[PATCH] x86-64: Safe interrupts in oops_begin/end
Rather than blindly re-enabling interrupts in oops_end(), save their state in oope_begin() and then restore that state. Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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@ -343,30 +343,33 @@ void out_of_line_bug(void)
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static DEFINE_SPINLOCK(die_lock);
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static int die_owner = -1;
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void oops_begin(void)
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unsigned long oops_begin(void)
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{
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int cpu = safe_smp_processor_id();
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/* racy, but better than risking deadlock. */
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local_irq_disable();
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int cpu = safe_smp_processor_id();
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unsigned long flags;
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/* racy, but better than risking deadlock. */
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local_irq_save(flags);
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if (!spin_trylock(&die_lock)) {
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if (cpu == die_owner)
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/* nested oops. should stop eventually */;
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else
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spin_lock(&die_lock);
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spin_lock(&die_lock);
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}
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die_owner = cpu;
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die_owner = cpu;
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console_verbose();
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bust_spinlocks(1);
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bust_spinlocks(1);
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return flags;
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}
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void oops_end(void)
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void oops_end(unsigned long flags)
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{
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die_owner = -1;
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bust_spinlocks(0);
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spin_unlock(&die_lock);
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bust_spinlocks(0);
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spin_unlock_irqrestore(&die_lock, flags);
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if (panic_on_oops)
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panic("Oops");
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}
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panic("Oops");
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}
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void __die(const char * str, struct pt_regs * regs, long err)
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{
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@ -392,10 +395,11 @@ void __die(const char * str, struct pt_regs * regs, long err)
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void die(const char * str, struct pt_regs * regs, long err)
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{
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oops_begin();
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unsigned long flags = oops_begin();
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handle_BUG(regs);
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__die(str, regs, err);
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oops_end();
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oops_end(flags);
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do_exit(SIGSEGV);
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}
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static inline void die_if_kernel(const char * str, struct pt_regs * regs, long err)
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@ -406,7 +410,8 @@ static inline void die_if_kernel(const char * str, struct pt_regs * regs, long e
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void die_nmi(char *str, struct pt_regs *regs)
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{
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oops_begin();
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unsigned long flags = oops_begin();
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/*
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* We are in trouble anyway, lets at least try
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* to get a message out.
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@ -416,7 +421,7 @@ void die_nmi(char *str, struct pt_regs *regs)
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if (panic_on_timeout || panic_on_oops)
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panic("nmi watchdog");
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printk("console shuts up ...\n");
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oops_end();
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oops_end(flags);
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do_exit(SIGSEGV);
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}
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@ -221,12 +221,13 @@ int unhandled_signal(struct task_struct *tsk, int sig)
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static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs,
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unsigned long error_code)
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{
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oops_begin();
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unsigned long flags = oops_begin();
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printk(KERN_ALERT "%s: Corrupted page table at address %lx\n",
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current->comm, address);
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dump_pagetable(address);
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__die("Bad pagetable", regs, error_code);
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oops_end();
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oops_end(flags);
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do_exit(SIGKILL);
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}
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@ -304,6 +305,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
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unsigned long address;
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const struct exception_table_entry *fixup;
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int write;
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unsigned long flags;
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siginfo_t info;
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#ifdef CONFIG_CHECKING
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@ -521,7 +523,7 @@ no_context:
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* terminate things with extreme prejudice.
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*/
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oops_begin();
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flags = oops_begin();
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if (address < PAGE_SIZE)
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printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
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@ -534,7 +536,7 @@ no_context:
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__die("Oops", regs, error_code);
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/* Executive summary in case the body of the oops scrolled away */
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printk(KERN_EMERG "CR2: %016lx\n", address);
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oops_end();
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oops_end(flags);
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do_exit(SIGKILL);
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/*
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@ -46,7 +46,7 @@ extern void die(const char *,struct pt_regs *,long);
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extern void __die(const char *,struct pt_regs *,long);
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extern void show_registers(struct pt_regs *regs);
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extern void dump_pagetable(unsigned long);
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extern void oops_begin(void);
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extern void oops_end(void);
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extern unsigned long oops_begin(void);
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extern void oops_end(unsigned long);
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#endif
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@ -74,9 +74,6 @@ extern void acpi_reserve_bootmem(void);
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extern void swap_low_mappings(void);
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extern void oops_begin(void);
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extern void die(const char *,struct pt_regs *,long);
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extern void __die(const char * str, struct pt_regs * regs, long err);
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extern void __show_regs(struct pt_regs * regs);
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extern void show_regs(struct pt_regs * regs);
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