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authorLinus Torvalds <torvalds@linux-foundation.org>2021-04-27 18:09:44 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-04-27 18:09:44 -0700
commit7f3d08b255d1806502e45fe70ca2ba9646eb3aa1 (patch)
treeb05f285f31a37dac5910c40a643c7d38b19dfe3c /lib
parent916a75965e5236f9e353416a703a0f4c8de2f56c (diff)
parentc8dbea6df351df211216b5f8877b020f21ecf75f (diff)
downloadlinux-7f3d08b255d1806502e45fe70ca2ba9646eb3aa1.tar.gz
Merge tag 'printk-for-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux
Pull printk updates from Petr Mladek: - Stop synchronizing kernel log buffer readers by logbuf_lock. As a result, the access to the buffer is fully lockless now. Note that printk() itself still uses locks because it tries to flush the messages to the console immediately. Also the per-CPU temporary buffers are still there because they prevent infinite recursion and serialize backtraces from NMI. All this is going to change in the future. - kmsg_dump API rework and cleanup as a side effect of the logbuf_lock removal. - Make bstr_printf() aware that %pf and %pF formats could deference the given pointer. - Show also page flags by %pGp format. - Clarify the documentation for plain pointer printing. - Do not show no_hash_pointers warning multiple times. - Update Senozhatsky email address. - Some clean up. * tag 'printk-for-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: (24 commits) lib/vsprintf.c: remove leftover 'f' and 'F' cases from bstr_printf() printk: clarify the documentation for plain pointer printing kernel/printk.c: Fixed mundane typos printk: rename vprintk_func to vprintk vsprintf: dump full information of page flags in pGp mm, slub: don't combine pr_err with INFO mm, slub: use pGp to print page flags MAINTAINERS: update Senozhatsky email address lib/vsprintf: do not show no_hash_pointers message multiple times printk: console: remove unnecessary safe buffer usage printk: kmsg_dump: remove _nolock() variants printk: remove logbuf_lock printk: introduce a kmsg_dump iterator printk: kmsg_dumper: remove @active field printk: add syslog_lock printk: use atomic64_t for devkmsg_user.seq printk: use seqcount_latch for clear_seq printk: introduce CONSOLE_LOG_MAX printk: consolidate kmsg_dump_get_buffer/syslog_print_all code printk: refactor kmsg_dump_get_buffer() ...
Diffstat (limited to 'lib')
-rw-r--r--lib/test_printf.c90
-rw-r--r--lib/vsprintf.c78
2 files changed, 149 insertions, 19 deletions
diff --git a/lib/test_printf.c b/lib/test_printf.c
index 95a2f82427c7..27b964ec723d 100644
--- a/lib/test_printf.c
+++ b/lib/test_printf.c
@@ -577,24 +577,98 @@ netdev_features(void)
{
}
+struct page_flags_test {
+ int width;
+ int shift;
+ int mask;
+ unsigned long value;
+ const char *fmt;
+ const char *name;
+};
+
+static struct page_flags_test pft[] = {
+ {SECTIONS_WIDTH, SECTIONS_PGSHIFT, SECTIONS_MASK,
+ 0, "%d", "section"},
+ {NODES_WIDTH, NODES_PGSHIFT, NODES_MASK,
+ 0, "%d", "node"},
+ {ZONES_WIDTH, ZONES_PGSHIFT, ZONES_MASK,
+ 0, "%d", "zone"},
+ {LAST_CPUPID_WIDTH, LAST_CPUPID_PGSHIFT, LAST_CPUPID_MASK,
+ 0, "%#x", "lastcpupid"},
+ {KASAN_TAG_WIDTH, KASAN_TAG_PGSHIFT, KASAN_TAG_MASK,
+ 0, "%#x", "kasantag"},
+};
+
+static void __init
+page_flags_test(int section, int node, int zone, int last_cpupid,
+ int kasan_tag, int flags, const char *name, char *cmp_buf)
+{
+ unsigned long values[] = {section, node, zone, last_cpupid, kasan_tag};
+ unsigned long page_flags = 0;
+ unsigned long size = 0;
+ bool append = false;
+ int i;
+
+ flags &= BIT(NR_PAGEFLAGS) - 1;
+ if (flags) {
+ page_flags |= flags;
+ snprintf(cmp_buf + size, BUF_SIZE - size, "%s", name);
+ size = strlen(cmp_buf);
+#if SECTIONS_WIDTH || NODES_WIDTH || ZONES_WIDTH || \
+ LAST_CPUPID_WIDTH || KASAN_TAG_WIDTH
+ /* Other information also included in page flags */
+ snprintf(cmp_buf + size, BUF_SIZE - size, "|");
+ size = strlen(cmp_buf);
+#endif
+ }
+
+ /* Set the test value */
+ for (i = 0; i < ARRAY_SIZE(pft); i++)
+ pft[i].value = values[i];
+
+ for (i = 0; i < ARRAY_SIZE(pft); i++) {
+ if (!pft[i].width)
+ continue;
+
+ if (append) {
+ snprintf(cmp_buf + size, BUF_SIZE - size, "|");
+ size = strlen(cmp_buf);
+ }
+
+ page_flags |= (pft[i].value & pft[i].mask) << pft[i].shift;
+ snprintf(cmp_buf + size, BUF_SIZE - size, "%s=", pft[i].name);
+ size = strlen(cmp_buf);
+ snprintf(cmp_buf + size, BUF_SIZE - size, pft[i].fmt,
+ pft[i].value & pft[i].mask);
+ size = strlen(cmp_buf);
+ append = true;
+ }
+
+ test(cmp_buf, "%pGp", &page_flags);
+}
+
static void __init
flags(void)
{
unsigned long flags;
- gfp_t gfp;
