Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/kernel/printk/Makefile b/kernel/printk/Makefile
index 4a2ffc3..4d052fc 100644
--- a/kernel/printk/Makefile
+++ b/kernel/printk/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
obj-y = printk.o
obj-$(CONFIG_PRINTK) += printk_safe.o
obj-$(CONFIG_A11Y_BRAILLE_CONSOLE) += braille.o
diff --git a/kernel/printk/braille.c b/kernel/printk/braille.c
index 1d21eba..17a9591 100644
--- a/kernel/printk/braille.c
+++ b/kernel/printk/braille.c
@@ -11,11 +11,18 @@
int _braille_console_setup(char **str, char **brl_options)
{
- if (!strncmp(*str, "brl,", 4)) {
+ size_t len;
+
+ len = str_has_prefix(*str, "brl,");
+ if (len) {
*brl_options = "";
- *str += 4;
- } else if (!strncmp(*str, "brl=", 4)) {
- *brl_options = *str + 4;
+ *str += len;
+ return 0;
+ }
+
+ len = str_has_prefix(*str, "brl=");
+ if (len) {
+ *brl_options = *str + len;
*str = strchr(*brl_options, ',');
if (!*str) {
pr_err("need port name after brl=\n");
diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h
index 0f18988..c8e6ab6 100644
--- a/kernel/printk/internal.h
+++ b/kernel/printk/internal.h
@@ -1,18 +1,6 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* internal.h - printk internal definitions
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version 2
- * of the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/percpu.h>
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 06045ab..ca65327 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/kernel/printk.c
*
@@ -16,6 +17,8 @@
* 01Mar01 Andrew Morton
*/
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/tty.h>
@@ -29,7 +32,6 @@
#include <linux/delay.h>
#include <linux/smp.h>
#include <linux/security.h>
-#include <linux/bootmem.h>
#include <linux/memblock.h>
#include <linux/syscalls.h>
#include <linux/crash_core.h>
@@ -64,6 +66,7 @@
CONSOLE_LOGLEVEL_MIN, /* minimum_console_loglevel */
CONSOLE_LOGLEVEL_DEFAULT, /* default_console_loglevel */
};
+EXPORT_SYMBOL_GPL(console_printk);
atomic_t ignore_console_lock_warning __read_mostly = ATOMIC_INIT(0);
EXPORT_SYMBOL(ignore_console_lock_warning);
@@ -84,6 +87,12 @@
struct console *console_drivers;
EXPORT_SYMBOL_GPL(console_drivers);
+/*
+ * System may need to suppress printk message under certain
+ * circumstances, like after kernel panic happens.
+ */
+int __read_mostly suppress_printk;
+
#ifdef CONFIG_LOCKDEP
static struct lockdep_map console_lock_dep_map = {
.name = "console_lock"
@@ -109,19 +118,29 @@
static int __control_devkmsg(char *str)
{
+ size_t len;
+
if (!str)
return -EINVAL;
- if (!strncmp(str, "on", 2)) {
+ len = str_has_prefix(str, "on");
+ if (len) {
devkmsg_log = DEVKMSG_LOG_MASK_ON;
- return 2;
- } else if (!strncmp(str, "off", 3)) {
- devkmsg_log = DEVKMSG_LOG_MASK_OFF;
- return 3;
- } else if (!strncmp(str, "ratelimit", 9)) {
- devkmsg_log = DEVKMSG_LOG_MASK_DEFAULT;
- return 9;
+ return len;
}
+
+ len = str_has_prefix(str, "off");
+ if (len) {
+ devkmsg_log = DEVKMSG_LOG_MASK_OFF;
+ return len;
+ }
+
+ len = str_has_prefix(str, "ratelimit");
+ if (len) {
+ devkmsg_log = DEVKMSG_LOG_MASK_DEFAULT;
+ return len;
+ }
+
return -EINVAL;
}
@@ -192,16 +211,7 @@
return 0;
}
-/*
- * Number of registered extended console drivers.
- *
- * If extended consoles are present, in-kernel cont reassembly is disabled
- * and each fragment is stored as a separate log entry with proper
- * continuation flag so that every emitted message has full metadata. This
- * doesn't change the result for regular consoles or /proc/kmsg. For
- * /dev/kmsg, as long as the reader concatenates messages according to
- * consecutive continuation flags, the end result should be the same too.
