From a70857e46dd13e87ae06bf0e64cb6a2d4f436265 Mon Sep 17 00:00:00 2001 From: Aaron Tomlin Date: Fri, 12 Sep 2014 14:16:18 +0100 Subject: [PATCH] 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: Aaron Tomlin Signed-off-by: Peter Zijlstra (Intel) 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 Cc: Benjamin Herrenschmidt Cc: Jiri Olsa Cc: Linus Torvalds Cc: Masami Hiramatsu Cc: Michael Ellerman Cc: Paul Mackerras Cc: Seiji Aguchi Cc: Steven Rostedt Cc: Yasuaki Ishimatsu Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/1410527779-8133-3-git-send-email-atomlin@redhat.com Signed-off-by: Ingo Molnar --- arch/powerpc/mm/fault.c | 4 +--- arch/x86/mm/fault.c | 4 +--- include/linux/sched.h | 2 ++ kernel/trace/trace_stack.c | 2 +- 4 files changed, 5 insertions(+), 7 deletions(-) diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index 35d0760c3fa4..99b2f2775658 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -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); diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index bc23a7043c65..6240bc7ae741 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -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; diff --git a/include/linux/sched.h b/include/linux/sched.h index 118dca7d5a28..18f52624eaa6 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -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) { diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index 1636e41828c2..16eddb308c33 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -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(); }