trace: judicious error checking of trace_seq results
Impact: bugfix and cleanup
Some callsites were returning either TRACE_ITER_PARTIAL_LINE if the
trace_seq routines (trace_seq_printf, etc) returned 0 meaning its buffer
was full, or zero otherwise.
But...
/* Return values for print_line callback */
enum print_line_t {
TRACE_TYPE_PARTIAL_LINE = 0, /* Retry after flushing the seq */
TRACE_TYPE_HANDLED = 1,
TRACE_TYPE_UNHANDLED = 2 /* Relay to other output functions */
};
In other cases the return value was not being relayed at all.
Most of the time it didn't hurt because the page wasn't get filled, but
for correctness sake, handle the return values everywhere.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/block/blktrace.c b/block/blktrace.c
index 8f5c37b..12df276 100644
--- a/block/blktrace.c
+++ b/block/blktrace.c
@@ -1165,7 +1165,7 @@
const u16 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
int ret;
- if (trace_print_context(iter))
+ if (!trace_print_context(iter))
return TRACE_TYPE_PARTIAL_LINE;
if (unlikely(what == 0 || what > ARRAY_SIZE(what2act)))
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index bbdfaa2..5822ff4 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1402,27 +1402,25 @@
unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
struct trace_event *event;
struct trace_entry *entry = iter->ent;
- int ret;
test_cpu_buff_start(iter);
event = ftrace_find_event(entry->type);
if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
- ret = trace_print_lat_context(iter);
- if (ret)
- return ret;
+ if (!trace_print_lat_context(iter))
+ goto partial;
}
- if (event && event->latency_trace) {
- ret = event->latency_trace(iter, sym_flags);
- if (ret)
- return ret;
- return TRACE_TYPE_HANDLED;
- }
+ if (event && event->latency_trace)
+ return event->latency_trace(iter, sym_flags);
- trace_seq_printf(s, "Unknown type %d\n", entry->type);
+ if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
+ goto partial;
+
return TRACE_TYPE_HANDLED;
+partial:
+ return TRACE_TYPE_PARTIAL_LINE;
}
static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
@@ -1431,7 +1429,6 @@
unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
struct trace_entry *entry;
struct trace_event *event;
- int ret;
entry = iter->ent;
@@ -1440,22 +1437,19 @@
event = ftrace_find_event(entry->type);
if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
- ret = trace_print_context(iter);
- if (ret)
- return ret;
+ if (!trace_print_context(iter))
+ goto partial;
}
- if (event && event->trace) {
- ret = event->trace(iter, sym_flags);
- if (ret)
- return ret;
- return TRACE_TYPE_HANDLED;
- }
- ret = trace_seq_printf(s, "Unknown type %d\n", entry->type);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ if (event && event->trace)
+ return event->trace(iter, sym_flags);
+
+ if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
+ goto partial;
return TRACE_TYPE_HANDLED;
+partial:
+ return TRACE_TYPE_PARTIAL_LINE;
}
static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
@@ -1463,29 +1457,25 @@
struct trace_seq *s = &iter->seq;
struct trace_entry *entry;
struct trace_event *event;
- int ret;
entry = iter->ent;
if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
- ret = trace_seq_printf(s, "%d %d %llu ",
- entry->pid, iter->cpu, iter->ts);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ if (!trace_seq_printf(s, "%d %d %llu ",
+ entry->pid, iter->cpu, iter->ts))
+ goto partial;
}
event = ftrace_find_event(entry->type);
- if (event && event->raw) {
- ret = event->raw(iter, 0);
- if (ret)
- return ret;
- return TRACE_TYPE_HANDLED;
- }
- ret = trace_seq_printf(s, "%d ?\n", entry->type);
- if (!ret)
- return TRACE_TYPE_PARTIAL_LINE;
+ if (event && event->raw)
+ return event->raw(iter, 0);
+
+ if (!trace_seq_printf(s, "%d ?\n", entry->type))
+ goto partial;
return TRACE_TYPE_HANDLED;
+partial:
+ return TRACE_TYPE_PARTIAL_LINE;
}
static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
@@ -1504,8 +1494,11 @@
}
event = ftrace_find_event(entry->type);
- if (event && event->hex)
- event->hex(iter, 0);
+ if (event && event->hex) {
+ int ret = event->hex(iter, 0);
+ if (ret != TRACE_TYPE_HANDLED)
+ return ret;
+ }
SEQ_PUT_FIELD_RET(s, newline);
@@ -1544,7 +1537,7 @@
event = ftrace_find_event(entry->type);
if (event && event->binary)
- event->binary(iter, 0);
+ return event->binary(iter, 0);
return TRACE_TYPE_HANDLED;
}
diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
index ea62f10..f6b35e1 100644
--- a/kernel/trace/trace_branch.c
+++ b/kernel/trace/trace_branch.c
@@ -173,7 +173,7 @@
field->line))
return TRACE_TYPE_PARTIAL_LINE;
- return 0;
+ return TRACE_TYPE_HANDLED;
}
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index c24503b..5b3c914 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -286,55 +286,41 @@
return ret;
}
-static void
+static int
lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
{
int hardirq, softirq;
char *comm;
comm = trace_find_cmdline(entry->pid);
-
- trace_seq_printf(s, "%8.8s-%-5d ", comm, entry->pid);
- trace_seq_printf(s, "%3d", cpu);
- trace_seq_printf(s, "%c%c",
- (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
- (entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' : '.',
- ((entry->flags & TRACE_FLAG_NEED_RESCHED) ? 'N' : '.'));
-
hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
- if (hardirq && softirq) {
- trace_seq_putc(s, 'H');
- } else {
- if (hardirq) {
- trace_seq_putc(s, 'h');
- } else {
- if (softirq)
- trace_seq_putc(s, 's');
- else
- trace_seq_putc(s, '.');
- }
- }
+
+ if (!trace_seq_printf(s, "%8.8s-%-5d %3d%c%c%c",
+ comm, entry->pid, cpu,
+ (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
+ (entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ?
