Merge tag 'printk-for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk

Pull printk updates from Petr Mladek:

 - Help userspace log daemons to catch up with a flood of messages. They
   will get woken after each message even if the console is far behind
   and handled by another process.

 - Flush printk safe buffers safely even when panic() happens in the
   normal context.

 - Fix possible va_list reuse when race happened in printk_safe().

 - Remove %pCr printf format to prevent sleeping in the atomic context.

 - Misc vsprintf code cleanup.

* tag 'printk-for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
  printk: drop in_nmi check from printk_safe_flush_on_panic()
  lib/vsprintf: Remove atomic-unsafe support for %pCr
  serial: sh-sci: Stop using printk format %pCr
  thermal: bcm2835: Stop using printk format %pCr
  clk: renesas: cpg-mssr: Stop using printk format %pCr
  printk: fix possible reuse of va_list variable
  printk: wake up klogd in vprintk_emit
  vsprintf: Tweak pF/pf comment
  lib/vsprintf: Mark expected switch fall-through
  lib/vsprintf: Replace space with '_' before crng is ready
  lib/vsprintf: Deduplicate pointer_string()
  lib/vsprintf: Move pointer_string() upper
  lib/vsprintf: Make flag_spec global
  lib/vsprintf: Make strspec global
  lib/vsprintf: Make dec_spec global
  lib/test_printf: Mark big constant with UL

Documentation/core-api/printk-formats.rst

@@ -419,11 +419,10 @@ struct clk
 
 	%pC	pll1
 	%pCn	pll1
-	%pCr	1560000000
 
 For printing struct clk structures. %pC and %pCn print the name
 (Common Clock Framework) or address (legacy clock framework) of the
-structure; %pCr prints the current clock rate.
+structure.
 
 Passed by reference.
 

drivers/clk/renesas/renesas-cpg-mssr.c

@@ -258,8 +258,9 @@ struct clk *cpg_mssr_clk_src_twocell_get(struct of_phandle_args *clkspec,
 		dev_err(dev, "Cannot get %s clock %u: %ld", type, clkidx,
 		       PTR_ERR(clk));
 	else
-		dev_dbg(dev, "clock (%u, %u) is %pC at %pCr Hz\n",
-			clkspec->args[0], clkspec->args[1], clk, clk);
+		dev_dbg(dev, "clock (%u, %u) is %pC at %lu Hz\n",
+			clkspec->args[0], clkspec->args[1], clk,
+			clk_get_rate(clk));
 	return clk;
 }
 
@@ -326,7 +327,7 @@ static void __init cpg_mssr_register_core_clk(const struct cpg_core_clk *core,
 	if (IS_ERR_OR_NULL(clk))
 		goto fail;
 
-	dev_dbg(dev, "Core clock %pC at %pCr Hz\n", clk, clk);
+	dev_dbg(dev, "Core clock %pC at %lu Hz\n", clk, clk_get_rate(clk));
 	priv->clks[id] = clk;
 	return;
 
@@ -392,7 +393,7 @@ static void __init cpg_mssr_register_mod_clk(const struct mssr_mod_clk *mod,
 	if (IS_ERR(clk))
 		goto fail;
 
-	dev_dbg(dev, "Module clock %pC at %pCr Hz\n", clk, clk);
+	dev_dbg(dev, "Module clock %pC at %lu Hz\n", clk, clk_get_rate(clk));
 	priv->clks[id] = clk;
 	priv->smstpcr_saved[clock->index / 32].mask |= BIT(clock->index % 32);
 	return;

drivers/thermal/broadcom/bcm2835_thermal.c

@@ -213,8 +213,8 @@ static int bcm2835_thermal_probe(struct platform_device *pdev)
 	rate = clk_get_rate(data->clk);
 	if ((rate < 1920000) || (rate > 5000000))
 		dev_warn(&pdev->dev,
-			 "Clock %pCn running at %pCr Hz is outside of the recommended range: 1.92 to 5MHz\n",
-			 data->clk, data->clk);
+			 "Clock %pCn running at %lu Hz is outside of the recommended range: 1.92 to 5MHz\n",
+			 data->clk, rate);
 
