diff options
| -rw-r--r-- | include/linux/kcsan-checks.h | 3 | ||||
| -rw-r--r-- | kernel/kcsan/core.c | 75 | ||||
| -rw-r--r-- | kernel/kcsan/kcsan.h | 8 | ||||
| -rw-r--r-- | kernel/kcsan/kcsan_test.c | 62 | ||||
| -rw-r--r-- | kernel/kcsan/report.c | 77 | ||||
| -rw-r--r-- | kernel/kcsan/selftest.c | 72 |
6 files changed, 186 insertions, 111 deletions
diff --git a/include/linux/kcsan-checks.h b/include/linux/kcsan-checks.h index 9fd0ad80fef6..5f5965246877 100644 --- a/include/linux/kcsan-checks.h +++ b/include/linux/kcsan-checks.h @@ -100,9 +100,12 @@ void kcsan_set_access_mask(unsigned long mask); /* Scoped access information. */ struct kcsan_scoped_access { struct list_head list; + /* Access information. */ const volatile void *ptr; size_t size; int type; + /* Location where scoped access was set up. */ + unsigned long ip; }; /* * Automatically call kcsan_end_scoped_access() when kcsan_scoped_access goes diff --git a/kernel/kcsan/core.c b/kernel/kcsan/core.c index 76e67d1e02d4..4b84c8e7884b 100644 --- a/kernel/kcsan/core.c +++ b/kernel/kcsan/core.c @@ -202,6 +202,9 @@ static __always_inline struct kcsan_ctx *get_ctx(void) return in_task() ? ¤t->kcsan_ctx : raw_cpu_ptr(&kcsan_cpu_ctx); } +static __always_inline void +check_access(const volatile void *ptr, size_t size, int type, unsigned long ip); + /* Check scoped accesses; never inline because this is a slow-path! */ static noinline void kcsan_check_scoped_accesses(void) { @@ -210,14 +213,16 @@ static noinline void kcsan_check_scoped_accesses(void) struct kcsan_scoped_access *scoped_access; ctx->scoped_accesses.prev = NULL; /* Avoid recursion. */ - list_for_each_entry(scoped_access, &ctx->scoped_accesses, list) - __kcsan_check_access(scoped_access->ptr, scoped_access->size, scoped_access->type); + list_for_each_entry(scoped_access, &ctx->scoped_accesses, list) { + check_access(scoped_access->ptr, scoped_access->size, + scoped_access->type, scoped_access->ip); + } ctx->scoped_accesses.prev = prev_save; } /* Rules for generic atomic accesses. Called from fast-path. */ static __always_inline bool -is_atomic(const volatile void *ptr, size_t size, int type, struct kcsan_ctx *ctx) +is_atomic(struct kcsan_ctx *ctx, const volatile void *ptr, size_t size, int type) { if (type & KCSAN_ACCESS_ATOMIC) return true; @@ -254,7 +259,7 @@ is_atomic(const volatile void *ptr, size_t size, int type, struct kcsan_ctx *ctx } static __always_inline bool -should_watch(const volatile void *ptr, size_t size, int type, struct kcsan_ctx *ctx) +should_watch(struct kcsan_ctx *ctx, const volatile void *ptr, size_t size, int type) { /* * Never set up watchpoints when memory operations are atomic. @@ -263,7 +268,7 @@ should_watch(const volatile void *ptr, size_t size, int type, struct kcsan_ctx * * should not count towards skipped instructions, and (2) to actually * decrement kcsan_atomic_next for consecutive instruction stream. */ - if (is_atomic(ptr, size, type, ctx)) + if (is_atomic(ctx, ptr, size, type)) return false; if (this_cpu_dec_return(kcsan_skip) >= 0) @@ -350,6 +355,7 @@ void kcsan_restore_irqtrace(struct task_struct *task) static noinline void kcsan_found_watchpoint(const volatile void *ptr, size_t size, int type, + unsigned long ip, atomic_long_t *watchpoint, long encoded_watchpoint) { @@ -396,7 +402,7 @@ static noinline void kcsan_found_watchpoint(const volatile