[Devel] [PATCH RHEL COMMIT] ve/printk: Virtualize console_*
Konstantin Khorenko
khorenko at virtuozzo.com
Fri Oct 1 18:23:36 MSK 2021
The commit is pushed to "branch-rh9-5.14.vz9.1.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after ark-5.14
------>
commit 037bdf09a9b12a4732c2b6f69d602401c8645b60
Author: Vladimir Davydov <vdavydov.dev at gmail.com>
Date: Wed Sep 29 21:28:39 2021 +0300
ve/printk: Virtualize console_*
https://jira.sw.ru/browse/PSBM-17899
Signed-off-by: Vladimir Davydov <vdavydov at parallels.com>
Signed-off-by: Stanislav Kinsburskiy <skinsbursky at virtuozzo.com>
+++
ve/printk: Fix printk virtualization
ve_printk() corrupts host's dmesg:
# dmesg|wc -l
599
# vzctl create 101
# vzctl set 101 --netif_add eth0 --save
# vzctl start 101
# vzctl exec 101 'tcpdump -w tcpdump.out -U -n -i eth0 esp'
# dmesg|wc -l
2
Add missing parts of prinkt virtualization to fix this.
https://jira.sw.ru/browse/PSBM-17899
https://jira.sw.ru/browse/PSBM-105442
Signed-off-by: Andrey Ryabinin <aryabinin at virtuozzo.com>
Rebasing to vz9: part of vz8 commit:
d63aeb311a64 ("ve/printk: printk virtualization")
https://jira.sw.ru/browse/PSBM-133985
Signed-off-by: Konstantin Khorenko <khorenko at virtuozzo.com>
---
kernel/printk/printk.c | 45 ++++++++++++++++++++++-----------------------
1 file changed, 22 insertions(+), 23 deletions(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index a994c2fe19c7..04244a3edeab 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -361,11 +361,6 @@ static DEFINE_RAW_SPINLOCK(syslog_lock);
#ifdef CONFIG_PRINTK
DECLARE_WAIT_QUEUE_HEAD(log_wait);
-/* All 3 protected by @console_sem. */
-/* the next printk record to write to the console */
-static u64 console_seq;
-static u64 exclusive_console_stop_seq;
-static unsigned long console_dropped;
struct latched_seq {
seqcount_latch_t latch;
@@ -418,6 +413,12 @@ static struct log_state {
size_t syslog_partial;
bool syslog_time;
+ /* All 3 protected by @console_sem. */
+ /* the next printk record to write to the console */
+ u64 console_seq;
+ u64 exclusive_console_stop_seq;
+ unsigned long console_dropped;
+
/*
* The next printk record to read after the last 'clear' command. There are
* two copies (updated with seqcount_latch) so that reads can locklessly
@@ -1954,6 +1955,7 @@ static int console_trylock_spinning(void)
static void call_console_drivers(const char *ext_text, size_t ext_len,
const char *text, size_t len)
{
+ struct log_state *log = &init_log_state;
static char dropped_text[64];
size_t dropped_len = 0;
struct console *con;
@@ -1963,11 +1965,11 @@ static void call_console_drivers(const char *ext_text, size_t ext_len,
if (!console_drivers)
return;
- if (console_dropped) {
+ if (log->console_dropped) {
dropped_len = snprintf(dropped_text, sizeof(dropped_text),
"** %lu printk messages dropped **\n",
- console_dropped);
- console_dropped = 0;
+ log->console_dropped);
+ log->console_dropped = 0;
}
for_each_console(con) {
@@ -2302,10 +2304,6 @@ EXPORT_SYMBOL(printk);
#define prb_read_valid(rb, seq, r) false
#define prb_first_valid_seq(rb) 0
-static u64 console_seq;
-static u64 exclusive_console_stop_seq;
-static unsigned long console_dropped;
-
static size_t record_print_text(const struct printk_record *r,
bool syslog, bool time)
{
@@ -2662,12 +2660,12 @@ void console_unlock(void)
printk_safe_enter_irqsave(flags);
skip:
- if (!prb_read_valid(log->prb, console_seq, &r))
+ if (!prb_read_valid(log->prb, log->console_seq, &r))
break;
- if (console_seq != r.info->seq) {
- console_dropped += r.info->seq - console_seq;
- console_seq = r.info->seq;
+ if (log->console_seq != r.info->seq) {
+ log->console_dropped += r.info->seq - log->console_seq;
+ log->console_seq = r.info->seq;
}
if (suppress_message_printing(r.info->level)) {
@@ -2676,13 +2674,14 @@ void console_unlock(void)
* directly to the console when we received it, and
* record that has level above the console loglevel.
*/
- console_seq++;
+ log->console_seq++;
goto skip;
}
/* Output to all consoles once old messages replayed. */
if (unlikely(exclusive_console &&
- console_seq >= exclusive_console_stop_seq)) {
+ log->console_seq >=
+ log->exclusive_console_stop_seq)) {
exclusive_console = NULL;
}
@@ -2703,7 +2702,7 @@ void console_unlock(void)
len = record_print_text(&r,
console_msg_format & MSG_FORMAT_SYSLOG,
printk_time);
- console_seq++;
+ log->console_seq++;
/*
* While actively printing out messages, if another printk()
@@ -2738,7 +2737,7 @@ void console_unlock(void)
* there's a new owner and the console_unlock() from them will do the
* flush, no worries.
*/
- retry = prb_read_valid(log->prb, console_seq, NULL);
+ retry = prb_read_valid(log->prb, log->console_seq, NULL);
printk_safe_exit_irqrestore(flags);
if (retry && console_trylock())
@@ -2808,7 +2807,7 @@ void console_flush_on_panic(enum con_flush_mode mode)
unsigned long flags;
printk_safe_enter_irqsave(flags);
- console_seq = prb_first_valid_seq(log->prb);
+ log->console_seq = prb_first_valid_seq(log->prb);
printk_safe_exit_irqrestore(flags);
}
console_unlock();
@@ -3048,11 +3047,11 @@ void register_console(struct console *newcon)
* ignores console_lock.
*/
exclusive_console = newcon;
- exclusive_console_stop_seq = console_seq;
+ log->exclusive_console_stop_seq = log->console_seq;
/* Get a consistent copy of @syslog_seq. */
raw_spin_lock_irqsave(&syslog_lock, flags);
- console_seq = log->syslog_seq;
+ log->console_seq = log->syslog_seq;
raw_spin_unlock_irqrestore(&syslog_lock, flags);
}
console_unlock();
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