[PATCH] x86: make oops_begin and oops_end equal

Alexander van Heukelum
2008-10-20T15:10:43Z

Mostly use the x86_64 version of oops_begin() and oops_end() on
i386 too. Changes to the original x86_64 version:

- move add_taint(TAINT_DIE) into oops_end()
- add a conditional crash_kexec() into oops_end()

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
---
arch/x86/kernel/dumpstack_32.c | 36 +++++++++++++++++++++---------------
arch/x86/kernel/dumpstack_64.c | 4 +++-
2 files changed, 24 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
index b361475..e45952b 100644
--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -289,35 +289,41 @@ static unsigned int die_nest_count;

unsigned __kprobes long oops_begin(void)
{
+ int cpu;
unsigned long flags;

oops_enter();

- if (die_owner != raw_smp_processor_id()) {
- console_verbose();
- raw_local_irq_save(flags);
- __raw_spin_lock(&die_lock);
- die_owner = smp_processor_id();
- die_nest_count = 0;
- bust_spinlocks(1);
- } else {
- raw_local_irq_save(flags);
+ /* racy, but better than risking deadlock. */
+ raw_local_irq_save(flags);
+ cpu = smp_processor_id();
+ if (!__raw_spin_trylock(&die_lock)) {
+ if (cpu == die_owner)
+ /* nested oops. should stop eventually */;
+ else
+ __raw_spin_lock(&die_lock);
}
die_nest_count++;
+ die_owner = cpu;
+ console_verbose();
+ bust_spinlocks(1);
return flags;
}

void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
{
- bust_spinlocks(0);
die_owner = -1;
+ bust_spinlocks(0);
+ die_nest_count--;
add_taint(TAINT_DIE);
- __raw_spin_unlock(&die_lock);
+ if (!die_nest_count)
+ /* Nest count reaches zero, release the lock. */
+ __raw_spin_unlock(&die_lock);
raw_local_irq_restore(flags);
-
- if (!regs)
+ if (!regs) {
+ oops_exit();
return;
-
+ }
if (kexec_should_crash(current))
crash_kexec(regs);
if (in_interrupt())
@@ -405,6 +411,7 @@ die_nmi(char *str, struct pt_regs *regs, int do_panic)
panic("Non maskable interrupt");
console_silent();
spin_unlock(&nmi_print_lock);
+ bust_spinlocks(0);

/*
* If we are in kernel we are probably nested up pretty bad
@@ -415,7 +422,6 @@ die_nmi(char *str, struct pt_regs *regs, int do_panic)
crash_kexec(regs);
}

- bust_spinlocks(0);
do_exit(SIGSEGV);
}

diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index 96a5db7..cd7b46b 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -461,6 +461,7 @@ void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
die_owner = -1;
bust_spinlocks(0);
die_nest_count--;
+ add_taint(TAINT_DIE);
if (!die_nest_count)
/* Nest count reaches zero, release the lock. */
__raw_spin_unlock(&die_lock);
@@ -469,6 +470,8 @@ void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
oops_exit();
return;
}
+ if (kexec_should_crash(current))
+ crash_kexec(regs);
if (in_interrupt())
panic("Fatal exception in interrupt");
if (panic_on_oops)
@@ -496,7 +499,6 @@ int __kprobes __die(const char *str, struct pt_regs *regs, long err)
return 1;

show_registers(regs);
- add_taint(TAINT_DIE);
/* Executive summary in case the oops scrolled away */
printk(KERN_ALERT "RIP ");
printk_address(regs->ip, 1);
--
1.5.4.3