diff options
| author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-24 20:30:04 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-24 20:30:04 +0200 |
| commit | 02bd610e858d764fb32ebfa123083fdbadd88a08 (patch) | |
| tree | 468f5319ab0dc0ef517b1adaedf7866b578ce88d /drivers/misc/lkdtm/bugs.c | |
| parent | 6660a04feb7ef648e50c792e19084d675fa6f3a2 (diff) | |
| parent | 24cccab42c4199c6daa0a6981e6f6a1ffb0b5a09 (diff) | |
| download | linux-02bd610e858d764fb32ebfa123083fdbadd88a08.tar.gz linux-02bd610e858d764fb32ebfa123083fdbadd88a08.tar.bz2 linux-02bd610e858d764fb32ebfa123083fdbadd88a08.zip | |
Merge tag 'lkdtm-next' of https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux into char-misc-linus
Kees writes:
lkdtm: various fixes
- Move KERNEL_DS test to non-canonical range
- Make stack exhaustion test more robust
* tag 'lkdtm-next' of https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
lkdtm/bugs: Adjust recursion test to avoid elision
lkdtm/usercopy: Moves the KERNEL_DS test to non-canonical
Diffstat (limited to 'drivers/misc/lkdtm/bugs.c')
| -rw-r--r-- | drivers/misc/lkdtm/bugs.c | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c index 7eebbdfbcacd..17f839dee976 100644 --- a/drivers/misc/lkdtm/bugs.c +++ b/drivers/misc/lkdtm/bugs.c @@ -32,12 +32,20 @@ static int recur_count = REC_NUM_DEFAULT; static DEFINE_SPINLOCK(lock_me_up); -static int recursive_loop(int remaining) +/* + * Make sure compiler does not optimize this function or stack frame away: + * - function marked noinline + * - stack variables are marked volatile + * - stack variables are written (memset()) and read (pr_info()) + * - function has external effects (pr_info()) + * */ +static int noinline recursive_loop(int remaining) { - char buf[REC_STACK_SIZE]; + volatile char buf[REC_STACK_SIZE]; - /* Make sure compiler does not optimize this away. */ - memset(buf, (remaining & 0xff) | 0x1, REC_STACK_SIZE); + memset((void *)buf, remaining & 0xFF, sizeof(buf)); + pr_info("loop %d/%d ...\n", (int)buf[remaining % sizeof(buf)], + recur_count); if (!remaining) return 0; else @@ -81,9 +89,12 @@ void lkdtm_LOOP(void) ; } -void lkdtm_OVERFLOW(void) +void lkdtm_EXHAUST_STACK(void) { - (void) recursive_loop(recur_count); + pr_info("Calling function with %d frame size to depth %d ...\n", + REC_STACK_SIZE, recur_count); + recursive_loop(recur_count); + pr_info("FAIL: survived without exhausting stack?!\n"); } static noinline void __lkdtm_CORRUPT_STACK(void *stack) |