[Devel] [PATCH RHEL COMMIT] ve/printk: Virtualize syslog_*
Konstantin Khorenko
khorenko at virtuozzo.com
Fri Oct 1 18:23:06 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 27c8a8c7a2bdfabee45bd6cf778a9f555ebf4f6f
Author: Vladimir Davydov <vdavydov.dev at gmail.com>
Date: Wed Sep 29 21:26:05 2021 +0300
ve/printk: Virtualize syslog_*
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 | 59 +++++++++++++++++++++++++-------------------------
1 file changed, 30 insertions(+), 29 deletions(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index a1dedbc88426..a994c2fe19c7 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -361,12 +361,6 @@ static DEFINE_RAW_SPINLOCK(syslog_lock);
#ifdef CONFIG_PRINTK
DECLARE_WAIT_QUEUE_HEAD(log_wait);
-/* All 3 protected by @syslog_lock. */
-/* the next printk record to read by syslog(READ) or /proc/kmsg */
-static u64 syslog_seq;
-static size_t syslog_partial;
-static bool syslog_time;
-
/* All 3 protected by @console_sem. */
/* the next printk record to write to the console */
static u64 console_seq;
@@ -418,6 +412,12 @@ static struct log_state {
char *buf;
u32 buf_len;
+ /* All 3 protected by @syslog_lock. */
+ /* the next printk record to read by syslog(READ) or /proc/kmsg */
+ u64 syslog_seq;
+ size_t syslog_partial;
+ bool syslog_time;
+
/*
* The next printk record to read after the last 'clear' command. There are
* two copies (updated with seqcount_latch) so that reads can locklessly
@@ -1546,35 +1546,35 @@ static int syslog_print(struct log_state *log,
printk_safe_enter_irq();
raw_spin_lock(&syslog_lock);
- if (!prb_read_valid(log->prb, syslog_seq, &r)) {
+ if (!prb_read_valid(log->prb, log->syslog_seq, &r)) {
raw_spin_unlock(&syslog_lock);
printk_safe_exit_irq();
break;
}
- if (r.info->seq != syslog_seq) {
+ if (r.info->seq != log->syslog_seq) {
/* message is gone, move to next valid one */
- syslog_seq = r.info->seq;
- syslog_partial = 0;
+ log->syslog_seq = r.info->seq;
+ log->syslog_partial = 0;
}
/*
* 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;
+ if (!log->syslog_partial)
+ log->syslog_time = printk_time;
- skip = syslog_partial;
- n = record_print_text(&r, true, syslog_time);
- if (n - syslog_partial <= size) {
+ skip = log->syslog_partial;
+ n = record_print_text(&r, true, log->syslog_time);
+ if (n - log->syslog_partial <= size) {
/* message fits into buffer, move forward */
- syslog_seq = r.info->seq + 1;
- n -= syslog_partial;
- syslog_partial = 0;
+ log->syslog_seq = r.info->seq + 1;
+ n -= log->syslog_partial;
+ log->syslog_partial = 0;
} else if (!len){
/* partial read(), remember position */
n = size;
- syslog_partial += n;
+ log->syslog_partial += n;
} else
n = 0;
raw_spin_unlock(&syslog_lock);
@@ -1669,10 +1669,11 @@ static void syslog_clear(struct log_state *log)
/* Return a consistent copy of @syslog_seq. */
static u64 read_syslog_seq_irq(void)
{
+ struct log_state *log = ve_log_state();
u64 seq;
raw_spin_lock_irq(&syslog_lock);
- seq = syslog_seq;
+ seq = log->syslog_seq;
raw_spin_unlock_irq(&syslog_lock);
return seq;
@@ -1707,7 +1708,7 @@ int do_syslog(int type, char __user *buf, int len, int source)
prb_read_valid(log->prb, read_syslog_seq_irq(), NULL));
if (error)
return error;
- error = syslog_print(buf, len);
+ error = syslog_print(log, buf, len);
break;
/* Read/clear last kernel messages */
case SYSLOG_ACTION_READ_CLEAR:
@@ -1760,10 +1761,10 @@ int do_syslog(int type, char __user *buf, int len, int source)
printk_safe_exit_irq();
return 0;
}
- if (info.seq != syslog_seq) {
+ if (info.seq != log->syslog_seq) {
/* messages are gone, move to first one */
- syslog_seq = info.seq;
- syslog_partial = 0;
+ log->syslog_seq = info.seq;
+ log->syslog_partial = 0;
}
if (source == SYSLOG_FROM_PROC) {
/*
@@ -1771,9 +1772,9 @@ int do_syslog(int type, char __user *buf, int len, int source)
* for pending data, not the size; return the count of
* records, not the length.
*/
- error = prb_next_seq(log->prb) - syslog_seq;
+ error = prb_next_seq(log->prb) - log->syslog_seq;
} else {
- bool time = syslog_partial ? syslog_time : printk_time;
+ bool time = log->syslog_partial ? log->syslog_time : printk_time;
unsigned int line_count;
u64 seq;
@@ -1783,7 +1784,7 @@ int do_syslog(int type, char __user *buf, int len, int source)
true, time);
time = printk_time;
}
- error -= syslog_partial;
+ error -= log->syslog_partial;
}
raw_spin_unlock(&syslog_lock);
printk_safe_exit_irq();
@@ -2301,7 +2302,6 @@ EXPORT_SYMBOL(printk);
#define prb_read_valid(rb, seq, r) false
#define prb_first_valid_seq(rb) 0
-static u64 syslog_seq;
static u64 console_seq;
static u64 exclusive_console_stop_seq;
static unsigned long console_dropped;
@@ -2945,6 +2945,7 @@ static int try_enable_new_console(struct console *newcon, bool user_specified)
*/
void register_console(struct console *newcon)
{
+ struct log_state *log = &init_log_state;
unsigned long flags;
struct console *bcon = NULL;
int err;
@@ -3051,7 +3052,7 @@ void register_console(struct console *newcon)
/* Get a consistent copy of @syslog_seq. */
raw_spin_lock_irqsave(&syslog_lock, flags);
- console_seq = syslog_seq;
+ console_seq = log->syslog_seq;
raw_spin_unlock_irqrestore(&syslog_lock, flags);
}
console_unlock();
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