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Commit 1209140c authored by Jan Beulich's avatar Jan Beulich Committed by Linus Torvalds
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[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: default avatarJan Beulich <jbeulich@novell.com>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 059bf0f6

arch/x86_64/kernel/traps.c

+21 −16
Original line number Diff line number Diff line
@@ -343,11 +343,13 @@ void out_of_line_bug(void) 
static DEFINE_SPINLOCK(die_lock);

static int die_owner = -1;



void oops_begin(void)

unsigned long oops_begin(void)

{

	int cpu = safe_smp_processor_id();

	unsigned long flags;



	/* racy, but better than risking deadlock. */

	local_irq_disable();

	local_irq_save(flags);

	if (!spin_trylock(&die_lock)) { 

		if (cpu == die_owner) 

			/* nested oops. should stop eventually */;
@@ -357,13 +359,14 @@ void oops_begin(void) 
	die_owner = cpu;

	console_verbose();

	bust_spinlocks(1);

	return flags;

}



void oops_end(void)

void oops_end(unsigned long flags)

{ 

	die_owner = -1;

	bust_spinlocks(0);

	spin_unlock(&die_lock); 

	spin_unlock_irqrestore(&die_lock, flags);

	if (panic_on_oops)

		panic("Oops");

}
@@ -392,10 +395,11 @@ void __die(const char * str, struct pt_regs * regs, long err) 


void die(const char * str, struct pt_regs * regs, long err)

{

	oops_begin();

	unsigned long flags = oops_begin();



	handle_BUG(regs);

	__die(str, regs, err);

	oops_end();

	oops_end(flags);

	do_exit(SIGSEGV); 

}

static inline void die_if_kernel(const char * str, struct pt_regs * regs, long err)
@@ -406,7 +410,8 @@ static inline void die_if_kernel(const char * str, struct pt_regs * regs, long e 


void die_nmi(char *str, struct pt_regs *regs)

{

	oops_begin();

	unsigned long flags = oops_begin();



	/*

	 * We are in trouble anyway, lets at least try

	 * to get a message out.
@@ -416,7 +421,7 @@ void die_nmi(char *str, struct pt_regs *regs) 
	if (panic_on_timeout || panic_on_oops)

		panic("nmi watchdog");

	printk("console shuts up ...\n");

	oops_end();

	oops_end(flags);

	do_exit(SIGSEGV);

}

arch/x86_64/mm/fault.c

+6 −4
Original line number Diff line number Diff line
@@ -221,12 +221,13 @@ int unhandled_signal(struct task_struct *tsk, int sig) 
static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs,

				 unsigned long error_code)

{

	oops_begin();

	unsigned long flags = oops_begin();



	printk(KERN_ALERT "%s: Corrupted page table at address %lx\n",

	       current->comm, address);

	dump_pagetable(address);

	__die("Bad pagetable", regs, error_code);

	oops_end();

	oops_end(flags);

	do_exit(SIGKILL);

}
@@ -304,6 +305,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, 
	unsigned long address;

	const struct exception_table_entry *fixup;

	int write;

	unsigned long flags;

	siginfo_t info;



#ifdef CONFIG_CHECKING
@@ -521,7 +523,7 @@ no_context: 
 * terminate things with extreme prejudice.

 */



	oops_begin(); 

	flags = oops_begin();



	if (address < PAGE_SIZE)

		printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
@@ -534,7 +536,7 @@ no_context: 
	__die("Oops", regs, error_code);

	/* Executive summary in case the body of the oops scrolled away */

	printk(KERN_EMERG "CR2: %016lx\n", address);

	oops_end(); 

	oops_end(flags);

	do_exit(SIGKILL);



/*

include/asm-x86_64/kdebug.h

+2 −2
Original line number Diff line number Diff line
@@ -46,7 +46,7 @@ extern void die(const char *,struct pt_regs *,long); 
extern void __die(const char *,struct pt_regs *,long);

extern void show_registers(struct pt_regs *regs);

extern void dump_pagetable(unsigned long);

extern void oops_begin(void);

extern void oops_end(void);

extern unsigned long oops_begin(void);

extern void oops_end(unsigned long);



#endif

include/asm-x86_64/proto.h

+0 −3
Original line number Diff line number Diff line
@@ -74,9 +74,6 @@ extern void acpi_reserve_bootmem(void); 


extern void swap_low_mappings(void);



extern void oops_begin(void);

extern void die(const char *,struct pt_regs *,long);

extern void __die(const char * str, struct pt_regs * regs, long err);

extern void __show_regs(struct pt_regs * regs);

extern void show_regs(struct pt_regs * regs);