From: Linus Torvalds <torvalds@linux-foundation.org>
To: Trent Piepho <xyzzy@speakeasy.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Harvey Harrison <harvey.harrison@gmail.com>,
"David S. Miller" <davem@davemloft.net>
Subject: Re: [PATCH] printk: Let %pR handle NULL pointers
Date: Sat, 3 Jan 2009 09:10:40 -0800 (PST) [thread overview]
Message-ID: <alpine.LFD.2.00.0901030905140.3179@localhost.localdomain> (raw)
In-Reply-To: <1230979341-23029-1-git-send-email-xyzzy@speakeasy.org>
On Sat, 3 Jan 2009, Trent Piepho wrote:
>
> Have %pR print "[NULL]" for the resource range when passed a NULL pointer.
Wouldn't it be much nicer to just do it for _all_ pointer types?
IOW, a patch more like the appended.
Also, I'm not 100% sure that "[NULL]" is the right thing to print. Not
that I know if there's anything better. Testing glibc, it prints "(nil)"
for a NULL string (%s) and "(null)" for a NULL pointer (%p). Which makes
no more sense than anything else, but maybe we could make the NULL %p case
at least match that if for no other reason than the fact that it would
match _something_.
Added the other people who added %pX modifiers to the cc - I guess the
networking people probably never have NULL pointers there anyway, but
maybe they have opinions.
Linus
---
lib/vsprintf.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 3b77702..4df1884 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -661,6 +661,9 @@ static char *ip4_addr_string(char *buf, char *end, u8 *addr, int field_width,
*/
static char *pointer(const char *fmt, char *buf, char *end, void *ptr, int field_width, int precision, int flags)
{
+ if (!ptr)
+ return string(buf, end, "[NULL]", field_width, precision, flags);
+
switch (*fmt) {
case 'F':
ptr = dereference_function_descriptor(ptr);
next prev parent reply other threads:[~2009-01-03 17:11 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-03 10:42 [PATCH] printk: Let %pR handle NULL pointers Trent Piepho
2009-01-03 17:10 ` Linus Torvalds [this message]
2009-01-03 19:33 ` Harvey Harrison
2009-01-03 21:53 ` Benjamin Herrenschmidt
2009-01-04 5:02 ` Trent Piepho
2009-01-04 5:14 ` Valdis.Kletnieks
2009-01-04 9:31 ` Johannes Berg
2009-01-04 9:48 ` Benjamin Herrenschmidt
2009-01-04 20:41 ` Trent Piepho
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