From 20bc8c1e972f29afcac85e524e430c11a6df5f58 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Tue, 11 May 2021 18:39:55 +0300 Subject: lib/vsprintf: Allow to override ISO 8601 date and time separator ISO 8601 defines 'T' as a separator between date and time. Though, some ABIs use time and date with ' ' (space) separator instead. Add a flavour to the %pt specifier to override default separator. Signed-off-by: Andy Shevchenko Reviewed-by: Petr Mladek Reviewed-by: Sergey Senozhatsky Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210511153958.34527-1-andriy.shevchenko@linux.intel.com --- lib/test_printf.c | 5 +++++ lib/vsprintf.c | 22 +++++++++++++++++----- 2 files changed, 22 insertions(+), 5 deletions(-) (limited to 'lib') diff --git a/lib/test_printf.c b/lib/test_printf.c index 27b964ec723d..69b04b531492 100644 --- a/lib/test_printf.c +++ b/lib/test_printf.c @@ -528,6 +528,11 @@ time_and_date(void) test("0119-00-04T15:32:23", "%ptTr", &t); test("15:32:23|2019-01-04", "%ptTt|%ptTd", &t, &t); test("15:32:23|0119-00-04", "%ptTtr|%ptTdr", &t, &t); + + test("2019-01-04 15:32:23", "%ptTs", &t); + test("0119-00-04 15:32:23", "%ptTsr", &t); + test("15:32:23|2019-01-04", "%ptTts|%ptTds", &t, &t); + test("15:32:23|0119-00-04", "%ptTtrs|%ptTdrs", &t, &t); } static void __init diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 6c56c62fd9a5..8d5142ae742e 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1798,7 +1798,8 @@ char *rtc_str(char *buf, char *end, const struct rtc_time *tm, struct printf_spec spec, const char *fmt) { bool have_t = true, have_d = true; - bool raw = false; + bool raw = false, iso8601_separator = true; + bool found = true; int count = 2; if (check_pointer(&buf, end, tm, spec)) @@ -1815,14 +1816,25 @@ char *rtc_str(char *buf, char *end, const struct rtc_time *tm, break; } - raw = fmt[count] == 'r'; + do { + switch (fmt[count++]) { + case 'r': + raw = true; + break; + case 's': + iso8601_separator = false; + break; + default: + found = false; + break; + } + } while (found); if (have_d) buf = date_str(buf, end, tm, raw); if (have_d && have_t) { - /* Respect ISO 8601 */ if (buf < end) - *buf = 'T'; + *buf = iso8601_separator ? 'T' : ' '; buf++; } if (have_t) @@ -2261,7 +2273,7 @@ early_param("no_hash_pointers", no_hash_pointers_enable); * - 'd[234]' For a dentry name (optionally 2-4 last components) * - 'D[234]' Same as 'd' but for a struct file * - 'g' For block_device name (gendisk + partition number) - * - 't[RT][dt][r]' For time and date as represented by: + * - 't[RT][dt][r][s]' For time and date as represented by: * R struct rtc_time * T time64_t * - 'C' For a clock, it prints the name (Common Clock Framework) or address -- cgit v1.2.3 From 11b3dda5e8b6cde957a6410233f30d6c48582998 Mon Sep 17 00:00:00 2001 From: Richard Fitzgerald Date: Fri, 14 May 2021 17:12:03 +0100 Subject: lib: vsprintf: scanf: Negative number must have field width > 1 If a signed number field starts with a '-' the field width must be > 1, or unlimited, to allow at least one digit after the '-'. This patch adds a check for this. If a signed field starts with '-' and field_width == 1 the scanf will quit. It is ok for a signed number field to have a field width of 1 if it starts with a digit. In that case the single digit can be converted. Signed-off-by: Richard Fitzgerald Reviewed-by: Petr Mladek Acked-by: Andy Shevchenko Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210514161206.30821-1-rf@opensource.cirrus.com --- lib/vsprintf.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'lib') diff --git a/lib/vsprintf.c b/lib/vsprintf.c index 6c56c62fd9a5..af307588ad8b 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -3526,8 +3526,12 @@ int vsscanf(const char *buf, const char *fmt, va_list args) str = skip_spaces(str); digit = *str; - if (is_sign && digit == '-') + if (is_sign && digit == '-') { + if (field_width == 1) + break; + digit = *(str + 1); + } if (!digit || (base == 16 && !isxdigit(digit)) -- cgit v1.2.3 From 900fdc4573766dd43b847b4f54bd4a1ee2bc7360 Mon Sep 17 00:00:00 2001 From: Richard Fitzgerald Date: Fri, 14 May 2021 17:12:04 +0100 Subject: lib: vsprintf: Fix handling of number field widths in vsscanf The existing code attempted to handle numbers by doing a strto[u]l(), ignoring the field width, and then repeatedly dividing to extract the field out of the full converted value. If the string contains a run of valid digits longer than will fit in a long or long long, this would overflow and no amount of dividing can recover the correct value. This patch fixes vsscanf() to obey number field widths when parsing the number. A new _parse_integer_limit() is added that takes a limit for the number of characters to parse. The number field conversion in vsscanf is changed to use this new function. If a number starts with a radix prefix, the field width must be long enough for at last one digit after the prefix. If not, it will be handled like this: sscanf("0x4", "%1i", &i): i=0, scanning continues with the 'x' sscanf("0x4", "%2i", &i): i=0, scanning continues with the '4' This is consistent with the observed behaviour of userland sscanf. Note that this patch does NOT fix the problem of a single field value overflowing the target type. So for example: sscanf("123456789abcdef", "%x", &i); Will not produce the correct result because the value obviously overflows INT_MAX. But sscanf will report a successful conversion. Note that where a very large number is used to mean "unlimited", the value INT_MAX is used for consistency with the behaviour of vsnprintf(). Signed-off-by: Richard Fitzgerald Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210514161206.30821-2-rf@opensource.cirrus.com --- lib/kstrtox.c | 13 +++++++--- lib/kstrtox.h | 2 ++ lib/vsprintf.c | 82 ++++++++++++++++++++++++++++++++++------------------------ 3 files changed, 60 insertions(+), 37 deletions(-) (limited to 'lib') diff --git a/lib/kstrtox.c b/lib/kstrtox.c index a118b0b1e9b2..0b5fe8b41173 100644 --- a/lib/kstrtox.c +++ b/lib/kstrtox.c @@ -39,20 +39,22 @@ const char *_parse_integer_fixup_radix(const char *s, unsigned int *base) /* * Convert non-negative integer string representation in explicitly given radix - * to an integer. + * to an integer. A maximum of max_chars characters will be converted. + * * Return number of characters consumed maybe or-ed with overflow bit. * If overflow occurs, result integer (incorrect) is still returned. * * Don't you dare use this function. */ -unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *p) +unsigned int _parse_integer_limit(const char *s, unsigned int base, unsigned long long *p, + size_t max_chars) { unsigned long long res; unsigned int rv; res = 0; rv = 0; - while (1) { + while (max_chars--) { unsigned int c = *s; unsigned int lc = c | 0x20; /* don't tolower() this line */ unsigned int val; @@ -82,6 +84,11 @@ unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long return rv; } +unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *p) +{ + return _parse_integer_limit(s, base, p, INT_MAX); +} + static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res) { unsigned long long _res; diff --git a/lib/kstrtox.h b/lib/kstrtox.h index 3b4637bcd254..158c400ca865 100644 --- a/lib/kstrtox.h +++ b/lib/kstrtox.h @@ -4,6 +4,8 @@ #define KSTRTOX_OVERFLOW (1U << 31) const char *_parse_integer_fixup_radix(const char *s, unsigned int *base); +unsigned int _parse_integer_limit(const char *s, unsigned int base, unsigned long long *res, + size_t max_chars); unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *res); #endif diff --git a/lib/vsprintf.c b/lib/vsprintf.c index af307588ad8b..3290eca46e47 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -53,6 +53,31 @@ #include #include "kstrtox.h" +static unsigned long long simple_strntoull(const char *startp, size_t max_chars, + char **endp, unsigned int base) +{ + const char *cp; + unsigned long long result = 0ULL; + size_t prefix_chars; + unsigned int rv; + + cp = _parse_integer_fixup_radix(startp, &base); + prefix_chars = cp - startp; + if (prefix_chars < max_chars) { + rv = _parse_integer_limit(cp, base, &result, max_chars - prefix_chars); + /* FIXME */ + cp += (rv & ~KSTRTOX_OVERFLOW); + } else { + /* Field too short for prefix + digit, skip over without converting */ + cp = startp + max_chars; + } + + if (endp) + *endp = (char *)cp; + + return result; +} + /** * simple_strtoull - convert a string to an unsigned long long * @cp: The start of the string @@ -63,18 +88,7 @@ */ unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base) { - unsigned long long result; - unsigned int rv; - - cp = _parse_integer_fixup_radix(cp, &base); - rv = _parse_integer(cp, base, &result); - /* FIXME */ - cp += (rv & ~KSTRTOX_OVERFLOW); - - if (endp) - *endp = (char *)cp; - - return result; + return simple_strntoull(cp, INT_MAX, endp, base); } EXPORT_SYMBOL(simple_strtoull); @@ -109,6 +123,21 @@ long simple_strtol(const char *cp, char **endp, unsigned int base) } EXPORT_SYMBOL(simple_strtol); +static long long simple_strntoll(const char *cp, size_t max_chars, char **endp, + unsigned int base) +{ + /* + * simple_strntoull() safely handles receiving max_chars==0 in the + * case cp[0] == '-' && max_chars == 1. + * If max_chars == 0 we can drop through and pass it to simple_strntoull() + * and the content of *cp is irrelevant. + */ + if (*cp == '-' && max_chars > 0) + return -simple_strntoull(cp + 1, max_chars - 1, endp, base); + + return simple_strntoull(cp, max_chars, endp, base); +} + /** * simple_strtoll - convert a string to a signed long long * @cp: The start of the string @@ -119,10 +148,7 @@ EXPORT_SYMBOL(simple_strtol); */ long long simple_strtoll(const char *cp, char **endp, unsigned int base) { - if (*cp == '-') - return -simple_strtoull(cp + 1, endp, base); - - return simple_strtoull(cp, endp, base); + return simple_strntoll(cp, INT_MAX, endp, base); } EXPORT_SYMBOL(simple_strtoll); @@ -3541,25 +3567,13 @@ int vsscanf(const char *buf, const char *fmt, va_list args) break; if (is_sign) - val.s = qualifier != 'L' ? - simple_strtol(str, &next, base) : - simple_strtoll(str, &next, base); + val.s = simple_strntoll(str, + field_width >= 0 ? field_width : INT_MAX, + &next, base); else - val.u = qualifier != 'L' ? - simple_strtoul(str, &next, base) : - simple_strtoull(str, &next, base); - - if (field_width > 0 && next - str > field_width) { - if (base == 0) - _parse_integer_fixup_radix(str, &base); - while (next - str > field_width) { - if (is_sign) - val.s = div_s64(val.s, base); - else - val.u = div_u64(val.u, base); - --next; - } - } + val.u = simple_strntoull(str, + field_width >= 0 ? field_width : INT_MAX, + &next, base); switch (qualifier) { case 'H': /* that's 'hh' in format */ -- cgit v1.2.3 From 50f530e176eac808e64416732e54c0686ce2c39b Mon Sep 17 00:00:00 2001 From: Richard Fitzgerald Date: Fri, 14 May 2021 17:12:05 +0100 Subject: lib: test_scanf: Add tests for sscanf number conversion Adds test_sscanf to test various number conversion cases, as number conversion was previously broken. This also tests the simple_strtoxxx() functions exported from vsprintf.c. Signed-off-by: Richard Fitzgerald Acked-by: Andy Shevchenko Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210514161206.30821-3-rf@opensource.cirrus.com --- MAINTAINERS | 1 + lib/Kconfig.debug | 3 + lib/Makefile | 1 + lib/test_scanf.c | 751 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 756 insertions(+) create mode 100644 lib/test_scanf.c (limited to 'lib') diff --git a/MAINTAINERS b/MAINTAINERS index 04e7de8c95be..eb05132f8ff1 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -19395,6 +19395,7 @@ S: Maintained T: git git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk.git F: Documentation/core-api/printk-formats.rst F: lib/test_printf.c +F: lib/test_scanf.c F: lib/vsprintf.c VT1211 HARDWARE MONITOR DRIVER diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 2c7f46b366f1..dc437a171c0f 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -2163,6 +2163,9 @@ config TEST_KSTRTOX config TEST_PRINTF tristate "Test printf() family of functions at runtime" +config