+ 'X' : '.',
+ (entry->flags & TRACE_FLAG_NEED_RESCHED) ?
+ 'N' : '.',
+ (hardirq && softirq) ? 'H' :
+ hardirq ? 'h' : softirq ? 's' : '.'))
+ return 0;
if (entry->preempt_count)
- trace_seq_printf(s, "%x", entry->preempt_count);
- else
- trace_seq_puts(s, ".");
+ return trace_seq_printf(s, "%x", entry->preempt_count);
+ return trace_seq_puts(s, ".");
}
static unsigned long preempt_mark_thresh = 100;
-static void
+static int
lat_print_timestamp(struct trace_seq *s, u64 abs_usecs,
unsigned long rel_usecs)
{
- trace_seq_printf(s, " %4lldus", abs_usecs);
- if (rel_usecs > preempt_mark_thresh)
- trace_seq_puts(s, "!: ");
- else if (rel_usecs > 1)
- trace_seq_puts(s, "+: ");
- else
- trace_seq_puts(s, " : ");
+ return trace_seq_printf(s, " %4lldus%c: ", abs_usecs,
+ rel_usecs > preempt_mark_thresh ? '!' :
+ rel_usecs > 1 ? '+' : ' ');
}
int trace_print_context(struct trace_iterator *iter)
@@ -346,22 +332,14 @@
unsigned long usec_rem = do_div(t, USEC_PER_SEC);
unsigned long secs = (unsigned long)t;
- if (!trace_seq_printf(s, "%16s-%-5d ", comm, entry->pid))
- goto partial;
- if (!trace_seq_printf(s, "[%03d] ", entry->cpu))
- goto partial;
- if (!trace_seq_printf(s, "%5lu.%06lu: ", secs, usec_rem))
- goto partial;
-
- return 0;
-
-partial:
- return TRACE_TYPE_PARTIAL_LINE;
+ return trace_seq_printf(s, "%16s-%-5d [%03d] %5lu.%06lu: ",
+ comm, entry->pid, entry->cpu, secs, usec_rem);
}
int trace_print_lat_context(struct trace_iterator *iter)
{
u64 next_ts;
+ int ret;
struct trace_seq *s = &iter->seq;
struct trace_entry *entry = iter->ent,
*next_entry = trace_find_next_entry(iter, NULL,
@@ -376,21 +354,22 @@
if (verbose) {
char *comm = trace_find_cmdline(entry->pid);
- trace_seq_printf(s, "%16s %5d %3d %d %08x %08lx [%08lx]"
- " %ld.%03ldms (+%ld.%03ldms): ",
- comm,
- entry->pid, entry->cpu, entry->flags,
- entry->preempt_count, iter->idx,
- ns2usecs(iter->ts),
- abs_usecs/1000,
- abs_usecs % 1000, rel_usecs/1000,
- rel_usecs % 1000);
+ ret = trace_seq_printf(s, "%16s %5d %3d %d %08x %08lx [%08lx]"
+ " %ld.%03ldms (+%ld.%03ldms): ", comm,
+ entry->pid, entry->cpu, entry->flags,
+ entry->preempt_count, iter->idx,
+ ns2usecs(iter->ts),
+ abs_usecs / USEC_PER_MSEC,
+ abs_usecs % USEC_PER_MSEC,
+ rel_usecs / USEC_PER_MSEC,
+ rel_usecs % USEC_PER_MSEC);
} else {
- lat_print_generic(s, entry, entry->cpu);
- lat_print_timestamp(s, abs_usecs, rel_usecs);
+ ret = lat_print_generic(s, entry, entry->cpu);
+ if (ret)
+ ret = lat_print_timestamp(s, abs_usecs, rel_usecs);
}
- return 0;
+ return ret;
}
static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
@@ -486,7 +465,7 @@
int trace_nop_print(struct trace_iterator *iter, int flags)
{
- return 0;
+ return TRACE_TYPE_HANDLED;
}
/* TRACE_FN */
@@ -506,7 +485,7 @@
