Messages in this thread Patch in this message | | | From | Alexander Popov <> | Subject | [PATCH v1 1/1] lkdtm/stackleak: Make the stack erasing test more verbose | Date | Thu, 19 Dec 2019 17:54:16 +0300 |
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Make the stack erasing test more verbose about the errors that it can detect. BUG() in case of test failure is useful when the test is running in a loop.
Signed-off-by: Alexander Popov <alex.popov@linux.com> --- drivers/misc/lkdtm/stackleak.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-)
diff --git a/drivers/misc/lkdtm/stackleak.c b/drivers/misc/lkdtm/stackleak.c index d5a084475abc..d198de4d4c7e 100644 --- a/drivers/misc/lkdtm/stackleak.c +++ b/drivers/misc/lkdtm/stackleak.c @@ -16,6 +16,7 @@ void lkdtm_STACKLEAK_ERASING(void) unsigned long *sp, left, found, i; const unsigned long check_depth = STACKLEAK_SEARCH_DEPTH / sizeof(unsigned long); + bool test_failed = false; /* * For the details about the alignment of the poison values, see @@ -34,7 +35,8 @@ void lkdtm_STACKLEAK_ERASING(void) left--; } else { pr_err("FAIL: not enough stack space for the test\n"); - return; + test_failed = true; + goto end; } pr_info("checking unused part of the thread stack (%lu bytes)...\n", @@ -52,22 +54,29 @@ void lkdtm_STACKLEAK_ERASING(void) } if (found <= check_depth) { - pr_err("FAIL: thread stack is not erased (checked %lu bytes)\n", + pr_err("FAIL: the erased part is not found (checked %lu bytes)\n", i * sizeof(unsigned long)); - return; + test_failed = true; + goto end; } - pr_info("first %lu bytes are unpoisoned\n", + pr_info("the erased part begins after %lu not poisoned bytes\n", (i - found) * sizeof(unsigned long)); /* The rest of thread stack should be erased */ for (; i < left; i++) { if (*(sp - i) != STACKLEAK_POISON) { - pr_err("FAIL: thread stack is NOT properly erased\n"); - return; + pr_err("FAIL: bad value number %lu in the erased part: 0x%lx\n", + i, *(sp - i)); + test_failed = true; } } - pr_info("OK: the rest of the thread stack is properly erased\n"); - return; +end: + if (test_failed) { + pr_err("FAIL: the thread stack is NOT properly erased\n"); + BUG(); + } else { + pr_info("OK: the rest of the thread stack is properly erased\n"); + } } -- 2.23.0
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