diff options
| author | Jason Wessel <jason.wessel@windriver.com> | 2011-07-28 12:42:23 -0500 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2017-02-08 10:03:02 -0500 |
| commit | 4035fc2c48509843a9eea2753ade347e9cee4f08 (patch) | |
| tree | a5a8385d90ce9e07aa6aa9dbea6d76d21a4e64d9 | |
| parent | 416ad9835496aa99831d5561e43a8993b5def15a (diff) | |
| download | linux-stable-rt-4035fc2c48509843a9eea2753ade347e9cee4f08.tar.gz | |
kgdb/serial: Short term workaround
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.
| -rw-r--r-- | drivers/tty/serial/8250/8250_core.c | 3 | ||||
| -rw-r--r-- | include/linux/kdb.h | 3 | ||||
| -rw-r--r-- | kernel/debug/kdb/kdb_io.c | 6 |
3 files changed, 6 insertions, 6 deletions
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index 91b28590422216..62fe18e31e0d95 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -38,6 +38,7 @@ #include <linux/nmi.h> #include <linux/mutex.h> #include <linux/slab.h> +#include <linux/kdb.h> #ifdef CONFIG_SPARC #include <linux/sunserialcore.h> #endif @@ -2867,7 +2868,7 @@ serial8250_console_write(struct console *co, const char *s, unsigned int count) touch_nmi_watchdog(); - if (port->sysrq || oops_in_progress) + if (port->sysrq || oops_in_progress || 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 7f6fe6e015bc8a..680ad231674f84 100644 --- a/include/linux/kdb.h +++ b/include/linux/kdb.h @@ -115,7 +115,7 @@ extern int kdb_trap_printk; extern __printf(1, 0) int vkdb_printf(const char *fmt, va_list args); 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 */ @@ -150,6 +150,7 @@ extern int kdb_register_repeat(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 14ff4849262c0c..399dba686b1971 100644 --- a/kernel/debug/kdb/kdb_io.c +++ b/kernel/debug/kdb/kdb_io.c @@ -554,7 +554,6 @@ int vkdb_printf(const char *fmt, va_list ap) int linecount; int colcount; int logging, saved_loglevel = 0; - int saved_trap_printk; int got_printf_lock = 0; int retlen = 0; int fnd, len; @@ -565,8 +564,6 @@ 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, @@ -833,7 +830,6 @@ kdb_print_out: } else { __release(kdb_printf_lock); } - kdb_trap_printk = saved_trap_printk; preempt_enable(); return retlen; } @@ -843,9 +839,11 @@ 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; } |