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Date: Fri, 24 Nov 2023 16:17:04 +0000
From: Greg KH <gregkh@linuxfoundation.org>
To: Francis Laniel <flaniel@linux.microsoft.com>
Cc: stable@vger.kernel.org, Masami Hiramatsu <mhiramat@kernel.org>
Subject: Re: [PATCH 4.19.y] tracing/kprobes: Return EADDRNOTAVAIL when func
 matches several symbols
Message-ID: <2023112447-prevent-unbalance-4448@gregkh>
References: <2023102138-riverbed-senator-e356@gregkh>
 <20231124122413.95544-1-flaniel@linux.microsoft.com>
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In-Reply-To: <20231124122413.95544-1-flaniel@linux.microsoft.com>

On Fri, Nov 24, 2023 at 01:24:13PM +0100, Francis Laniel wrote:
> When a kprobe is attached to a function that's name is not unique (is
> static and shares the name with other functions in the kernel), the
> kprobe is attached to the first function it finds. This is a bug as the
> function that it is attaching to is not necessarily the one that the
> user wants to attach to.
> 
> Instead of blindly picking a function to attach to what is ambiguous,
> error with EADDRNOTAVAIL to let the user know that this function is not
> unique, and that the user must use another unique function with an
> address offset to get to the function they want to attach to.
> 
> Link: https://lore.kernel.org/all/20231020104250.9537-2-flaniel@linux.microsoft.com/
> 
> Cc: stable@vger.kernel.org
> Fixes: 413d37d1eb69 ("tracing: Add kprobe-based event tracer")
> Suggested-by: Masami Hiramatsu <mhiramat@kernel.org>
> Signed-off-by: Francis Laniel <flaniel@linux.microsoft.com>
> Link: https://lore.kernel.org/lkml/20230819101105.b0c104ae4494a7d1f2eea742@kernel.org/
> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> (cherry picked from commit b022f0c7e404887a7c5229788fc99eff9f9a80d5)
> ---
>  kernel/trace/trace_kprobe.c | 48 +++++++++++++++++++++++++++++++++++++
>  1 file changed, 48 insertions(+)

Again, we need a version for 5.4.y as well before we can take this
version.

thanks,

greg k-h