 	/* register of thermal sensor and get info from DT */
 	tz = thermal_zone_of_sensor_register(&pdev->dev, 0, data,

drivers/tty/serial/sh-sci.c

@@ -2724,8 +2724,8 @@ static int sci_init_clocks(struct sci_port *sci_port, struct device *dev)
 			dev_dbg(dev, "failed to get %s (%ld)\n", clk_names[i],
 				PTR_ERR(clk));
 		else
-			dev_dbg(dev, "clk %s is %pC rate %pCr\n", clk_names[i],
-				clk, clk);
+			dev_dbg(dev, "clk %s is %pC rate %lu\n", clk_names[i],
+				clk, clk_get_rate(clk));
 		sci_port->clks[i] = IS_ERR(clk) ? NULL : clk;
 	}
 	return 0;

kernel/printk/printk.c

@@ -1908,6 +1908,7 @@ asmlinkage int vprintk_emit(int facility, int level,
 		preempt_enable();
 	}
 
+	wake_up_klogd();
 	return printed_len;
 }
 EXPORT_SYMBOL(vprintk_emit);
@@ -2289,9 +2290,7 @@ void console_unlock(void)
 {
 	static char ext_text[CONSOLE_EXT_LOG_MAX];
 	static char text[LOG_LINE_MAX + PREFIX_MAX];
-	static u64 seen_seq;
 	unsigned long flags;
-	bool wake_klogd = false;
 	bool do_cond_resched, retry;
 
 	if (console_suspended) {
@@ -2335,11 +2334,6 @@ void console_unlock(void)
 
 		printk_safe_enter_irqsave(flags);
 		raw_spin_lock(&logbuf_lock);
-		if (seen_seq != log_next_seq) {
-			wake_klogd = true;
-			seen_seq = log_next_seq;
-		}
-
 		if (console_seq < log_first_seq) {
 			len = sprintf(text, "** %u printk messages dropped **\n",
 				      (unsigned)(log_first_seq - console_seq));
@@ -2397,7 +2391,7 @@ void console_unlock(void)
 
 		if (console_lock_spinning_disable_and_check()) {
 			printk_safe_exit_irqrestore(flags);
-			goto out;
+			return;
 		}
 
 		printk_safe_exit_irqrestore(flags);
@@ -2429,10 +2423,6 @@ void console_unlock(void)
 
 	if (retry && console_trylock())
 		goto again;
-
-out:
-	if (wake_klogd)
-		wake_up_klogd();
 }
 EXPORT_SYMBOL(console_unlock);
 

kernel/printk/printk_safe.c

@@ -82,6 +82,7 @@ static __printf(2, 0) int printk_safe_log_store(struct printk_safe_seq_buf *s,
 {
 	int add;
 	size_t len;
+	va_list ap;
 
 again:
 	len = atomic_read(&s->len);
@@ -100,7 +101,9 @@ static __printf(2, 0) int printk_safe_log_store(struct printk_safe_seq_buf *s,
 	if (!len)
 		smp_rmb();
 
-	add = vscnprintf(s->buffer + len, sizeof(s->buffer) - len, fmt, args);
+	va_copy(ap, args);
+	add = vscnprintf(s->buffer + len, sizeof(s->buffer) - len, fmt, ap);
+	va_end(ap);
 	if (!add)
 		return 0;
 
@@ -278,7 +281,7 @@ void printk_safe_flush_on_panic(void)
 	 * Make sure that we could access the main ring buffer.
 	 * Do not risk a double release when more CPUs are up.
 	 */
-	if (in_nmi() && raw_spin_is_locked(&logbuf_lock)) {
+	if (raw_spin_is_locked(&logbuf_lock)) {
 		if (num_online_cpus() > 1)
 			return;
 

lib/test_printf.c

@@ -204,7 +204,7 @@ test_string(void)
 #if BITS_PER_LONG == 64
 
 #define PTR_WIDTH 16
-#define PTR ((void *)0xffff0123456789ab)
+#define PTR ((void *)0xffff0123456789abUL)
 #define PTR_STR "ffff0123456789ab"
 #define ZEROS "00000000"	/* hex 32 zero bits */
 

lib/vsprintf.c

@@ -703,6 +703,22 @@ char *symbol_string(char *buf, char *end, void *ptr,
 #endif
 }
 
