panic: decrease oops_in_progress only after having done the panic
Impact: eliminate secondary warnings during panic()
We can panic() in a number of difficult, atomic contexts, hence
we use bust_spinlocks(1) in panic() to increase oops_in_progress,
which prevents various debug checks we have in place.
But in practice this protection only covers the first few printk's
done by panic() - it does not cover the later attempt to stop all
other CPUs and kexec(). If a secondary warning triggers in one of
those facilities that can make the panic message scroll off.
So do bust_spinlocks(0) only much later in panic(). (which code
is only reached if panic policy is relaxed that it can return
after a warning message)
Reported-by: Jan Beulich <jbeulich@novell.com>
LKML-Reference: <49B91A7E.76E4.0078.0@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/panic.c b/kernel/panic.c
index 32fe4ef..57fb005 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -77,7 +77,6 @@
#ifdef CONFIG_DEBUG_BUGVERBOSE
dump_stack();
#endif
- bust_spinlocks(0);
/*
* If we have crashed and we have a crash kernel loaded let it handle
@@ -136,6 +135,7 @@
mdelay(1);
i++;
}
+ bust_spinlocks(0);
}
EXPORT_SYMBOL(panic);