- */
+/* Number of registered extended console drivers. */
static int nr_ext_console_drivers;
/*
@@ -352,7 +362,6 @@
enum log_flags {
LOG_NEWLINE = 2, /* text ended with a newline */
- LOG_PREFIX = 4, /* text started with a prefix */
LOG_CONT = 8, /* text is a fragment of a continuation line */
};
@@ -364,6 +373,9 @@
u8 facility; /* syslog facility */
u8 flags:5; /* internal record flags */
u8 level:3; /* syslog level */
+#ifdef CONFIG_PRINTK_CALLER
+ u32 caller_id; /* thread id or processor id */
+#endif
}
#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
__packed __aligned(4)
@@ -411,6 +423,7 @@
static u64 syslog_seq;
static u32 syslog_idx;
static size_t syslog_partial;
+static bool syslog_time;
/* index and sequence number of the first record stored in the buffer */
static u64 log_first_seq;
@@ -423,12 +436,17 @@
/* the next printk record to write to the console */
static u64 console_seq;
static u32 console_idx;
+static u64 exclusive_console_stop_seq;
/* the next printk record to read after the last 'clear' command */
static u64 clear_seq;
static u32 clear_idx;
+#ifdef CONFIG_PRINTK_CALLER
+#define PREFIX_MAX 48
+#else
#define PREFIX_MAX 32
+#endif
#define LOG_LINE_MAX (1024 - PREFIX_MAX)
#define LOG_LEVEL(v) ((v) & 0x07)
@@ -437,6 +455,7 @@
/* record buffer */
#define LOG_ALIGN __alignof__(struct printk_log)
#define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT)
+#define LOG_BUF_LEN_MAX (u32)(1 << 31)
static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN);
static char *log_buf = __log_buf;
static u32 log_buf_len = __LOG_BUF_LEN;
@@ -582,7 +601,7 @@
}
/* insert record into the buffer, discard old ones, update heads */
-static int log_store(int facility, int level,
+static int log_store(u32 caller_id, int facility, int level,
enum log_flags flags, u64 ts_nsec,
const char *dict, u16 dict_len,
const char *text, u16 text_len)
@@ -630,6 +649,9 @@
msg->ts_nsec = ts_nsec;
else
msg->ts_nsec = local_clock();
+#ifdef CONFIG_PRINTK_CALLER
+ msg->caller_id = caller_id;
+#endif
memset(log_dict(msg) + dict_len, 0, pad_len);
msg->len = size;
@@ -693,12 +715,21 @@
struct printk_log *msg, u64 seq)
{
u64 ts_usec = msg->ts_nsec;
+ char caller[20];
+#ifdef CONFIG_PRINTK_CALLER
+ u32 id = msg->caller_id;
+
+ snprintf(caller, sizeof(caller), ",caller=%c%u",
+ id & 0x80000000 ? 'C' : 'T', id & ~0x80000000);
+#else
+ caller[0] = '\0';
+#endif
do_div(ts_usec, 1000);
- return scnprintf(buf, size, "%u,%llu,%llu,%c;",
- (msg->facility << 3) | msg->level, seq, ts_usec,
- msg->flags & LOG_CONT ? 'c' : '-');
+ return scnprintf(buf, size, "%u,%llu,%llu,%c%s;",
+ (msg->facility << 3) | msg->level, seq, ts_usec,
+ msg->flags & LOG_CONT ? 'c' : '-', caller);
}
static ssize_t msg_print_ext_body(char *buf, size_t size,
@@ -758,6 +789,19 @@
char buf[CONSOLE_EXT_LOG_MAX];
};
+static __printf(3, 4) __cold
+int devkmsg_emit(int facility, int level, const char *fmt, ...)
