Re: [GIT PULL] Block fixes for 6.3-rc3

From: Linus Torvalds <torvalds@linux-foundation.org>
To: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>,
	 "HeungJun, Kim" <riverful.kim@samsung.com>,
	Sylwester Nawrocki <s.nawrocki@samsung.com>,
	 Kyungmin Park <kyungmin.park@samsung.com>,
	Mauro Carvalho Chehab <mchehab@redhat.com>
Cc: Kees Cook <keescook@chromium.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	 Jens Axboe <axboe@kernel.dk>,
	Nathan Chancellor <nathan@kernel.org>,
	 "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	clang-built-linux <llvm@lists.linux.dev>,
	 linux-hardening@vger.kernel.org
Subject: Re: [GIT PULL] Block fixes for 6.3-rc3
Date: Sat, 18 Mar 2023 11:20:22 -0700	[thread overview]
Message-ID: <CAHk-=wiYUWaa676WN5hoyarKeKFDq3nfPg0haRRXeirtHyMg=A@mail.gmail.com> (raw)
In-Reply-To: <CAHk-=wgTSdKYbmB1JYM5vmHMcD9J9UZr0mn7BOYM_LudrP+Xvw@mail.gmail.com>

On Fri, Mar 17, 2023 at 1:51 PM Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> I do think that on the kernel side, the fix is to just change
>
>         } while (type++ != SIZE_DEFAULT_FFMT);
>
> to
>
>         } while (++type != SIZE_DEFAULT_FFMT);

Ok, I ended up deciding to just commit that minimal change, even
though it might have been better to just make it a normal for-loop
(and use M5MOLS_RESTYPE_MAX instead as the end condition).

So maybe it would be more legible (and less likely to have had that
off-by-one) if the loop had been

        for (type = 0; type < M5MOLS_RESTYPE_MAX; type++)

instead. But I'll leave that decision to the driver authors (now cc'd).

For people brought in late, this is now commit efbcbb12ee99 ("media:
m5mols: fix off-by-one loop termination error") with link to the
discussion here

    https://lore.kernel.org/linux-block/CAHk-=wgTSdKYbmB1JYM5vmHMcD9J9UZr0mn7BOYM_LudrP+Xvw@mail.gmail.com/

so you can see the history of it (me having initially blamed UBSAN,
but the problem can be triggered at least in theory without it).

                  Linus