char *cmp_buffer;
+ gfp_t gfp;
+
+ cmp_buffer = kmalloc(BUF_SIZE, GFP_KERNEL);
+ if (!cmp_buffer)
+ return;
flags = 0;
- test("", "%pGp", &flags);
+ page_flags_test(0, 0, 0, 0, 0, flags, "", cmp_buffer);
- /* Page flags should filter the zone id */
flags = 1UL << NR_PAGEFLAGS;
- test("", "%pGp", &flags);
+ page_flags_test(0, 0, 0, 0, 0, flags, "", cmp_buffer);
flags |= 1UL << PG_uptodate | 1UL << PG_dirty | 1UL << PG_lru
| 1UL << PG_active | 1UL << PG_swapbacked;
- test("uptodate|dirty|lru|active|swapbacked", "%pGp", &flags);
-
+ page_flags_test(1, 1, 1, 0x1fffff, 1, flags,
+ "uptodate|dirty|lru|active|swapbacked",
+ cmp_buffer);
flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC
| VM_DENYWRITE;
@@ -609,10 +683,6 @@ flags(void)
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);
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 41ddc353ebb8..6c56c62fd9a5 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1916,6 +1916,66 @@ char *format_flags(char *buf, char *end, unsigned long flags,
return buf;
}
+struct page_flags_fields {
+ int width;
+ int shift;
+ int mask;
+ const struct printf_spec *spec;
+ const char *name;
+};
+
+static const struct page_flags_fields pff[] = {
+ {SECTIONS_WIDTH, SECTIONS_PGSHIFT, SECTIONS_MASK,
+ &default_dec_spec, "section"},
+ {NODES_WIDTH, NODES_PGSHIFT, NODES_MASK,
+ &default_dec_spec, "node"},
+ {ZONES_WIDTH, ZONES_PGSHIFT, ZONES_MASK,
+ &default_dec_spec, "zone"},
+ {LAST_CPUPID_WIDTH, LAST_CPUPID_PGSHIFT, LAST_CPUPID_MASK,
+ &default_flag_spec, "lastcpupid"},
+ {KASAN_TAG_WIDTH, KASAN_TAG_PGSHIFT, KASAN_TAG_MASK,
+ &default_flag_spec, "kasantag"},
+};
+
+static
+char *format_page_flags(char *buf, char *end, unsigned long flags)
+{
+ unsigned long main_flags = flags & (BIT(NR_PAGEFLAGS) - 1);
+ bool append = false;
+ int i;
+
+ /* Page flags from the main area. */
+ if (main_flags) {
+ buf = format_flags(buf, end, main_flags, pageflag_names);
+ append = true;
+ }
+
+ /* Page flags from the fields area */
+ for (i = 0; i < ARRAY_SIZE(pff); i++) {
+ /* Skip undefined fields. */
+ if (!pff[i].width)
+ continue;
+
+ /* Format: Flag Name + '=' (equals sign) + Number + '|' (separator) */
+ if (append) {
+ if (buf < end)
+ *buf = '|';
+ buf++;
+ }
+
+ buf = string(buf, end, pff[i].name, default_str_spec);
+ if (buf < end)
+ *buf = '=';
+ buf++;
+ buf = number(buf, end, (flags >> pff[i].shift) & pff[i].mask,
+ *pff[i].spec);
+
+ append = true;
+ }
+
+ return buf;
+}
+
static noinline_for_stack
char *flags_string(char *buf, char *end, void *flags_ptr,
struct printf_spec spec, const char *fmt)
@@ -1928,11 +1988,7 @@ char *flags_string(char *buf, char *end, void *flags_ptr,
switch (fmt[1]) {
case 'p':
- flags = *(unsigned long *)flags_ptr;
- /* Remove zone id */
- flags &= (1UL << NR_PAGEFLAGS) - 1;
- names = pageflag_names;
- break;
+ return format_page_flags(buf, end, *(unsigned long *)flags_ptr);
case 'v':
flags = *(unsigned long *)flags_ptr;
names = vmaflag_names;
@@ -2096,6 +2152,9 @@ EXPORT_SYMBOL_GPL(no_hash_pointers);
static int __init no_hash_pointers_enable(char *str)
{
+ if (no_hash_pointers)
+ return 0;
+
no_hash_pointers = true;
pr_warn("**********************************************************\n");
@@ -2186,7 +2245,9 @@ early_param("no_hash_pointers", no_hash_pointers_enable);
* Implements a "recursive vsnprintf".
* Do not use this feature without some mechanism to verify the
* correctness of the format string and va_list arguments.
- * - 'K' For a kernel pointer that should be hidden from unprivileged users
+ * - 'K' For a kernel pointer that should be hidden from unprivileged users.
+ * Use only for procfs, sysfs and similar files, not printk(); please
+ * read the documentation (path below) first.
* - 'NF' For a netdev_features_t
* - 'h[CDN]' For a variable-length buffer, it prints it as a hex string with
* a certain separator (' ' by default):
@@ -2225,7 +2286,8 @@ early_param("no_hash_pointers", no_hash_pointers_enable);
* Without an option prints the full name of the node
* f full name
* P node name, including a possible unit address
- * - 'x' For printing the address. Equivalent to "%lx".
+ * - 'x' For printing the address unmodified. Equivalent to "%lx".
+ * Please read the documentation (path below) before using!
* - '[ku]s' For a BPF/tracing related format specifier, e.g. used out of
* bpf_trace_printk() where [ku] prefix specifies either kernel (k)
* or user (u) memory to probe, and:
@@ -3135,8 +3197,6 @@ int bstr_printf(char *buf, size_t size, const char *fmt, const u32 *bin_buf)
switch (*fmt) {
case 'S':
case 's':
- case 'F':
- case 'f':
case 'x':
case 'K':
case 'e':