> -----Original Message-----
> From: Sergei Shtylyov [mailto:[EMAIL PROTECTED]
> >>>+
> >>> if(!CHECK_EXCEPTION_STACK()) {
>
> Worth fixing if stmt style while at it. :-)
>
Noted and adjusted.
Attached are the patches to be committed to core-lite.patch in the
2.6.21_uprev branch.
Now that this is tested and confirmed to work, these will be committed
with in the hour.
Thanks,
Jason.
Remove the breakpoint tasklet from the early initialization and defer
breakpoints to the late_init.
On SMP x86_64 in particular scheduling
a tasklet too early can result in a silent death hang in the system,
as there is a race to setup the exception stack vs the schduling
context vs kgdb having the ability to debug the exception.
Signed-off-by: Jason Wessel <[EMAIL PROTECTED]>
---
kernel/kgdb.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
Index: linux-2.6.21-standard/kernel/kgdb.c
===================================================================
--- linux-2.6.21-standard.orig/kernel/kgdb.c
+++ linux-2.6.21-standard/kernel/kgdb.c
@@ -1670,7 +1670,7 @@ void kgdb_unregister_io_module(struct kg
*/
static void kgdb_tasklet_bpt(unsigned long ing)
{
- if(CHECK_EXCEPTION_STACK())
+ if (CHECK_EXCEPTION_STACK())
breakpoint();
}
@@ -1682,20 +1682,21 @@ DECLARE_TASKLET(kgdb_tasklet_breakpoint,
*/
static void __init kgdb_early_entry(void)
{
+ /* Let the architecture do any setup that it needs to. */
+ kgdb_arch_init();
+
/*
* Don't try and do anything until the architecture is able to
* setup the exception stack. In this case, it is up to the
* architecture to hook in and look at us when they are ready.
*/
- if(!CHECK_EXCEPTION_STACK()) {
+
+ if (!CHECK_EXCEPTION_STACK()) {
kgdb_initialized = -1;
- tasklet_schedule(&kgdb_tasklet_breakpoint);
+ /* any kind of break point is deferred to late_init */
return;
}
- /* Let the architecture do any setup that it needs to. */
- kgdb_arch_init();
-
/* Now try the I/O. */
/* For early entry kgdb_io_ops.init must be defined */
if (!kgdb_io_ops.init || kgdb_io_ops.init()) {
@@ -1879,7 +1880,7 @@ static int __init opt_kgdb_enter(char *s
"gdb...\n");
else {
printk(KERN_CRIT "KGDB cannot initialize I/O yet.\n");
- return;
+ return 0;
}
}
This patch moves the early initialization code into a .init_text section
vs having the possibility to call a function that has been deleted after
the .init_text has been destroyed.
In general this cannot happen but it does fix the compiler's concern about
the possibility for it to happen.
Signed-off-by: Jason Wessel <[EMAIL PROTECTED]>
---
kernel/kgdb.c | 23 +++++++++++------------
1 file changed, 11 insertions(+), 12 deletions(-)
Index: linux-2.6.21-standard/kernel/kgdb.c
===================================================================
--- linux-2.6.21-standard.orig/kernel/kgdb.c
+++ linux-2.6.21-standard/kernel/kgdb.c
@@ -1788,17 +1788,6 @@ late_initcall(kgdb_late_entry);
*/
void breakpoint(void)
{
- if (kgdb_initialized != 1) {
- kgdb_early_entry();
- if (kgdb_initialized == 1)
- printk(KERN_CRIT "Waiting for connection from remote "
- "gdb...\n");
- else {
- printk(KERN_CRIT "KGDB cannot initialize I/O yet.\n");
- return;
- }
- }
-
atomic_set(&kgdb_setting_breakpoint, 1);
wmb();
BREAKPOINT();
@@ -1883,7 +1872,17 @@ static int __init opt_kgdb_enter(char *s
if (kgdb_initialized)
return 0;
- /* Call breakpoint() which will take care of init. */
+ if (kgdb_initialized != 1) {
+ kgdb_early_entry();
+ if (kgdb_initialized == 1)
+ printk(KERN_CRIT "Waiting for connection from remote "
+ "gdb...\n");
+ else {
+ printk(KERN_CRIT "KGDB cannot initialize I/O yet.\n");
+ return;
+ }
+ }
+
breakpoint();
return 0;
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