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Groups > linux.kernel > #1591562
| From | Joe Perches <joe@perches.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 24/26] ocfs2: reduce stack size with KASAN |
| Date | 2017-03-03 01:00 +0100 |
| Message-ID | <tgINz-13L-5@gated-at.bofh.it> (permalink) |
| References | (1 earlier) <tgDbc-5KR-27@gated-at.bofh.it> <tgDbc-5KR-25@gated-at.bofh.it> <tgHHP-ok-15@gated-at.bofh.it> <tgHHP-ok-13@gated-at.bofh.it> <tgI1d-KT-39@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
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) ({ \
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
[PATCH 00/26] bring back stack frame warning with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-02 18:20 +0100
[PATCH 07/26] brcmsmac: reduce stack size with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-02 18:20 +0100
Re: [PATCH 07/26] brcmsmac: reduce stack size with KASAN Arend Van Spriel <arend.vanspriel@broadcom.com> - 2017-03-06 10:50 +0100
Re: [PATCH 07/26] brcmsmac: reduce stack size with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-06 12:00 +0100
Re: [PATCH 07/26] brcmsmac: reduce stack size with KASAN Arend Van Spriel <arend.vanspriel@broadcom.com> - 2017-03-06 12:20 +0100
Re: [PATCH 07/26] brcmsmac: reduce stack size with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-06 12:20 +0100
Re: [PATCH 07/26] brcmsmac: reduce stack size with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-06 12:40 +0100
[PATCH 15/26] [media] tuners: i2c: reduce stack usage for tuner_i2c_xfer_* Arnd Bergmann <arnd@arndb.de> - 2017-03-02 18:20 +0100
[PATCH 11/26] rtlwifi: reduce stack usage for KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-02 18:20 +0100
[PATCH 04/26] tty: kbd: reduce stack size with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-02 18:20 +0100
[PATCH 12/26] wl3501_cs: reduce stack size for KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-02 18:20 +0100
[PATCH 09/26] brcmsmac: split up wlc_phy_workarounds_nphy Arnd Bergmann <arnd@arndb.de> - 2017-03-02 18:20 +0100
Re: [PATCH 09/26] brcmsmac: split up wlc_phy_workarounds_nphy Arend Van Spriel <arend.vanspriel@broadcom.com> - 2017-03-06 10:40 +0100
[PATCH 01/26] compiler: introduce noinline_for_kasan annotation Arnd Bergmann <arnd@arndb.de> - 2017-03-02 18:20 +0100
Re: [PATCH 01/26] compiler: introduce noinline_for_kasan annotation Alexander Potapenko <glider@google.com> - 2017-03-03 15:00 +0100
Re: [PATCH 01/26] compiler: introduce noinline_for_kasan annotation Alexander Potapenko <glider@google.com> - 2017-03-03 15:40 +0100
Re: [PATCH 01/26] compiler: introduce noinline_for_kasan annotation Arnd Bergmann <arnd@arndb.de> - 2017-03-03 16:10 +0100
Re: [PATCH 01/26] compiler: introduce noinline_for_kasan annotation Arnd Bergmann <arnd@arndb.de> - 2017-03-03 15:40 +0100
RE: [PATCH 01/26] compiler: introduce noinline_for_kasan annotation David Laight <David.Laight@ACULAB.COM> - 2017-03-03 18:10 +0100
[PATCH 05/26] netlink: mark nla_put_{u8,u16,u32} noinline_for_kasan Arnd Bergmann <arnd@arndb.de> - 2017-03-02 18:20 +0100
[PATCH 08/26] brcmsmac: make some local variables 'static const' to reduce stack size Arnd Bergmann <arnd@arndb.de> - 2017-03-02 18:20 +0100
Re: [PATCH 08/26] brcmsmac: make some local variables 'static const' to reduce stack size Arend Van Spriel <arend.vanspriel@broadcom.com> - 2017-03-06 10:40 +0100
Re: [PATCH 08/26] brcmsmac: make some local variables 'static const' to reduce stack size Kalle Valo <kvalo@codeaurora.org> - 2017-03-06 17:40 +0100
Re: [PATCH 08/26] brcmsmac: make some local variables 'static const' to reduce stack size Arnd Bergmann <arnd@arndb.de> - 2017-03-06 22:40 +0100
Re: [PATCH 08/26] brcmsmac: make some local variables 'static const' to reduce stack size Kalle Valo <kvalo@codeaurora.org> - 2017-03-07 10:50 +0100
Re: [PATCH 08/26] brcmsmac: make some local variables 'static const' to reduce stack size Arend Van Spriel <arend.vanspriel@broadcom.com> - 2017-03-07 11:10 +0100
[PATCH 22/26] drm/i915/gvt: don't overflow the kernel stack with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-02 18:40 +0100
Re: [PATCH 24/26] ocfs2: reduce stack size with KASAN Joe Perches <joe@perches.com> - 2017-03-02 19:00 +0100
Re: [PATCH 24/26] ocfs2: reduce stack size with KASAN Joe Perches <joe@perches.com> - 2017-03-02 23:50 +0100
Re: [PATCH 24/26] ocfs2: reduce stack size with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-03 00:10 +0100
Re: [PATCH 24/26] ocfs2: reduce stack size with KASAN Joe Perches <joe@perches.com> - 2017-03-03 01:00 +0100
Re: [PATCH 24/26] ocfs2: reduce stack size with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-03 00:00 +0100
[PATCH 24/26] ocfs2: reduce stack size with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-02 20:10 +0100
[PATCH 23/26] mtd: cfi: reduce stack size with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-02 20:20 +0100
[PATCH 18/26] [media] i2c: cx25840: avoid stack overflow with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-02 23:30 +0100
Re: [PATCH 00/26] bring back stack frame warning with KASAN Alexander Potapenko <glider@google.com> - 2017-03-03 13:30 +0100
Re: [PATCH 00/26] bring back stack frame warning with KASAN Arnd Bergmann <arnd@arndb.de> - 2017-03-03 14:00 +0100
Re: [PATCH 10/26] brcmsmac: reindent split functions Kalle Valo <kvalo@codeaurora.org> - 2017-03-06 17:50 +0100
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