+{
+ va_list args;
+ int r;
+
+ va_start(args, fmt);
+ r = vprintk_emit(facility, level, NULL, 0, fmt, args);
+ va_end(args);
+
+ return r;
+}
+
static ssize_t devkmsg_write(struct kiocb *iocb, struct iov_iter *from)
{
char *buf, *line;
@@ -816,7 +860,7 @@
}
}
- printk_emit(facility, level, NULL, 0, "%s", line);
+ devkmsg_emit(facility, level, "%s", line);
kfree(buf);
return ret;
}
@@ -1030,6 +1074,9 @@
VMCOREINFO_OFFSET(printk_log, len);
VMCOREINFO_OFFSET(printk_log, text_len);
VMCOREINFO_OFFSET(printk_log, dict_len);
+#ifdef CONFIG_PRINTK_CALLER
+ VMCOREINFO_OFFSET(printk_log, caller_id);
+#endif
}
#endif
@@ -1037,18 +1084,23 @@
static unsigned long __initdata new_log_buf_len;
/* we practice scaling the ring buffer by powers of 2 */
-static void __init log_buf_len_update(unsigned size)
+static void __init log_buf_len_update(u64 size)
{
+ if (size > (u64)LOG_BUF_LEN_MAX) {
+ size = (u64)LOG_BUF_LEN_MAX;
+ pr_err("log_buf over 2G is not supported.\n");
+ }
+
if (size)
size = roundup_pow_of_two(size);
if (size > log_buf_len)
- new_log_buf_len = size;
+ new_log_buf_len = (unsigned long)size;
}
/* save requested log_buf_len since it's too early to process it */
static int __init log_buf_len_setup(char *str)
{
- unsigned int size;
+ u64 size;
if (!str)
return -EINVAL;
@@ -1098,7 +1150,7 @@
{
unsigned long flags;
char *new_log_buf;
- int free;
+ unsigned int free;
if (log_buf != __log_buf)
return;
@@ -1109,16 +1161,9 @@
if (!new_log_buf_len)
return;
- if (early) {
- new_log_buf =
- memblock_virt_alloc(new_log_buf_len, LOG_ALIGN);
- } else {
- new_log_buf = memblock_virt_alloc_nopanic(new_log_buf_len,
- LOG_ALIGN);
- }
-
+ new_log_buf = memblock_alloc(new_log_buf_len, LOG_ALIGN);
if (unlikely(!new_log_buf)) {
- pr_err("log_buf_len: %ld bytes not available\n",
+ pr_err("log_buf_len: %lu bytes not available\n",
new_log_buf_len);
return;
}
@@ -1131,8 +1176,8 @@
memcpy(log_buf, __log_buf, __LOG_BUF_LEN);
logbuf_unlock_irqrestore(flags);
- pr_info("log_buf_len: %d bytes\n", log_buf_len);
- pr_info("early log buf free: %d(%d%%)\n",
+ pr_info("log_buf_len: %u bytes\n", log_buf_len);
+ pr_info("early log buf free: %u(%u%%)\n",
free, (free * 100) / __LOG_BUF_LEN);
}
@@ -1214,50 +1259,61 @@
static bool printk_time = IS_ENABLED(CONFIG_PRINTK_TIME);
module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR);
+static size_t print_syslog(unsigned int level, char *buf)
+{
+ return sprintf(buf, "<%u>", level);
+}
+
static size_t print_time(u64 ts, char *buf)
{
- unsigned long rem_nsec;
+ unsigned long rem_nsec = do_div(ts, 1000000000);
- if (!printk_time)
- return 0;
-
- rem_nsec = do_div(ts, 1000000000);
-
- if (!buf)
- return snprintf(NULL, 0, "[%5lu.000000] ", (unsigned long)ts);
-
- return sprintf(buf, "[%5lu.%06lu] ",
+ return sprintf(buf, "[%5lu.%06lu]",
(unsigned long)ts, rem_nsec / 1000);
}
-static size_t print_prefix(const struct printk_log *msg, bool syslog, char *buf)
+#ifdef CONFIG_PRINTK_CALLER
+static size_t print_caller(u32 id, char *buf)
+{
+ char caller[12];
+
+ snprintf(caller, sizeof(caller), "%c%u",
+ id & 0x80000000 ? 'C' : 'T', id & ~0x80000000);
+ return sprintf(buf, "[%6s]", caller);
+}
+#else
