Merge tag 'printk-for-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux

Pull printk updates from Petr Mladek:

 - Extend %pGp print format to print hex value of the page flags

 - Use kvmalloc instead of kmalloc to allocate devkmsg buffers

 - Misc cleanup and warning fixes

* tag 'printk-for-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
  vsprintf: Update %pGp documentation about that it prints hex value
  lib/vsprintf.c: Amend static asserts for format specifier flags
  vsprintf: Make %pGp print the hex value
  test_printf: Append strings more efficiently
  test_printf: Remove custom appending of '|'
  test_printf: Remove separate page_flags variable
  test_printf: Make pft array const
  ia64: don't do IA64_CMPXCHG_DEBUG without CONFIG_PRINTK
  printk: use gnu_printf format attribute for printk_sprint()
  printk: avoid -Wsometimes-uninitialized warning
  printk: use kvmalloc instead of kmalloc for devkmsg_user

Author: torvalds

Documentation/core-api/printk-formats.rst

@@ -580,7 +580,7 @@ Flags bitfields such as page flags, gfp_flags
 
 ::
 
-	%pGp	referenced|uptodate|lru|active|private|node=0|zone=2|lastcpupid=0x1fffff
+	%pGp	0x17ffffc0002036(referenced|uptodate|lru|active|private|node=0|zone=2|lastcpupid=0x1fffff)
 	%pGg	GFP_USER|GFP_DMA32|GFP_NOWARN
 	%pGv	read|exec|mayread|maywrite|mayexec|denywrite
 

arch/ia64/Kconfig.debug

@@ -39,7 +39,7 @@ config DISABLE_VHPT
 
 config IA64_DEBUG_CMPXCHG
 	bool "Turn on compare-and-exchange bug checking (slow!)"
-	depends on DEBUG_KERNEL
+	depends on DEBUG_KERNEL && PRINTK
 	help
 	  Selecting this option turns on bug checking for the IA-64
 	  compare-and-exchange instructions.  This is slow!  Itaniums

kernel/printk/index.c

@@ -26,10 +26,9 @@ static struct pi_entry *pi_get_entry(const struct module *mod, loff_t pos)
 	if (mod) {
 		entries = mod->printk_index_start;
 		nr_entries = mod->printk_index_size;
-	}
+	} else
 #endif
-
-	if (!mod) {
+	{
 		/* vmlinux, comes from linker symbols */
 		entries = __start_printk_index;
 		nr_entries = __stop_printk_index - __start_printk_index;

kernel/printk/printk.c

@@ -847,7 +847,7 @@ static int devkmsg_open(struct inode *inode, struct file *file)
 			return err;
 	}
 
-	user = kmalloc(sizeof(struct devkmsg_user), GFP_KERNEL);
+	user = kvmalloc(sizeof(struct devkmsg_user), GFP_KERNEL);
 	if (!user)
 		return -ENOMEM;
 
@@ -875,7 +875,7 @@ static int devkmsg_release(struct inode *inode, struct file *file)
 	ratelimit_state_exit(&user->rs);
 
 	mutex_destroy(&user->lock);
-	kfree(user);
+	kvfree(user);
 	return 0;
 }
 
@@ -2066,6 +2066,7 @@ u16 printk_parse_prefix(const char *text, int *level,
 	return prefix_len;
 }
 
+__printf(5, 0)
 static u16 printk_sprint(char *text, u16 size, int facility,
 			 enum printk_info_flags *flags, const char *fmt,
 			 va_list args)

lib/test_printf.c

@@ -586,70 +586,59 @@ 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[] = {
+static const struct page_flags_test pft[] = {
 	{SECTIONS_WIDTH, SECTIONS_PGSHIFT, SECTIONS_MASK,
-	 0, "%d", "section"},
+	 "%d", "section"},
 	{NODES_WIDTH, NODES_PGSHIFT, NODES_MASK,
-	 0, "%d", "node"},
+	 "%d", "node"},
 	{ZONES_WIDTH, ZONES_PGSHIFT, ZONES_MASK,
-	 0, "%d", "zone"},
+	 "%d", "zone"},
 	{LAST_CPUPID_WIDTH, LAST_CPUPID_PGSHIFT, LAST_CPUPID_MASK,
-	 0, "%#x", "lastcpupid"},
+	 "%#x", "lastcpupid"},
 	{KASAN_TAG_WIDTH, KASAN_TAG_PGSHIFT, KASAN_TAG_MASK,
-	 0, "%#x", "kasantag"},
+	 "%#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)
+		int kasan_tag, unsigned long 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;
+	unsigned long size;
 	bool append = false;
 	int i;
 
-	flags &= PAGEFLAGS_MASK;
-	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
-	}
+	for (i = 0; i < ARRAY_SIZE(values); i++)
+		flags |= (values[i] & pft[i].mask) << pft[i].shift;
 