void *ptr, if (consumed) { kcsan_save_irqtrace(current); - kcsan_report_set_info(ptr, size, type, watchpoint - watchpoints); + kcsan_report_set_info(ptr, size, type, ip, watchpoint - watchpoints); kcsan_restore_irqtrace(current); } else { /* @@ -416,7 +422,7 @@ static noinline void kcsan_found_watchpoint(const volatile void *ptr, } static noinline void -kcsan_setup_watchpoint(const volatile void *ptr, size_t size, int type) +kcsan_setup_watchpoint(const volatile void *ptr, size_t size, int type, unsigned long ip) { const bool is_write = (type & KCSAN_ACCESS_WRITE) != 0; const bool is_assert = (type & KCSAN_ACCESS_ASSERT) != 0; @@ -568,8 +574,8 @@ kcsan_setup_watchpoint(const volatile void *ptr, size_t size, int type) if (is_assert && value_change == KCSAN_VALUE_CHANGE_TRUE) atomic_long_inc(&kcsan_counters[KCSAN_COUNTER_ASSERT_FAILURES]); - kcsan_report_known_origin(ptr, size, type, value_change, - watchpoint - watchpoints, + kcsan_report_known_origin(ptr, size, type, ip, + value_change, watchpoint - watchpoints, old, new, access_mask); } else if (value_change == KCSAN_VALUE_CHANGE_TRUE) { /* Inferring a race, since the value should not have changed. */ @@ -578,8 +584,10 @@ kcsan_setup_watchpoint(const volatile void *ptr, size_t size, int type) if (is_assert) atomic_long_inc(&kcsan_counters[KCSAN_COUNTER_ASSERT_FAILURES]); - if (IS_ENABLED(CONFIG_KCSAN_REPORT_RACE_UNKNOWN_ORIGIN) || is_assert) - kcsan_report_unknown_origin(ptr, size, type, old, new, access_mask); + if (IS_ENABLED(CONFIG_KCSAN_REPORT_RACE_UNKNOWN_ORIGIN) || is_assert) { + kcsan_report_unknown_origin(ptr, size, type, ip, + old, new, access_mask); + } } /* @@ -596,8 +604,8 @@ out: user_access_restore(ua_flags); } -static __always_inline void check_access(const volatile void *ptr, size_t size, - int type) +static __always_inline void +check_access(const volatile void *ptr, size_t size, int type, unsigned long ip) { const bool is_write = (type & KCSAN_ACCESS_WRITE) != 0; atomic_long_t *watchpoint; @@ -625,13 +633,12 @@ static __always_inline void check_access(const volatile void *ptr, size_t size, */ if (unlikely(watchpoint != NULL)) - kcsan_found_watchpoint(ptr, size, type, watchpoint, - encoded_watchpoint); + kcsan_found_watchpoint(ptr, size, type, ip, watchpoint, encoded_watchpoint); else { struct kcsan_ctx *ctx = get_ctx(); /* Call only once in fast-path. */ - if (unlikely(should_watch(ptr, size, type, ctx))) - kcsan_setup_watchpoint(ptr, size, type); + if (unlikely(should_watch(ctx, ptr, size, type))) + kcsan_setup_watchpoint(ptr, size, type, ip); else if (unlikely(ctx->scoped_accesses.prev)) kcsan_check_scoped_accesses(); } @@ -757,7 +764,7 @@ kcsan_begin_scoped_access(const volatile void *ptr, size_t size, int type, { struct kcsan_ctx *ctx = get_ctx(); - __kcsan_check_access(ptr, size, type); + check_access(ptr, size, type, _RET_IP_); ctx->disable_count++; /* Disable KCSAN, in case list debugging is on. */ @@ -765,6 +772,7 @@ kcsan_begin_scoped_access(const volatile void *ptr, size_t size, int type, sa->ptr = ptr; sa->size = size; sa->type = type; + sa->ip = _RET_IP_; if (!ctx->scoped_accesses.prev) /* Lazy initialize list head. */ INIT_LIST_HEAD(&ctx->scoped_accesses); @@ -796,13 +804,13 @@ void kcsan_end_scoped_access(struct kcsan_scoped_access *sa) ctx->disable_count--; - __kcsan_check_access(sa->ptr, sa->size, sa->type); + check_access(sa->ptr, sa->size, sa->type, sa->ip); } EXPORT_SYMBOL(kcsan_end_scoped_access); void __kcsan_check_access(const volatile void *ptr, size_t size, int type) { - check_access(ptr, size, type); + check_access(ptr, size, type, _RET_IP_); } EXPORT_SYMBOL(__kcsan_check_access); @@ -823,7 +831,7 @@ EXPORT_SYMBOL(__kcsan_check_access); void __tsan_read##size(void *ptr); \ void __tsan_read##size(void *ptr) \ { \ - check_access(ptr, size, 0); \ + check_access(ptr, size, 0, _RET_IP_); \ } \ EXPORT_SYMBOL(__tsan_read##size); \ void __tsan_unaligned_read##size(void *ptr) \ @@ -832,7 +840,7 @@ EXPORT_SYMBOL(__kcsan_check_access); void __tsan_write##size(void *ptr); \ void __tsan_write##size(void *ptr) \ { \ - check_access(ptr, size, KCSAN_ACCESS_WRITE); \ + check_access(ptr, size, KCSAN_ACCESS_WRITE, _RET_IP_); \ } \ EXPORT_SYMBOL(__tsan_write##size); \ void __tsan_unaligned_write##size(void *ptr) \ @@ -842,7 +850,8 @@ EXPORT_SYMBOL(__kcsan_check_access); void __tsan_read_write##size(void *ptr) \ { \ check_access(ptr, size, \ - KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE); \ + KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE, \ + _RET_IP_); \ } \ EXPORT_SYMBOL(__tsan_read_write##size); \ void __tsan_unaligned_read_write##size(void *ptr) \ @@ -858,14 +867,14 @@ DEFINE_TSAN_READ_WRITE(16); void __tsan_read_range(void *ptr, size_t size); void __tsan_read_range(void *ptr, size_t size) { - check_access(ptr, size, 0); + check_access(ptr, size, 0, _RET_IP_); } EXPORT_SYMBOL(__tsan_read_range); void __tsan_write_range(void *ptr, size_t size); void __tsan_write_range(void *ptr, size_t size) { - check_access(ptr, size, KCSAN_ACCESS_WRITE); + check_access(ptr, size, KCSAN_ACCESS_WRITE, _RET_IP_); } EXPORT_SYMBOL(__tsan_write_range); @@ -886,7 +895,8 @@ EXPORT_SYMBOL(__tsan_write_range); IS_ALIGNED((unsigned long)ptr, size); \ if (IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS) && is_atomic) \ return; \ - check_access(ptr, size, is_atomic ? KCSAN_ACCESS_ATOMIC : 0); \ + check_access(ptr, size, is_atomic ? KCSAN_ACCESS_ATOMIC : 0, \ + _RET_IP_); \ } \ EXPORT_SYMBOL(__tsan_volatile_read##size); \ void __tsan_unaligned_volatile_read##size(void *ptr) \ @@ -901,7 +911,8 @@ EXPORT_SYMBOL(__tsan_write_range); return; \ check_access(ptr, size, \ KCSAN_ACCESS_WRITE | \ - (is_atomic ? KCSAN_ACCESS_ATOMIC : 0)); \ + (is_atomic ? KCSAN_ACCESS_ATOMIC : 0), \ + _RET_IP_); \ } \ EXPORT_SYMBOL(__tsan_volatile_write##size); \ void __tsan_unaligned_volatile_write##size(void *ptr) \ @@ -955,7 +966,7 @@ EXPORT_SYMBOL(__tsan_init); u##bits __tsan_atomic##bits##_load(const u##bits *ptr, int memorder) \ { \ if (!IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)) { \ - check_access(ptr, bits / BITS_PER_BYTE, KCSAN_ACCESS_ATOMIC); \ + check_access(ptr, bits / BITS_PER_BYTE, KCSAN_ACCESS_ATOMIC, _RET_IP_); \ } \ return __atomic_load_n(ptr, memorder); \ } \ @@ -965,7 +976,7 @@ EXPORT_SYMBOL(__tsan_init); { \ if (!IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)) { \ check_access(ptr, bits / BITS_PER_BYTE, \ - KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ATOMIC); \ + KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ATOMIC, _RET_IP_); \ } \ __atomic_store_n(ptr, v, memorder); \ } \ @@ -978,7 +989,7 @@ EXPORT_SYMBOL(__tsan_init); if (!IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)) { \ check_access(ptr, bits / BITS_PER_BYTE, \ KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE | \ - KCSAN_ACCESS_ATOMIC); \ + KCSAN_ACCESS_ATOMIC, _RET_IP_); \ } \ return __atomic_##op##suffix(ptr, v, memorder); \ } \ @@ -1010,7 +1021,7 @@ EXPORT_SYMBOL(__tsan_init); if (!IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)) { \ check_access(ptr, bits / BITS_PER_BYTE, \ KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE | \ - KCSAN_ACCESS_ATOMIC); \ + KCSAN_ACCESS_ATOMIC, _RET_IP_); \ } \ return __atomic_compare_exchange_n(ptr, exp, val, weak, mo, fail_mo); \ } \ @@ -1025,7 +1036,7 @@ EXPORT_SYMBOL(__tsan_init); if (!IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)) { \ check_access(ptr, bits / BITS_PER_BYTE, \ KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE | \ - KCSAN_ACCESS_ATOMIC); \ + KCSAN_ACCESS_ATOMIC, _RET_IP_); \ } \ __atomic_compare_exchange_n(ptr, &exp, val, 0, mo, fail_mo); \ return exp; \ diff --git a/kernel/kcsan/kcsan.h b/kernel/kcsan/kcsan.h index f36e25c497ed..ae33c2a7f07e 100644 --- a/kernel/kcsan/kcsan.h +++ b/kernel/kcsan/kcsan.h @@ -121,7 +121,7 @@ enum kcsan_value_change { * to be consumed by the reporting thread. No report is printed yet. */ void kcsan_report_set_info(const volatile void *ptr, size_t size, int access_type, - int watchpoint_idx); + unsigned long ip, int watchpoint_idx); /* * The calling thread observed that the watchpoint it set up was hit and @@ -129,14 +129,14 @@ void kcsan_report_set_info(const volatile void *ptr, size_t size, int access_typ * thread. */ void kcsan_report_known_origin(const volatile void *ptr, size_t size, int access_type, - enum kcsan_value_change value_change, int watchpoint_idx, - u64 old, u64 new, u64 mask); + unsigned long ip, enum kcsan_value_change value_change, + int watchpoint_idx, u64 old, u64 new, u64 mask); /* * No other thread was observed to race with the access, but the data value * before and after the stall differs. Reports a race of "unknown origin". */ void kcsan_report_unknown_origin(const volatile void *ptr, size_t size, int access_type, - u64 old, u64 new, u64 mask); + unsigned long ip, u64 old, u64 new, u64 mask); #endif /* _KERNEL_KCSAN_KCSAN_H */ diff --git a/kernel/kcsan/kcsan_test.c b/kernel/kcsan/kcsan_test.c index dc55fd5a36fc..660729238588 100644 --- a/kernel/kcsan/kcsan_test.c +++ b/kernel/kcsan/kcsan_test.c @@ -29,6 +29,11 @@ #include <linux/types.h> #include <trace/events/printk.h> +#define KCSAN_TEST_REQUIRES(test, cond) do { \ + if (!(cond)) \ + kunit_skip((test), "Test requires: " #cond); \ +} while (0) + #ifdef CONFIG_CC_HAS_TSAN_COMPOUND_READ_BEFORE_WRITE #define __KCSAN_ACCESS_RW(alt) (KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE) #else @@ -205,10 +210,12 @@ static bool report_matches(const struct expect_report *r) "read-write" : "write") : "read"); + const bool is_atomic = (ty & KCSAN_ACCESS_ATOMIC); + const bool is_scoped = (ty & KCSAN_ACCESS_SCOPED); const char *const access_type_aux = - (ty & KCSAN_ACCESS_ATOMIC) ? - " (marked)" : - ((ty & KCSAN_ACCESS_SCOPED) ? " (scoped)" : ""); + (is_atomic && is_scoped) ? " (marked, scoped)" + : (is_atomic ? " (marked)" + : (is_scoped ? " (scoped)" : "")); if (i == 1) { /* Access 2 */ @@ -333,7 +340,10 @@ static noinline void test_kernel_assert_bits_nochange(void) ASSERT_EXCLUSIVE_BITS(test_var, ~TEST_CHANGE_BITS); } -/* To check