linux-sg2042/lib/test_printf.c

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/*
* Test cases for printf facility.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/printk.h>
#include <linux/random.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/bitmap.h>
#include <linux/dcache.h>
#include <linux/socket.h>
#include <linux/in.h>
mm, printk: introduce new format string for flags In mm we use several kinds of flags bitfields that are sometimes printed for debugging purposes, or exported to userspace via sysfs. To make them easier to interpret independently on kernel version and config, we want to dump also the symbolic flag names. So far this has been done with repeated calls to pr_cont(), which is unreliable on SMP, and not usable for e.g. sysfs export. To get a more reliable and universal solution, this patch extends printk() format string for pointers to handle the page flags (%pGp), gfp_flags (%pGg) and vma flags (%pGv). Existing users of dump_flag_names() are converted and simplified. It would be possible to pass flags by value instead of pointer, but the %p format string for pointers already has extensions for various kernel structures, so it's a good fit, and the extra indirection in a non-critical path is negligible. [linux@rasmusvillemoes.dk: lots of good implementation suggestions] Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-16 05:55:56 +08:00
#include <linux/gfp.h>
#include <linux/mm.h>
#include "../tools/testing/selftests/kselftest_module.h"
#define BUF_SIZE 256
#define PAD_SIZE 16
#define FILL_CHAR '$'
static unsigned total_tests __initdata;
static unsigned failed_tests __initdata;
static char *test_buffer __initdata;
static char *alloced_buffer __initdata;
static int __printf(4, 0) __init
do_test(int bufsize, const char *expect, int elen,
const char *fmt, va_list ap)
{
va_list aq;
int ret, written;
total_tests++;
memset(alloced_buffer, FILL_CHAR, BUF_SIZE + 2*PAD_SIZE);
va_copy(aq, ap);
ret = vsnprintf(test_buffer, bufsize, fmt, aq);
va_end(aq);
if (ret != elen) {
pr_warn("vsnprintf(buf, %d, \"%s\", ...) returned %d, expected %d\n",
bufsize, fmt, ret, elen);
return 1;
}
if (memchr_inv(alloced_buffer, FILL_CHAR, PAD_SIZE)) {
pr_warn("vsnprintf(buf, %d, \"%s\", ...) wrote before buffer\n", bufsize, fmt);
return 1;
}
if (!bufsize) {
if (memchr_inv(test_buffer, FILL_CHAR, BUF_SIZE + PAD_SIZE)) {
pr_warn("vsnprintf(buf, 0, \"%s\", ...) wrote to buffer\n",
fmt);
return 1;
}
return 0;
}
written = min(bufsize-1, elen);
if (test_buffer[written]) {
pr_warn("vsnprintf(buf, %d, \"%s\", ...) did not nul-terminate buffer\n",
bufsize, fmt);
return 1;
}
if (memchr_inv(test_buffer + written + 1, FILL_CHAR, BUF_SIZE + PAD_SIZE - (written + 1))) {
pr_warn("vsnprintf(buf, %d, \"%s\", ...) wrote beyond the nul-terminator\n",
bufsize, fmt);
return 1;
}
if (memcmp(test_buffer, expect, written)) {
pr_warn("vsnprintf(buf, %d, \"%s\", ...) wrote '%s', expected '%.*s'\n",
bufsize, fmt, test_buffer, written, expect);
return 1;
}
return 0;
}
static void __printf(3, 4) __init
__test(const char *expect, int elen, const char *fmt, ...)
{
va_list ap;
int rand;
char *p;
if (elen >= BUF_SIZE) {
pr_err("error in test suite: expected output length %d too long. Format was '%s'.\n",
elen, fmt);
failed_tests++;
return;
}
va_start(ap, fmt);
/*
* Every fmt+args is subjected to four tests: Three where we
* tell vsnprintf varying buffer sizes (plenty, not quite
* enough and 0), and then we also test that kvasprintf would
* be able to print it as expected.
