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-rw-r--r--drivers/tty/serial/8250.c13
-rw-r--r--include/linux/kdb.h2
-rw-r--r--kernel/debug/kdb/kdb_io.c6
3 files changed, 13 insertions, 8 deletions
diff --git a/drivers/tty/serial/8250.c b/drivers/tty/serial/8250.c
index 3bf482cb7f51..0596a359d30c 100644
--- a/drivers/tty/serial/8250.c
+++ b/drivers/tty/serial/8250.c
@@ -38,6 +38,7 @@
#include <linux/nmi.h>
#include <linux/mutex.h>
#include <linux/slab.h>
+#include <linux/kdb.h>
#include <asm/io.h>
#include <asm/irq.h>
@@ -2855,10 +2856,14 @@ serial8250_console_write(struct console *co, const char *s, unsigned int count)
touch_nmi_watchdog();
- if (up->port.sysrq || oops_in_progress)
- locked = spin_trylock_irqsave(&up->port.lock, flags);
- else
- spin_lock_irqsave(&up->port.lock, flags);
+ if (unlikely(in_kdb_printk())) {
+ locked = 0;
+ } else {
+ if (up->port.sysrq || oops_in_progress)
+ locked = spin_trylock_irqsave(&up->port.lock, flags);
+ else
+ spin_lock_irqsave(&up->port.lock, flags);
+ }
/*
* First save the IER then disable the interrupts
diff --git a/include/linux/kdb.h b/include/linux/kdb.h
index 064725854db8..0d1ebfc9ff43 100644
--- a/include/linux/kdb.h
+++ b/include/linux/kdb.h
@@ -150,12 +150,14 @@ extern int kdb_register(char *, kdb_func_t, char *, char *, short);
extern int kdb_register_repeat(char *, kdb_func_t, char *, char *,
short, kdb_repeat_t);
extern int kdb_unregister(char *);
+#define in_kdb_printk() (kdb_trap_printk)
#else /* ! CONFIG_KGDB_KDB */
#define kdb_printf(...)
#define kdb_init(x)
#define kdb_register(...)
#define kdb_register_repeat(...)
#define kdb_uregister(x)
+#define in_kdb_printk() (0)
#endif /* CONFIG_KGDB_KDB */
enum {
KDB_NOT_INITIALIZED,
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 4802eb5840e1..5b7455fada1e 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -553,7 +553,6 @@ int vkdb_printf(const char *fmt, va_list ap)
int diag;
int linecount;
int logging, saved_loglevel = 0;
- int saved_trap_printk;
int got_printf_lock = 0;
int retlen = 0;
int fnd, len;
@@ -564,8 +563,6 @@ int vkdb_printf(const char *fmt, va_list ap)
unsigned long uninitialized_var(flags);
preempt_disable();
- saved_trap_printk = kdb_trap_printk;
- kdb_trap_printk = 0;
/* Serialize kdb_printf if multiple cpus try to write at once.
* But if any cpu goes recursive in kdb, just print the output,
@@ -821,7 +818,6 @@ kdb_print_out:
} else {
__release(kdb_printf_lock);
}
- kdb_trap_printk = saved_trap_printk;
preempt_enable();
return retlen;
}
@@ -831,9 +827,11 @@ int kdb_printf(const char *fmt, ...)
va_list ap;
int r;
+ kdb_trap_printk++;
va_start(ap, fmt);
r = vkdb_printf(fmt, ap);
va_end(ap);
+ kdb_trap_printk--;
return r;
}