From: Arnd Bergmann <arnd@arndb.de>
To: Joe Perches <joe@perches.com>
Cc: kasan-dev <kasan-dev@googlegroups.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Networking <netdev@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-media@vger.kernel.org,
linux-wireless <linux-wireless@vger.kernel.org>,
kernel-build-reports@lists.linaro.org,
"David S . Miller" <davem@davemloft.net>
Subject: Re: [PATCH 24/26] ocfs2: reduce stack size with KASAN
Date: Thu, 2 Mar 2017 23:22:26 +0100 [thread overview]
Message-ID: <CAK8P3a1gW9UqMKD2ijzxMH4rv1zAji0GUoz+bLY_oi0yvLU1cw@mail.gmail.com> (raw)
In-Reply-To: <1488476770.2179.6.camel@perches.com>
On Thu, Mar 2, 2017 at 6:46 PM, Joe Perches <joe@perches.com> wrote:
> On Thu, 2017-03-02 at 17:38 +0100, Arnd Bergmann wrote:
>> The internal logging infrastructure in ocfs2 causes special warning code to be
>> used with KASAN, which produces rather large stack frames:
>
>> fs/ocfs2/super.c: In function 'ocfs2_fill_super':
>> fs/ocfs2/super.c:1219:1: error: the frame size of 3264 bytes is larger than 3072 bytes [-Werror=frame-larger-than=]
>
> At least by default it doesn't seem to.
>
> gcc 6.2 allyesconfig, CONFIG_KASAN=y
> with either CONFIG_KASAN_INLINE or CONFIG_KASAN_OUTLINE
>
> gcc doesn't emit a stack warning
The warning is disabled until patch 26/26. which picks the 3072 default.
The 3264 number was with gcc-7, which is worse than gcc-6 since it enables
an extra check.
>> By simply passing the mask by value instead of reference, we can avoid the
>> problem completely.
>
> Any idea why that's so?
With KASAN, every time we inline the function, the compiler has to allocate
space for another copy of the variable plus a redzone to detect whether
passing it by reference into another function causes an overflow at runtime.
>> On 64-bit architectures, this is also more efficient,
>
> Efficient true, but the same overall stack no?
Here is what I see with CONFIG_FRAME_WARN=300 and x86_64-linux-gcc-6.3.1:
before:
fs/ocfs2/super.c: In function 'ocfs2_parse_options.isra.3':
fs/ocfs2/super.c:1508:1: error: the frame size of 352 bytes is larger
than 300 bytes [-Werror=frame-larger-than=]
fs/ocfs2/super.c: In function 'ocfs2_enable_quotas':
fs/ocfs2/super.c:974:1: error: the frame size of 344 bytes is larger
than 300 bytes [-Werror=frame-larger-than=]
fs/ocfs2/super.c: In function 'ocfs2_fill_super':
fs/ocfs2/super.c:1219:1: error: the frame size of 552 bytes is larger
than 300 bytes [-Werror=frame-larger-than=]
after:
fs/ocfs2/super.c: In function 'ocfs2_fill_super':
fs/ocfs2/super.c:1219:1: error: the frame size of 472 bytes is larger
than 300 bytes [-Werror=frame-larger-than=]
and with gcc-7.0.1 (including -fsanitize-address-use-after-scope), before:
fs/ocfs2/super.c: In function 'ocfs2_check_volume':
fs/ocfs2/super.c:2512:1: error: the frame size of 768 bytes is larger
than 300 bytes [-Werror=frame-larger-than=]
fs/ocfs2/super.c: In function 'ocfs2_statfs':
fs/ocfs2/super.c:1717:1: error: the frame size of 320 bytes is larger
than 300 bytes [-Werror=frame-larger-than=]
fs/ocfs2/super.c: In function 'ocfs2_parse_options.isra.3':
fs/ocfs2/super.c:1508:1: error: the frame size of 464 bytes is larger
than 300 bytes [-Werror=frame-larger-than=]
fs/ocfs2/super.c: In function 'ocfs2_enable_quotas':
fs/ocfs2/super.c:974:1: error: the frame size of 320 bytes is larger
than 300 bytes [-Werror=frame-larger-than=]
fs/ocfs2/super.c: In function 'ocfs2_remount':
fs/ocfs2/super.c:752:1: error: the frame size of 568 bytes is larger
than 300 bytes [-Werror=frame-larger-than=]
fs/ocfs2/super.c: In function 'ocfs2_initialize_super.isra.8':
fs/ocfs2/super.c:2339:1: error: the frame size of 1712 bytes is larger
than 300 bytes [-Werror=frame-larger-than=]
fs/ocfs2/super.c: In function 'ocfs2_fill_super':
fs/ocfs2/super.c:1219:1: error: the frame size of 3264 bytes is larger
than 300 bytes [-Werror=frame-larger-than=]
after:
fs/ocfs2/super.c: In function 'ocfs2_fill_super':
fs/ocfs2/super.c:1219:1: error: the frame size of 704 bytes is larger
than 300 bytes [-Werror=frame-larger-than=]
Arnd