TEST_SCANF + tristate "Test scanf() family of functions at runtime" + config TEST_BITMAP tristate "Test bitmap_*() family of functions at runtime" help diff --git a/lib/Makefile b/lib/Makefile index e11cfc18b6c0..5f7f246241b1 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -83,6 +83,7 @@ obj-$(CONFIG_TEST_USER_COPY) += test_user_copy.o obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_keys.o obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_key_base.o obj-$(CONFIG_TEST_PRINTF) += test_printf.o +obj-$(CONFIG_TEST_SCANF) += test_scanf.o obj-$(CONFIG_TEST_BITMAP) += test_bitmap.o obj-$(CONFIG_TEST_STRSCPY) += test_strscpy.o obj-$(CONFIG_TEST_UUID) += test_uuid.o diff --git a/lib/test_scanf.c b/lib/test_scanf.c new file mode 100644 index 000000000000..8d577aec6c28 --- /dev/null +++ b/lib/test_scanf.c @@ -0,0 +1,751 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Test cases for sscanf facility. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "../tools/testing/selftests/kselftest_module.h" + +#define BUF_SIZE 1024 + +KSTM_MODULE_GLOBALS(); +static char *test_buffer __initdata; +static char *fmt_buffer __initdata; +static struct rnd_state rnd_state __initdata; + +typedef int (*check_fn)(const void *check_data, const char *string, + const char *fmt, int n_args, va_list ap); + +static void __scanf(4, 6) __init +_test(check_fn fn, const void *check_data, const char *string, const char *fmt, + int n_args, ...) +{ + va_list ap, ap_copy; + int ret; + + total_tests++; + + va_start(ap, n_args); + va_copy(ap_copy, ap); + ret = vsscanf(string, fmt, ap_copy); + va_end(ap_copy); + + if (ret != n_args) { + pr_warn("vsscanf(\"%s\", \"%s\", ...) returned %d expected %d\n", + string, fmt, ret, n_args); + goto fail; + } + + ret = (*fn)(check_data, string, fmt, n_args, ap); + if (ret) + goto fail; + + va_end(ap); + + return; + +fail: + failed_tests++; + va_end(ap); +} + +#define _check_numbers_template(arg_fmt, expect, str, fmt, n_args, ap) \ +do { \ + pr_debug("\"%s\", \"%s\" ->\n", str, fmt); \ + for (; n_args > 0; n_args--, expect++) { \ + typeof(*expect) got = *va_arg(ap, typeof(expect)); \ + pr_debug("\t" arg_fmt "\n", got); \ + if (got != *expect) { \ + pr_warn("vsscanf(\"%s\", \"%s\", ...) expected " arg_fmt " got " arg_fmt "\n", \ + str, fmt, *expect, got); \ + return 1; \ + } \ + } \ + return 0; \ +} while (0) + +static int __init check_ull(const void *check_data, const char *string, + const char *fmt, int n_args, va_list ap) +{ + const unsigned long long *pval = check_data; + + _check_numbers_template("%llu", pval, string, fmt, n_args, ap); +} + +static int __init check_ll(const void *check_data, const char *string, + const char *fmt, int n_args, va_list ap) +{ + const long long *pval = check_data; + + _check_numbers_template("%lld", pval, string, fmt, n_args, ap); +} + +static int __init check_ulong(const void *check_data, const char *string, + const char *fmt, int n_args, va_list ap) +{ + const unsigned long *pval = check_data; + + _check_numbers_template("%lu", pval, string, fmt, n_args, ap); +} + +static int __init check_long(const void *check_data, const char *string, + const char *fmt, int n_args, va_list ap) +{ + const long *pval = check_data; + + _check_numbers_template("%ld", pval, string, fmt, n_args, ap); +} + +static int __init check_uint(const void *check_data, const char *string, + const char *fmt, int n_args, va_list ap) +{ + const unsigned int *pval = check_data; + + _check_numbers_template("%u", pval, string, fmt, n_args, ap); +} + +static int __init check_int(const void *check_data, const char *string, + const char *fmt, int n_args, va_list ap) +{ + const int *pval = check_data; + + _check_numbers_template("%d", pval, string, fmt, n_args, ap); +} + +static int __init check_ushort(const void *check_data, const char *string, + const char *fmt, int n_args, va_list ap) +{ + const unsigned short *pval = check_data; + + _check_numbers_template("%hu", pval, string, fmt, n_args, ap); +} + +static int __init check_short(const void *check_data, const char *string, + const char *fmt, int n_args, va_list ap) +{ + const short *pval = check_data; + + _check_numbers_template("%hd", pval, string, fmt, n_args, ap); +} + +static int __init check_uchar(const void *check_data, const char *string, + const char *fmt, int n_args, va_list ap) +{ + const unsigned char *pval = check_data; + + _check_numbers_template("%hhu", pval, string, fmt, n_args, ap); +} + +static int __init check_char(const void *check_data, const char *string, + const char *fmt, int n_args, va_list ap) +{ + const signed char *pval = check_data; + + _check_numbers_template("%hhd", pval, string, fmt, n_args, ap); +} + +/* Selection of interesting numbers to test, copied from test-kstrtox.c */ +static const unsigned long long numbers[] __initconst = { + 0x0ULL, + 0x1ULL, + 0x7fULL, + 0x80ULL, + 0x81ULL, + 0xffULL, + 0x100ULL, + 0x101ULL, + 0x7fffULL, + 0x8000ULL, + 0x8001ULL, + 0xffffULL, + 0x10000ULL, + 0x10001ULL, + 0x7fffffffULL, + 0x80000000ULL, + 0x80000001ULL, + 0xffffffffULL, + 0x100000000ULL, + 0x100000001ULL, + 0x7fffffffffffffffULL, + 0x8000000000000000ULL, + 0x8000000000000001ULL, + 0xfffffffffffffffeULL, + 0xffffffffffffffffULL, +}; + +#define value_representable_in_type(T, val) \ +(is_signed_type(T) \ + ? ((long long)(val) >= type_min(T)) && ((long long)(val) <= type_max(T)) \ + : ((unsigned long long)(val) >= type_min(T)) && \ + ((unsigned long long)(val) <= type_max(T))) + +#define test_one_number(T, gen_fmt, scan_fmt, val, fn) \ +do { \ + const T expect_val = (T)(val); \ + T result = ~expect_val; /* should be overwritten */ \ + \ + snprintf(test_buffer, BUF_SIZE, gen_fmt, expect_val); \ + _test(fn, &expect_val, test_buffer, "%" scan_fmt, 1, &result); \ +} while (0) + +#define simple_numbers_loop(T, gen_fmt, scan_fmt, fn) \ +do { \ + int i; \ + \ + for (i = 0; i < ARRAY_SIZE(numbers); i++) { \ + if (!value_representable_in_type(T, numbers[i])) \ + continue; \ + \ + test_one_number(T, gen_fmt, scan_fmt, numbers[i], fn); \ + \ + if (is_signed_type(T)) \ + test_one_number(T, gen_fmt, scan_fmt, \ + -numbers[i], fn); \ + } \ +} while (0) + +static void __init numbers_simple(void) +{ + simple_numbers_loop(unsigned long long, "%llu", "llu", check_ull); + simple_numbers_loop(long long, "%lld", "lld", check_ll); + simple_numbers_loop(long long, "%lld", "lli", check_ll); + simple_numbers_loop(unsigned long long, "%llx", "llx", check_ull); + simple_numbers_loop(long long, "%llx", "llx", check_ll); + simple_numbers_loop(long long, "0x%llx", "lli", check_ll); + simple_numbers_loop(unsigned long long, "0x%llx", "llx", check_ull); + simple_numbers_loop(long long, "0x%llx", "llx", check_ll); + + simple_numbers_loop(unsigned long, "%lu", "lu", check_ulong); + simple_numbers_loop(long, "%ld", "ld", check_long); + simple_numbers_loop(long, "%ld", "li", check_long); + simple_numbers_loop(unsigned long, "%lx", "lx", check_ulong); + simple_numbers_loop(long, "%lx", "lx", check_long); + simple_numbers_loop(long, "0x%lx", "li", check_long); + simple_numbers_loop(unsigned long, "0x%lx", "lx", check_ulong); + simple_numbers_loop(long, "0x%lx", "lx", check_long); + + simple_numbers_loop(unsigned int, "%u", "u", check_uint); + simple_numbers_loop(int, "%d", "d", check_int); + simple_numbers_loop(int, "%d", "i", check_int); + simple_numbers_loop(unsigned int, "%x", "x", check_uint); + simple_numbers_loop(int, "%x", "x", check_int); + simple_numbers_loop(int, "0x%x", "i", check_int); + simple_numbers_loop(unsigned int, "0x%x", "x", check_uint); + simple_numbers_loop(int, "0x%x", "x", check_int); + + simple_numbers_loop(unsigned short, "%hu", "hu", check_ushort); + simple_numbers_loop(short, "%hd", "hd", check_short); + simple_numbers_loop(short, "%hd", "hi", check_short); + simple_numbers_loop(unsigned short, "%hx", "hx", check_ushort); + simple_numbers_loop(short, "%hx", "hx", check_short); + simple_numbers_loop(short, "0x%hx", "hi", check_short); + simple_numbers_loop(unsigned short, "0x%hx", "hx", check_ushort); + simple_numbers_loop(short, "0x%hx", "hx", check_short); + + simple_numbers_loop(unsigned char, "%hhu", "hhu", check_uchar); + simple_numbers_loop(signed char, "%hhd", "hhd", check_char); + simple_numbers_loop(signed char, "%hhd", "hhi", check_char); + simple_numbers_loop(unsigned char, "%hhx", "hhx", check_uchar); + simple_numbers_loop(signed char, "%hhx", "hhx", check_char); + simple_numbers_loop(signed char, "0x%hhx", "hhi", check_char); + simple_numbers_loop(unsigned char, "0x%hhx", "hhx", check_uchar); + simple_numbers_loop(signed char, "0x%hhx", "hhx", check_char); +} + +/* + * This gives a better variety of number "lengths" in a small sample than + * the raw prandom*() functions (Not mathematically rigorous!!). + * Variabilty of length and value is more important than perfect randomness. + */ +static u32 __init next_test_random(u32 max_bits) +{ + u32 n_bits = hweight32(prandom_u32_state(&rnd_state)) % (max_bits + 1); + + return prandom_u32_state(&rnd_state) & (UINT_MAX >> (32 - n_bits)); +} + +static unsigned long long __init next_test_random_ull(void) +{ + u32 rand1 = prandom_u32_state(&rnd_state); + u32 n_bits = (hweight32(rand1) * 3) % 64; + u64 val = (u64)prandom_u32_state(&rnd_state) * rand1; + + return val & (ULLONG_MAX >> (64 - n_bits)); +} + +#define random_for_type(T) \ + ((T)(sizeof(T) <= sizeof(u32) \ + ? next_test_random(BITS_PER_TYPE(T)) \ + : next_test_random_ull())) + +/* + * Define a pattern of negative and positive numbers to ensure we get + * some of both within the small number of samples in a test string. + */ +#define NEGATIVES_PATTERN 0x3246 /* 00110010 01000110 */ + +#define fill_random_array(arr) \ +do { \ + unsigned int neg_pattern = NEGATIVES_PATTERN; \ + int i; \ + \ + for (i = 0; i < ARRAY_SIZE(arr); i++, neg_pattern >>= 1) { \ + (arr)[i] = random_for_type(typeof((arr)[0])); \ + if (is_signed_type(typeof((arr)[0])) && (neg_pattern & 1)) \ + (arr)[i] = -(arr)[i]; \ + } \ +} while (0) + +/* + * Convenience wrapper around snprintf() to append at buf_pos in buf, + * updating buf_pos and returning the number of characters appended. + * On error buf_pos is not changed and return value is 0. + */ +static int __init __printf(4, 5) +append_fmt(char *buf, int *buf_pos, int buf_len, const char *val_fmt, ...) +{ + va_list ap; + int field_len; + + va_start(ap, val_fmt); + field_len = vsnprintf(buf + *buf_pos, buf_len - *buf_pos, val_fmt, ap); + va_end(ap); + + if (field_len < 0) + field_len = 0; + + *buf_pos += field_len; + + return field_len; +} + +/* + * Convenience function to append the field delimiter string + * to both the value string and format string buffers. + */ +static void __init append_delim(char *str_buf, int *str_buf_pos, int str_buf_len, + char *fmt_buf, int *fmt_buf_pos, int fmt_buf_len, + const char *delim_str) +{ + append_fmt(str_buf, str_buf_pos, str_buf_len, delim_str); + append_fmt(fmt_buf, fmt_buf_pos, fmt_buf_len, delim_str); +} + +#define test_array_8(fn, check_data, string, fmt, arr) \ +do { \ + BUILD_BUG_ON(ARRAY_SIZE(arr) != 8); \ + _test(fn, check_data, string, fmt, 8, \ + &(arr)[0], &(arr)[1], &(arr)[2], &(arr)[3], \ + &(arr)[4], &(arr)[5], &(arr)[6], &(arr)[7]); \ +} while (0) + +#define numbers_list_8(T, gen_fmt, field_sep, scan_fmt, fn) \ +do { \ + int i, pos = 0, fmt_pos = 0; \ + T expect[8], result[8]; \ + \ + fill_random_array(expect); \ + \ + for (i = 0; i < ARRAY_SIZE(expect); i++) { \ + if (i != 0) \ + append_delim(test_buffer, &pos, BUF_SIZE, \ + fmt_buffer, &fmt_pos, BUF_SIZE, \ + field_sep); \ + \ + append_fmt(test_buffer, &pos, BUF_SIZE, gen_fmt, expect[i]); \ + append_fmt(fmt_buffer, &fmt_pos, BUF_SIZE, "%%%s", scan_fmt); \ + } \ + \ + test_array_8(fn, expect, test_buffer, fmt_buffer, result); \ +} while (0) + +#define numbers_list_fix_width(T, gen_fmt, field_sep, width, scan_fmt, fn) \ +do { \ + char full_fmt[16]; \ + \ + snprintf(full_fmt, sizeof(full_fmt), "%u%s", width, scan_fmt); \ + numbers_list_8(T, gen_fmt, field_sep, full_fmt, fn); \ +} while (0) + +#define numbers_list_val_width(T, gen_fmt, field_sep, scan_fmt, fn) \ +do { \ + int i, val_len, pos = 0, fmt_pos = 0; \ + T expect[8], result[8]; \ + \ + fill_random_array(expect); \ + \ + for (i = 0; i < ARRAY_SIZE(expect); i++) { \ + if (i != 0) \ + append_delim(test_buffer, &pos, BUF_SIZE, \ + fmt_buffer, &fmt_pos, BUF_SIZE, field_sep);\ + \ + val_len = append_fmt(test_buffer, &pos, BUF_SIZE, gen_fmt, \ + expect[i]); \ + append_fmt(fmt_buffer, &fmt_pos, BUF_SIZE, \ + "%%%u%s", val_len, scan_fmt); \ + } \ + \ + test_array_8(fn, expect, test_buffer, fmt_buffer, result); \ +} while (0) + +static void __init numbers_list(const char *delim) +{ + numbers_list_8(unsigned long long, "%llu", delim, "llu", check_ull); + numbers_list_8(long long, "%lld", delim, "lld", check_ll); + numbers_list_8(long long, "%lld", delim, "lli", check_ll); + numbers_list_8(unsigned long long, "%llx", delim, "llx", check_ull); + numbers_list_8(unsigned long long, "0x%llx", delim, "llx", check_ull); + numbers_list_8(long long, "0x%llx", delim, "lli", check_ll); + + numbers_list_8(unsigned long, "%lu", delim, "lu", check_ulong); + numbers_list_8(long, "%ld", delim, "ld", check_long); + numbers_list_8(long, "%ld", delim, "li", check_long); + numbers_list_8(unsigned long, "%lx", delim, "lx", check_ulong); + numbers_list_8(unsigned long, "0x%lx", delim, "lx", check_ulong); + numbers_list_8(long, "0x%lx", delim, "li", check_long); + + numbers_list_8(unsigned int, "%u", delim, "u", check_uint); + numbers_list_8(int, "%d", delim, "d", check_int); + numbers_list_8(int, "%d", delim, "i", check_int); + numbers_list_8(unsigned int, "%x", delim, "x", check_uint); + numbers_list_8(unsigned int, "0x%x", delim, "x", check_uint); + numbers_list_8(int, "0x%x", delim, "i", check_int); + + numbers_list_8(unsigned short, "%hu", delim, "hu", check_ushort); + numbers_list_8(short, "%hd", delim, "hd", check_short); + numbers_list_8(short, "%hd", delim, "hi", check_short); + numbers_list_8(unsigned short, "%hx", delim, "hx", check_ushort); + numbers_list_8(unsigned short, "0x%hx", delim, "hx", check_ushort); + numbers_list_8(short, "0x%hx", delim, "hi", check_short); + + numbers_list_8(unsigned char, "%hhu", delim, "hhu", check_uchar); + numbers_list_8(signed char, "%hhd", delim, "hhd", check_char); + numbers_list_8(signed char, "%hhd", delim, "hhi", check_char); + numbers_list_8(unsigned char, "%hhx", delim, "hhx", check_uchar); + numbers_list_8(unsigned char, "0x%hhx", delim, "hhx", check_uchar); + numbers_list_8(signed char, "0x%hhx", delim, "hhi", check_char); +} + +/* + * List of numbers separated by delim. Each field width specifier is the + * maximum possible digits for the given type and base. + */ +static void __init numbers_list_field_width_typemax(const char *delim) +{ + numbers_list_fix_width(unsigned long long, "%llu", delim, 20, "llu", check_ull); + numbers_list_fix_width(long long, "%lld", delim, 20, "lld", check_ll); + numbers_list_fix_width(long long, "%lld", delim, 20, "lli", check_ll); + numbers_list_fix_width(unsigned long long, "%llx", delim, 16, "llx", check_ull); + numbers_list_fix_width(unsigned long long, "0x%llx", delim, 18, "llx", check_ull); + numbers_list_fix_width(long long, "0x%llx", delim, 18, "lli", check_ll); + +#if BITS_PER_LONG == 64 + numbers_list_fix_width(unsigned long, "%lu", delim, 20, "lu", check_ulong); + numbers_list_fix_width(long, "%ld", delim, 20, "ld", check_long); + numbers_list_fix_width(long, "%ld", delim, 20, "li", check_long); + numbers_list_fix_width(unsigned long, "%lx", delim, 16, "lx", check_ulong); + numbers_list_fix_width(unsigned long, "0x%lx", delim, 18, "lx", check_ulong); + numbers_list_fix_width(long, "0x%lx", delim, 18, "li", check_long); +#else + numbers_list_fix_width(unsigned long, "%lu", delim, 10, "lu", check_ulong); + numbers_list_fix_width(long, "%ld", delim, 11, "ld", check_long); + numbers_list_fix_width(long, "%ld", delim, 11, "li", check_long); + numbers_list_fix_width(unsigned long, "%lx", delim, 8, "lx", check_ulong); + numbers_list_fix_width(unsigned long, "0x%lx", delim, 10, "lx", check_ulong); + numbers_list_fix_width(long, "0x%lx", delim, 10, "li", check_long); +#endif + + numbers_list_fix_width(unsigned int, "%u", delim, 10, "u", check_uint); + numbers_list_fix_width(int, "%d", delim, 11, "d", check_int); + numbers_list_fix_width(int, "%d", delim, 11, "i", check_int); + numbers_list_fix_width(unsigned int, "%x", delim, 8, "x", check_uint); + numbers_list_fix_width(unsigned int, "0x%x", delim, 10, "x", check_uint); + numbers_list_fix_width(int, "0x%x", delim, 10, "i", check_int); + + numbers_list_fix_width(unsigned short, "%hu", delim, 5, "hu", check_ushort); + numbers_list_fix_width(short, "%hd", delim, 6, "hd", check_short); + numbers_list_fix_width(short, "%hd", delim, 6, "hi", check_short); + numbers_list_fix_width(unsigned short, "%hx", delim, 4, "hx", check_ushort); + numbers_list_fix_width(unsigned short, "0x%hx", delim, 6, "hx", check_ushort); + numbers_list_fix_width(short, "0x%hx", delim, 6, "hi", check_short); + + numbers_list_fix_width(unsigned char, "%hhu", delim, 3, "hhu", check_uchar); + numbers_list_fix_width(signed char, "%hhd", delim, 4, "hhd", check_char); + numbers_list_fix_width(signed char, "%hhd", delim, 4, "hhi", check_char); + numbers_list_fix_width(unsigned char, "%hhx", delim, 2, "hhx", check_uchar); + numbers_list_fix_width(unsigned char, "0x%hhx", delim, 4, "hhx", check_uchar); + numbers_list_fix_width(signed char, "0x%hhx", delim, 4, "hhi", check_char); +} + +/* + * List of numbers separated by delim. Each field width specifier is the + * exact length of the corresponding value digits in the string being scanned. + */ +static void __init numbers_list_field_width_val_width(const char *delim) +{ + numbers_list_val_width(unsigned long long, "%llu", delim, "llu", check_ull); + numbers_list_val_width(long long, "%lld", delim, "lld", check_ll); + numbers_list_val_width(long long, "%lld", delim, "lli", check_ll); + numbers_list_val_width(unsigned long long, "%llx", delim, "llx", check_ull); + numbers_list_val_width(unsigned long long, "0x%llx", delim, "llx", check_ull); + numbers_list_val_width(long