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authorJason Wessel <jason.wessel@windriver.com>2010-05-20 21:04:27 -0500
committerJason Wessel <jason.wessel@windriver.com>2010-05-20 21:04:27 -0500
commitd37d39ae3b4a8f9a21114921fb344fe7cadb1abd (patch)
tree2c20219725a12c343429758ec378b5c9d08b04bd /kernel
parentefe2f29e324fd20e0449bcd6dc6dbe4734c2ba94 (diff)
printk,kdb: capture printk() when in kdb shell
Certain calls from the kdb shell will call out to printk(), and any of these calls should get vectored back to the kdb_printf() so that the kdb pager and processing can be used, as well as to properly channel I/O to the polled I/O devices. CC: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Acked-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/debug/kdb/kdb_bt.c2
-rw-r--r--kernel/debug/kdb/kdb_io.c24
-rw-r--r--kernel/debug/kdb/kdb_main.c4
-rw-r--r--kernel/printk.c9
4 files changed, 35 insertions, 4 deletions
diff --git a/kernel/debug/kdb/kdb_bt.c b/kernel/debug/kdb/kdb_bt.c
index 483fa4e7aaac..2f62fe85f16a 100644
--- a/kernel/debug/kdb/kdb_bt.c
+++ b/kernel/debug/kdb/kdb_bt.c
@@ -23,6 +23,7 @@ static void kdb_show_stack(struct task_struct *p, void *addr)
{
int old_lvl = console_loglevel;
console_loglevel = 15;
+ kdb_trap_printk++;
kdb_set_current_task(p);
if (addr) {
show_stack((struct task_struct *)p, addr);
@@ -36,6 +37,7 @@ static void kdb_show_stack(struct task_struct *p, void *addr)
show_stack(p, NULL);
}
console_loglevel = old_lvl;
+ kdb_trap_printk--;
}
/*
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 58be7e9c9e95..c9b7f4f90bba 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -29,6 +29,7 @@
#define CMD_BUFLEN 256
char kdb_prompt_str[CMD_BUFLEN];
+int kdb_trap_printk;
static void kgdb_transition_check(char *buffer)
{
@@ -533,12 +534,12 @@ static int kdb_search_string(char *searched, char *searchfor)
return 0;
}
-int kdb_printf(const char *fmt, ...)
+int vkdb_printf(const char *fmt, va_list ap)
{
- 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;
@@ -549,6 +550,9 @@ int kdb_printf(const char *fmt, ...)
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,
* even if it is interleaved with any other text.
@@ -575,9 +579,7 @@ int kdb_printf(const char *fmt, ...)
next_avail = kdb_buffer;
size_avail = sizeof(kdb_buffer);
}
- va_start(ap, fmt);
vsnprintf(next_avail, size_avail, fmt, ap);
- va_end(ap);
/*
* If kdb_parse() found that the command was cmd xxx | grep yyy
@@ -805,6 +807,20 @@ kdb_print_out:
} else {
__release(kdb_printf_lock);
}
+ kdb_trap_printk = saved_trap_printk;
preempt_enable();
return retlen;
}
+
+int kdb_printf(const char *fmt, ...)
+{
+ va_list ap;
+ int r;
+
+ va_start(ap, fmt);
+ r = vkdb_printf(fmt, ap);
+ va_end(ap);
+
+ return r;
+}
+
diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
index 64ef9ac14ba9..b724c791b6d4 100644
--- a/kernel/debug/kdb/kdb_main.c
+++ b/kernel/debug/kdb/kdb_main.c
@@ -1056,7 +1056,9 @@ static void kdb_dumpregs(struct pt_regs *regs)
{
int old_lvl = console_loglevel;
console_loglevel = 15;
+ kdb_trap_printk++;
show_regs(regs);
+ kdb_trap_printk--;
kdb_printf("\n");
console_loglevel = old_lvl;
}
@@ -1819,7 +1821,9 @@ static int kdb_sr(int argc, const char **argv)
if (argc != 1)
return KDB_ARGCOUNT;
sysrq_toggle_support(1);
+ kdb_trap_printk++;
handle_sysrq(*argv[1], NULL);
+ kdb_trap_printk--;
return 0;
}
diff --git a/kernel/printk.c b/kernel/printk.c
index 9213b8b5bb4f..444b770c9595 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -33,6 +33,7 @@
#include <linux/bootmem.h>
#include <linux/syscalls.h>
#include <linux/kexec.h>
+#include <linux/kdb.h>
#include <linux/ratelimit.h>
#include <linux/kmsg_dump.h>
#include <linux/syslog.h>
@@ -602,6 +603,14 @@ asmlinkage int printk(const char *fmt, ...)
va_list args;
int r;
+#ifdef CONFIG_KGDB_KDB
+ if (unlikely(kdb_trap_printk)) {
+ va_start(args, fmt);
+ r = vkdb_printf(fmt, args);
+ va_end(args);
+ return r;
+ }
+#endif
va_start(args, fmt);
r = vprintk(fmt, args);
va_end(args);