*/
failed_tests += do_test(BUF_SIZE, expect, elen, fmt, ap);
rand = 1 + prandom_u32_max(elen+1);
/* Since elen < BUF_SIZE, we have 1 <= rand <= BUF_SIZE. */
failed_tests += do_test(rand, expect, elen, fmt, ap);
failed_tests += do_test(0, expect, elen, fmt, ap);
p = kvasprintf(GFP_KERNEL, fmt, ap);
if (p) {
total_tests++;
if (memcmp(p, expect, elen+1)) {
pr_warn("kvasprintf(..., \"%s\", ...) returned '%s', expected '%s'\n",
fmt, p, expect);
failed_tests++;
}
kfree(p);
}
va_end(ap);
}
#define test(expect, fmt, ...) \
__test(expect, strlen(expect), fmt, ##__VA_ARGS__)
static void __init
test_basic(void)
{
/* Work around annoying "warning: zero-length gnu_printf format string". */
char nul = '\0';
test("", &nul);
test("100%", "100%%");
test("xxx%yyy", "xxx%cyyy", '%');
__test("xxx\0yyy", 7, "xxx%cyyy", '\0');
}
static void __init
test_number(void)
{
test("0x1234abcd ", "%#-12x", 0x1234abcd);
test(" 0x1234abcd", "%#12x", 0x1234abcd);
test("0|001| 12|+123| 1234|-123|-1234", "%d|%03d|%3d|%+d|% d|%+d|% d", 0, 1, 12, 123, 1234, -123, -1234);
test("0|1|1|128|255", "%hhu|%hhu|%hhu|%hhu|%hhu", 0, 1, 257, 128, -1);
test("0|1|1|-128|-1", "%hhd|%hhd|%hhd|%hhd|%hhd", 0, 1, 257, 128, -1);
test("2015122420151225", "%ho%ho%#ho", 1037, 5282, -11627);
/*
* POSIX/C99: »The result of converting zero with an explicit
* precision of zero shall be no characters.« Hence the output
* from the below test should really be "00|0||| ". However,
* the kernel's printf also produces a single 0 in that
* case. This test case simply documents the current
* behaviour.
*/
test("00|0|0|0|0", "%.2d|%.1d|%.0d|%.*d|%1.0d", 0, 0, 0, 0, 0, 0);
#ifndef __CHAR_UNSIGNED__
{
/*
* Passing a 'char' to a %02x specifier doesn't do
* what was presumably the intention when char is
* signed and the value is negative. One must either &
* with 0xff or cast to u8.
*/
char val = -16;
test("0xfffffff0|0xf0|0xf0", "%#02x|%#02x|%#02x", val, val & 0xff, (u8)val);
}
#endif
}
static void __init
test_string(void)
{
test("", "%s%.0s", "", "123");
test("ABCD|abc|123", "%s|%.3s|%.*s", "ABCD", "abcdef", 3, "123456");
test("1 | 2|3 | 4|5 ", "%-3s|%3s|%-*s|%*s|%*s", "1", "2", 3, "3", 3, "4", -3, "5");
test("1234 ", "%-10.4s", "123456");
test(" 1234", "%10.4s", "123456");
/*
* POSIX and C99 say that a negative precision (which is only
* possible to pass via a * argument) should be treated as if
* the precision wasn't present, and that if the precision is
* omitted (as in %.s), the precision should be taken to be
* 0. However, the kernel's printf behave exactly opposite,
* treating a negative precision as 0 and treating an omitted
* precision specifier as if no precision was given.
*
* These test cases document the current behaviour; should
* anyone ever feel the need to follow the standards more
* closely, this can be revisited.
