From: Joe Perches <joe@perches.com>
To: Arnd Bergmann <arnd@arndb.de>
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, 02 Mar 2017 15:58:17 -0800 [thread overview]
Message-ID: <1488499097.2179.27.camel@perches.com> (raw)
In-Reply-To: <CAK8P3a2ZQR8ukt6Aky7onD2Y=b+Cz+pp+C0+Svb2EyK2474j-g@mail.gmail.com>
On Thu, 2017-03-02 at 23:59 +0100, Arnd Bergmann wrote:
> KASAN decides that passing a pointer to _m into an extern function
> (_mlog_printk) is potentially dangerous, as that function might
> keep a reference to that pointer after it goes out of scope,
> or it might not know the correct length of the stack object pointed to.
>
> We can see from looking at the __mlog_printk() function definition
> that it's actually safe, but the compiler cannot see that when looking
> at another source file.
OK, thanks.
btw:
changing __mlog_printk can save ~11% (90+KB) of object text size
by removing __func__ and __LINE__ and using vsprintf pointer extension
%pS, __builtin_return_address(0) as it is already used in dlmmaster.
(defconfig x86-64, with ocfs2)
$ size fs/ocfs2/built-in.o*
text data bss dec hex filename
759791 111373 105688 976852 ee7d4 fs/ocfs2/built-in.o.new
852959 111373 105688 1070020 1053c4 fs/ocfs2/built-in.o.old
It's nearly the same output.
---
fs/ocfs2/cluster/masklog.c | 8 ++++----
fs/ocfs2/cluster/masklog.h | 8 +++-----
2 files changed, 7 insertions(+), 9 deletions(-)
diff --git a/fs/ocfs2/cluster/masklog.c b/fs/ocfs2/cluster/masklog.c
index d331c2386b94..a3f080f37108 100644
--- a/fs/ocfs2/cluster/masklog.c
+++ b/fs/ocfs2/cluster/masklog.c
@@ -64,8 +64,7 @@ static ssize_t mlog_mask_store(u64 mask, const char *buf, size_t count)
return count;
}
-void __mlog_printk(const u64 *mask, const char *func, int line,
- const char *fmt, ...)
+void __mlog_printk(const u64 *mask, const char *fmt, ...)
{
struct va_format vaf;
va_list args;
@@ -90,9 +89,10 @@ void __mlog_printk(const u64 *mask, const char *func, int line,
vaf.fmt = fmt;
vaf.va = &args;
- printk("%s(%s,%u,%u):%s:%d %s%pV",
+ printk("%s(%s,%u,%u):%pS %s%pV",
level, current->comm, task_pid_nr(current),
- raw_smp_processor_id(), func, line, prefix, &vaf);
+ raw_smp_processor_id(), __builtin_return_address(0),
+ prefix, &vaf);
va_end(args);
}
diff --git a/fs/ocfs2/cluster/masklog.h b/fs/ocfs2/cluster/masklog.h
index 3c16da69605d..56ba5baf625b 100644
--- a/fs/ocfs2/cluster/masklog.h
+++ b/fs/ocfs2/cluster/masklog.h
@@ -162,9 +162,8 @@ extern struct mlog_bits mlog_and_bits, mlog_not_bits;
#endif
-__printf(4, 5) __nocapture(2)
-void __mlog_printk(const u64 *m, const char *func, int line,
- const char *fmt, ...);
+__printf(2, 3) __nocapture(2)
+void __mlog_printk(const u64 *m, const char *fmt, ...);
/*
* Testing before the __mlog_printk call lets the compiler eliminate the
@@ -174,8 +173,7 @@ void __mlog_printk(const u64 *m, const char *func, int line,
do { \
u64 _m = MLOG_MASK_PREFIX | (mask); \
if (_m & ML_ALLOWED_BITS) \
- __mlog_printk(&_m, __func__, __LINE__, fmt, \
- ##__VA_ARGS__); \
+ __mlog_printk(&_m, fmt, ##__VA_ARGS__); \
} while (0)
#define mlog_errno(st) ({ \
next prev parent reply other threads:[~2017-03-02 23:59 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
2017-03-02 22:40 ` Joe Perches
2017-03-02 22:59 ` Arnd Bergmann
2017-03-02 23:58 ` Joe Perches [this message]
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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