+#define print_caller(id, buf) 0
+#endif
+
+static size_t print_prefix(const struct printk_log *msg, bool syslog,
+ bool time, char *buf)
{
size_t len = 0;
- unsigned int prefix = (msg->facility << 3) | msg->level;
- if (syslog) {
- if (buf) {
- len += sprintf(buf, "<%u>", prefix);
- } else {
- len += 3;
- if (prefix > 999)
- len += 3;
- else if (prefix > 99)
- len += 2;
- else if (prefix > 9)
- len++;
- }
+ if (syslog)
+ len = print_syslog((msg->facility << 3) | msg->level, buf);
+
+ if (time)
+ len += print_time(msg->ts_nsec, buf + len);
+
+ len += print_caller(msg->caller_id, buf + len);
+
+ if (IS_ENABLED(CONFIG_PRINTK_CALLER) || time) {
+ buf[len++] = ' ';
+ buf[len] = '\0';
}
- len += print_time(msg->ts_nsec, buf ? buf + len : NULL);
return len;
}
-static size_t msg_print_text(const struct printk_log *msg, bool syslog, char *buf, size_t size)
+static size_t msg_print_text(const struct printk_log *msg, bool syslog,
+ bool time, char *buf, size_t size)
{
const char *text = log_text(msg);
size_t text_size = msg->text_len;
size_t len = 0;
+ char prefix[PREFIX_MAX];
+ const size_t prefix_len = print_prefix(msg, syslog, time, prefix);
do {
const char *next = memchr(text, '\n', text_size);
@@ -1272,19 +1328,17 @@
}
if (buf) {
- if (print_prefix(msg, syslog, NULL) +
- text_len + 1 >= size - len)
+ if (prefix_len + text_len + 1 >= size - len)
break;
- len += print_prefix(msg, syslog, buf + len);
+ memcpy(buf + len, prefix, prefix_len);
+ len += prefix_len;
memcpy(buf + len, text, text_len);
len += text_len;
buf[len++] = '\n';
} else {
/* SYSLOG_ACTION_* buffer size only calculation */
- len += print_prefix(msg, syslog, NULL);
- len += text_len;
- len++;
+ len += prefix_len + text_len + 1;
}
text = next;
@@ -1319,9 +1373,17 @@
break;
}
+ /*
+ * To keep reading/counting partial line consistent,
+ * use printk_time value as of the beginning of a line.
+ */
+ if (!syslog_partial)
+ syslog_time = printk_time;
+
skip = syslog_partial;
msg = log_from_idx(syslog_idx);
- n = msg_print_text(msg, true, text, LOG_LINE_MAX + PREFIX_MAX);
+ n = msg_print_text(msg, true, syslog_time, text,
+ LOG_LINE_MAX + PREFIX_MAX);
if (n - syslog_partial <= size) {
/* message fits into buffer, move forward */
syslog_idx = log_next(syslog_idx);
@@ -1361,11 +1423,13 @@
u64 next_seq;
u64 seq;
u32 idx;
+ bool time;
text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);
if (!text)
return -ENOMEM;
+ time = printk_time;
logbuf_lock_irq();
/*
* Find first record that fits, including all following records,
@@ -1376,7 +1440,7 @@
while (seq < log_next_seq) {
struct printk_log *msg = log_from_idx(idx);
- len += msg_print_text(msg, true, NULL, 0);
+ len += msg_print_text(msg, true, time, NULL, 0);
idx = log_next(idx);
seq++;
}
@@ -1387,7 +1451,7 @@
while (len > size && seq < log_next_seq) {
struct printk_log *msg = log_from_idx(idx);
- len -= msg_print_text(msg, true, NULL, 0);
+ len -= msg_print_text(msg, true, time, NULL, 0);
idx = log_next(idx);
seq++;
}
@@ -1398,14 +1462,9 @@
len = 0;
while (len >= 0 && seq < next_seq) {
struct printk_log *msg = log_from_idx(idx);
- int textlen;
+ int textlen = msg_print_text(msg, true, time, text,
+ LOG_LINE_MAX + PREFIX_MAX);