long, "0x%llx", delim, "lli", check_ll); + + numbers_list_val_width(unsigned long, "%lu", delim, "lu", check_ulong); + numbers_list_val_width(long, "%ld", delim, "ld", check_long); + numbers_list_val_width(long, "%ld", delim, "li", check_long); + numbers_list_val_width(unsigned long, "%lx", delim, "lx", check_ulong); + numbers_list_val_width(unsigned long, "0x%lx", delim, "lx", check_ulong); + numbers_list_val_width(long, "0x%lx", delim, "li", check_long); + + numbers_list_val_width(unsigned int, "%u", delim, "u", check_uint); + numbers_list_val_width(int, "%d", delim, "d", check_int); + numbers_list_val_width(int, "%d", delim, "i", check_int); + numbers_list_val_width(unsigned int, "%x", delim, "x", check_uint); + numbers_list_val_width(unsigned int, "0x%x", delim, "x", check_uint); + numbers_list_val_width(int, "0x%x", delim, "i", check_int); + + numbers_list_val_width(unsigned short, "%hu", delim, "hu", check_ushort); + numbers_list_val_width(short, "%hd", delim, "hd", check_short); + numbers_list_val_width(short, "%hd", delim, "hi", check_short); + numbers_list_val_width(unsigned short, "%hx", delim, "hx", check_ushort); + numbers_list_val_width(unsigned short, "0x%hx", delim, "hx", check_ushort); + numbers_list_val_width(short, "0x%hx", delim, "hi", check_short); + + numbers_list_val_width(unsigned char, "%hhu", delim, "hhu", check_uchar); + numbers_list_val_width(signed char, "%hhd", delim, "hhd", check_char); + numbers_list_val_width(signed char, "%hhd", delim, "hhi", check_char); + numbers_list_val_width(unsigned char, "%hhx", delim, "hhx", check_uchar); + numbers_list_val_width(unsigned char, "0x%hhx", delim, "hhx", check_uchar); + numbers_list_val_width(signed char, "0x%hhx", delim, "hhi", check_char); +} + +/* + * Slice a continuous string of digits without field delimiters, containing + * numbers of varying length, using the field width to extract each group + * of digits. For example the hex values c0,3,bf01,303 would have a + * string representation of "c03bf01303" and extracted with "%2x%1x%4x%3x". + */ +static void __init numbers_slice(void) +{ + numbers_list_field_width_val_width(""); +} + +#define test_number_prefix(T, str, scan_fmt, expect0, expect1, n_args, fn) \ +do { \ + const T expect[2] = { expect0, expect1 }; \ + T result[2] = {~expect[0], ~expect[1]}; \ + \ + _test(fn, &expect, str, scan_fmt, n_args, &result[0], &result[1]); \ +} while (0) + +/* + * Number prefix is >= field width. + * Expected behaviour is derived from testing userland sscanf. + */ +static void __init numbers_prefix_overflow(void) +{ + /* + * Negative decimal with a field of width 1, should quit scanning + * and return 0. + */ + test_number_prefix(long long, "-1 1", "%1lld %lld", 0, 0, 0, check_ll); + test_number_prefix(long, "-1 1", "%1ld %ld", 0, 0, 0, check_long); + test_number_prefix(int, "-1 1", "%1d %d", 0, 0, 0, check_int); + test_number_prefix(short, "-1 1", "%1hd %hd", 0, 0, 0, check_short); + test_number_prefix(signed char, "-1 1", "%1hhd %hhd", 0, 0, 0, check_char); + + test_number_prefix(long long, "-1 1", "%1lli %lli", 0, 0, 0, check_ll); + test_number_prefix(long, "-1 1", "%1li %li", 0, 0, 0, check_long); + test_number_prefix(int, "-1 1", "%1i %i", 0, 0, 0, check_int); + test_number_prefix(short, "-1 1", "%1hi %hi", 0, 0, 0, check_short); + test_number_prefix(signed char, "-1 1", "%1hhi %hhi", 0, 0, 0, check_char); + + /* + * 0x prefix in a field of width 1: 0 is a valid digit so should + * convert. Next field scan starts at the 'x' which isn't a digit so + * scan quits with one field converted. + */ + test_number_prefix(unsigned long long, "0xA7", "%1llx%llx", 0, 0, 1, check_ull); + test_number_prefix(unsigned long, "0xA7", "%1lx%lx", 0, 0, 1, check_ulong); + test_number_prefix(unsigned int, "0xA7", "%1x%x", 0, 0, 1, check_uint); + test_number_prefix(unsigned short, "0xA7", "%1hx%hx", 0, 0, 1, check_ushort); + test_number_prefix(unsigned char, "0xA7", "%1hhx%hhx", 0, 0, 1, check_uchar); + test_number_prefix(long long, "0xA7", "%1lli%llx", 0, 0, 1, check_ll); + test_number_prefix(long, "0xA7", "%1li%lx", 0, 0, 1, check_long); + test_number_prefix(int, "0xA7", "%1i%x", 0, 0, 1, check_int); + test_number_prefix(short, "0xA7", "%1hi%hx", 0, 0, 1, check_short); + test_number_prefix(char, "0xA7", "%1hhi%hhx", 0, 0, 1, check_char); + + /* + * 0x prefix in a field of width 2 using %x conversion: first field + * converts to 0. Next field scan starts at the character after "0x". + * Both fields will convert. + */ + test_number_prefix(unsigned long long, "0xA7", "%2llx%llx", 0, 0xa7, 2, check_ull); + test_number_prefix(unsigned long, "0xA7", "%2lx%lx", 0, 0xa7, 2, check_ulong); + test_number_prefix(unsigned int, "0xA7", "%2x%x", 0, 0xa7, 2, check_uint); + test_number_prefix(unsigned short, "0xA7", "%2hx%hx", 0, 0xa7, 2, check_ushort); + test_number_prefix(unsigned char, "0xA7", "%2hhx%hhx", 0, 0xa7, 2, check_uchar); + + /* + * 0x prefix in a field of width 2 using %i conversion: first field + * converts to 0. Next field scan starts at the character after "0x", + * which will convert if can be intepreted as decimal but will fail + * if it contains any hex digits (since no 0x prefix). + */ + test_number_prefix(long long, "0x67", "%2lli%lli", 0, 67, 2, check_ll); + test_number_prefix(long, "0x67", "%2li%li", 0, 67, 2, check_long); + test_number_prefix(int, "0x67", "%2i%i", 0, 67, 2, check_int); + test_number_prefix(short, "0x67", "%2hi%hi", 0, 67, 2, check_short); + test_number_prefix(char, "0x67", "%2hhi%hhi", 0, 67, 2, check_char); + + test_number_prefix(long long, "0xA7", "%2lli%lli", 0, 0, 1, check_ll); + test_number_prefix(long, "0xA7", "%2li%li", 0, 0, 1, check_long); + test_number_prefix(int, "0xA7", "%2i%i", 0, 0, 1, check_int); + test_number_prefix(short, "0xA7", "%2hi%hi", 0, 0, 1, check_short); + test_number_prefix(char, "0xA7", "%2hhi%hhi", 0, 0, 1, check_char); +} + +#define _test_simple_strtoxx(T, fn, gen_fmt, expect, base) \ +do { \ + T got; \ + char *endp; \ + int len; \ + bool fail = false; \ + \ + total_tests++; \ + len = snprintf(test_buffer, BUF_SIZE, gen_fmt, expect); \ + got = (fn)(test_buffer, &endp, base); \ + pr_debug(#fn "(\"%s\", %d) -> " gen_fmt "\n", test_buffer, base, got); \ + if (got != (expect)) { \ + fail = true; \ + pr_warn(#fn "(\"%s\", %d): got " gen_fmt " expected " gen_fmt "\n", \ + test_buffer, base, got, expect); \ + } else if (endp != test_buffer + len) { \ + fail = true; \ + pr_warn(#fn "(\"%s\", %d) startp=0x%px got endp=0x%px expected 0x%px\n", \ + test_buffer, base, test_buffer, \ + test_buffer + len, endp); \ + } \ + \ + if (fail) \ + failed_tests++; \ +} while (0) + +#define test_simple_strtoxx(T, fn, gen_fmt, base) \ +do { \ + int i; \ + \ + for (i = 0; i < ARRAY_SIZE(numbers); i++) { \ + _test_simple_strtoxx(T, fn, gen_fmt, (T)numbers[i], base); \ + \ + if (is_signed_type(T)) \ + _test_simple_strtoxx(T, fn, gen_fmt, \ + -(T)numbers[i], base); \ + } \ +} while (0) + +static void __init test_simple_strtoull(void) +{ + test_simple_strtoxx(unsigned long long, simple_strtoull, "%llu", 10); + test_simple_strtoxx(unsigned long long, simple_strtoull, "%llu", 0); + test_simple_strtoxx(unsigned long long, simple_strtoull, "%llx", 16); + test_simple_strtoxx(unsigned long long, simple_strtoull, "0x%llx", 16); + test_simple_strtoxx(unsigned long long, simple_strtoull, "0x%llx", 0); +} + +static void __init test_simple_strtoll(void) +{ + test_simple_strtoxx(long long, simple_strtoll, "%lld", 10); + test_simple_strtoxx(long long, simple_strtoll, "%lld", 0); + test_simple_strtoxx(long long, simple_strtoll, "%llx", 16); + test_simple_strtoxx(long long, simple_strtoll, "0x%llx", 16); + test_simple_strtoxx(long long, simple_strtoll, "0x%llx", 0); +} + +static void __init test_simple_strtoul(void) +{ + test_simple_strtoxx(unsigned long, simple_strtoul, "%lu", 10); + test_simple_strtoxx(unsigned long, simple_strtoul, "%lu", 0); + test_simple_strtoxx(unsigned long, simple_strtoul, "%lx", 16); + test_simple_strtoxx(unsigned long, simple_strtoul, "0x%lx", 16); + test_simple_strtoxx(unsigned long, simple_strtoul, "0x%lx", 0); +} + +static void __init test_simple_strtol(void) +{ + test_simple_strtoxx(long, simple_strtol, "%ld", 10); + test_simple_strtoxx(long, simple_strtol, "%ld", 0); + test_simple_strtoxx(long, simple_strtol, "%lx", 16); + test_simple_strtoxx(long, simple_strtol, "0x%lx", 16); + test_simple_strtoxx(long, simple_strtol, "0x%lx", 0); +} + +/* Selection of common delimiters/separators between numbers in a string. */ +static const char * const number_delimiters[] __initconst = { + " ", ":", ",", "-", "/", +}; + +static void __init test_numbers(void) +{ + int i; + + /* String containing only one number. */ + numbers_simple(); + + /* String with multiple numbers separated by delimiter. */ + for (i = 0; i < ARRAY_SIZE(number_delimiters); i++) { + numbers_list(number_delimiters[i]); + + /* Field width may be longer than actual field digits. */ + numbers_list_field_width_typemax(number_delimiters[i]); + + /* Each field width exactly length of actual field digits. */ + numbers_list_field_width_val_width(number_delimiters[i]); + } + + /* Slice continuous sequence of digits using field widths. */ + numbers_slice(); + + numbers_prefix_overflow(); +} + +static void __init selftest(void) +{ + test_buffer = kmalloc(BUF_SIZE, GFP_KERNEL); + if (!test_buffer) + return; + + fmt_buffer = kmalloc(BUF_SIZE, GFP_KERNEL); + if (!fmt_buffer) { + kfree(test_buffer); + return; + } + + prandom_seed_state(&rnd_state, 3141592653589793238ULL); + + test_numbers(); + + test_simple_strtoull(); + test_simple_strtoll(); + test_simple_strtoul(); + test_simple_strtol(); + + kfree(fmt_buffer); + kfree(test_buffer); +} + +KSTM_MODULE_LOADERS(test_scanf); +MODULE_AUTHOR("Richard Fitzgerald "); +MODULE_LICENSE("GPL v2"); -- cgit v1.2.3 From 1b932689c77766b68e2ead51ca0fb84ec5bb8965 Mon Sep 17 00:00:00 2001 From: Richard Fitzgerald Date: Tue, 25 May 2021 13:20:11 +0100 Subject: lib: test_scanf: Remove pointless use of type_min() with unsigned types sparse was producing warnings of the form: sparse: cast truncates bits from constant value (ffff0001 becomes 1) There is no actual problem here. Using type_min() on an unsigned type results in an (expected) truncation. However, there is no need to test an unsigned value against type_min(). The minimum value of an unsigned is obviously 0, and any value cast to an unsigned type is >= 0, so for unsigneds only type_max() need be tested. This patch also takes the opportunity to clean up the implementation of simple_numbers_loop() to use a common pattern for the positive and negative test. Reported-by: kernel test robot Signed-off-by: Richard Fitzgerald Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210525122012.6336-2-rf@opensource.cirrus.com --- lib/test_scanf.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) (limited to 'lib') diff --git a/lib/test_scanf.c b/lib/test_scanf.c index 8d577aec6c28..48ff5747a4da 100644 --- a/lib/test_scanf.c +++ b/lib/test_scanf.c @@ -187,8 +187,8 @@ static const unsigned long long numbers[] __initconst = { #define value_representable_in_type(T, val) \ (is_signed_type(T) \ ? ((long long)(val) >= type_min(T)) && ((long long)(val) <= type_max(T)) \ - : ((unsigned long long)(val) >= type_min(T)) && \ - ((unsigned long long)(val) <= type_max(T))) + : ((unsigned long long)(val) <= type_max(T))) + #define test_one_number(T, gen_fmt, scan_fmt, val, fn) \ do { \ @@ -204,12 +204,11 @@ do { \ int i; \ \ for (i = 0; i < ARRAY_SIZE(numbers); i++) { \ - if (!value_representable_in_type(T, numbers[i])) \ - continue; \ - \ - test_one_number(T, gen_fmt, scan_fmt, numbers[i], fn); \ + if (value_representable_in_type(T, numbers[i])) \ + test_one_number(T, gen_fmt, scan_fmt, \ + numbers[i], fn); \ \ - if (is_signed_type(T)) \ + if (value_representable_in_type(T, -numbers[i])) \ test_one_number(T, gen_fmt, scan_fmt, \ -numbers[i], fn); \ } \ -- cgit v1.2.3 From 766c268bc6d39b8124e50d075a36b8a3305bc8e2 Mon Sep 17 00:00:00 2001 From: John Ogness Date: Thu, 17 Jun 2021 11:56:50 +0206 Subject: lib/dump_stack: move cpu lock to printk.c dump_stack() implements