Adding debian version 4.19.249-2.debian/4.19.249-2debian

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 114 insertions, 0 deletions

diff --git a/debian/patches-rt/0206-printk-Make-rt-aware.patch b/debian/patches-rt/0206-printk-Make-rt-aware.patch
new file mode 100644
index 000000000..0ca16f202
--- /dev/null
+++ b/debian/patches-rt/0206-printk-Make-rt-aware.patch
@@ -0,0 +1,114 @@
+From fe512f6331aa2cda166c08988965010dd06d68e3 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Wed, 19 Sep 2012 14:50:37 +0200
+Subject: [PATCH 206/347] printk: Make rt aware
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz
+
+Drop the lock before calling the console driver and do not disable
+interrupts while printing to a serial console.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ kernel/printk/printk.c | 33 ++++++++++++++++++++++++++++++---
+ 1 file changed, 30 insertions(+), 3 deletions(-)
+
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index 7b774743e1ac..c06b1e00448d 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -1654,6 +1654,7 @@ SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len)
+ 	return do_syslog(type, buf, len, SYSLOG_FROM_READER);
+ }
+ 
++#ifndef CONFIG_PREEMPT_RT_FULL
+ /*
+  * Special console_lock variants that help to reduce the risk of soft-lockups.
+  * They allow to pass console_lock to another printk() call using a busy wait.
+@@ -1794,6 +1795,15 @@ static int console_trylock_spinning(void)
+ 	return 1;
+ }
+ 
++#else
++
++static int console_trylock_spinning(void)
++{
++	return console_trylock();
++}
++
++#endif
++
+ /*
+  * Call the console drivers, asking them to write out
+  * log_buf[start] to log_buf[end - 1].
+@@ -1809,6 +1819,7 @@ static void call_console_drivers(const char *ext_text, size_t ext_len,
+ 	if (!console_drivers)
+ 		return;
+ 
++	migrate_disable();
+ 	for_each_console(con) {
+ 		if (exclusive_console && con != exclusive_console)
+ 			continue;
+@@ -1824,6 +1835,7 @@ static void call_console_drivers(const char *ext_text, size_t ext_len,
+ 		else
+ 			con->write(con, text, len);
+ 	}
++	migrate_enable();
+ }
+ 
+ int printk_delay_msec __read_mostly;
+@@ -2018,20 +2030,30 @@ asmlinkage int vprintk_emit(int facility, int level,
+ 
+ 	/* If called from the scheduler, we can not call up(). */
+ 	if (!in_sched && pending_output) {
++		int may_trylock = 1;
++
++#ifdef CONFIG_PREEMPT_RT_FULL
++		/*
++		 * we can't take a sleeping lock with IRQs or preeption disabled
++		 * so we can't print in these contexts
++		 */
++		if (!(preempt_count() == 0 && !irqs_disabled()))
++			may_trylock = 0;
++#endif
+ 		/*
+ 		 * Disable preemption to avoid being preempted while holding
+ 		 * console_sem which would prevent anyone from printing to
+ 		 * console
+ 		 */
+-		preempt_disable();
++		migrate_disable();
+ 		/*
+ 		 * Try to acquire and then immediately release the console
+ 		 * semaphore.  The release will print out buffers and wake up
+ 		 * /dev/kmsg and syslog() users.
+ 		 */
+-		if (console_trylock_spinning())
++		if (may_trylock && console_trylock_spinning())
+ 			console_unlock();
+-		preempt_enable();
++		migrate_enable();
+ 	}
+ 
+ 	if (pending_output)
+@@ -2503,6 +2525,10 @@ void console_unlock(void)
+ 		console_seq++;
+ 		raw_spin_unlock(&logbuf_lock);
+ 
++#ifdef CONFIG_PREEMPT_RT_FULL
++		printk_safe_exit_irqrestore(flags);
++		call_console_drivers(ext_text, ext_len, text, len);
++#else
+ 		/*
+ 		 * While actively printing out messages, if another printk()
+ 		 * were to occur on another CPU, it may wait for this one to
+@@ -2521,6 +2547,7 @@ void console_unlock(void)
+ 		}
+ 
+ 		printk_safe_exit_irqrestore(flags);
++#endif
+ 
+ 		if (do_cond_resched)
+ 			cond_resched();
+-- 
+2.36.1
+