-	/* Set the test value */
-	for (i = 0; i < ARRAY_SIZE(pft); i++)
-		pft[i].value = values[i];
+	size = scnprintf(cmp_buf, BUF_SIZE, "%#lx(", flags);
+	if (flags & PAGEFLAGS_MASK) {
+		size += scnprintf(cmp_buf + size, BUF_SIZE - size, "%s", name);
+		append = true;
+	}
 
 	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);
-		}
+		if (append)
+			size += scnprintf(cmp_buf + size, BUF_SIZE - size, "|");
 
-		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);
+		size += scnprintf(cmp_buf + size, BUF_SIZE - size, "%s=",
+				pft[i].name);
+		size += scnprintf(cmp_buf + size, BUF_SIZE - size, pft[i].fmt,
+				values[i] & pft[i].mask);
 		append = true;
 	}
 
-	test(cmp_buf, "%pGp", &page_flags);
+	snprintf(cmp_buf + size, BUF_SIZE - size, ")");
+
+	test(cmp_buf, "%pGp", &flags);
 }
 
 static void __init

lib/vsprintf.c

@@ -408,8 +408,9 @@ int num_to_str(char *buf, int size, unsigned long long num, unsigned int width)
 #define SMALL	32		/* use lowercase in hex (must be 32 == 0x20) */
 #define SPECIAL	64		/* prefix hex with "0x", octal with "0" */
 
+static_assert(SIGN == 1);
 static_assert(ZEROPAD == ('0' - ' '));
-static_assert(SMALL == ' ');
+static_assert(SMALL == ('a' ^ 'A'));
 
 enum format_type {
 	FORMAT_TYPE_NONE, /* Just a string part */
@@ -2023,6 +2024,11 @@ char *format_page_flags(char *buf, char *end, unsigned long flags)
 	bool append = false;
 	int i;
 
+	buf = number(buf, end, flags, default_flag_spec);
+	if (buf < end)
+		*buf = '(';
+	buf++;
+
 	/* Page flags from the main area. */
 	if (main_flags) {
 		buf = format_flags(buf, end, main_flags, pageflag_names);
@@ -2051,6 +2057,9 @@ char *format_page_flags(char *buf, char *end, unsigned long flags)
 
 		append = true;
 	}
+	if (buf < end)
+		*buf = ')';
+	buf++;
 
 	return buf;
 }

mm/debug.c

@@ -162,7 +162,7 @@ static void __dump_page(struct page *page)
 out_mapping:
 	BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
 
-	pr_warn("%sflags: %#lx(%pGp)%s\n", type, head->flags, &head->flags,
+	pr_warn("%sflags: %pGp%s\n", type, &head->flags,
 		page_cma ? " CMA" : "");
 	print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
 			sizeof(unsigned long), page,

mm/memory-failure.c

@@ -2109,14 +2109,14 @@ static int __soft_offline_page(struct page *page)
 			if (!list_empty(&pagelist))
 				putback_movable_pages(&pagelist);
 
-			pr_info("soft offline: %#lx: %s migration failed %d, type %lx (%pGp)\n",
-				pfn, msg_page[huge], ret, page->flags, &page->flags);
+			pr_info("soft offline: %#lx: %s migration failed %d, type %pGp\n",
+				pfn, msg_page[huge], ret, &page->flags);
 			if (ret > 0)
 				ret = -EBUSY;
 		}
 	} else {
-		pr_info("soft offline: %#lx: %s isolation failed, page count %d, type %lx (%pGp)\n",
-			pfn, msg_page[huge], page_count(page), page->flags, &page->flags);
+		pr_info("soft offline: %#lx: %s isolation failed, page count %d, type %pGp\n",
+			pfn, msg_page[huge], page_count(page), &page->flags);
 		ret = -EBUSY;
 	}
 	return ret;

mm/page_owner.c

@@ -351,12 +351,12 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn,
 	pageblock_mt = get_pageblock_migratetype(page);
 	page_mt  = gfp_migratetype(page_owner->gfp_mask);
 	ret += snprintf(kbuf + ret, count - ret,
-			"PFN %lu type %s Block %lu type %s Flags %#lx(%pGp)\n",
+			"PFN %lu type %s Block %lu type %s Flags %pGp\n",
 			pfn,
 			migratetype_names[page_mt],
 			pfn >> pageblock_order,
 			migratetype_names[pageblock_mt],
-			page->flags, &page->flags);
+			&page->flags);
 
 	if (ret >= count)
 		goto err;

mm/slub.c

@@ -763,9 +763,9 @@ void print_tracking(struct kmem_cache *s, void *object)
 
 static void print_page_info(struct page *page)
 {
-	pr_err("Slab 0x%p objects=%u used=%u fp=0x%p flags=%#lx(%pGp)\n",
+	pr_err("Slab 0x%p objects=%u used=%u fp=0x%p flags=%pGp\n",
 	       page, page->objects, page->inuse, page->freelist,
-	       page->flags, &page->flags);
+	       &page->flags);
 
 }