From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753878AbeCFSMD (ORCPT ); Tue, 6 Mar 2018 13:12:03 -0500 Received: from tartarus.angband.pl ([89.206.35.136]:54354 "EHLO tartarus.angband.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753042AbeCFSMC (ORCPT ); Tue, 6 Mar 2018 13:12:02 -0500 From: Adam Borowski To: Petr Mladek , Rasmus Villemoes , Andy Shevchenko , "Tobin C . Harding" , Joe Perches , linux-kernel@vger.kernel.org, Andrew Morton , Michal Hocko Cc: Adam Borowski Date: Tue, 6 Mar 2018 19:11:21 +0100 Message-Id: <20180306181122.11449-1-kilobyte@angband.pl> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180306092513.ibodfsnv4xrxdlub@pathway.suse.cz> References: <20180306092513.ibodfsnv4xrxdlub@pathway.suse.cz> X-SA-Exim-Connect-IP: 2a02:a312:c201:ce80::6 X-SA-Exim-Mail-From: kilobyte@angband.pl Subject: [PATCH 1/2] vsprintf: distinguish between (null), (err) and (invalid) pointer derefs X-SA-Exim-Version: 4.2.1 (built Tue, 02 Aug 2016 21:08:31 +0000) X-SA-Exim-Scanned: Yes (on tartarus.angband.pl) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Attempting to print an object pointed to by a bad (usually ERR_PTR) pointer is a not so surprising error. Our code handles them inconsistently: * two places print (null) if ptr --- lib/vsprintf.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/lib/vsprintf.c b/lib/vsprintf.c index d7a708f82559..1c2c3cc5a321 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -47,6 +47,8 @@ #include #include "kstrtox.h" +#define BAD_PTR_STRING(x) (!(x) ? "(null)" : IS_ERR(x) ? "(err)" : "(invalid)") + /** * simple_strtoull - convert a string to an unsigned long long * @cp: The start of the string @@ -588,7 +590,7 @@ char *string(char *buf, char *end, const char *s, struct printf_spec spec) size_t lim = spec.precision; if ((unsigned long)s < PAGE_SIZE) - s = "(null)"; + s = BAD_PTR_STRING(s); while (lim--) { char c = *s++; @@ -1582,7 +1584,7 @@ char *device_node_string(char *buf, char *end, struct device_node *dn, return string(buf, end, "(!OF)", spec); if ((unsigned long)dn < PAGE_SIZE) - return string(buf, end, "(null)", spec); + return string(buf, end, BAD_PTR_STRING(dn), spec); /* simple case without anything any more format specifiers */ fmt++; @@ -1851,12 +1853,12 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, if (!ptr && *fmt != 'K' && *fmt != 'x') { /* - * Print (null) with the same width as a pointer so it makes - * tabular output look nice. + * Print (null)/etc with the same width as a pointer so it + * makes tabular output look nice. */ if (spec.field_width == -1) spec.field_width = default_width; - return string(buf, end, "(null)", spec); + return string(buf, end, BAD_PTR_STRING(ptr), spec); } switch (*fmt) { @@ -2575,7 +2577,7 @@ int vbin_printf(u32 *bin_buf, size_t size, const char *fmt, va_list args) if ((unsigned long)save_str > (unsigned long)-PAGE_SIZE || (unsigned long)save_str < PAGE_SIZE) - save_str = "(null)"; + save_str = BAD_PTR_STRING(save_str); len = strlen(save_str) + 1; if (str + len < end) memcpy(str, save_str, len); -- 2.16.2