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Date:   Thu, 1 Dec 2022 08:53:02 -0800
From:   Kees Cook <keescook@chromium.org>
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     "Masami Hiramatsu (Google)" <mhiramat@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Borislav Petkov <bp@alien8.de>,
        Alexei Starovoitov <alexei.starovoitov@gmail.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        KP Singh <kpsingh@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Florent Revest <revest@chromium.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Christoph Hellwig <hch@infradead.org>,
        Chris Mason <clm@meta.com>
Subject: Re: [RFC PATCH] panic: Add new taint flag for fault injection
Message-ID: <202212010852.6D4B542@keescook>
References: <20221201234121.8925fdf83115747ac4ac116a@kernel.org>
 <166991263326.311919.16890937584677289681.stgit@devnote3>
 <202212010838.B0B109DA@keescook>
 <20221201114848.13a87aca@gandalf.local.home>
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On Thu, Dec 01, 2022 at 11:48:48AM -0500, Steven Rostedt wrote:
> On Thu, 1 Dec 2022 08:39:28 -0800
> Kees Cook <keescook@chromium.org> wrote:
> 
> > On Fri, Dec 02, 2022 at 01:37:13AM +0900, Masami Hiramatsu (Google) wrote:
> > > From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> > > 
> > > Since the function error injection framework in the fault injection
> > > subsystem can change the function code flow forcibly, it may cause
> > > unexpected behavior (but that is the purpose of this feature).
> > > To identify this in the kernel oops message, add a new taint flag
> > > for this, and set it if it is (and similar things in BPF) used.  
> > 
> > Why is hooking through BPF considered to be "fault injection" here?
> > 
> 
> Have you not been reading this thread?

I skimmed it -- trying to catch up from turkey week. If this was already
covered, then please ignore me. It just wasn't obvious from the commit
log why it was included.

-- 
Kees Cook