From: Linus Torvalds <torvalds@linux-foundation.org>
To: Miguel Ojeda <miguel.ojeda.sandonis@gmail.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: Fri, 17 Mar 2023 13:51:17 -0700 [thread overview]
Message-ID: <CAHk-=wgTSdKYbmB1JYM5vmHMcD9J9UZr0mn7BOYM_LudrP+Xvw@mail.gmail.com> (raw)
In-Reply-To: <CANiq72m46OzQPtZbS_VaQGgGknFV-hKvhBw8sVZx9ef=AzupTQ@mail.gmail.com>
On Fri, Mar 17, 2023 at 1:42 PM Miguel Ojeda
<miguel.ojeda.sandonis@gmail.com> wrote:
>
> It is comparing against just the `.code` in the `m5mols_default_ffmt`
> table, i.e. the `MEDIA_BUS_FMT_VYUY8_2X8` (8199 = 0x2007) and
> `MEDIA_BUS_FMT_JPEG_1X8` (16385 = 0x4001), see
Yeah, I see what it's doing.
But:
> If the condition had `++type` instead, it would not be a problem,
> because the loop stops before we go into the out of bounds access thus
> no UB.
Yeah, but clang really should have generated a proper third iteration,
which calls that "out of bounds" case, and then returns, instead fo
falling off the end.
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);
but I would *really* like clang to be fixed to not silently generate
code that does insane things and would be basically impossible to
debug if it ever triggers.
We would have spent a *lot* of time wondering how the heck we Oopsed
in m5mols_get_frame_desc().
Linus
next prev parent reply other threads:[~2023-03-17 20:51 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-17 17:16 [GIT PULL] Block fixes for 6.3-rc3 Jens Axboe
2023-03-17 18:35 ` Linus Torvalds
2023-03-17 18:50 ` Linus Torvalds
2023-03-17 20:31 ` Miguel Ojeda
2023-03-17 20:45 ` Linus Torvalds
2023-03-17 18:59 ` Nick Desaulniers
2023-03-17 19:50 ` Kees Cook
2023-03-17 20:30 ` Linus Torvalds
2023-03-17 20:42 ` Miguel Ojeda
2023-03-17 20:51 ` Linus Torvalds [this message]
2023-03-17 21:00 ` Linus Torvalds
2023-03-17 22:56 ` Nick Desaulniers
2023-03-17 21:01 ` Miguel Ojeda
2023-03-18 18:20 ` Linus Torvalds
2023-03-19 0:48 ` Mauro Carvalho Chehab
2023-03-17 20:35 ` Nick Desaulniers
2023-03-17 19:44 ` Jens Axboe
2023-03-17 18:52 ` pr-tracker-bot
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