- textlen = msg_print_text(msg, true, text,
- LOG_LINE_MAX + PREFIX_MAX);
- if (textlen < 0) {
- len = textlen;
- break;
- }
idx = log_next(idx);
seq++;
@@ -1461,7 +1520,7 @@
return -EINVAL;
if (!len)
return 0;
- if (!access_ok(VERIFY_WRITE, buf, len))
+ if (!access_ok(buf, len))
return -EFAULT;
error = wait_event_interruptible(log_wait,
syslog_seq != log_next_seq);
@@ -1479,7 +1538,7 @@
return -EINVAL;
if (!len)
return 0;
- if (!access_ok(VERIFY_WRITE, buf, len))
+ if (!access_ok(buf, len))
return -EFAULT;
error = syslog_print_all(buf, len, clear);
break;
@@ -1529,11 +1588,14 @@
} else {
u64 seq = syslog_seq;
u32 idx = syslog_idx;
+ bool time = syslog_partial ? syslog_time : printk_time;
while (seq < log_next_seq) {
struct printk_log *msg = log_from_idx(idx);
- error += msg_print_text(msg, true, NULL, 0);
+ error += msg_print_text(msg, true, time, NULL,
+ 0);
+ time = printk_time;
idx = log_next(idx);
seq++;
}
@@ -1744,6 +1806,12 @@
}
}
+static inline u32 printk_caller_id(void)
+{
+ return in_task() ? task_pid_nr(current) :
+ 0x80000000 + raw_smp_processor_id();
+}
+
/*
* Continuation lines are buffered, and not committed to the record buffer
* until the line is complete, or a race forces it. The line fragments
@@ -1753,7 +1821,7 @@
static struct cont {
char buf[LOG_LINE_MAX];
size_t len; /* length == 0 means unused buffer */
- struct task_struct *owner; /* task of first print*/
+ u32 caller_id; /* printk_caller_id() of first print */
u64 ts_nsec; /* time of first print */
u8 level; /* log level of first message */
u8 facility; /* log facility of first message */
@@ -1765,19 +1833,16 @@
if (cont.len == 0)
return;
- log_store(cont.facility, cont.level, cont.flags, cont.ts_nsec,
- NULL, 0, cont.buf, cont.len);
+ log_store(cont.caller_id, cont.facility, cont.level, cont.flags,
+ cont.ts_nsec, NULL, 0, cont.buf, cont.len);
cont.len = 0;
}
-static bool cont_add(int facility, int level, enum log_flags flags, const char *text, size_t len)
+static bool cont_add(u32 caller_id, int facility, int level,
+ enum log_flags flags, const char *text, size_t len)
{
- /*
- * If ext consoles are present, flush and skip in-kernel
- * continuation. See nr_ext_console_drivers definition. Also, if
- * the line gets too long, split it up in separate records.
- */
- if (nr_ext_console_drivers || cont.len + len > sizeof(cont.buf)) {
+ /* If the line gets too long, split it up in separate records. */
+ if (cont.len + len > sizeof(cont.buf)) {
cont_flush();
return false;
}
@@ -1785,7 +1850,7 @@
if (!cont.len) {
cont.facility = facility;
cont.level = level;
- cont.owner = current;
+ cont.caller_id = caller_id;
cont.ts_nsec = local_clock();
cont.flags = flags;
}
@@ -1800,21 +1865,20 @@
cont_flush();
}
- if (cont.len > (sizeof(cont.buf) * 80) / 100)
- cont_flush();
-
return true;
}
static size_t log_output(int facility, int level, enum log_flags lflags, const char *dict, size_t dictlen, char *text, size_t text_len)
{
+ const u32 caller_id = printk_caller_id();
+
/*
* If an earlier line was buffered, and we're a continuation
- * write from the same process, try to add it to the buffer.
+ * write from the same context, try to add it to the buffer.
