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-rw-r--r--include/linux/kdb.h1
-rw-r--r--kernel/debug/kdb/kdb_io.c9
-rw-r--r--kernel/printk/printk.c3
3 files changed, 5 insertions, 8 deletions
diff --git a/include/linux/kdb.h b/include/linux/kdb.h
index eb706188dc23..68bd88223417 100644
--- a/include/linux/kdb.h
+++ b/include/linux/kdb.h
@@ -161,6 +161,7 @@ enum kdb_msgsrc {
};
extern int kdb_trap_printk;
+extern int kdb_printf_cpu;
extern __printf(2, 0) int vkdb_printf(enum kdb_msgsrc src, const char *fmt,
va_list args);
extern __printf(1, 2) int kdb_printf(const char *, ...);
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index daa76154fb1b..e74be38245ad 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -30,6 +30,7 @@
char kdb_prompt_str[CMD_BUFLEN];
int kdb_trap_printk;
+int kdb_printf_cpu = -1;
static int kgdb_transition_check(char *buffer)
{
@@ -554,24 +555,19 @@ int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap)
int linecount;
int colcount;
int logging, saved_loglevel = 0;
- int saved_trap_printk;
int retlen = 0;
int fnd, len;
int this_cpu, old_cpu;
- static int kdb_printf_cpu = -1;
char *cp, *cp2, *cphold = NULL, replaced_byte = ' ';
char *moreprompt = "more> ";
struct console *c = console_drivers;
unsigned long uninitialized_var(flags);
- local_irq_save(flags);
- 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,
* even if it is interleaved with any other text.
*/
+ local_irq_save(flags);
this_cpu = smp_processor_id();
for (;;) {
old_cpu = cmpxchg(&kdb_printf_cpu, -1, this_cpu);
@@ -849,7 +845,6 @@ kdb_print_out:
console_loglevel = saved_loglevel;
/* kdb_printf_cpu locked the code above. */
smp_store_release(&kdb_printf_cpu, old_cpu);
- kdb_trap_printk = saved_trap_printk;
local_irq_restore(flags);
return retlen;
}
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 577f2288d19f..a3ce35e0fa1e 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1926,7 +1926,8 @@ int vprintk_default(const char *fmt, va_list args)
int r;
#ifdef CONFIG_KGDB_KDB
- if (unlikely(kdb_trap_printk)) {
+ /* Allow to pass printk() to kdb but avoid a recursion. */
+ if (unlikely(kdb_trap_printk && kdb_printf_cpu < 0)) {
r = vkdb_printf(KDB_MSGSRC_PRINTK, fmt, args);
return r;
}

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