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authorLinus Torvalds <torvalds@linux-foundation.org>2018-06-06 16:04:55 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-06-06 16:04:55 -0700
commitd75ae5bdf2353e5c6a1f83da5f6f2d31582f09a3 (patch)
treede5fc796d1148baaca18497b6f62cc58a6f742e6 /kernel/printk
parent0eb0061381b2bac082cc26d573fc48fe99db3922 (diff)
parent8bafa2a44ff3647904eaa3c9228bfbd36742b9b4 (diff)
downloadlinux-d75ae5bdf2353e5c6a1f83da5f6f2d31582f09a3.tar.bz2
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
Diffstat (limited to 'kernel/printk')
-rw-r--r--kernel/printk/printk.c14
-rw-r--r--kernel/printk/printk_safe.c7
2 files changed, 7 insertions, 14 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 2f4af216bd6e..247808333ba4 100644
--- a/kernel/printk/printk.c
+++ b/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 @@ again:
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 @@ skip:
if (console_lock_spinning_disable_and_check()) {
printk_safe_exit_irqrestore(flags);
- goto out;
+ return;
}
printk_safe_exit_irqrestore(flags);
@@ -2429,10 +2423,6 @@ skip:
if (retry && console_trylock())
goto again;
-
-out:
- if (wake_klogd)
- wake_up_klogd();
}
EXPORT_SYMBOL(console_unlock);
diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c
index 3e3c2004bb23..d7d091309054 100644
--- a/kernel/printk/printk_safe.c
+++ b/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 @@ again:
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;