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Commit a70857e4 authored by Aaron Tomlin's avatar Aaron Tomlin Committed by Ingo Molnar
Browse files

sched: Add helper for task stack page overrun checking 



This facility is used in a few places so let's introduce
a helper function to improve code readability.

Signed-off-by: default avatarAaron Tomlin <atomlin@redhat.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: aneesh.kumar@linux.vnet.ibm.com
Cc: dzickus@redhat.com
Cc: bmr@redhat.com
Cc: jcastillo@redhat.com
Cc: oleg@redhat.com
Cc: riel@redhat.com
Cc: prarit@redhat.com
Cc: jgh@redhat.com
Cc: minchan@kernel.org
Cc: mpe@ellerman.id.au
Cc: tglx@linutronix.de
Cc: hannes@cmpxchg.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/1410527779-8133-3-git-send-email-atomlin@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent d4311ff1

arch/powerpc/mm/fault.c

+1 −3
Original line number Diff line number Diff line
@@ -507,7 +507,6 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address, 
void bad_page_fault(struct pt_regs *regs, unsigned long address, int sig)

{

	const struct exception_table_entry *entry;

	unsigned long *stackend;



	/* Are we prepared to handle this fault?  */

	if ((entry = search_exception_tables(regs->nip)) != NULL) {
@@ -536,8 +535,7 @@ void bad_page_fault(struct pt_regs *regs, unsigned long address, int sig) 
	printk(KERN_ALERT "Faulting instruction address: 0x%08lx\n",

		regs->nip);



	stackend = end_of_stack(current);

	if (*stackend != STACK_END_MAGIC)

	if (task_stack_end_corrupted(current))

		printk(KERN_ALERT "Thread overran stack, or stack corrupted\n");



	die("Kernel access of bad area", regs, sig);

arch/x86/mm/fault.c

+1 −3
Original line number Diff line number Diff line
@@ -648,7 +648,6 @@ no_context(struct pt_regs *regs, unsigned long error_code, 
	   unsigned long address, int signal, int si_code)

{

	struct task_struct *tsk = current;

	unsigned long *stackend;

	unsigned long flags;

	int sig;
@@ -708,8 +707,7 @@ no_context(struct pt_regs *regs, unsigned long error_code, 


	show_fault_oops(regs, error_code, address);



	stackend = end_of_stack(tsk);

	if (*stackend != STACK_END_MAGIC)

	if (task_stack_end_corrupted(tsk))

		printk(KERN_EMERG "Thread overran stack, or stack corrupted\n");



	tsk->thread.cr2		= address;

include/linux/sched.h

+2 −0
Original line number Diff line number Diff line
@@ -2617,6 +2617,8 @@ static inline unsigned long *end_of_stack(struct task_struct *p) 
}



#endif

#define task_stack_end_corrupted(task) \

		(*(end_of_stack(task)) != STACK_END_MAGIC)



static inline int object_is_on_stack(void *obj)

{

kernel/trace/trace_stack.c

+1 −1
Original line number Diff line number Diff line
@@ -170,7 +170,7 @@ check_stack(unsigned long ip, unsigned long *stack) 
			i++;

	}



	if (*end_of_stack(current) != STACK_END_MAGIC) {

	if (task_stack_end_corrupted(current)) {

		print_max_stack();

		BUG();

	}