litmus-rt.git - The LITMUS^RT kernel.

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Diffstat (limited to 'arch/m32r/mm/fault.c')

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/* * This is for all the tests related to refcount bugs (e.g. overflow, * underflow, reaching zero untested, etc). */ #include "lkdtm.h" #include <linux/refcount.h> #ifdef CONFIG_REFCOUNT_FULL #define REFCOUNT_MAX (UINT_MAX - 1) #define REFCOUNT_SATURATED UINT_MAX #else #define REFCOUNT_MAX INT_MAX #define REFCOUNT_SATURATED (INT_MIN / 2) #endif static void overflow_check(refcount_t *ref) { switch (refcount_read(ref)) { case REFCOUNT_SATURATED: pr_info("Overflow detected: saturated\n"); break; case REFCOUNT_MAX: pr_warn("Overflow detected: unsafely reset to max\n"); break; default: pr_err("Fail: refcount wrapped to %d\n", refcount_read(ref)); } } /* * A refcount_inc() above the maximum value of the refcount implementation, * should at least saturate, and at most also WARN. */ void lkdtm_REFCOUNT_INC_OVERFLOW(void) { refcount_t over = REFCOUNT_INIT(REFCOUNT_MAX - 1); pr_info("attempting good refcount_inc() without overflow\n"); refcount_dec(&over); refcount_inc(&over); pr_info("attempting bad refcount_inc() overflow\n"); refcount_inc(&over); refcount_inc(&over); overflow_check(&over); } /* refcount_add() should behave just like refcount_inc() above. */ void lkdtm_REFCOUNT_ADD_OVERFLOW(void) { refcount_t over = REFCOUNT_INIT(REFCOUNT_MAX - 1); pr_info("attempting good refcount_add() without overflow\n"); refcount_dec(&over); refcount_dec(&over); refcount_dec(&over); refcount_dec(&over); refcount_add(4, &over); pr_info("attempting bad refcount_add() overflow\n"); refcount_add(4, &over); overflow_check(&over); } /* refcount_inc_not_zero() should behave just like refcount_inc() above. */ void lkdtm_REFCOUNT_INC_NOT_ZERO_OVERFLOW(void) { refcount_t over = REFCOUNT_INIT(REFCOUNT_MAX); pr_info("attempting bad refcount_inc_not_zero() overflow\n"); if (!refcount_inc_not_zero(&over)) pr_warn("Weird: refcount_inc_not_zero() reported zero\n"); overflow_check(&over); } /* refcount_add_not_zero() should behave just like refcount_inc() above. */ void lkdtm_REFCOUNT_ADD_NOT_ZERO_OVERFLOW(void) { refcount_t over = REFCOUNT_INIT(REFCOUNT_MAX); pr_info("attempting bad refcount_add_not_zero() overflow\n"); if (!refcount_add_not_zero(6, &over)) pr_warn("Weird: refcount_add_not_zero() reported zero\n"); overflow_check(&over); } static void check_zero(refcount_t *ref) { switch (refcount_read(ref)) { case REFCOUNT_SATURATED: pr_info("Zero detected: saturated\n"); break; case REFCOUNT_MAX: pr_warn("Zero detected: unsafely reset to max\n"); break; case 0: pr_warn("Still at zero: refcount_inc/add() must not inc-from-0\n"); break; default: pr_err("Fail: refcount went crazy: %d\n", refcount_read(ref)); } } /* * A refcount_dec(), as opposed to a refcount_dec_and_test(), when it hits * zero it should either saturate (when inc-from-zero isn't protected) * or stay at zero (when inc-from-zero is protected) and should WARN for both. */ void lkdtm_REFCOUNT_DEC_ZERO(void) { refcount_t zero = REFCOUNT_INIT(2); pr_info("attempting good refcount_dec()\n"); refcount_dec(&zero); pr_info("attempting bad refcount_dec() to zero\n"); refcount_dec(&zero); check_zero(&zero); } static void check_negative(refcount_t *ref, int start) { /* * CONFIG_REFCOUNT_FULL refuses to move a refcount at all on an * over-sub, so we have to track our starting position instead of * looking only at zero-pinning. */ if (refcount_read(ref) == start) { pr_warn("Still at %d: refcount_inc/add() must not inc-from-0\n", start); return; } switch (refcount_read(ref)) { case REFCOUNT_SATURATED: pr_info("Negative detected: saturated\n"); break; case REFCOUNT_MAX: pr_warn("Negative detected: unsafely reset to max\n"); break; default: pr_err("Fail: refcount went crazy: %d\n", refcount_read(ref)); } } /* A refcount_dec() going negative should saturate and may WARN. */ void lkdtm_REFCOUNT_DEC_NEGATIVE(void) { refcount_t neg = REFCOUNT_INIT(0); pr_info("attempting bad refcount_dec() below zero\n"); refcount_dec(&neg); check_negative(&neg, 0); } /* * A refcount_dec_and_test() should act like refcount_dec() above when * going negative. */ void lkdtm_REFCOUNT_DEC_AND_TEST_NEGATIVE(void) { refcount_t neg = REFCOUNT_INIT(0); pr_info("attempting bad refcount_dec_and_test() below zero\n"); if (refcount_dec_and_test(&neg)) pr_warn("Weird: refcount_dec_and_test() reported zero\n"); check_negative(&neg, 0); } /* * A refcount_sub_and_test() should act like refcount_dec_and_test() * above when going negative. */ void lkdtm_REFCOUNT_SUB_AND_TEST_NEGATIVE(void) { refcount_t neg = REFCOUNT_INIT(3); pr_info("attempting bad refcount_sub_and_test() below zero\n"); if (refcount_sub_and_test(5, &neg)) pr_warn("Weird: refcount_sub_and_test() reported zero\n"); check_negative(&neg, 3); } static void check_from_zero(refcount_t *ref) { switch (refcount_read(ref)) { case 0: pr_info("Zero detected: stayed at zero\n"); break;


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