*/
test(" ", "%4.*s", -5, "123456");
test("123456", "%.s", "123456");
test("a||", "%.s|%.0s|%.*s", "a", "b", 0, "c");
test("a | | ", "%-3.s|%-3.0s|%-3.*s", "a", "b", 0, "c");
}
#define PLAIN_BUF_SIZE 64 /* leave some space so we don't oops */
#if BITS_PER_LONG == 64
#define PTR_WIDTH 16
#define PTR ((void *)0xffff0123456789abUL)
#define PTR_STR "ffff0123456789ab"
#define PTR_VAL_NO_CRNG "(____ptrval____)"
#define ZEROS "00000000" /* hex 32 zero bits */
static int __init
plain_format(void)
{
char buf[PLAIN_BUF_SIZE];
int nchars;
nchars = snprintf(buf, PLAIN_BUF_SIZE, "%p", PTR);
if (nchars != PTR_WIDTH)
return -1;
if (strncmp(buf, PTR_VAL_NO_CRNG, PTR_WIDTH) == 0) {
pr_warn("crng possibly not yet initialized. plain 'p' buffer contains \"%s\"",
PTR_VAL_NO_CRNG);
return 0;
}
if (strncmp(buf, ZEROS, strlen(ZEROS)) != 0)
return -1;
return 0;
}
#else
#define PTR_WIDTH 8
#define PTR ((void *)0x456789ab)
#define PTR_STR "456789ab"
#define PTR_VAL_NO_CRNG "(ptrval)"
vsprintf: Prevent crash when dereferencing invalid pointers We already prevent crash when dereferencing some obviously broken pointers. But the handling is not consistent. Sometimes we print "(null)" only for pure NULL pointer, sometimes for pointers in the first page and sometimes also for pointers in the last page (error codes). Note that printk() call this code under logbuf_lock. Any recursive printks are redirected to the printk_safe implementation and the messages are stored into per-CPU buffers. These buffers might be eventually flushed in printk_safe_flush_on_panic() but it is not guaranteed. This patch adds a check using probe_kernel_read(). It is not a full-proof test. But it should help to see the error message in 99% situations where the kernel would silently crash otherwise. Also it makes the error handling unified for "%s" and the many %p* specifiers that need to read the data from a given address. We print: + (null) when accessing data on pure pure NULL address + (efault) when accessing data on an invalid address It does not affect the %p* specifiers that just print the given address in some form, namely %pF, %pf, %pS, %ps, %pB, %pK, %px, and plain %p. Note that we print (efault) from security reasons. In fact, the real address can be seen only by %px or eventually %pK. Link: http://lkml.kernel.org/r/20190417115350.20479-9-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>
2019-04-17 19:53:48 +08:00
#define ZEROS ""
static int __init
plain_format(void)
{
/* Format is implicitly tested for 32 bit machines by plain_hash() */
return 0;
}
#endif /* BITS_PER_LONG == 64 */
static int __init
plain_hash_to_buffer(const void *p, char *buf, size_t len)
{
int nchars;
nchars = snprintf(buf, len, "%p", p);
if (nchars != PTR_WIDTH)
return -1;
if (strncmp(buf, PTR_VAL_NO_CRNG, PTR_WIDTH) == 0) {
pr_warn("crng possibly not yet initialized. plain 'p' buffer contains \"%s\"",
PTR_VAL_NO_CRNG);
return 0;
}
return 0;
}
static int __init
plain_hash(void)
{
char buf[PLAIN_BUF_SIZE];
int ret;
ret = plain_hash_to_buffer(PTR, buf, PLAIN_BUF_SIZE);
if (ret)
return ret;
if (strncmp(buf, PTR_STR, PTR_WIDTH) == 0)
return -1;
return 0;
}
/*
* We can't use test() to test %p because we don't know what output to expect
* after an address is hashed.
*/
static void __init
plain(void)
{
int err;
err = plain_hash();
if (err) {
pr_warn("plain 'p' does not appear to be hashed\n");
failed_tests++;
return;
}
err = plain_format();
if (err) {
pr_warn("hashing plain 'p' has unexpected format\n");
failed_tests++;
}
}
static void __init
test_hashed(const char *fmt, const void *p)
{
char buf[PLAIN_BUF_SIZE];
int ret;
/*
* No need to increase failed test counter since this is assumed
* to be called after plain().