+static const struct printf_spec default_str_spec = {
+	.field_width = -1,
+	.precision = -1,
+};
+
+static const struct printf_spec default_flag_spec = {
+	.base = 16,
+	.precision = -1,
+	.flags = SPECIAL | SMALL,
+};
+
+static const struct printf_spec default_dec_spec = {
+	.base = 10,
+	.precision = -1,
+};
+
 static noinline_for_stack
 char *resource_string(char *buf, char *end, struct resource *res,
 		      struct printf_spec spec, const char *fmt)
@@ -732,21 +748,11 @@ char *resource_string(char *buf, char *end, struct resource *res,
 		.precision = -1,
 		.flags = SMALL | ZEROPAD,
 	};
-	static const struct printf_spec dec_spec = {
-		.base = 10,
-		.precision = -1,
-		.flags = 0,
-	};
 	static const struct printf_spec str_spec = {
 		.field_width = -1,
 		.precision = 10,
 		.flags = LEFT,
 	};
-	static const struct printf_spec flag_spec = {
-		.base = 16,
-		.precision = -1,
-		.flags = SPECIAL | SMALL,
-	};
 
 	/* 32-bit res (sizeof==4): 10 chars in dec, 10 in hex ("0x" + 8)
 	 * 64-bit res (sizeof==8): 20 chars in dec, 18 in hex ("0x" + 16) */
@@ -770,10 +776,10 @@ char *resource_string(char *buf, char *end, struct resource *res,
 		specp = &mem_spec;
 	} else if (res->flags & IORESOURCE_IRQ) {
 		p = string(p, pend, "irq ", str_spec);
-		specp = &dec_spec;
+		specp = &default_dec_spec;
 	} else if (res->flags & IORESOURCE_DMA) {
 		p = string(p, pend, "dma ", str_spec);
-		specp = &dec_spec;
+		specp = &default_dec_spec;
 	} else if (res->flags & IORESOURCE_BUS) {
 		p = string(p, pend, "bus ", str_spec);
 		specp = &bus_spec;
@@ -803,7 +809,7 @@ char *resource_string(char *buf, char *end, struct resource *res,
 			p = string(p, pend, " disabled", str_spec);
 	} else {
 		p = string(p, pend, " flags ", str_spec);
-		p = number(p, pend, res->flags, flag_spec);
+		p = number(p, pend, res->flags, default_flag_spec);
 	}
 	*p++ = ']';
 	*p = '\0';
@@ -913,9 +919,6 @@ char *bitmap_list_string(char *buf, char *end, unsigned long *bitmap,
 	int cur, rbot, rtop;
 	bool first = true;
 
-	/* reused to print numbers */
-	spec = (struct printf_spec){ .base = 10 };
-
 	rbot = cur = find_first_bit(bitmap, nr_bits);
 	while (cur < nr_bits) {
 		rtop = cur;
@@ -930,13 +933,13 @@ char *bitmap_list_string(char *buf, char *end, unsigned long *bitmap,
 		}
 		first = false;
 
-		buf = number(buf, end, rbot, spec);
+		buf = number(buf, end, rbot, default_dec_spec);
 		if (rbot < rtop) {
 			if (buf < end)
 				*buf = '-';
 			buf++;
 
-			buf = number(buf, end, rtop, spec);
+			buf = number(buf, end, rtop, default_dec_spec);
 		}
 
 		rbot = cur;
@@ -1354,10 +1357,8 @@ char *uuid_string(char *buf, char *end, const u8 *addr,
 	return string(buf, end, uuid, spec);
 }
 
