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authorJohannes Berg <johannes@sipsolutions.net>2009-11-25 16:10:14 +0100
committerSteven Rostedt <rostedt@goodmis.org>2009-12-09 14:05:49 -0500
commitd184b31c0e403580aafb3f8955ecc185a3d04801 (patch)
treeca3fc8371382ce8dbe43eb684313847b7555573e /kernel
parenta63ce5b306855bccdacba95c03bfc293316c8ae3 (diff)
downloadlinux-linaro-d184b31c0e403580aafb3f8955ecc185a3d04801.tar.gz
tracing: Add full state to trace_seq
The trace_seq buffer might fill up, and right now one needs to check the return value of each printf into the buffer to check for that. Instead, have the buffer keep track of whether it is full or not, and reject more input if it is full or would have overflowed with an input that wasn't added. Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace_output.c61
1 files changed, 50 insertions, 11 deletions
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index e5cf90fef34..8e46b3323cd 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -93,7 +93,7 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
va_list ap;
int ret;
- if (!len)
+ if (s->full || !len)
return 0;
va_start(ap, fmt);
@@ -101,8 +101,10 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
va_end(ap);
/* If we can't write it all, don't bother writing anything */
- if (ret >= len)
+ if (ret >= len) {
+ s->full = 1;
return 0;
+ }
s->len += ret;
@@ -127,14 +129,16 @@ trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
int len = (PAGE_SIZE - 1) - s->len;
int ret;
- if (!len)
+ if (s->full || !len)
return 0;
ret = vsnprintf(s->buffer + s->len, len, fmt, args);
/* If we can't write it all, don't bother writing anything */
- if (ret >= len)
+ if (ret >= len) {
+ s->full = 1;
return 0;
+ }
s->len += ret;
@@ -147,14 +151,16 @@ int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
int len = (PAGE_SIZE - 1) - s->len;
int ret;
- if (!len)
+ if (s->full || !len)
return 0;
ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
/* If we can't write it all, don't bother writing anything */
- if (ret >= len)
+ if (ret >= len) {
+ s->full = 1;
return 0;
+ }
s->len += ret;
@@ -175,9 +181,14 @@ int trace_seq_puts(struct trace_seq *s, const char *str)
{
int len = strlen(str);
- if (len > ((PAGE_SIZE - 1) - s->len))
+ if (s->full)
return 0;
+ if (len > ((PAGE_SIZE - 1) - s->len)) {
+ s->full = 1;
+ return 0;
+ }
+
memcpy(s->buffer + s->len, str, len);
s->len += len;
@@ -186,9 +197,14 @@ int trace_seq_puts(struct trace_seq *s, const char *str)
int trace_seq_putc(struct trace_seq *s, unsigned char c)
{
- if (s->len >= (PAGE_SIZE - 1))
+ if (s->full)
return 0;
+ if (s->len >= (PAGE_SIZE - 1)) {
+ s->full = 1;
+ return 0;
+ }
+
s->buffer[s->len++] = c;
return 1;
@@ -196,9 +212,14 @@ int trace_seq_putc(struct trace_seq *s, unsigned char c)
int trace_seq_putmem(struct trace_seq *s, const void *mem, size_t len)
{
- if (len > ((PAGE_SIZE - 1) - s->len))
+ if (s->full)
return 0;
+ if (len > ((PAGE_SIZE - 1) - s->len)) {
+ s->full = 1;
+ return 0;
+ }
+
memcpy(s->buffer + s->len, mem, len);
s->len += len;
@@ -211,6 +232,9 @@ int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, size_t len)
const unsigned char *data = mem;
int i, j;
+ if (s->full)
+ return 0;
+
#ifdef __BIG_ENDIAN
for (i = 0, j = 0; i < len; i++) {
#else
@@ -228,8 +252,13 @@ void *trace_seq_reserve(struct trace_seq *s, size_t len)
{
void *ret;
- if (len > ((PAGE_SIZE - 1) - s->len))
+ if (s->full)
+ return 0;
+
+ if (len > ((PAGE_SIZE - 1) - s->len)) {
+ s->full = 1;
return NULL;
+ }
ret = s->buffer + s->len;
s->len += len;
@@ -241,8 +270,14 @@ int trace_seq_path(struct trace_seq *s, struct path *path)
{
unsigned char *p;
- if (s->len >= (PAGE_SIZE - 1))
+ if (s->full)
return 0;
+
+ if (s->len >= (PAGE_SIZE - 1)) {
+ s->full = 1;
+ return 0;
+ }
+
p = d_path(path, s->buffer + s->len, PAGE_SIZE - s->len);
if (!IS_ERR(p)) {
p = mangle_path(s->buffer + s->len, p, "\n");
@@ -255,6 +290,7 @@ int trace_seq_path(struct trace_seq *s, struct path *path)
return 1;
}
+ s->full = 1;
return 0;
}
@@ -381,6 +417,9 @@ int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
unsigned long vmstart = 0;
int ret = 1;
+ if (s->full)
+ return 0;
+
if (mm) {
const struct vm_area_struct *vma;