that scoped assertions do trigger anywhere in scope. */ +/* + * Scoped assertions do trigger anywhere in scope. However, the report should + * still only point at the start of the scope. + */ static noinline void test_enter_scope(void) { int x = 0; @@ -488,17 +498,24 @@ static void test_concurrent_races(struct kunit *test) __no_kcsan static void test_novalue_change(struct kunit *test) { - const struct expect_report expect = { + const struct expect_report expect_rw = { .access = { { test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE }, { test_kernel_read, &test_var, sizeof(test_var), 0 }, }, }; + const struct expect_report expect_ww = { + .access = { + { test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE }, + { test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE }, + }, + }; bool match_expect = false; + test_kernel_write_nochange(); /* Reset value. */ begin_test_checks(test_kernel_write_nochange, test_kernel_read); do { - match_expect = report_matches(&expect); + match_expect = report_matches(&expect_rw) || report_matches(&expect_ww); } while (!end_test_checks(match_expect)); if (IS_ENABLED(CONFIG_KCSAN_REPORT_VALUE_CHANGE_ONLY)) KUNIT_EXPECT_FALSE(test, match_expect); @@ -513,17 +530,24 @@ static void test_novalue_change(struct kunit *test) __no_kcsan static void test_novalue_change_exception(struct kunit *test) { - const struct expect_report expect = { + const struct expect_report expect_rw = { .access = { { test_kernel_write_nochange_rcu, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE }, { test_kernel_read, &test_var, sizeof(test_var), 0 }, }, }; + const struct expect_report expect_ww = { + .access = { + { test_kernel_write_nochange_rcu, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE }, + { test_kernel_write_nochange_rcu, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE }, + }, + }; bool match_expect = false; + test_kernel_write_nochange_rcu(); /* Reset value. */ begin_test_checks(test_kernel_write_nochange_rcu, test_kernel_read); do { - match_expect = report_matches(&expect); + match_expect = report_matches(&expect_rw) || report_matches(&expect_ww); } while (!end_test_checks(match_expect)); KUNIT_EXPECT_TRUE(test, match_expect); } @@ -642,8 +666,7 @@ static void test_read_plain_atomic_write(struct kunit *test) }; bool match_expect = false; - if (IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)) - return; + KCSAN_TEST_REQUIRES(test, !IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)); begin_test_checks(test_kernel_read, test_kernel_write_atomic); do { @@ -665,8 +688,7 @@ static void test_read_plain_atomic_rmw(struct kunit *test) }; bool match_expect = false; - if (IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)) - return; + KCSAN_TEST_REQUIRES(test, !IS_ENABLED(CONFIG_KCSAN_IGNORE_ATOMICS)); begin_test_checks(test_kernel_read, test_kernel_atomic_rmw); do { @@ -828,22 +850,22 @@ static void test_assert_exclusive_writer_scoped(struct kunit *test) { test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE }, }, }; - const struct expect_report expect_anywhere = { + const struct expect_report expect_inscope = { .access = { { test_enter_scope, &test_var, sizeof(test_var), KCSAN_ACCESS_ASSERT | KCSAN_ACCESS_SCOPED }, { test_kernel_write_nochange, &test_var, sizeof(test_var), KCSAN_ACCESS_WRITE }, }, }; bool match_expect_start = false; - bool