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Date: Tue, 19 Mar 2024 17:27:44 -0400
From: Steven Rostedt <rostedt@goodmis.org>
To: Nathan Chancellor <nathan@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>, 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>, llvm@lists.linux.dev
Subject: Re: [GIT PULL v2] tracing: Updates for v6.9
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On Tue, 19 Mar 2024 14:03:29 -0700
Nathan Chancellor <nathan@kernel.org> wrote:

> > #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.  
> 
> For what it's worth, I applied that change and built ARCH=x86_64
> defconfig with LLVM 18.1.1 from [1] but it does not appear to help the
> instances of -Wstring-compare; in fact, it adds some additional warnings
> that I have not seen before. I have attached the full build log.

That was just me posting what I was going to do before testing it. You want
the actual patch that Linus pulled in.

  https://lore.kernel.org/all/20240319133959.349f5082@gandalf.local.home/

-- Steve