*/
if (cont.len) {
- if (cont.owner == current && (lflags & LOG_CONT)) {
- if (cont_add(facility, level, lflags, text, text_len))
+ if (cont.caller_id == caller_id && (lflags & LOG_CONT)) {
+ if (cont_add(caller_id, facility, level, lflags, text, text_len))
return text_len;
}
/* Otherwise, make sure it's flushed */
@@ -1827,12 +1891,13 @@
/* If it doesn't end in a newline, try to buffer the current line */
if (!(lflags & LOG_NEWLINE)) {
- if (cont_add(facility, level, lflags, text, text_len))
+ if (cont_add(caller_id, facility, level, lflags, text, text_len))
return text_len;
}
/* Store it in the record log */
- return log_store(facility, level, lflags, 0, dict, dictlen, text, text_len);
+ return log_store(caller_id, facility, level, lflags, 0,
+ dict, dictlen, text, text_len);
}
/* Must be called under logbuf_lock. */
@@ -1866,9 +1931,6 @@
case '0' ... '7':
if (level == LOGLEVEL_DEFAULT)
level = kern_level - '0';
- /* fallthrough */
- case 'd': /* KERN_DEFAULT */
- lflags |= LOG_PREFIX;
break;
case 'c': /* KERN_CONT */
lflags |= LOG_CONT;
@@ -1883,7 +1945,7 @@
level = default_message_loglevel;
if (dict)
- lflags |= LOG_PREFIX|LOG_NEWLINE;
+ lflags |= LOG_NEWLINE;
return log_output(facility, level, lflags,
dict, dictlen, text, text_len);
@@ -1894,8 +1956,13 @@
const char *fmt, va_list args)
{
int printed_len;
- bool in_sched = false;
+ bool in_sched = false, pending_output;
unsigned long flags;
+ u64 curr_log_seq;
+
+ /* Suppress unimportant messages after panic happens */
+ if (unlikely(suppress_printk))
+ return 0;
if (level == LOGLEVEL_SCHED) {
level = LOGLEVEL_DEFAULT;
@@ -1907,11 +1974,13 @@
/* This stops the holder of console_sem just where we want him */
logbuf_lock_irqsave(flags);
+ curr_log_seq = log_next_seq;
printed_len = vprintk_store(facility, level, dict, dictlen, fmt, args);
+ pending_output = (curr_log_seq != log_next_seq);
logbuf_unlock_irqrestore(flags);
/* If called from the scheduler, we can not call up(). */
- if (!in_sched) {
+ if (!in_sched && pending_output) {
/*
* Disable preemption to avoid being preempted while holding
* console_sem which would prevent anyone from printing to
@@ -1928,7 +1997,8 @@
preempt_enable();
}
- wake_up_klogd();
+ if (pending_output)
+ wake_up_klogd();
return printed_len;
}
EXPORT_SYMBOL(vprintk_emit);
@@ -1939,21 +2009,6 @@
}
EXPORT_SYMBOL(vprintk);
-asmlinkage int printk_emit(int facility, int level,
- const char *dict, size_t dictlen,
- const char *fmt, ...)
-{
- va_list args;
- int r;
-
- va_start(args, fmt);
- r = vprintk_emit(facility, level, dict, dictlen, fmt, args);
- va_end(args);
-
- return r;
-}
-EXPORT_SYMBOL(printk_emit);
-
int vprintk_default(const char *fmt, va_list args)
{
int r;
@@ -2009,11 +2064,13 @@
#define LOG_LINE_MAX 0
#define PREFIX_MAX 0
+#define printk_time false
static u64 syslog_seq;
static u32 syslog_idx;
static u64 console_seq;
static u32 console_idx;
+static u64 exclusive_console_stop_seq;
static u64 log_first_seq;
static u32 log_first_idx;
static u64 log_next_seq;
@@ -2031,8 +2088,8 @@
static int console_lock_spinning_disable_and_check(void) { return 0; }
static void call_console_drivers(const char *ext_text, size_t ext_len,
const char *text, size_t len) {}
-static size_t msg_print_text(const struct printk_log *msg,
- bool syslog, char *buf, size_t size) { return 0; }
+static size_t msg_print_text(const struct printk_log *msg, bool syslog,
+ bool time, char *buf, size_t size) { return 0; }
static bool suppress_message_printing(int level) { return false; }
#endif /* CONFIG_PRINTK */
@@ -2356,8 +2413,9 @@
printk_safe_enter_irqsave(flags);
raw_spin_lock(&logbuf_lock);
if (console_seq < log_first_seq) {
- len = sprintf(text, "** %u printk messages dropped **\n",
- (unsigned)(log_first_seq - console_seq));
+ len = sprintf(text,
+ "** %llu printk messages dropped **\n",
+ log_first_seq - console_seq);
/* messages are gone, move to first one */
console_seq = log_first_seq;
@@ -2381,10 +2439,15 @@
goto skip;
}
+ /* Output to all consoles once old messages replayed. */
+ if (unlikely(exclusive_console &&
+ console_seq >= exclusive_console_stop_seq)) {
+ exclusive_console = NULL;
+ }
+
len += msg_print_text(msg,
console_msg_format & MSG_FORMAT_SYSLOG,
- text + len,
- sizeof(text) - len);
+ printk_time, text + len, sizeof(text) - len);
if (nr_ext_console_drivers) {
ext_len = msg_print_ext_header(ext_text,
sizeof(ext_text),
@@ -2423,10 +2486,6 @@
console_locked = 0;
- /* Release the exclusive_console once it is used */
- if (unlikely(exclusive_console))
- exclusive_console = NULL;
-
raw_spin_unlock(&logbuf_lock);
up_console_sem();
@@ -2487,10 +2546,11 @@
/**
* console_flush_on_panic - flush console content on panic
+ * @mode: flush all messages in buffer or just the pending ones
*
* Immediately output all pending messages no matter what.
