linux-kernel - Re: [PATCH] Illustration of warning explosion silliness

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:	Wed, 27 Sep 2006 21:36:28 -0700
From:	Andrew Morton <akpm@...l.org>
To:	Jeff Garzik <jeff@...zik.org>
Cc:	linux-scsi@...r.kernel.org, Greg KH <greg@...ah.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Linus Torvalds <torvalds@...l.org>
Subject: Re: [PATCH] Illustration of warning explosion silliness

On Thu, 28 Sep 2006 00:19:36 -0400
Jeff Garzik <jeff@...zik.org> wrote:

> Andrew Morton wrote:
> > And it's not sufficient to say "gee, I can't think of any reason why this
> > handler would return an error, so I'll design its callers to assume that". 
> > It is _much_ better to design the callers to assume that callees _can_
> > fail, and to stick the `return 0;' into the terminal callee.  Because
> > things can change.
> 
> huh?  You're going off on a tangent.  I agree with the above, just like 
> I already agreed that SCSI needs better error checking.

No I'm not.  I'm saying that the bugs which this exposed are a far, far
more serious matter than a few false-positive warnings which need
workarounds.

> You're ignoring the API issue at hand.  Let me say it again for the 
> cheap seats:  "search"  You search a list, and stick a pointer somewhere 
> when found.  No hardware touched.  No allocations.  Real world.  There 
> is an example of usage in the kernel today.

If it's called in that fashion then the caller should still check the
device_for_each_child() return value to find out if it actually got a
match.

Now it could be that the mysterious caller to which you refer uses the
non-NULLness of some pointer to work out if a match occurred.  Well shrug -
add a BUG_ON(!device_for_each_child_return_value) or something.

Or write a new version of device_for_each_child() which returns void and
don't tell anyone about it.

But let's not encourage error-ignoring.

-
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/