*/
ret = plain_hash_to_buffer(p, buf, PLAIN_BUF_SIZE);
if (ret)
return;
test(buf, fmt, p);
}
vsprintf: Prevent crash when dereferencing invalid pointers We already prevent crash when dereferencing some obviously broken pointers. But the handling is not consistent. Sometimes we print "(null)" only for pure NULL pointer, sometimes for pointers in the first page and sometimes also for pointers in the last page (error codes). Note that printk() call this code under logbuf_lock. Any recursive printks are redirected to the printk_safe implementation and the messages are stored into per-CPU buffers. These buffers might be eventually flushed in printk_safe_flush_on_panic() but it is not guaranteed. This patch adds a check using probe_kernel_read(). It is not a full-proof test. But it should help to see the error message in 99% situations where the kernel would silently crash otherwise. Also it makes the error handling unified for "%s" and the many %p* specifiers that need to read the data from a given address. We print: + (null) when accessing data on pure pure NULL address + (efault) when accessing data on an invalid address It does not affect the %p* specifiers that just print the given address in some form, namely %pF, %pf, %pS, %ps, %pB, %pK, %px, and plain %p. Note that we print (efault) from security reasons. In fact, the real address can be seen only by %px or eventually %pK. Link: http://lkml.kernel.org/r/20190417115350.20479-9-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>
2019-04-17 19:53:48 +08:00
static void __init
null_pointer(void)
{
test_hashed("%p", NULL);
test(ZEROS "00000000", "%px", NULL);
test("(null)", "%pE", NULL);
}
#define PTR_INVALID ((void *)0x000000ab)
static void __init
invalid_pointer(void)
{
test_hashed("%p", PTR_INVALID);
test(ZEROS "000000ab", "%px", PTR_INVALID);
test("(efault)", "%pE", PTR_INVALID);
}
static void __init
symbol_ptr(void)
{
}
static void __init
kernel_ptr(void)
{
/* We can't test this without access to kptr_restrict. */
}
static void __init
struct_resource(void)
{
}
static void __init
addr(void)
{
}
static void __init
escaped_str(void)
{
}
static void __init
hex_string(void)
{
const char buf[3] = {0xc0, 0xff, 0xee};
test("c0 ff ee|c0:ff:ee|c0-ff-ee|c0ffee",
"%3ph|%3phC|%3phD|%3phN", buf, buf, buf, buf);
test("c0 ff ee|c0:ff:ee|c0-ff-ee|c0ffee",
"%*ph|%*phC|%*phD|%*phN", 3, buf, 3, buf, 3, buf, 3, buf);
}
static void __init
mac(void)
{
const u8 addr[6] = {0x2d, 0x48, 0xd6, 0xfc, 0x7a, 0x05};
test("2d:48:d6:fc:7a:05", "%pM", addr);
test("05:7a:fc:d6:48:2d", "%pMR", addr);
test("2d-48-d6-fc-7a-05", "%pMF", addr);
test("2d48d6fc7a05", "%pm", addr);
test("057afcd6482d", "%pmR", addr);
}
static void __init
ip4(void)
{
struct sockaddr_in sa;
sa.sin_family = AF_INET;
sa.sin_port = cpu_to_be16(12345);
sa.sin_addr.s_addr = cpu_to_be32(0x7f000001);
test("127.000.000.001|127.0.0.1", "%pi4|%pI4", &sa.sin_addr, &sa.sin_addr);
test("127.000.000.001|127.0.0.1", "%piS|%pIS", &sa, &sa);
sa.sin_addr.s_addr = cpu_to_be32(0x01020304);
test("001.002.003.004:12345|1.2.3.4:12345", "%piSp|%pISp", &sa, &sa);
}
static void __init
ip6(void)
{
}
static void __init
ip(void)
{
ip4();
ip6();
}
static void __init
uuid(void)
{
const char uuid[16] = {0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7,
0x8, 0x9, 0xa, 0xb, 0xc, 0xd, 0xe, 0xf};
test("00010203-0405-0607-0809-0a0b0c0d0e0f", "%pUb", uuid);
test("00010203-0405-0607-0809-0A0B0C0D0E0F", "%pUB", uuid);
test("03020100-0504-0706-0809-0a0b0c0d0e0f", "%pUl", uuid);
test("03020100-0504-0706-0809-0A0B0C0D0E0F", "%pUL", uuid);
}
static struct dentry test_dentry[4] __initdata = {
{ .d_parent = &test_dentry[0],
.d_name = QSTR_INIT(test_dentry[0].d_iname, 3),
.d_iname = "foo" },
{ .d_parent = &test_dentry[0],