match_expect_anywhere = false; + bool match_expect_inscope = false; begin_test_checks(test_kernel_assert_writer_scoped, test_kernel_write_nochange); do { match_expect_start |= report_matches(&expect_start); - match_expect_anywhere |= report_matches(&expect_anywhere); - } while (!end_test_checks(match_expect_start && match_expect_anywhere)); + match_expect_inscope |= report_matches(&expect_inscope); + } while (!end_test_checks(match_expect_inscope)); KUNIT_EXPECT_TRUE(test, match_expect_start); - KUNIT_EXPECT_TRUE(test, match_expect_anywhere); + KUNIT_EXPECT_FALSE(test, match_expect_inscope); } __no_kcsan @@ -872,9 +894,9 @@ static void test_assert_exclusive_access_scoped(struct kunit *test) do { match_expect_start |= report_matches(&expect_start1) || report_matches(&expect_start2); match_expect_inscope |= report_matches(&expect_inscope); - } while (!end_test_checks(match_expect_start && match_expect_inscope)); + } while (!end_test_checks(match_expect_inscope)); KUNIT_EXPECT_TRUE(test, match_expect_start); - KUNIT_EXPECT_TRUE(test, match_expect_inscope); + KUNIT_EXPECT_FALSE(test, match_expect_inscope); } /* @@ -1224,7 +1246,7 @@ static void kcsan_test_exit(void) tracepoint_synchronize_unregister(); } -late_initcall(kcsan_test_init); +late_initcall_sync(kcsan_test_init); module_exit(kcsan_test_exit); MODULE_LICENSE("GPL v2"); diff --git a/kernel/kcsan/report.c b/kernel/kcsan/report.c index 21137929d428..fc15077991c4 100644 --- a/kernel/kcsan/report.c +++ b/kernel/kcsan/report.c @@ -8,6 +8,7 @@ #include <linux/debug_locks.h> #include <linux/delay.h> #include <linux/jiffies.h> +#include <linux/kallsyms.h> #include <linux/kernel.h> #include <linux/lockdep.h> #include <linux/preempt.h> @@ -31,6 +32,7 @@ struct access_info { int access_type; int task_pid; int cpu_id; + unsigned long ip; }; /* @@ -245,6 +247,10 @@ static const char *get_access_type(int type) return "write (scoped)"; case KCSAN_ACCESS_SCOPED | KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ATOMIC: return "write (marked, scoped)"; + case KCSAN_ACCESS_SCOPED | KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE: + return "read-write (scoped)"; + case KCSAN_ACCESS_SCOPED | KCSAN_ACCESS_COMPOUND | KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ATOMIC: + return "read-write (marked, scoped)"; default: BUG(); } @@ -300,6 +306,48 @@ static int get_stack_skipnr(const unsigned long stack_entries[], int num_entries return skip; } +/* + * Skips to the first entry that matches the function of @ip, and then replaces + * that entry with @ip, returning the entries to skip. + */ +static int +replace_stack_entry(unsigned long stack_entries[], int num_entries, unsigned long ip) +{ + unsigned long symbolsize, offset; + unsigned long target_func; + int skip; + + if (kallsyms_lookup_size_offset(ip, &symbolsize, &offset)) + target_func = ip - offset; + else + goto fallback; + + for (skip = 0; skip < num_entries; ++skip) { + unsigned long func = stack_entries[skip]; + + if (!kallsyms_lookup_size_offset(func, &symbolsize, &offset)) + goto fallback; + func -= offset; + + if (func == target_func) { + stack_entries[skip] = ip; + return skip; + } + } + +fallback: + /* Should not happen; the resulting stack trace is likely misleading. */ + WARN_ONCE(1, "Cannot find frame for %pS in stack trace", (void *)ip); + return get_stack_skipnr(stack_entries, num_entries); +} + +static