diff options
Diffstat (limited to 'debian/patches-rt/0213-kgdb-serial-Short-term-workaround.patch')
| -rw-r--r-- | debian/patches-rt/0213-kgdb-serial-Short-term-workaround.patch | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/debian/patches-rt/0213-kgdb-serial-Short-term-workaround.patch b/debian/patches-rt/0213-kgdb-serial-Short-term-workaround.patch new file mode 100644 index 000000000..464f4b0d7 --- /dev/null +++ b/debian/patches-rt/0213-kgdb-serial-Short-term-workaround.patch @@ -0,0 +1,86 @@ +From 63a68f078dbbdde2ffc3a7cb2928cef6b17a38a3 Mon Sep 17 00:00:00 2001 +From: Jason Wessel <jason.wessel@windriver.com> +Date: Thu, 28 Jul 2011 12:42:23 -0500 +Subject: [PATCH 213/347] kgdb/serial: Short term workaround +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz + +On 07/27/2011 04:37 PM, Thomas Gleixner wrote: +> - KGDB (not yet disabled) is reportedly unusable on -rt right now due +> to missing hacks in the console locking which I dropped on purpose. +> + +To work around this in the short term you can use this patch, in +addition to the clocksource watchdog patch that Thomas brewed up. + +Comments are welcome of course. Ultimately the right solution is to +change separation between the console and the HW to have a polled mode ++ work queue so as not to introduce any kind of latency. + +Thanks, +Jason. +--- + drivers/tty/serial/8250/8250_port.c | 3 +++ + include/linux/kdb.h | 2 ++ + kernel/debug/kdb/kdb_io.c | 2 ++ + 3 files changed, 7 insertions(+) + +diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c +index ef8bccc0823c..418b9c818b2e 100644 +--- a/drivers/tty/serial/8250/8250_port.c ++++ b/drivers/tty/serial/8250/8250_port.c +@@ -31,6 +31,7 @@ + #include <linux/nmi.h> + #include <linux/mutex.h> + #include <linux/slab.h> ++#include <linux/kdb.h> + #include <linux/uaccess.h> + #include <linux/pm_runtime.h> + #include <linux/ktime.h> +@@ -3296,6 +3297,8 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s, + + if (port->sysrq || oops_in_progress) + locked = 0; ++ else if (in_kdb_printk()) ++ locked = spin_trylock_irqsave(&port->lock, flags); + else + spin_lock_irqsave(&port->lock, flags); + +diff --git a/include/linux/kdb.h b/include/linux/kdb.h +index 68bd88223417..e033b25b0b72 100644 +--- a/include/linux/kdb.h ++++ b/include/linux/kdb.h +@@ -167,6 +167,7 @@ extern __printf(2, 0) int vkdb_printf(enum kdb_msgsrc src, const char *fmt, + extern __printf(1, 2) int kdb_printf(const char *, ...); + typedef __printf(1, 2) int (*kdb_printf_t)(const char *, ...); + ++#define in_kdb_printk() (kdb_trap_printk) + extern void kdb_init(int level); + + /* Access to kdb specific polling devices */ +@@ -201,6 +202,7 @@ extern int kdb_register_flags(char *, kdb_func_t, char *, char *, + extern int kdb_unregister(char *); + #else /* ! CONFIG_KGDB_KDB */ + static inline __printf(1, 2) int kdb_printf(const char *fmt, ...) { return 0; } ++#define in_kdb_printk() (0) + static inline void kdb_init(int level) {} + static inline int kdb_register(char *cmd, kdb_func_t func, char *usage, + char *help, short minlen) { return 0; } +diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c +index b45576ca3b0d..ad1a3bc7908f 100644 +--- a/kernel/debug/kdb/kdb_io.c ++++ b/kernel/debug/kdb/kdb_io.c +@@ -861,9 +861,11 @@ int kdb_printf(const char *fmt, ...) + va_list ap; + int r; + ++ kdb_trap_printk++; + va_start(ap, fmt); + r = vkdb_printf(KDB_MSGSRC_INTERNAL, fmt, ap); + va_end(ap); ++ kdb_trap_printk--; + + return r; + } +-- +2.36.1 + |