.d_name = QSTR_INIT(test_dentry[1].d_iname, 5),
.d_iname = "bravo" },
{ .d_parent = &test_dentry[1],
.d_name = QSTR_INIT(test_dentry[2].d_iname, 4),
.d_iname = "alfa" },
{ .d_parent = &test_dentry[2],
.d_name = QSTR_INIT(test_dentry[3].d_iname, 5),
.d_iname = "romeo" },
};
static void __init
dentry(void)
{
test("foo", "%pd", &test_dentry[0]);
test("foo", "%pd2", &test_dentry[0]);
test("romeo", "%pd", &test_dentry[3]);
test("alfa/romeo", "%pd2", &test_dentry[3]);
test("bravo/alfa/romeo", "%pd3", &test_dentry[3]);
test("/bravo/alfa/romeo", "%pd4", &test_dentry[3]);
test("/bravo/alfa", "%pd4", &test_dentry[2]);
test("bravo/alfa |bravo/alfa ", "%-12pd2|%*pd2", &test_dentry[2], -12, &test_dentry[2]);
test(" bravo/alfa| bravo/alfa", "%12pd2|%*pd2", &test_dentry[2], 12, &test_dentry[2]);
}
static void __init
struct_va_format(void)
{
}
static void __init
struct_rtc_time(void)
{
/* 1543210543 */
const struct rtc_time tm = {
.tm_sec = 43,
.tm_min = 35,
.tm_hour = 5,
.tm_mday = 26,
.tm_mon = 10,
.tm_year = 118,
};
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);
test("05:35:43|0118-10-26", "%ptRtr|%ptRdr", &tm, &tm);
test("05:35:43|2018-11-26", "%ptRttr|%ptRdtr", &tm, &tm);
test("05:35:43 tr|2018-11-26 tr", "%ptRt tr|%ptRd tr", &tm, &tm);
}
static void __init
struct_clk(void)
{
}
static void __init
large_bitmap(void)
{
const int nbits = 1 << 16;
unsigned long *bits = bitmap_zalloc(nbits, GFP_KERNEL);
if (!bits)
return;
bitmap_set(bits, 1, 20);
bitmap_set(bits, 60000, 15);
test("1-20,60000-60014", "%*pbl", nbits, bits);
bitmap_free(bits);
}
static void __init
bitmap(void)
{
DECLARE_BITMAP(bits, 20);
const int primes[] = {2,3,5,7,11,13,17,19};
int i;
bitmap_zero(bits, 20);
test("00000|00000", "%20pb|%*pb", bits, 20, bits);
test("|", "%20pbl|%*pbl", bits, 20, bits);
for (i = 0; i < ARRAY_SIZE(primes); ++i)
set_bit(primes[i], bits);
test("a28ac|a28ac", "%20pb|%*pb", bits, 20, bits);
test("2-3,5,7,11,13,17,19|2-3,5,7,11,13,17,19", "%20pbl|%*pbl", bits, 20, bits);
bitmap_fill(bits, 20);
test("fffff|fffff", "%20pb|%*pb", bits, 20, bits);
test("0-19|0-19", "%20pbl|%*pbl", bits, 20, bits);
large_bitmap();
}
static void __init
netdev_features(void)
{
}
mm, printk: introduce new format string for flags In mm we use several kinds of flags bitfields that are sometimes printed for debugging purposes, or exported to userspace via sysfs. To make them easier to interpret independently on kernel version and config, we want to dump also the symbolic flag names. So far this has been done with repeated calls to pr_cont(), which is unreliable on SMP, and not usable for e.g. sysfs export. To get a more reliable and universal solution, this patch extends printk() format string for pointers to handle the page flags (%pGp), gfp_flags (%pGg) and vma flags (%pGv). Existing users of dump_flag_names() are converted and simplified. It would be possible to pass flags by value instead of pointer, but the %p format string for pointers already has extensions for various kernel structures, so it's a good fit, and the extra indirection in a non-critical path is negligible. [linux@rasmusvillemoes.dk: lots of good implementation suggestions] Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-16 05:55:56 +08:00
static void __init
flags(void)
{
unsigned long flags;
gfp_t gfp;
char *cmp_buffer;
flags = 0;
test("", "%pGp", &flags);
/* Page flags should filter the zone id */
flags = 1UL << NR_PAGEFLAGS;
test("", "%pGp", &flags);
flags |= 1UL << PG_uptodate | 1UL << PG_dirty | 1UL << PG_lru
| 1UL << PG_active | 1UL << PG_swapbacked;
test("uptodate|dirty|lru|active|swapbacked", "%pGp", &flags);
flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC
| VM_DENYWRITE;
test("read|exec|mayread|maywrite|mayexec|denywrite", "%pGv", &flags);
