Re: [PATCH v5 4/4] lib/test_printf.c: add test cases for '%pD'

From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
To: Jia He <justin.he@arm.com>, Petr Mladek <pmladek@suse.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Sergey Senozhatsky <senozhatsky@chromium.org>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>,
	Eric Biggers <ebiggers@google.com>,
	"Ahmed S. Darwish" <a.darwish@linutronix.de>,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-fsdevel@vger.kernel.org,
	Matthew Wilcox <willy@infradead.org>,
	Christoph Hellwig <hch@infradead.org>,
	nd@arm.com
Subject: Re: [PATCH v5 4/4] lib/test_printf.c: add test cases for '%pD'
Date: Tue, 22 Jun 2021 22:51:56 +0200	[thread overview]
Message-ID: <03f59e85-bba3-2e2c-ebaa-48daa93d6fec@rasmusvillemoes.dk> (raw)
In-Reply-To: <20210622140634.2436-5-justin.he@arm.com>

On 22/06/2021 16.06, Jia He wrote:
> After the behaviour of specifier '%pD' is changed to print the full path
> of struct file, the related test cases are also updated.
> 
> Given the full path string of '%pD' is prepended from the end of the scratch
> buffer, the check of "wrote beyond the nul-terminator" should be skipped
> for '%pD'.
> 
> Parameterize the new using_scratch_space in __test, do_test to skip the
> test case mentioned above,

I actually prefer the first suggestion of just having a file-global bool.

If and when we get other checks that need to be done selectively [e.g.
"snprintf into a too short buffer produces a prefix of the full string",
which also came up during this discussion but was ultimately kept]
depending on the %<whatever> being exercised, we can add a "u32 nocheck"
with a bunch of bits saying what to elide.

Not insisting either way, just my $0.02.

Rasmus