-int kptr_restrict __read_mostly;
-
 static noinline_for_stack
-char *restricted_pointer(char *buf, char *end, const void *ptr,
+char *pointer_string(char *buf, char *end, const void *ptr,
 		     struct printf_spec spec)
 {
 	spec.base = 16;
@@ -1367,6 +1368,15 @@ char *restricted_pointer(char *buf, char *end, const void *ptr,
 		spec.flags |= ZEROPAD;
 	}
 
+	return number(buf, end, (unsigned long int)ptr, spec);
+}
+
+int kptr_restrict __read_mostly;
+
+static noinline_for_stack
+char *restricted_pointer(char *buf, char *end, const void *ptr,
+			 struct printf_spec spec)
+{
 	switch (kptr_restrict) {
 	case 0:
 		/* Always print %pK values */
@@ -1378,8 +1388,11 @@ char *restricted_pointer(char *buf, char *end, const void *ptr,
 		 * kptr_restrict==1 cannot be used in IRQ context
 		 * because its test for CAP_SYSLOG would be meaningless.
 		 */
-		if (in_irq() || in_serving_softirq() || in_nmi())
+		if (in_irq() || in_serving_softirq() || in_nmi()) {
+			if (spec.field_width == -1)
+				spec.field_width = 2 * sizeof(ptr);
 			return string(buf, end, "pK-error", spec);
+		}
 
 		/*
 		 * Only print the real pointer value if the current
@@ -1404,7 +1417,7 @@ char *restricted_pointer(char *buf, char *end, const void *ptr,
 		break;
 	}
 
-	return number(buf, end, (unsigned long)ptr, spec);
+	return pointer_string(buf, end, ptr, spec);
 }
 
 static noinline_for_stack
@@ -1456,9 +1469,6 @@ char *clock(char *buf, char *end, struct clk *clk, struct printf_spec spec,
 		return string(buf, end, NULL, spec);
 
 	switch (fmt[1]) {
-	case 'r':
-		return number(buf, end, clk_get_rate(clk), spec);
-
 	case 'n':
 	default:
 #ifdef CONFIG_COMMON_CLK
@@ -1474,23 +1484,13 @@ char *format_flags(char *buf, char *end, unsigned long flags,
 					const struct trace_print_flags *names)
 {
 	unsigned long mask;
-	const struct printf_spec strspec = {
-		.field_width = -1,
-		.precision = -1,
-	};
-	const struct printf_spec numspec = {
-		.flags = SPECIAL|SMALL,
-		.field_width = -1,
-		.precision = -1,
-		.base = 16,
-	};
 
 	for ( ; flags && names->name; names++) {
 		mask = names->mask;
 		if ((flags & mask) != mask)
 			continue;
 
-		buf = string(buf, end, names->name, strspec);
+		buf = string(buf, end, names->name, default_str_spec);
 
 		flags &= ~mask;
 		if (flags) {
@@ -1501,7 +1501,7 @@ char *format_flags(char *buf, char *end, unsigned long flags,
 	}
 
 	if (flags)
-		buf = number(buf, end, flags, numspec);
+		buf = number(buf, end, flags, default_flag_spec);
 
 	return buf;
 }
@@ -1548,22 +1548,18 @@ char *device_node_gen_full_name(const struct device_node *np, char *buf, char *e
 {
 	int depth;
 	const struct device_node *parent = np->parent;
-	static const struct printf_spec strspec = {
-		.field_width = -1,
-		.precision = -1,
-	};
 
 	/* special case for root node */
 	if (!parent)
-		return string(buf, end, "/", strspec);
+		return string(buf, end, "/", default_str_spec);
 
 	for (depth = 0; parent->parent; depth++)
 		parent = parent->parent;
 
 	for ( ; depth >= 0; depth--) {
-		buf = string(buf, end, "/", strspec);
+		buf = string(buf, end, "/", default_str_spec);
 		buf = string(buf, end, device_node_name_for_depth(np, depth),
-			     strspec);
+			     default_str_spec);
 	}
 	return buf;
 }
@@ -1655,20 +1651,6 @@ char *device_node_string(char *buf, char *end, struct device_node *dn,
 	return widen_string(buf, buf - buf_start, end, spec);
 }
 