gfp = GFP_TRANSHUGE;
test("GFP_TRANSHUGE", "%pGg", &gfp);
gfp = GFP_ATOMIC|__GFP_DMA;
test("GFP_ATOMIC|GFP_DMA", "%pGg", &gfp);
gfp = __GFP_ATOMIC;
test("__GFP_ATOMIC", "%pGg", &gfp);
cmp_buffer = kmalloc(BUF_SIZE, GFP_KERNEL);
if (!cmp_buffer)
return;
/* Any flags not translated by the table should remain numeric */
gfp = ~__GFP_BITS_MASK;
snprintf(cmp_buffer, BUF_SIZE, "%#lx", (unsigned long) gfp);
test(cmp_buffer, "%pGg", &gfp);
snprintf(cmp_buffer, BUF_SIZE, "__GFP_ATOMIC|%#lx",
(unsigned long) gfp);
gfp |= __GFP_ATOMIC;
test(cmp_buffer, "%pGg", &gfp);
kfree(cmp_buffer);
}
static void __init
test_pointer(void)
{
plain();
vsprintf: Prevent crash when dereferencing invalid pointers We already prevent crash when dereferencing some obviously broken pointers. But the handling is not consistent. Sometimes we print "(null)" only for pure NULL pointer, sometimes for pointers in the first page and sometimes also for pointers in the last page (error codes). Note that printk() call this code under logbuf_lock. Any recursive printks are redirected to the printk_safe implementation and the messages are stored into per-CPU buffers. These buffers might be eventually flushed in printk_safe_flush_on_panic() but it is not guaranteed. This patch adds a check using probe_kernel_read(). It is not a full-proof test. But it should help to see the error message in 99% situations where the kernel would silently crash otherwise. Also it makes the error handling unified for "%s" and the many %p* specifiers that need to read the data from a given address. We print: + (null) when accessing data on pure pure NULL address + (efault) when accessing data on an invalid address It does not affect the %p* specifiers that just print the given address in some form, namely %pF, %pf, %pS, %ps, %pB, %pK, %px, and plain %p. Note that we print (efault) from security reasons. In fact, the real address can be seen only by %px or eventually %pK. Link: http://lkml.kernel.org/r/20190417115350.20479-9-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>
2019-04-17 19:53:48 +08:00
null_pointer();
invalid_pointer();
symbol_ptr();
kernel_ptr();
struct_resource();
addr();
escaped_str();
hex_string();
mac();
ip();
uuid();
dentry();
struct_va_format();
struct_rtc_time();
struct_clk();
bitmap();
netdev_features();
mm, printk: introduce new format string for flags In mm we use several kinds of flags bitfields that are sometimes printed for debugging purposes, or exported to userspace via sysfs. To make them easier to interpret independently on kernel version and config, we want to dump also the symbolic flag names. So far this has been done with repeated calls to pr_cont(), which is unreliable on SMP, and not usable for e.g. sysfs export. To get a more reliable and universal solution, this patch extends printk() format string for pointers to handle the page flags (%pGp), gfp_flags (%pGg) and vma flags (%pGv). Existing users of dump_flag_names() are converted and simplified. It would be possible to pass flags by value instead of pointer, but the %p format string for pointers already has extensions for various kernel structures, so it's a good fit, and the extra indirection in a non-critical path is negligible. [linux@rasmusvillemoes.dk: lots of good implementation suggestions] Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-16 05:55:56 +08:00
flags();
}
static void __init selftest(void)
{
alloced_buffer = kmalloc(BUF_SIZE + 2*PAD_SIZE, GFP_KERNEL);
if (!alloced_buffer)
return;
test_buffer = alloced_buffer + PAD_SIZE;
test_basic();
test_number();
test_string();
test_pointer();
kfree(alloced_buffer);
}
KSTM_MODULE_LOADERS(test_printf);
MODULE_AUTHOR("Rasmus Villemoes <linux@rasmusvillemoes.dk>");
MODULE_LICENSE("GPL");