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    SubjectRe: [PATCH 1/2] sched: Add helper for task stack page overrun checking
    On 09/04, Aaron Tomlin wrote:
    >
    > +#define task_stack_end_corrupted(task) \
    > + (*(end_of_stack(task)) != STACK_END_MAGIC)

    and it is always used along with "tsk != init_task".

    But why we exclude swapper/0? Can't we add

    end_of_stack(current) = STACK_END_MAGIC;

    somewhere at the start of start_kernel() ?

    If not, perhaps this new helper should check "task != &init_task"
    itself so that we can simplify its users?

    Oleg.

    >
    > static inline int object_is_on_stack(void *obj)
    > {
    > diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
    > index 8a4e5cb..06c7390 100644
    > --- a/kernel/trace/trace_stack.c
    > +++ b/kernel/trace/trace_stack.c
    > @@ -13,7 +13,6 @@
    > #include <linux/sysctl.h>
    > #include <linux/init.h>
    > #include <linux/fs.h>
    > -#include <linux/magic.h>
    >
    > #include <asm/setup.h>
    >
    > @@ -171,8 +170,8 @@ check_stack(unsigned long ip, unsigned long *stack)
    > i++;
    > }
    >
    > - if ((current != &init_task &&
    > - *(end_of_stack(current)) != STACK_END_MAGIC)) {
    > + if (current != &init_task &&
    > + task_stack_end_corrupted(current)) {
    > print_max_stack();
    > BUG();
    > }
    > --
    > 1.9.3
    >



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