if (!trace_seq_puts(s, ")\n"))
goto partial;
- return 0;
+ return TRACE_TYPE_HANDLED;
partial:
return TRACE_TYPE_PARTIAL_LINE;
@@ -533,7 +512,7 @@
if (!trace_seq_printf(s, "\n"))
goto partial;
- return 0;
+ return TRACE_TYPE_HANDLED;
partial:
return TRACE_TYPE_PARTIAL_LINE;
@@ -550,7 +529,7 @@
field->parent_ip))
return TRACE_TYPE_PARTIAL_LINE;
- return 0;
+ return TRACE_TYPE_HANDLED;
}
static int trace_fn_hex(struct trace_iterator *iter, int flags)
@@ -563,7 +542,7 @@
SEQ_PUT_HEX_FIELD_RET(s, field->ip);
SEQ_PUT_HEX_FIELD_RET(s, field->parent_ip);
- return 0;
+ return TRACE_TYPE_HANDLED;
}
static int trace_fn_bin(struct trace_iterator *iter, int flags)
@@ -576,7 +555,7 @@
SEQ_PUT_FIELD_RET(s, field->ip);
SEQ_PUT_FIELD_RET(s, field->parent_ip);
- return 0;
+ return TRACE_TYPE_HANDLED;
}
static struct trace_event trace_fn_event = {
@@ -611,7 +590,7 @@
T, comm))
return TRACE_TYPE_PARTIAL_LINE;
- return 0;
+ return TRACE_TYPE_HANDLED;
}
static int trace_ctx_print(struct trace_iterator *iter, int flags)
@@ -644,7 +623,7 @@
T))
return TRACE_TYPE_PARTIAL_LINE;
- return 0;
+ return TRACE_TYPE_HANDLED;
}
static int trace_ctx_raw(struct trace_iterator *iter, int flags)
@@ -678,7 +657,7 @@
SEQ_PUT_HEX_FIELD_RET(s, field->next_prio);
SEQ_PUT_HEX_FIELD_RET(s, T);
- return 0;
+ return TRACE_TYPE_HANDLED;
}
static int trace_ctx_hex(struct trace_iterator *iter, int flags)
@@ -705,7 +684,7 @@
SEQ_PUT_FIELD_RET(s, field->next_prio);
SEQ_PUT_FIELD_RET(s, field->next_state);
- return 0;
+ return TRACE_TYPE_HANDLED;
}
static struct trace_event trace_ctx_event = {
@@ -739,7 +718,7 @@
field->arg3))
return TRACE_TYPE_PARTIAL_LINE;
- return 0;
+ return TRACE_TYPE_HANDLED;
}
static int trace_special_hex(struct trace_iterator *iter, int flags)
@@ -753,7 +732,7 @@
SEQ_PUT_HEX_FIELD_RET(s, field->arg2);
SEQ_PUT_HEX_FIELD_RET(s, field->arg3);
- return 0;
+ return TRACE_TYPE_HANDLED;
}
static int trace_special_bin(struct trace_iterator *iter, int flags)
@@ -767,7 +746,7 @@
SEQ_PUT_FIELD_RET(s, field->arg2);
SEQ_PUT_FIELD_RET(s, field->arg3);
- return 0;
+ return TRACE_TYPE_HANDLED;
}
static struct trace_event trace_special_event = {
@@ -801,7 +780,7 @@
goto partial;
}
- return 0;
+ return TRACE_TYPE_HANDLED;
partial:
return TRACE_TYPE_PARTIAL_LINE;
@@ -830,7 +809,7 @@
if (!trace_seq_putc(s, '\n'))
goto partial;
- return 0;
+ return TRACE_TYPE_HANDLED;
partial:
return TRACE_TYPE_PARTIAL_LINE;
@@ -859,7 +838,7 @@
if (!trace_seq_printf(s, ": %s", field->buf))
goto partial;
- return 0;
+ return TRACE_TYPE_HANDLED;
partial:
return TRACE_TYPE_PARTIAL_LINE;
@@ -874,7 +853,7 @@
if (!trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf))
goto partial;
- return 0;
+ return TRACE_TYPE_HANDLED;
partial:
return TRACE_TYPE_PARTIAL_LINE;
