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authorShunyong Yang <shunyong.yang@hxt-semitech.com>2018-02-16 23:07:09 +0200
committerPetr Mladek <pmladek@suse.com>2018-04-11 11:18:43 +0200
commit91efafb1dd8f471177a3dddb4841d75d3df1cc46 (patch)
tree87923e6f1ea1c0b8163a0ac710c85432a41ba029 /lib
parent496a9a5f3806d58b14ae06b390d5b1ffa26e9f9a (diff)
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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')
-rw-r--r--lib/vsprintf.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 9004bbb..97be2d0 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
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