Are they intended only
for unreliable data?

As I see it, they could be replaced by one of the following:
- Have them only export atomic data, that is atomic_t variables.
- Have them take a lock as a parameter, which the read() / write()
  handler grabs. The kernel code that exported the variable should also
  do r/w while holding that same lock.

Or am I wrong?


	Thanks,
	Eduard

--
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/