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| author | Shunyong Yang <shunyong.yang@hxt-semitech.com> | 2018-02-17 00:07:09 +0300 |
|---|---|---|
| committer | Petr Mladek <pmladek@suse.com> | 2018-04-11 12:18:43 +0300 |
| commit | 91efafb1dd8f471177a3dddb4841d75d3df1cc46 (patch) | |
| tree | 87923e6f1ea1c0b8163a0ac710c85432a41ba029 /lib/vsprintf.c | |
| parent | 496a9a5f3806d58b14ae06b390d5b1ffa26e9f9a (diff) | |
| download | linux-91efafb1dd8f471177a3dddb4841d75d3df1cc46.tar.xz | |
lib/vsprintf: Replace space with '_' before crng is ready
Before crng is ready, output of "%p" composes of "(ptrval)" and
left padding spaces for alignment as no random address can be
generated. This seems a little strange when default string width
is larger than strlen("(ptrval)").
For example, when irq domain names are built with "%p", the nodes
under /sys/kernel/debug/irq/domains like this on AArch64 system,
[root@y irq]# ls domains/
default irqchip@ (ptrval)-2
irqchip@ (ptrval)-4 \_SB_.TCS0.QIC1 \_SB_.TCS0.QIC3
irqchip@ (ptrval) irqchip@ (ptrval)-3
\_SB_.TCS0.QIC0 \_SB_.TCS0.QIC2
The name "irqchip@ (ptrval)-2" is not so readable in console
output.
This patch replaces space with readable "_" when output needs padding.
Following is the output after applying the patch,
[root@y domains]# ls
default irqchip@(____ptrval____)-2
irqchip@(____ptrval____)-4 \_SB_.TCS0.QIC1 \_SB_.TCS0.QIC3
irqchip@(____ptrval____) irqchip@(____ptrval____)-3 \_SB_.TCS0.QIC0
\_SB_.TCS0.QIC2
There is same problem in some subsystem's dmesg output. Moreover,
someone may call "%p" in a similar case. In addition, the timing of
crng initialization done may vary on different system. So, the change
is made in vsprintf.c.
Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Link: http://lkml.kernel.org/r/20180216210711.79901-7-andriy.shevchenko@linux.intel.com
To: "Tobin C . Harding" <me@tobin.cc>
To: linux@rasmusvillemoes.dk
To: Joe Perches <joe@perches.com>
To: linux-kernel@vger.kernel.org
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Joey Zheng <yu.zheng@hxt-semitech.com>
Signed-off-by: Shunyong Yang <shunyong.yang@hxt-semitech.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Diffstat (limited to 'lib/vsprintf.c')
| -rw-r--r-- | lib/vsprintf.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 9004bbb3d84d..97be2d07297a 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1681,12 +1681,13 @@ early_initcall(initialize_ptr_random); /* Maps a pointer to a 32 bit unique identifier. */ static char *ptr_to_id(char *buf, char *end, void *ptr, struct printf_spec spec) { + const char *str = sizeof(ptr) == 8 ? "(____ptrval____)" : "(ptrval)"; unsigned long hashval; if (unlikely(!have_filled_random_ptr_key)) { spec.field_width = 2 * sizeof(ptr); /* string length must be less than default_width */ - return string(buf, end, "(ptrval)", spec); + return string(buf, end, str, spec); } #ifdef CONFIG_64BIT |