diff options
Diffstat (limited to 'kernel/stackleak.c')
| -rw-r--r-- | kernel/stackleak.c | 30 |
1 files changed, 14 insertions, 16 deletions
diff --git a/kernel/stackleak.c b/kernel/stackleak.c index 24b7cf01b297..d5f684dc0a2d 100644 --- a/kernel/stackleak.c +++ b/kernel/stackleak.c @@ -73,40 +73,38 @@ late_initcall(stackleak_sysctls_init); static __always_inline void __stackleak_erase(void) { const unsigned long task_stack_low = stackleak_task_low_bound(current); - - /* It would be nice not to have 'kstack_ptr' and 'boundary' on stack */ - unsigned long kstack_ptr = current->lowest_stack; - unsigned long boundary = task_stack_low; + unsigned long erase_low = current->lowest_stack; + unsigned long erase_high; unsigned int poison_count = 0; const unsigned int depth = STACKLEAK_SEARCH_DEPTH / sizeof(unsigned long); /* Search for the poison value in the kernel stack */ - while (kstack_ptr > boundary && poison_count <= depth) { - if (*(unsigned long *)kstack_ptr == STACKLEAK_POISON) + while (erase_low > task_stack_low && poison_count <= depth) { + if (*(unsigned long *)erase_low == STACKLEAK_POISON) poison_count++; else poison_count = 0; - kstack_ptr -= sizeof(unsigned long); + erase_low -= sizeof(unsigned long); } #ifdef CONFIG_STACKLEAK_METRICS - current->prev_lowest_stack = kstack_ptr; + current->prev_lowest_stack = erase_low; #endif /* - * Now write the poison value to the kernel stack. Start from - * 'kstack_ptr' and move up till the new 'boundary'. We assume that - * the stack pointer doesn't change when we write poison. + * Now write the poison value to the kernel stack between 'erase_low' + * and 'erase_high'. We assume that the stack pointer doesn't change + * when we write poison. */ if (on_thread_stack()) - boundary = current_stack_pointer; + erase_high = current_stack_pointer; else - boundary = current_top_of_stack(); + erase_high = current_top_of_stack(); - while (kstack_ptr < boundary) { - *(unsigned long *)kstack_ptr = STACKLEAK_POISON; - kstack_ptr += sizeof(unsigned long); + while (erase_low < erase_high) { + *(unsigned long *)erase_low = STACKLEAK_POISON; + erase_low += sizeof(unsigned long); } /* Reset the 'lowest_stack' value for the next syscall */ |