From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ramsay Jones Subject: Re: [PATCH 2/3] add support for -Wmemcpy-max-count Date: Fri, 2 Jun 2017 01:23:57 +0100 Message-ID: References: <84e547c2-8a5b-225c-1363-361e091821f4@ramsayjones.plus.com> <20170601202724.77597-1-luc.vanoostenryck@gmail.com> <20170601202724.77597-3-luc.vanoostenryck@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Received: from avasout08.plus.net ([212.159.14.20]:53672 "EHLO avasout08.plus.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751134AbdFBAYA (ORCPT ); Thu, 1 Jun 2017 20:24:00 -0400 In-Reply-To: <20170601202724.77597-3-luc.vanoostenryck@gmail.com> Content-Language: en-GB Sender: linux-sparse-owner@vger.kernel.org List-Id: linux-sparse@vger.kernel.org To: Luc Van Oostenryck , linux-sparse@vger.kernel.org Cc: Chris Li , Junio C Hamano On 01/06/17 21:27, Luc Van Oostenryck wrote: > sparse will warn if memcpy() (or memset(), copy_from_user(), > copy_to_user()) is called with a very large static byte-count. > > But this warning is given unconditionaly while there are projects > where this warning may not be not desired. > > Change this by making this warning conditional on a new warning > flag: -Wmemcpy-max-count=COUNT. As always, the hardest part for me is naming. I can't remember exactly what I called it, but I wanted something which would kinda sum up all the functions. So, it was something like -Wmem-move-limit=n, or something like that, and so the test was disabled by setting it to zero. -Wmemcpy-max-count=count is probably a better name! ;-) > > Signed-off-by: Luc Van Oostenryck > --- > lib.c | 2 ++ > lib.h | 1 + > sparse.1 | 8 ++++++++ > sparse.c | 3 ++- > 4 files changed, 13 insertions(+), 1 deletion(-) > > diff --git a/lib.c b/lib.c > index e1e6a1cbf..90fd2b494 100644 > --- a/lib.c > +++ b/lib.c > @@ -229,6 +229,7 @@ int Wdo_while = 0; > int Winit_cstring = 0; > int Wenum_mismatch = 1; > int Wsparse_error = 0; > +int Wmemcpy_max_count = 1; > int Wnon_pointer_null = 1; > int Wold_initializer = 1; > int Wone_bit_signed_bitfield = 1; > @@ -506,6 +507,7 @@ static const struct warning { > { "enum-mismatch", &Wenum_mismatch }, > { "sparse-error", &Wsparse_error }, > { "init-cstring", &Winit_cstring }, > + { "memcpy-max-count", &Wmemcpy_max_count }, > { "non-pointer-null", &Wnon_pointer_null }, > { "old-initializer", &Wold_initializer }, > { "one-bit-signed-bitfield", &Wone_bit_signed_bitfield }, > diff --git a/lib.h b/lib.h > index 2c8529f93..8090fe247 100644 > --- a/lib.h > +++ b/lib.h > @@ -116,6 +116,7 @@ extern int Wdo_while; > extern int Wenum_mismatch; > extern int Wsparse_error; > extern int Winit_cstring; > +extern int Wmemcpy_max_count; > extern int Wnon_pointer_null; > extern int Wold_initializer; > extern int Wone_bit_signed_bitfield; > diff --git a/sparse.1 b/sparse.1 > index c924b3a59..efbd78d01 100644 > --- a/sparse.1 > +++ b/sparse.1 > @@ -210,6 +210,14 @@ trouble. > Sparse does not issue these warnings by default. > . > .TP > +.B \-Wmemcpy\-max\-count > +Warn about call of \fBmemset()\fR, \fBmemset()\fR, \fBcopy_from_user()\fR, or ^^^^^^^ ^^^^^^^^ memcpy() and memset() ATB, Ramsay Jones > +\fBcopy_to_user()\fR with a large compile-time byte count. > + > +Sparse issues these warnings by default. To turn them off, use > +\fB\-Wno\-memcpy\-max\-count\fR. > +. > +.TP > .B \-Wnon\-pointer\-null > Warn about the use of 0 as a NULL pointer. > > diff --git a/sparse.c b/sparse.c > index 1cb90e20d..aa5979f1a 100644 > --- a/sparse.c > +++ b/sparse.c > @@ -153,7 +153,8 @@ static void check_byte_count(struct instruction *insn, pseudo_t count) > return; > if (count->type == PSEUDO_VAL) { > unsigned long long val = count->value; > - if (val > 100000ULL) > + if (Wmemcpy_max_count && val > 100000ULL) > + > warning(insn->pos, "%s with byte count of %llu", > show_ident(insn->func->sym->ident), val); > return; >