linux/drivers/misc/lkdtm_bugs.c

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/*
* This is for all the tests related to logic bugs (e.g. bad dereferences,
* bad alignment, bad loops, bad locking, bad scheduling, deep stacks, and
* lockups) along with other things that don't fit well into existing LKDTM
* test source files.
*/
#include "lkdtm.h"
#include <linux/sched.h>
/*
* Make sure our attempts to over run the kernel stack doesn't trigger
* a compiler warning when CONFIG_FRAME_WARN is set. Then make sure we
* recurse past the end of THREAD_SIZE by default.
*/
#if defined(CONFIG_FRAME_WARN) && (CONFIG_FRAME_WARN > 0)
#define REC_STACK_SIZE (CONFIG_FRAME_WARN / 2)
#else
#define REC_STACK_SIZE (THREAD_SIZE / 8)
#endif
#define REC_NUM_DEFAULT ((THREAD_SIZE / REC_STACK_SIZE) * 2)
static int recur_count = REC_NUM_DEFAULT;
static DEFINE_SPINLOCK(lock_me_up);
static int recursive_loop(int remaining)
{
char buf[REC_STACK_SIZE];
/* Make sure compiler does not optimize this away. */
memset(buf, (remaining & 0xff) | 0x1, REC_STACK_SIZE);
if (!remaining)
return 0;
else
return recursive_loop(remaining - 1);
}
/* If the depth is negative, use the default, otherwise keep parameter. */
void __init lkdtm_bugs_init(int *recur_param)
{
if (*recur_param < 0)
*recur_param = recur_count;
else
recur_count = *recur_param;
}
void lkdtm_PANIC(void)
{
panic("dumptest");
}
void lkdtm_BUG(void)
{
BUG();
}
void lkdtm_WARNING(void)
{
WARN_ON(1);
}
void lkdtm_EXCEPTION(void)
{
*((int *) 0) = 0;
}
void lkdtm_LOOP(void)
{
for (;;)
;
}
void lkdtm_OVERFLOW(void)
{
(void) recursive_loop(recur_count);
}
noinline void lkdtm_CORRUPT_STACK(void)
{
/* Use default char array length that triggers stack protection. */
char data[8];
memset((void *)data, 0, 64);
}
void lkdtm_UNALIGNED_LOAD_STORE_WRITE(void)
{
static u8 data[5] __attribute__((aligned(4))) = {1, 2, 3, 4, 5};
u32 *p;
u32 val = 0x12345678;
p = (u32 *)(data + 1);
if (*p == 0)
val = 0x87654321;
*p = val;
}
void lkdtm_SOFTLOCKUP(void)
{
preempt_disable();
for (;;)
cpu_relax();
}
void lkdtm_HARDLOCKUP(void)
{
local_irq_disable();
for (;;)
cpu_relax();
}
void lkdtm_SPINLOCKUP(void)
{
/* Must be called twice to trigger. */
spin_lock(&lock_me_up);
/* Let sparse know we intended to exit holding the lock. */
__release(&lock_me_up);
}
void lkdtm_HUNG_TASK(void)
{
set_current_state(TASK_UNINTERRUPTIBLE);
schedule();
}
void lkdtm_ATOMIC_UNDERFLOW(void)
{
atomic_t under = ATOMIC_INIT(INT_MIN);
pr_info("attempting good atomic increment\n");
atomic_inc(&under);
atomic_dec(&under);
pr_info("attempting bad atomic underflow\n");
atomic_dec(&under);
}
void lkdtm_ATOMIC_OVERFLOW(void)
{
atomic_t over = ATOMIC_INIT(INT_MAX);
pr_info("attempting good atomic decrement\n");
atomic_dec(&over);
atomic_inc(&over);
pr_info("attempting bad atomic overflow\n");
atomic_inc(&over);
}