expr_str() already has failure cases for invalid recursion depth and allocation failure, but it currently reports them as a bare NULL. Teach it to return ERR_PTR()-encoded errors and update parse_unary() and parse_expr() to propagate those errors.
This keeps the error conversion separate from the string-building change so the follow-up seq_buf patch can stay focused on the overflow fix itself. Signed-off-by: Pengpeng Hou <[email protected]> --- Changes since v2: - split the ERR_PTR() conversion out as its own patch as requested by Steven Rostedt kernel/trace/trace_events_hist.c | 33 +++++++++++++++++----- 1 file changed, 26 insertions(+), 7 deletions(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 73ea180cad55..954e0beb7f0a 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -1764,13 +1764,14 @@ static void expr_field_str(struct hist_field *field, char *expr) static char *expr_str(struct hist_field *field, unsigned int level) { char *expr; + int ret = -EINVAL; if (level > 1) - return NULL; + return ERR_PTR(-EINVAL); expr = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL); if (!expr) - return NULL; + return ERR_PTR(-ENOMEM); if (!field->operands[0]) { expr_field_str(field, expr); @@ -1782,9 +1783,9 @@ static char *expr_str(struct hist_field *field, unsigned int level) strcat(expr, "-("); subexpr = expr_str(field->operands[0], ++level); - if (!subexpr) { - kfree(expr); - return NULL; + if (IS_ERR(subexpr)) { + ret = PTR_ERR(subexpr); + goto free; } strcat(expr, subexpr); strcat(expr, ")"); @@ -1810,13 +1811,16 @@ static char *expr_str(struct hist_field *field, unsigned int level) strcat(expr, "*"); break; default: - kfree(expr); - return NULL; + goto free; } expr_field_str(field->operands[1], expr); return expr; + +free: + kfree(expr); + return ERR_PTR(ret); } /* @@ -2630,6 +2634,11 @@ static struct hist_field *parse_unary(struct hist_trigger_data *hist_data, expr->is_signed = operand1->is_signed; expr->operator = FIELD_OP_UNARY_MINUS; expr->name = expr_str(expr, 0); + if (IS_ERR(expr->name)) { + ret = PTR_ERR(expr->name); + expr->name = NULL; + goto free; + } expr->type = kstrdup_const(operand1->type, GFP_KERNEL); if (!expr->type) { ret = -ENOMEM; @@ -2842,6 +2851,11 @@ static struct hist_field *parse_expr(struct hist_trigger_data *hist_data, destroy_hist_field(operand1, 0); expr->name = expr_str(expr, 0); + if (IS_ERR(expr->name)) { + ret = PTR_ERR(expr->name); + expr->name = NULL; + goto free_expr; + } } else { /* The operand sizes should be the same, so just pick one */ expr->size = operand1->size; @@ -2855,6 +2869,11 @@ static struct hist_field *parse_expr(struct hist_trigger_data *hist_data, } expr->name = expr_str(expr, 0); + if (IS_ERR(expr->name)) { + ret = PTR_ERR(expr->name); + expr->name = NULL; + goto free_expr; + } } return expr; -- 2.50.1 (Apple Git-155)