-static noinline_for_stack
-char *pointer_string(char *buf, char *end, const void *ptr,
-		     struct printf_spec spec)
-{
-	spec.base = 16;
-	spec.flags |= SMALL;
-	if (spec.field_width == -1) {
-		spec.field_width = 2 * sizeof(ptr);
-		spec.flags |= ZEROPAD;
-	}
-
-	return number(buf, end, (unsigned long int)ptr, spec);
-}
-
 static DEFINE_STATIC_KEY_TRUE(not_filled_random_ptr_key);
 static siphash_key_t ptr_key __read_mostly;
 
@@ -1710,13 +1692,13 @@ early_initcall(initialize_ptr_random);
 /* Maps a pointer to a 32 bit unique identifier. */
 static char *ptr_to_id(char *buf, char *end, void *ptr, struct printf_spec spec)
 {
+	const char *str = sizeof(ptr) == 8 ? "(____ptrval____)" : "(ptrval)";
 	unsigned long hashval;
-	const int default_width = 2 * sizeof(ptr);
 
 	if (static_branch_unlikely(&not_filled_random_ptr_key)) {
-		spec.field_width = default_width;
+		spec.field_width = 2 * sizeof(ptr);
 		/* string length must be less than default_width */
-		return string(buf, end, "(ptrval)", spec);
+		return string(buf, end, str, spec);
 	}
 
 #ifdef CONFIG_64BIT
@@ -1729,15 +1711,7 @@ static char *ptr_to_id(char *buf, char *end, void *ptr, struct printf_spec spec)
 #else
 	hashval = (unsigned long)siphash_1u32((u32)ptr, &ptr_key);
 #endif
-
-	spec.flags |= SMALL;
-	if (spec.field_width == -1) {
-		spec.field_width = default_width;
-		spec.flags |= ZEROPAD;
-	}
-	spec.base = 16;
-
-	return number(buf, end, hashval, spec);
+	return pointer_string(buf, end, (const void *)hashval, spec);
 }
 
 /*
@@ -1750,10 +1724,10 @@ static char *ptr_to_id(char *buf, char *end, void *ptr, struct printf_spec spec)
  *
  * Right now we handle:
  *
- * - 'F' For symbolic function descriptor pointers with offset
- * - 'f' For simple symbolic function names without offset
- * - 'S' For symbolic direct pointers with offset
- * - 's' For symbolic direct pointers without offset
+ * - 'S' For symbolic direct pointers (or function descriptors) with offset
+ * - 's' For symbolic direct pointers (or function descriptors) without offset
+ * - 'F' Same as 'S'
+ * - 'f' Same as 's'
  * - '[FfSs]R' as above with __builtin_extract_return_addr() translation
  * - 'B' For backtraced symbolic direct pointers with offset
  * - 'R' For decoded struct resource, e.g., [mem 0x0-0x1f 64bit pref]
@@ -1850,10 +1824,6 @@ static char *ptr_to_id(char *buf, char *end, void *ptr, struct printf_spec spec)
  * ** When making changes please also update:
  *	Documentation/core-api/printk-formats.rst
  *
- * Note: The difference between 'S' and 'F' is that on ia64 and ppc64
- * function pointers are really function descriptors, which contain a
- * pointer to the real address.
- *
  * Note: The default behaviour (unadorned %p) is to hash the address,
  * rendering it useful as a unique identifier.
  */
@@ -2129,6 +2099,7 @@ int format_decode(const char *fmt, struct printf_spec *spec)
 
 	case 'x':
 		spec->flags |= SMALL;
+		/* fall through */
 
 	case 'X':
 		spec->base = 16;
@@ -3087,8 +3058,10 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
 			break;
 		case 'i':
 			base = 0;
+			/* fall through */
 		case 'd':
 			is_sign = true;
+			/* fall through */
 		case 'u':
 			break;
 		case '%':