From: Tom Zanussi <zanussi@kernel.org> mainline inclusion from mainline-v7.1-rc1 commit 9236eebd138aa2753f7b30fc6cee7b7202841247 category: bugfix bugzilla: https://atomgit.com/openeuler/kernel/issues/9232 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- The syntax for fully-qualified variable references in histograms is subsys.event.$var, which is parsed correctly, but not displayed correctly when printing a histogram spec. The current code puts the $ reference at the beginning of the fully-qualified variable name i.e. $subsys.event.var, which is incorrect. Before: trigger info: hist:keys=next_comm:vals=hitcount:wakeup_lat=common_timestamp.usecs-$sched.sched_wakeup.ts0: ... After: trigger info: hist:keys=next_comm:vals=hitcount:wakeup_lat=common_timestamp.usecs-sched.sched_wakeup.$ts0: ... Link: https://patch.msgid.link/5dee9a86d062a4dd68c2214f3d90ac93811e1951.1776112478... Signed-off-by: Tom Zanussi <zanussi@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Conflicts: kernel/trace/trace_events_hist.c [Context conflict] Signed-off-by: Tengda Wu <wutengda@huaweicloud.com> --- kernel/trace/trace_events_hist.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index b6c4e2f26e3f..c2ad3498796d 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -1349,9 +1349,12 @@ static const char *hist_field_name(struct hist_field *field, field->flags & HIST_FIELD_FL_VAR_REF) { if (field->system) { static char full_name[MAX_FILTER_STR_VAL]; + static char *fmt; int len; - len = snprintf(full_name, sizeof(full_name), "%s.%s.%s", + fmt = field->flags & HIST_FIELD_FL_VAR_REF ? "%s.%s.$%s" : "%s.%s.%s"; + + len = snprintf(full_name, sizeof(full_name), fmt, field->system, field->event_name, field->name); if (len >= sizeof(full_name)) @@ -1733,9 +1736,10 @@ static const char *get_hist_field_flags(struct hist_field *hist_field) static void expr_field_str(struct hist_field *field, char *expr) { - if (field->flags & HIST_FIELD_FL_VAR_REF) - strcat(expr, "$"); - else if (field->flags & HIST_FIELD_FL_CONST) { + if (field->flags & HIST_FIELD_FL_VAR_REF) { + if (!field->system) + strcat(expr, "$"); + } else if (field->flags & HIST_FIELD_FL_CONST) { char str[HIST_CONST_DIGITS_MAX]; snprintf(str, HIST_CONST_DIGITS_MAX, "%llu", field->constant); @@ -5953,7 +5957,8 @@ static void hist_field_print(struct seq_file *m, struct hist_field *hist_field) else if (field_name) { if (hist_field->flags & HIST_FIELD_FL_VAR_REF || hist_field->flags & HIST_FIELD_FL_ALIAS) - seq_putc(m, '$'); + if (!hist_field->system) + seq_putc(m, '$'); seq_printf(m, "%s", field_name); } else if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP) seq_puts(m, "common_timestamp"); -- 2.34.1