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vsprintf: Consolidate handling of unknown pointer specifiers

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There are few printk formats that make sense only with two or more
specifiers. Also some specifiers make sense only when a kernel feature
is enabled.

The handling of unknown specifiers is inconsistent and not helpful.
Using WARN() looks like an overkill for this type of error. pr_warn()
is not good either. It would by handled via printk_safe buffer and
it might be hard to match it with the problematic string.

A reasonable compromise seems to be writing the unknown format specifier
into the original string with a question mark, for example (%pC?).
It should be self-explaining enough. Note that it is in brackets
to follow the (null) style.

Note that it introduces a warning about that test_hashed() function
is unused. It is going to be used again by a later patch.

Link: http://lkml.kernel.org/r/20190417115350.20479-8-pmladek@suse.com
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Tobin C . Harding" <me@tobin.cc>
Cc: Joe Perches <joe@perches.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
This commit is contained in:
Petr Mladek 2019-04-17 13:53:47 +02:00
parent 798cc27a30
commit 0b74d4d763
2 changed files with 18 additions and 13 deletions
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3
lib/test_printf.c
View File

@ -462,8 +462,7 @@ struct_rtc_time(void)
.tm_year = 118,
};
test_hashed("%pt", &tm);
test("(%ptR?)", "%pt", &tm);
test("2018-11-26T05:35:43", "%ptR", &tm);
test("0118-10-26T05:35:43", "%ptRr", &tm);
test("05:35:43|2018-11-26", "%ptRt|%ptRd", &tm, &tm);

28
lib/vsprintf.c
View File

@ -1435,6 +1435,8 @@ static noinline_for_stack
char *ip_addr_string(char *buf, char *end, const void *ptr,
struct printf_spec spec, const char *fmt)
{
char *err_fmt_msg;
switch (fmt[1]) {
case '6':
return ip6_addr_string(buf, end, ptr, spec, fmt);
@ -1457,7 +1459,8 @@ char *ip_addr_string(char *buf, char *end, const void *ptr,
}}
}
return ptr_to_id(buf, end, ptr, spec);
err_fmt_msg = fmt[0] == 'i' ? "(%pi?)" : "(%pI?)";
return string_nocheck(buf, end, err_fmt_msg, spec);
}
static noinline_for_stack
@ -1585,7 +1588,7 @@ char *netdev_bits(char *buf, char *end, const void *addr,
size = sizeof(netdev_features_t);
break;
default:
return ptr_to_id(buf, end, addr, spec);
return string_nocheck(buf, end, "(%pN?)", spec);
}
return special_hex_number(buf, end, num, size);
@ -1689,7 +1692,7 @@ char *time_and_date(char *buf, char *end, void *ptr, struct printf_spec spec,
case 'R':
return rtc_str(buf, end, (const struct rtc_time *)ptr, fmt);
default:
return ptr_to_id(buf, end, ptr, spec);
return string_nocheck(buf, end, "(%ptR?)", spec);
}
}
@ -1697,7 +1700,10 @@ static noinline_for_stack
char *clock(char *buf, char *end, struct clk *clk, struct printf_spec spec,
const char *fmt)
{
if (!IS_ENABLED(CONFIG_HAVE_CLK) || !clk)
if (!IS_ENABLED(CONFIG_HAVE_CLK))
return string_nocheck(buf, end, "(%pC?)", spec);
if (!clk)
return string(buf, end, NULL, spec);
switch (fmt[1]) {
@ -1706,7 +1712,7 @@ char *clock(char *buf, char *end, struct clk *clk, struct printf_spec spec,
#ifdef CONFIG_COMMON_CLK
return string(buf, end, __clk_get_name(clk), spec);
#else
return ptr_to_id(buf, end, clk, spec);
return string_nocheck(buf, end, "(%pC?)", spec);
#endif
}
}
@ -1739,7 +1745,8 @@ char *format_flags(char *buf, char *end, unsigned long flags,
}
static noinline_for_stack
char *flags_string(char *buf, char *end, void *flags_ptr, const char *fmt)
char *flags_string(char *buf, char *end, void *flags_ptr,
struct printf_spec spec, const char *fmt)
{
unsigned long flags;
const struct trace_print_flags *names;
@ -1760,8 +1767,7 @@ char *flags_string(char *buf, char *end, void *flags_ptr, const char *fmt)
names = gfpflag_names;
break;
default:
WARN_ONCE(1, "Unsupported flags modifier: %c\n", fmt[1]);
return buf;
return string_nocheck(buf, end, "(%pG?)", spec);
}
return format_flags(buf, end, flags, names);
@ -1817,7 +1823,7 @@ char *device_node_string(char *buf, char *end, struct device_node *dn,
str_spec.field_width = -1;
if (!IS_ENABLED(CONFIG_OF))
return string_nocheck(buf, end, "(!OF)", spec);
return string_nocheck(buf, end, "(%pOF?)", spec);
if ((unsigned long)dn < PAGE_SIZE)
return string_nocheck(buf, end, "(null)", spec);
@ -1896,7 +1902,7 @@ static char *kobject_string(char *buf, char *end, void *ptr,
return device_node_string(buf, end, ptr, spec, fmt + 1);
}
return ptr_to_id(buf, end, ptr, spec);
return string_nocheck(buf, end, "(%pO?)", spec);
}
/*
@ -2091,7 +2097,7 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
#endif
case 'G':
return flags_string(buf, end, ptr, fmt);
return flags_string(buf, end, ptr, spec, fmt);
case 'O':
return kobject_string(buf, end, ptr, spec, fmt);
case 'x':