its own cpu-reentrant spinning lock to best-effort serialize stack traces in the printk log. However, there are other functions (such as show_regs()) that can also benefit from this serialization. Move the cpu-reentrant spinning lock (cpu lock) into new helper functions printk_cpu_lock_irqsave()/printk_cpu_unlock_irqrestore() so that it is available for others as well. For !CONFIG_SMP the cpu lock is a NOP. Note that having multiple cpu locks in the system can easily lead to deadlock. Code needing a cpu lock should use the printk cpu lock, since the printk cpu lock could be acquired from any code and any context. Also note that it is not necessary for a cpu lock to disable interrupts. However, in upcoming work this cpu lock will be used for emergency tasks (for example, atomic consoles during kernel crashes) and any interruptions while holding the cpu lock should be avoided if possible. Signed-off-by: John Ogness Reviewed-by: Sergey Senozhatsky Reviewed-by: Petr Mladek [pmladek@suse.com: Backported on top of 5.13-rc1.] Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210617095051.4808-2-john.ogness@linutronix.de --- include/linux/printk.h | 41 ++++++++++++++++++++++++++++++ kernel/printk/printk.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++ lib/dump_stack.c | 38 ++------------------------- 3 files changed, 112 insertions(+), 36 deletions(-) (limited to 'lib') diff --git a/include/linux/printk.h b/include/linux/printk.h index fe7eb2351610..1790a5521fd9 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -282,6 +282,47 @@ static inline void printk_safe_flush_on_panic(void) } #endif +#ifdef CONFIG_SMP +extern int __printk_cpu_trylock(void); +extern void __printk_wait_on_cpu_lock(void); +extern void __printk_cpu_unlock(void); + +/** + * printk_cpu_lock_irqsave() - Acquire the printk cpu-reentrant spinning + * lock and disable interrupts. + * @flags: Stack-allocated storage for saving local interrupt state, + * to be passed to printk_cpu_unlock_irqrestore(). + * + * If the lock is owned by another CPU, spin until it becomes available. + * Interrupts are restored while spinning. + */ +#define printk_cpu_lock_irqsave(flags) \ + for (;;) { \ + local_irq_save(flags); \ + if (__printk_cpu_trylock()) \ + break; \ + local_irq_restore(flags); \ + __printk_wait_on_cpu_lock(); \ + } + +/** + * printk_cpu_unlock_irqrestore() - Release the printk cpu-reentrant spinning + * lock and restore interrupts. + * @flags: Caller's saved interrupt state, from printk_cpu_lock_irqsave(). + */ +#define printk_cpu_unlock_irqrestore(flags) \ + do { \ + __printk_cpu_unlock(); \ + local_irq_restore(flags); \ + } while (0) \ + +#else + +#define printk_cpu_lock_irqsave(flags) ((void)flags) +#define printk_cpu_unlock_irqrestore(flags) ((void)flags) + +#endif /* CONFIG_SMP */ + extern int kptr_restrict; /** diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 421c35571797..9dfad0efb67f 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -3531,3 +3531,72 @@ void kmsg_dump_rewind(struct kmsg_dump_iter *iter) EXPORT_SYMBOL_GPL(kmsg_dump_rewind); #endif + +#ifdef CONFIG_SMP +static atomic_t printk_cpulock_owner = ATOMIC_INIT(-1); +static atomic_t printk_cpulock_nested = ATOMIC_INIT(0); + +/** + * __printk_wait_on_cpu_lock() - Busy wait until the printk cpu-reentrant + * spinning lock is not owned by any CPU. + * + * Context: Any context. + */ +void __printk_wait_on_cpu_lock(void) +{ + do { + cpu_relax(); + } while (atomic_read(&printk_cpulock_owner) != -1); +} +EXPORT_SYMBOL(__printk_wait_on_cpu_lock); + +/** + * __printk_cpu_trylock() - Try to acquire the printk cpu-reentrant + * spinning lock. + * + * If no processor has the lock, the calling processor takes the lock and + * becomes the owner. If the calling processor is already the owner of the + * lock, this function succeeds immediately. + * + * Context: Any context. Expects interrupts to be disabled. + * Return: 1 on success, otherwise 0. + */ +int __printk_cpu_trylock(void) +{ + int cpu; + int old; + + cpu = smp_processor_id(); + + old = atomic_cmpxchg(&printk_cpulock_owner, -1, cpu); + if (old == -1) { + /* This CPU is now the owner. */ + return 1; + } else if (old == cpu) { + /* This CPU is already the owner. */ + atomic_inc(&printk_cpulock_nested); + return 1; + } + + return 0; +} +EXPORT_SYMBOL(__printk_cpu_trylock); + +/** + * __printk_cpu_unlock() - Release the printk cpu-reentrant spinning lock. + * + * The calling processor must be the owner of the lock. + * + * Context: Any context. Expects interrupts to be disabled. + */ +void __printk_cpu_unlock(void) +{ + if (atomic_read(&printk_cpulock_nested)) { + atomic_dec(&printk_cpulock_nested); + return; + } + + atomic_set(&printk_cpulock_owner, -1); +} +EXPORT_SYMBOL(__printk_cpu_unlock); +#endif /* CONFIG_SMP */ diff --git a/lib/dump_stack.c b/lib/dump_stack.c index f5a33b6f773f..5ebf4375fa8c 100644 --- a/lib/dump_stack.c +++ b/lib/dump_stack.c @@ -84,50 +84,16 @@ static void __dump_stack(void) * * Architectures can override this implementation by implementing its own. */ -#ifdef CONFIG_SMP -static atomic_t dump_lock = ATOMIC_INIT(-1); - asmlinkage __visible void dump_stack(void) { unsigned long flags; - int was_locked; - int old; - int cpu; /* * Permit this cpu to perform nested stack dumps while serialising * against other CPUs */ -retry: - local_irq_save(flags); - cpu = smp_processor_id(); - old = atomic_cmpxchg(&dump_lock, -1, cpu); - if (old == -1) { - was_locked = 0; - } else if (old == cpu) { - was_locked = 1; - } else { - local_irq_restore(flags); - /* - * Wait for the lock to release before jumping to - * atomic_cmpxchg() in order to mitigate the thundering herd - * problem. - */ - do { cpu_relax(); } while (atomic_read(&dump_lock) != -1); - goto retry; - } - - __dump_stack(); - - if (!was_locked) - atomic_set(&dump_lock, -1); - - local_irq_restore(flags); -} -#else -asmlinkage __visible void dump_stack(void) -{ + printk_cpu_lock_irqsave(flags); __dump_stack(); + printk_cpu_unlock_irqrestore(flags); } -#endif EXPORT_SYMBOL(dump_stack); -- cgit v1.2.3