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[PATCH] x86_64: fix die_lock nesting

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I noticed this when poking around in this area.

The oops_begin() function in x86_64 would only conditionally claim
the die_lock if the call is nested, but oops_end() would always
release the spinlock. This patch adds a nest count for the die lock
so that the release of the lock is only done on the final oops_end().

Signed-off-by: Corey Minyard <minyard@acm.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Corey Minyard 2006-05-08 15:17:22 +02:00 committed by Linus Torvalds
parent 5192d84e4c
commit cdc60a4c8e
1 changed files with 9 additions and 1 deletions
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10
arch/x86_64/kernel/traps.c
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@ -385,6 +385,7 @@ void out_of_line_bug(void)
static DEFINE_SPINLOCK(die_lock); static DEFINE_SPINLOCK(die_lock);
static int die_owner = -1; static int die_owner = -1;
static unsigned int die_nest_count;
unsigned __kprobes long oops_begin(void) unsigned __kprobes long oops_begin(void)
{ {
@ -399,6 +400,7 @@ unsigned __kprobes long oops_begin(void)
else else
spin_lock(&die_lock); spin_lock(&die_lock);
} }
die_nest_count++;
die_owner = cpu; die_owner = cpu;
console_verbose(); console_verbose();
bust_spinlocks(1); bust_spinlocks(1);
@ -409,7 +411,13 @@ void __kprobes oops_end(unsigned long flags)
{ {
die_owner = -1; die_owner = -1;
bust_spinlocks(0); bust_spinlocks(0);
spin_unlock_irqrestore(&die_lock, flags); die_nest_count--;
if (die_nest_count)
/* We still own the lock */
local_irq_restore(flags);
else
/* Nest count reaches zero, release the lock. */
spin_unlock_irqrestore(&die_lock, flags);
if (panic_on_oops) if (panic_on_oops)
panic("Oops"); panic("Oops");
} }