*/
-void console_flush_on_panic(void)
+void console_flush_on_panic(enum con_flush_mode mode)
{
/*
* If someone else is holding the console lock, trylock will fail
@@ -2501,6 +2561,15 @@
*/
console_trylock();
console_may_schedule = 0;
+
+ if (mode == CONSOLE_REPLAY_ALL) {
+ unsigned long flags;
+
+ logbuf_lock_irqsave(flags);
+ console_seq = log_first_seq;
+ console_idx = log_first_idx;
+ logbuf_unlock_irqrestore(flags);
+ }
console_unlock();
}
@@ -2693,8 +2762,7 @@
}
if (newcon->flags & CON_EXTENDED)
- if (!nr_ext_console_drivers++)
- pr_info("printk: continuation disabled due to ext consoles, expect more fragments in /dev/kmsg\n");
+ nr_ext_console_drivers++;
if (newcon->flags & CON_PRINTBUFFER) {
/*
@@ -2704,13 +2772,18 @@
logbuf_lock_irqsave(flags);
console_seq = syslog_seq;
console_idx = syslog_idx;
- logbuf_unlock_irqrestore(flags);
/*
* We're about to replay the log buffer. Only do this to the
* just-registered console to avoid excessive message spam to
* the already-registered consoles.
+ *
+ * Set exclusive_console with disabled interrupts to reduce
+ * race window with eventual console_flush_on_panic() that
+ * ignores console_lock.
*/
exclusive_console = newcon;
+ exclusive_console_stop_seq = console_seq;
+ logbuf_unlock_irqrestore(flags);
}
console_unlock();
console_sysfs_notify();
@@ -3108,7 +3181,7 @@
goto out;
msg = log_from_idx(dumper->cur_idx);
- l = msg_print_text(msg, syslog, line, size);
+ l = msg_print_text(msg, syslog, printk_time, line, size);
dumper->cur_idx = log_next(dumper->cur_idx);
dumper->cur_seq++;
@@ -3179,6 +3252,7 @@
u32 next_idx;
size_t l = 0;
bool ret = false;
+ bool time = printk_time;
if (!dumper->active)
goto out;
@@ -3202,7 +3276,7 @@
while (seq < dumper->next_seq) {
struct printk_log *msg = log_from_idx(idx);
- l += msg_print_text(msg, true, NULL, 0);
+ l += msg_print_text(msg, true, time, NULL, 0);
idx = log_next(idx);
seq++;
}
@@ -3210,10 +3284,10 @@
/* move first record forward until length fits into the buffer */
seq = dumper->cur_seq;
idx = dumper->cur_idx;
- while (l > size && seq < dumper->next_seq) {
+ while (l >= size && seq < dumper->next_seq) {
struct printk_log *msg = log_from_idx(idx);
- l -= msg_print_text(msg, true, NULL, 0);
+ l -= msg_print_text(msg, true, time, NULL, 0);
idx = log_next(idx);
seq++;
}
@@ -3226,7 +3300,7 @@
while (seq < dumper->next_seq) {
struct printk_log *msg = log_from_idx(idx);
- l += msg_print_text(msg, syslog, buf + l, size - l);
+ l += msg_print_text(msg, syslog, time, buf + l, size - l);
idx = log_next(idx);
seq++;
}
diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c
index 0913b4d..b4045e7 100644
--- a/kernel/printk/printk_safe.c
+++ b/kernel/printk/printk_safe.c
@@ -1,18 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
/*
* printk_safe.c - Safe printk for printk-deadlock-prone contexts
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version 2
- * of the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/preempt.h>