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From: Francis Laniel <flaniel@linux.microsoft.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org, Masami Hiramatsu <mhiramat@kernel.org>
Subject: Re: [PATCH 5.10.y] tracing/kprobes: Return EADDRNOTAVAIL when func matches several symbols
Date: Mon, 27 Nov 2023 12:21:50 +0100
Message-ID: <12330827.O9o76ZdvQC@pwmachine>
In-Reply-To: <2023112415-salutary-visible-1485@gregkh>
References: <2023102135-shuffle-blank-783e@gregkh> <20231124130935.168451-1-flaniel@linux.microsoft.com> <2023112415-salutary-visible-1485@gregkh>
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Hi!


Le vendredi 24 novembre 2023, 17:16:43 CET Greg KH a =E9crit :
> On Fri, Nov 24, 2023 at 02:09:35PM +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.
> >=20
> > 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.
> >=20
> > Link:
> > https://lore.kernel.org/all/20231020104250.9537-2-flaniel@linux.microso=
ft
> > .com/
> >=20
> > 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@ke=
rn
> > el.org/ Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> > Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> > (cherry picked from commit b022f0c7e404887a7c5229788fc99eff9f9a80d5)
> > ---
> >=20
> >  kernel/trace/trace_kprobe.c | 74 +++++++++++++++++++++++++++++++++++++
> >  kernel/trace/trace_probe.h  |  1 +
> >  2 files changed, 75 insertions(+)
>=20
> We also need a version for 5.15.y before we can take this, you do not
> want to upgrade and have a regression.

I sent the corresponding 5.15.y patch some times ago here:
https://lore.kernel.org/stable/20231023122217.302483-2-flaniel@linux.micros=
oft.com/

If this is easier for you, I can resend it without problems.

> thanks,
>=20
> greg k-h


Best regards.