The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From a9d10ca4986571bffc19778742d508cc8dd13e02 Mon Sep 17 00:00:00 2001

From: Masami Hiramatsu mhiramat@kernel.org Date: Wed, 28 Jul 2021 07:55:43 +0900 Subject: [PATCH] tracing: Reject string operand in the histogram expression

Since the string type can not be the target of the addition / subtraction operation, it must be rejected. Without this fix, the string type silently converted to digits.

Link: https://lkml.kernel.org/r/162742654278.290973.1523000673366456634.stgit@devn...

Cc: stable@vger.kernel.org Fixes: 100719dcef447 ("tracing: Add simple expression support to hist triggers") Signed-off-by: Masami Hiramatsu mhiramat@kernel.org Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 362db9b81b8d..949ef09dc537 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -65,7 +65,8 @@ C(INVALID_SORT_MODIFIER,"Invalid sort modifier"), \ C(EMPTY_SORT_FIELD, "Empty sort field"), \ C(TOO_MANY_SORT_FIELDS, "Too many sort fields (Max = 2)"), \ - C(INVALID_SORT_FIELD, "Sort field must be a key or a val"), + C(INVALID_SORT_FIELD, "Sort field must be a key or a val"), \ + C(INVALID_STR_OPERAND, "String type can not be an operand in expression"),

#undef C #define C(a, b) HIST_ERR_##a @@ -2156,6 +2157,13 @@ static struct hist_field *parse_unary(struct hist_trigger_data *hist_data, ret = PTR_ERR(operand1); goto free; } + if (operand1->flags & HIST_FIELD_FL_STRING) { + /* String type can not be the operand of unary operator. */ + hist_err(file->tr, HIST_ERR_INVALID_STR_OPERAND, errpos(str)); + destroy_hist_field(operand1, 0); + ret = -EINVAL; + goto free; + }

expr->flags |= operand1->flags & (HIST_FIELD_FL_TIMESTAMP | HIST_FIELD_FL_TIMESTAMP_USECS); @@ -2257,6 +2265,11 @@ static struct hist_field *parse_expr(struct hist_trigger_data *hist_data, operand1 = NULL; goto free; } + if (operand1->flags & HIST_FIELD_FL_STRING) { + hist_err(file->tr, HIST_ERR_INVALID_STR_OPERAND, errpos(operand1_str)); + ret = -EINVAL; + goto free; + }

/* rest of string could be another expression e.g. b+c in a+b+c */ operand_flags = 0; @@ -2266,6 +2279,11 @@ static struct hist_field *parse_expr(struct hist_trigger_data *hist_data, operand2 = NULL; goto free; } + if (operand2->flags & HIST_FIELD_FL_STRING) { + hist_err(file->tr, HIST_ERR_INVALID_STR_OPERAND, errpos(str)); + ret = -EINVAL; + goto free; + }

ret = check_expr_operands(file->tr, operand1, operand2); if (ret)