tracing: Propagate is_signed to expression

During expression parsing, a new expression field is created which
should inherit the properties of the operands, such as size and
is_signed.

is_signed propagation was missing, causing spurious errors with signed
operands.  Add it in parse_expr() and parse_unary() to fix the problem.

Link: https://lkml.kernel.org/r/f4dac08742fd7a0920bf80a73c6c44042f5eaa40.1643319703.git.zanussi@kernel.org
Cc: stable@vger.kernel.org
Fixes: 1ed38f5f12c16 ("tracing: Add simple expression support to hist triggers")
Reported-by: Yordan Karadzhov <ykaradzhov@vmware.com>
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=215513
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index b894d68082ea500c4f471c44671ba4c60d67f391..ada87bfb5bb85da4430ff6cb6d3ed295a8a1a084 100644 (file)
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -2503,6 +2503,8 @@ static struct hist_field *parse_unary(struct hist_trigger_data *hist_data,
                (HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS);
        expr->fn = hist_field_unary_minus;
        expr->operands[0] = operand1;
+       expr->size = operand1->size;
+       expr->is_signed = operand1->is_signed;
        expr->operator = FIELD_OP_UNARY_MINUS;
        expr->name = expr_str(expr, 0);
        expr->type = kstrdup_const(operand1->type, GFP_KERNEL);
@@ -2719,6 +2721,7 @@ static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
 
                /* The operand sizes should be the same, so just pick one */
                expr->size = operand1->size;
+               expr->is_signed = operand1->is_signed;
 
                expr->operator = field_op;
                expr->type = kstrdup_const(operand1->type, GFP_KERNEL);