int +sanitize_stack_entries(unsigned long stack_entries[], int num_entries, unsigned long ip) +{ + return ip ? replace_stack_entry(stack_entries, num_entries, ip) : + get_stack_skipnr(stack_entries, num_entries); +} + /* Compares symbolized strings of addr1 and addr2. */ static int sym_strcmp(void *addr1, void *addr2) { @@ -327,12 +375,12 @@ static void print_verbose_info(struct task_struct *task) static void print_report(enum kcsan_value_change value_change, const struct access_info *ai, - const struct other_info *other_info, + struct other_info *other_info, u64 old, u64 new, u64 mask) { unsigned long stack_entries[NUM_STACK_ENTRIES] = { 0 }; int num_stack_entries = stack_trace_save(stack_entries, NUM_STACK_ENTRIES, 1); - int skipnr = get_stack_skipnr(stack_entries, num_stack_entries); + int skipnr = sanitize_stack_entries(stack_entries, num_stack_entries, ai->ip); unsigned long this_frame = stack_entries[skipnr]; unsigned long other_frame = 0; int other_skipnr = 0; /* silence uninit warnings */ @@ -344,8 +392,9 @@ static void print_report(enum kcsan_value_change value_change, return; if (other_info) { - other_skipnr = get_stack_skipnr(other_info->stack_entries, - other_info->num_stack_entries); + other_skipnr = sanitize_stack_entries(other_info->stack_entries, + other_info->num_stack_entries, + other_info->ai.ip); other_frame = other_info->stack_entries[other_skipnr]; /* @value_change is only known for the other thread */ @@ -576,21 +625,23 @@ discard: } static struct access_info prepare_access_info(const volatile void *ptr, size_t size, - int access_type) + int access_type, unsigned long ip) { return (struct access_info) { .ptr = ptr, .size = size, .access_type = access_type, .task_pid = in_task() ? task_pid_nr(current) : -1, - .cpu_id = raw_smp_processor_id() + .cpu_id = raw_smp_processor_id(), + /* Only replace stack entry with @ip if scoped access. */ + .ip = (access_type & KCSAN_ACCESS_SCOPED) ? ip : 0, }; } void kcsan_report_set_info(const volatile void *ptr, size_t size, int access_type, - int watchpoint_idx) + unsigned long ip, int watchpoint_idx) { - const struct access_info ai = prepare_access_info(ptr, size, access_type); + const struct access_info ai = prepare_access_info(ptr, size, access_type, ip); unsigned long flags; kcsan_disable_current(); @@ -603,10 +654,10 @@ void kcsan_report_set_info(const volatile void *ptr, size_t size, int access_typ } void kcsan_report_known_origin(const volatile void *ptr, size_t size, int access_type, - enum kcsan_value_change value_change, int watchpoint_idx, - u64 old, u64 new, u64 mask) + unsigned long ip, enum kcsan_value_change value_change, + int watchpoint_idx, u64 old, u64 new, u64 mask) { - const struct access_info ai = prepare_access_info(ptr, size, access_type); + const struct access_info ai = prepare_access_info(ptr, size, access_type, ip); struct other_info *other_info = &other_infos[watchpoint_idx]; unsigned long flags = 0; @@ -637,9 +688,9 @@ out: } void kcsan_report_unknown_origin(const volatile void *ptr, size_t size, int access_type, - u64 old, u64 new, u64 mask) + unsigned long ip, u64 old, u64 new, u64 mask) { - const struct access_info ai = prepare_access_info(ptr, size, access_type); + const struct access_info ai = prepare_access_info(ptr, size, access_type, ip); unsigned long flags; kcsan_disable_current(); diff --git a/kernel/kcsan/selftest.c b/kernel/kcsan/selftest.c index 7f29cb0f5e63..b4295a3892b7 100644 --- a/kernel/kcsan/selftest.c +++ b/kernel/kcsan/selftest.c @@ -18,7 +18,7 @@ #define ITERS_PER_TEST 2000 /* Test requirements. */ -static bool test_requires(void) +static bool __init test_requires(void) { /* random should be initialized for the below tests */ return prandom_u32() + prandom_u32() != 0; @@ -28,14 +28,18 @@ static bool test_requires(void) * Test watchpoint encode and decode: check that encoding some access's info, * and then subsequent decode preserves the access's info. */ -static bool test_encode_decode(void) +static bool __init test_encode_decode(void) { int i; for (i = 0; i < ITERS_PER_TEST; ++i) { size_t size = prandom_u32_max(MAX_ENCODABLE_SIZE) + 1; bool is_write = !!prandom_u32_max(2); + unsigned long verif_masked_addr; + long encoded_watchpoint; + bool verif_is_write; unsigned long addr; + size_t verif_size; prandom_bytes(&addr, sizeof(addr)); if (addr < PAGE_SIZE) @@ -44,53 +48,37 @@ static bool test_encode_decode(void) if (WARN_ON(!check_encodable(addr, size))) return false; - /* Encode and decode */ - { - const long encoded_watchpoint = - encode_watchpoint(addr, size, is_write); - unsigned long verif_masked_addr; - size_t verif_size; - bool verif_is_write; - - /* Check special watchpoints */ - if (WARN_ON(decode_watchpoint( - INVALID_WATCHPOINT, &verif_masked_addr, - &verif_size, &verif_is_write))) - return false; - if (WARN_ON(decode_watchpoint( - CONSUMED_WATCHPOINT, &verif_masked_addr, - &verif_size, &verif_is_write))) - return false; - - /* Check decoding watchpoint returns same data */ - if (WARN_ON(!decode_watchpoint( - encoded_watchpoint, &verif_masked_addr, - &verif_size, &verif_is_write))) - return false; - if (WARN_ON(verif_masked_addr != - (addr & WATCHPOINT_ADDR_MASK))) - goto fail; - if (WARN_ON(verif_size != size)) - goto fail; - if (WARN_ON(is_write != verif_is_write)) - goto fail; - - continue; -fail: - pr_err("%s fail: %s %zu bytes @ %lx -> encoded: %lx -> %s %zu bytes @ %lx\n", - __func__, is_write ? "write" : "read", size, - addr, encoded_watchpoint, - verif_is_write ? "write" : "read", verif_size, - verif_masked_addr); + encoded_watchpoint = encode_watchpoint(addr, size, is_write); + + /* Check special watchpoints */ + if (WARN_ON(decode_watchpoint(INVALID_WATCHPOINT, &verif_masked_addr, &verif_size, &verif_is_write))) return false; - } + if (WARN_ON(decode_watchpoint(CONSUMED_WATCHPOINT, &verif_masked_addr, &verif_size, &verif_is_write))) + return false; + + /* Check decoding watchpoint returns same data */ + if (WARN_ON(!decode_watchpoint(encoded_watchpoint, &verif_masked_addr, &verif_size, &verif_is_write))) + return false; + if (WARN_ON(verif_masked_addr != (addr & WATCHPOINT_ADDR_MASK))) + goto fail; + if (WARN_ON(verif_size != size)) + goto fail; + if (WARN_ON(is_write != verif_is_write)) + goto fail; + + continue; +fail: + pr_err("%s fail: %s %zu bytes @ %lx -> encoded: %lx -> %s %zu bytes @ %lx\n", + __func__, is_write ? "write" : "read", size, addr, encoded_watchpoint, + verif_is_write ? "write" : "read", verif_size, verif_masked_addr); + return false; } return true; } /* Test access matching function. */ -static bool test_matching_access(void) +static bool __init test_matching_access(void) { if (WARN_ON(!matching_access(10, 1, 10, 1))) return false; |