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From: Guenter Roeck <linux@roeck-us.net>
To: Kees Cook <kees@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Jaegeuk Kim <jaegeuk@kernel.org>, Chao Yu <chao@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Vlastimil Babka <vbabka@suse.cz>,
	Peter Zijlstra <peterz@infradead.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Kees Cook <keescook@chromium.org>
Subject: Re: Linux 6.2-rc1
Date: Mon, 26 Dec 2022 21:52:12 -0800	[thread overview]
Message-ID: <20221227055212.GA2711289@roeck-us.net> (raw)
In-Reply-To: <D8BDBF66-E44C-45D4-9758-BAAA4F0C1998@kernel.org>

On Mon, Dec 26, 2022 at 05:32:28PM -0800, Kees Cook wrote:
> On December 26, 2022 4:29:41 PM PST, Guenter Roeck <linux@roeck-us.net> wrote:
> >On Mon, Dec 26, 2022 at 01:03:59PM -0800, Kees Cook wrote:
> >> On December 26, 2022 12:56:29 PM PST, Linus Torvalds <torvalds@linux-foundation.org> wrote:
> >> >On Mon, Dec 26, 2022 at 11:52 AM Guenter Roeck <linux@roeck-us.net> wrote:
> >> >>
> >> >> fs/f2fs/inline.c: In function 'f2fs_move_inline_dirents':
> >> >> include/linux/fortify-string.h:59:33: error: '__builtin_memset' pointer overflow between offset [28, 898293814] and size [-898293787, -1] [-Werror=array-bounds]
> >> >> fs/f2fs/inline.c:430:9: note: in expansion of macro 'memset'
> >> >>   430 |         memset(dst.bitmap + src.nr_bitmap, 0, dst.nr_bitmap - src.nr_bitmap);
> >> >>       |         ^~~~~~
> >> >
> >> >Well, that's unfortunate.
> >> 
> >> I'll look into this.
> >> 
> >
> >I did some more testing. The problem is seen with gcc 11.3.0, but not with
> >gcc 12.2.0 nor with gcc 10.3.0.
> 
> That's what I'd expect: 10 didn't have variable range tracking wired up to -Warray-bounds, 11 does, and we disable -Warray-bounds on 12 because of 3 separate 12-only GCC bugs.
> 
> > gcc bug ? Should I switch to gcc 12.2.0 for
> >powerpc when build testing the latest kernel ?
> 
> Sure? But that'll just hide it. I suspect GCC has found a way for dst.nr_bitmap to be compile-time 27, so the size is always negative.
> 
dst.nr_bitmap is initialized with SIZE_OF_DENTRY_BITMAP,
which is defined as:

#define NR_DENTRY_IN_BLOCK      214     /* the number of dentry in a block */
#define SIZE_OF_DIR_ENTRY       11      /* by byte */
#define SIZE_OF_DENTRY_BITMAP   ((NR_DENTRY_IN_BLOCK + BITS_PER_BYTE - 1) / \
                                        BITS_PER_BYTE)

((214 + 8 - 1) / 8 = 27, so dst.nr_bitmap is indeed compile-time 27.

Not sure how would know that src.nr_bitmap can be > 27, though.
Am I missing something ?

Thanks,
Guenter

  reply	other threads:[~2022-12-27  5:52 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-25 22:07 Linux 6.2-rc1 Linus Torvalds
2022-12-26 19:52 ` Guenter Roeck
2022-12-26 20:56   ` Linus Torvalds
2022-12-26 21:03     ` Kees Cook
2022-12-26 22:10       ` Guenter Roeck
2022-12-27  0:29       ` Guenter Roeck
2022-12-27  1:32         ` Kees Cook
2022-12-27  5:52           ` Guenter Roeck [this message]
2022-12-28  3:40             ` Kees Cook
2022-12-28 14:44               ` Guenter Roeck
2023-01-07  0:06                 ` Jaegeuk Kim
2022-12-26 22:41     ` Vlastimil Babka
2022-12-26 21:10   ` Max Filippov
2022-12-26 22:08     ` Guenter Roeck
2022-12-27  8:29 ` Build regressions/improvements in v6.2-rc1 Geert Uytterhoeven
2022-12-27  8:35   ` Geert Uytterhoeven
2023-01-01  1:33     ` Rob Landley
2023-01-01 12:24       ` Geert Uytterhoeven
2023-01-04  6:32         ` Michael Ellerman
2023-01-06 15:10     ` John Paul Adrian Glaubitz
2023-01-06 15:17       ` Geert Uytterhoeven
2023-01-06 15:18         ` Geert Uytterhoeven
2023-01-17 16:42         ` Calculating array sizes in C - was: " John Paul Adrian Glaubitz
2023-01-17 17:01           ` Geert Uytterhoeven
2023-01-17 17:06             ` John Paul Adrian Glaubitz
2023-01-17 20:05               ` Geert Uytterhoeven
2023-01-17 20:37                 ` John Paul Adrian Glaubitz
2023-01-19 22:11                   ` Michael.Karcher
2023-01-20  3:31                     ` Rob Landley
2023-01-20 10:53                       ` Segher Boessenkool
2023-01-20 18:29                         ` Michael.Karcher
2023-01-20  8:49                     ` John Paul Adrian Glaubitz
2023-01-20 19:29                       ` Michael Karcher
2023-01-21 21:26                         ` John Paul Adrian Glaubitz
2023-01-06 15:39     ` Alex Deucher
2023-01-04 19:01 ` Linux 6.2-rc1 Pali Rohár
2023-01-04 19:25   ` Linus Torvalds
2023-01-04 20:56     ` Pali Rohár
2023-01-04 21:27       ` Pali Rohár
2023-01-04 21:32       ` Linus Torvalds
2023-01-04 21:43         ` Jens Axboe
2023-01-05 11:25           ` Greg Kroah-Hartman
2023-01-05 15:26             ` Jens Axboe
2023-01-05 17:42           ` Pali Rohár
2023-01-05 17:45             ` Jens Axboe
2023-01-05 19:06               ` Linus Torvalds
2023-01-05 19:22                 ` Pali Rohár
2023-01-05 19:40                 ` Jens Axboe
2023-01-05 20:03                   ` Linus Torvalds
2023-01-05 20:33                     ` Jens Axboe
2023-01-06 16:58                       ` Pali Rohár
2023-01-06 17:04                         ` Jens Axboe
2023-01-28 19:34                           ` pktcdvd Pali Rohár
2023-01-28 19:43                             ` pktcdvd Linus Torvalds
2023-01-29 21:53                               ` pktcdvd Jens Axboe
2023-01-29 21:55                             ` pktcdvd Jens Axboe
2023-01-29 22:21                               ` pktcdvd Pali Rohár
2023-01-29 22:34                                 ` pktcdvd Jens Axboe

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