next prev parent reply other threads:[~2017-03-02 22:52 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-02 16:38 [PATCH 00/26] bring back stack frame warning with KASAN Arnd Bergmann
2017-03-02 16:38 ` [PATCH 01/26] compiler: introduce noinline_for_kasan annotation Arnd Bergmann
2017-03-03 13:50 ` Andrey Ryabinin
2017-03-03 13:55 ` Alexander Potapenko
2017-03-03 14:30 ` Arnd Bergmann
2017-03-03 14:33 ` Alexander Potapenko
2017-03-03 14:51 ` Arnd Bergmann
2017-03-03 16:34 ` David Laight
2017-03-02 16:38 ` [PATCH 02/26] rewrite READ_ONCE/WRITE_ONCE Arnd Bergmann
2017-03-02 16:51 ` Christian Borntraeger
2017-03-02 17:55 ` Arnd Bergmann
2017-03-02 19:00 ` Christian Borntraeger
2017-03-02 21:45 ` Arnd Bergmann
2017-03-03 8:26 ` Christian Borntraeger
2017-03-03 9:54 ` Arnd Bergmann
2017-03-03 14:49 ` Peter Zijlstra
2017-03-03 14:57 ` Peter Zijlstra
2017-03-02 16:38 ` [PATCH 03/26] typecheck.h: avoid local variables in typecheck() macro Arnd Bergmann
2017-03-02 16:38 ` [PATCH 04/26] tty: kbd: reduce stack size with KASAN Arnd Bergmann
2017-03-02 16:38 ` [PATCH 05/26] netlink: mark nla_put_{u8,u16,u32} noinline_for_kasan Arnd Bergmann
2017-03-02 16:38 ` [PATCH 06/26] rocker: mark rocker_tlv_put_* functions as noinline_for_kasan Arnd Bergmann
2017-03-02 16:38 ` [PATCH 07/26] brcmsmac: reduce stack size with KASAN Arnd Bergmann
2017-03-06 9:16 ` Arend Van Spriel
2017-03-06 10:38 ` Arnd Bergmann
2017-03-06 11:02 ` Arend Van Spriel
2017-03-06 11:16 ` Arnd Bergmann
2017-03-06 11:18 ` Arnd Bergmann
2017-03-02 16:38 ` [PATCH 08/26] brcmsmac: make some local variables 'static const' to reduce stack size Arnd Bergmann
2017-03-06 9:30 ` Arend Van Spriel
2017-03-06 16:19 ` Kalle Valo
2017-03-06 21:34 ` Arnd Bergmann
2017-03-07 9:44 ` Kalle Valo
2017-03-07 9:55 ` Arend Van Spriel
2017-03-02 16:38 ` [PATCH 09/26] brcmsmac: split up wlc_phy_workarounds_nphy Arnd Bergmann
2017-03-06 9:31 ` Arend Van Spriel
2017-03-02 16:38 ` [PATCH 10/26] brcmsmac: reindent split functions Arnd Bergmann
2017-03-06 9:33 ` Arend Van Spriel
2017-03-06 16:24 ` Kalle Valo
2017-03-02 16:38 ` [PATCH 11/26] rtlwifi: reduce stack usage for KASAN Arnd Bergmann
2017-03-02 16:38 ` [PATCH 12/26] wl3501_cs: reduce stack size " Arnd Bergmann
2017-03-02 16:38 ` [PATCH 13/26] rtl8180: " Arnd Bergmann
2017-03-02 16:38 ` [PATCH 14/26] [media] dvb-frontends: reduce stack size in i2c access Arnd Bergmann
2017-03-02 16:38 ` [PATCH 15/26] [media] tuners: i2c: reduce stack usage for tuner_i2c_xfer_* Arnd Bergmann
2017-03-02 16:38 ` [PATCH 16/26] [media] i2c: adv7604: mark register access as noinline_for_kasan Arnd Bergmann
2017-03-02 16:38 ` [PATCH 17/26] [media] i2c: ks0127: reduce stack frame size for KASAN Arnd Bergmann
2017-03-02 16:38 ` [PATCH 18/26] [media] i2c: cx25840: avoid stack overflow with KASAN Arnd Bergmann
2017-03-02 16:38 ` [PATCH 19/26] [media] r820t: mark register functions as noinline_for_kasan Arnd Bergmann
2017-03-02 16:38 ` [PATCH 20/26] [media] em28xx: split up em28xx_dvb_init to reduce stack size Arnd Bergmann
2017-03-02 16:38 ` [PATCH 21/26] drm/bridge: ps8622: reduce stack size for KASAN Arnd Bergmann
2017-03-02 16:38 ` [PATCH 22/26] drm/i915/gvt: don't overflow the kernel stack with KASAN Arnd Bergmann
2017-03-02 16:38 ` [PATCH 23/26] mtd: cfi: reduce stack size " Arnd Bergmann
2017-03-02 16:38 ` [PATCH 24/26] ocfs2: " Arnd Bergmann
2017-03-02 17:46 ` Joe Perches
2017-03-02 22:22 ` Arnd Bergmann [this message]
2017-03-02 22:40 ` Joe Perches
2017-03-02 22:59 ` Arnd Bergmann
2017-03-02 23:58 ` Joe Perches
2017-03-02 16:38 ` [PATCH 25/26] isdn: eicon: mark divascapi incompatible with kasan Arnd Bergmann
2017-03-03 14:20 ` Andrey Ryabinin
2017-03-03 14:54 ` Arnd Bergmann
2017-03-03 15:22 ` Andrey Ryabinin
2017-03-03 15:37 ` Arnd Bergmann
2017-03-02 16:38 ` [PATCH 26/26] kasan: rework Kconfig settings Arnd Bergmann
2017-03-03 14:51 ` Andrey Ryabinin
2017-03-03 15:03 ` Arnd Bergmann
2017-03-03 12:25 ` [PATCH 00/26] bring back stack frame warning with KASAN Alexander Potapenko
2017-03-03 12:54 ` Arnd Bergmann
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