perf timechart: Include file offset in CPU bounds check messages

Add the perf.data file offset to the out-of-bounds CPU debug messages
in process_sample_cpu_idle(), process_sample_cpu_frequency(),
process_sample_sched_wakeup(), and process_sample_sched_switch().

Reviewed-by: Ian Rogers <irogers@google.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-timechart.c b/tools/perf/builtin-timechart.c
index 630756bebe3242dc5ef6cbae6953b55c68d8a2e0..071987241a528ba4092ec561c2f526e45b7ac02b 100644 (file)
--- a/tools/perf/builtin-timechart.c
+++ b/tools/perf/builtin-timechart.c
@@ -605,8 +605,10 @@ process_sample_cpu_idle(struct timechart *tchart __maybe_unused,
        u32 state  = perf_sample__intval(sample, "state");
        u32 cpu_id = perf_sample__intval(sample, "cpu_id");
 
+       /* perf.data is untrusted input — cpu_id may be corrupted */
        if (cpu_id >= MAX_CPUS) {
-               pr_debug("Out-of-bounds cpu_id %u\n", cpu_id);
+               pr_debug("at offset %#" PRIx64 ": out-of-bounds cpu_id %u\n",
+                        sample->file_offset, cpu_id);
                return -1;
        }
        if (state == (u32)PWR_EVENT_EXIT)
@@ -624,8 +626,10 @@ process_sample_cpu_frequency(struct timechart *tchart,
        u32 state  = perf_sample__intval(sample, "state");
        u32 cpu_id = perf_sample__intval(sample, "cpu_id");
 
+       /* perf.data is untrusted input — cpu_id may be corrupted */
        if (cpu_id >= MAX_CPUS) {
-               pr_debug("Out-of-bounds cpu_id %u\n", cpu_id);
+               pr_debug("at offset %#" PRIx64 ": out-of-bounds cpu_id %u\n",
+                        sample->file_offset, cpu_id);
                return -1;
        }
        p_state_change(tchart, cpu_id, sample->time, state);
@@ -641,8 +645,10 @@ process_sample_sched_wakeup(struct timechart *tchart,
        int waker = perf_sample__intval(sample, "common_pid");
        int wakee = perf_sample__intval(sample, "pid");
 
+       /* perf.data is untrusted input — CPU may be absent or corrupted */
        if (sample->cpu >= MAX_CPUS) {
-               pr_debug("Out-of-bounds cpu %u\n", sample->cpu);
+               pr_debug("at offset %#" PRIx64 ": out-of-bounds cpu %u\n",
+                        sample->file_offset, sample->cpu);
                return -1;
        }
        sched_wakeup(tchart, sample->cpu, sample->time, waker, wakee, flags, backtrace);
@@ -658,8 +664,10 @@ process_sample_sched_switch(struct timechart *tchart,
        int next_pid   = perf_sample__intval(sample, "next_pid");
        u64 prev_state = perf_sample__intval(sample, "prev_state");
 
+       /* perf.data is untrusted input — CPU may be absent or corrupted */
        if (sample->cpu >= MAX_CPUS) {
-               pr_debug("Out-of-bounds cpu %u\n", sample->cpu);
+               pr_debug("at offset %#" PRIx64 ": out-of-bounds cpu %u\n",
+                        sample->file_offset, sample->cpu);
                return -1;
        }
        sched_switch(tchart, sample->cpu, sample->time, prev_pid, next_pid,
@@ -676,6 +684,7 @@ process_sample_power_start(struct timechart *tchart __maybe_unused,
        u64 cpu_id = perf_sample__intval(sample, "cpu_id");
        u64 value  = perf_sample__intval(sample, "value");
 
+       /* perf.data is untrusted input — cpu_id may be corrupted */
        if (cpu_id >= MAX_CPUS) {
                pr_debug("Out-of-bounds cpu_id %llu\n", (unsigned long long)cpu_id);
                return -1;
@@ -689,6 +698,7 @@ process_sample_power_end(struct timechart *tchart,
                         struct perf_sample *sample,
                         const char *backtrace __maybe_unused)
 {
+       /* perf.data is untrusted input — CPU may be absent or corrupted */
        if (sample->cpu >= MAX_CPUS) {
                pr_debug("Out-of-bounds cpu %u\n", sample->cpu);
                return -1;
@@ -705,6 +715,7 @@ process_sample_power_frequency(struct timechart *tchart,
        u64 cpu_id = perf_sample__intval(sample, "cpu_id");
        u64 value  = perf_sample__intval(sample, "value");
 
+       /* perf.data is untrusted input — cpu_id may be corrupted */
        if (cpu_id >= MAX_CPUS) {
                pr_debug("Out-of-bounds cpu_id %llu\n", (unsigned long long)cpu_id);
                return -1;