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.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
---
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
+\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;
--
2.13.0
--
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