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Date: Tue, 19 Mar 2024 13:13:33 -0400
From: Steven Rostedt <rostedt@goodmis.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: LKML <linux-kernel@vger.kernel.org>, Masami Hiramatsu
 <mhiramat@kernel.org>, Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
 Alison Schofield <alison.schofield@intel.com>, Beau Belgrave
 <beaub@linux.microsoft.com>, Huang Yiwei <quic_hyiwei@quicinc.com>, John
 Garry <john.g.garry@oracle.com>, Randy Dunlap <rdunlap@infradead.org>,
 Thorsten Blum <thorsten.blum@toblux.com>, Vincent Donnefort
 <vdonnefort@google.com>, linke li <lilinke99@qq.com>
Subject: Re: [GIT PULL v2] tracing: Updates for v6.9
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On Tue, 19 Mar 2024 13:06:53 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> This is in the fast path (where the trace event happens), but I can make it
> always do strcmp(), even though it will slow down what is being recorded,
> as I plan on removing the parameter in the next merge window anyway.

I'll change it to this:

#define __assign_str(dst, src)						\
	do {								\
		char *__str__ = __get_str(dst);				\
		int __len__ = __get_dynamic_array_len(dst) - 1;		\
		WARN_ON_ONCE(!src != !__data_offsets.dst##_ptr_);	\
		WARN_ON_ONCE(src && strcmp((src), __data_offsets.dst##_ptr_)); \
		memcpy(__str__, __data_offsets.dst##_ptr_ ? :		\
		       EVENT_NULL_STR, __len__);			\
		__str__[__len__] = '\0';				\
	} while (0)

The first WARN_ON() will report the bug if src is not NULL and the pointer
is even though the strcmp() will likely crash in that case. But that's a
bug if that happens anyway.

-- Steve