diff options
| -rw-r--r-- | Documentation/dev-tools/kmsan.rst | 11 | ||||
| -rw-r--r-- | include/linux/kmsan.h | 24 | ||||
| -rw-r--r-- | include/linux/kmsan_types.h | 2 | ||||
| -rw-r--r-- | mm/kmsan/core.c | 1 | ||||
| -rw-r--r-- | mm/kmsan/hooks.c | 18 | ||||
| -rw-r--r-- | mm/kmsan/report.c | 7 | ||||
| -rw-r--r-- | tools/objtool/check.c | 2 |
7 files changed, 55 insertions, 10 deletions
diff --git a/Documentation/dev-tools/kmsan.rst b/Documentation/dev-tools/kmsan.rst index 323eedad53cd..6a48d96c5c85 100644 --- a/Documentation/dev-tools/kmsan.rst +++ b/Documentation/dev-tools/kmsan.rst @@ -110,6 +110,13 @@ in the Makefile. Think of this as applying ``__no_sanitize_memory`` to every function in the file or directory. Most users won't need KMSAN_SANITIZE, unless their code gets broken by KMSAN (e.g. runs at early boot time). +KMSAN checks can also be temporarily disabled for the current task using +``kmsan_disable_current()`` and ``kmsan_enable_current()`` calls. Each +``kmsan_enable_current()`` call must be preceded by a +``kmsan_disable_current()`` call; these call pairs may be nested. One needs to +be careful with these calls, keeping the regions short and preferring other +ways to disable instrumentation, where possible. + Support ======= @@ -338,11 +345,11 @@ Per-task KMSAN state ~~~~~~~~~~~~~~~~~~~~ Every task_struct has an associated KMSAN task state that holds the KMSAN -context (see above) and a per-task flag disallowing KMSAN reports:: +context (see above) and a per-task counter disallowing KMSAN reports:: struct kmsan_context { ... - bool allow_reporting; + unsigned int depth; struct kmsan_context_state cstate; ... } diff --git a/include/linux/kmsan.h b/include/linux/kmsan.h index fe6c2212bdb1..14b5ea6d3a43 100644 --- a/include/linux/kmsan.h +++ b/include/linux/kmsan.h @@ -239,6 +239,22 @@ void kmsan_unpoison_entry_regs(const struct pt_regs *regs); */ void *kmsan_get_metadata(void *addr, bool is_origin); +/** + * kmsan_enable_current(): Enable KMSAN for the current task. + * + * Each kmsan_enable_current() current call must be preceded by a + * kmsan_disable_current() call. These call pairs may be nested. + */ +void kmsan_enable_current(void); + +/** + * kmsan_disable_current(): Disable KMSAN for the current task. + * + * Each kmsan_disable_current() current call must be followed by a + * kmsan_enable_current() call. These call pairs may be nested. + */ +void kmsan_disable_current(void); + #else static inline void kmsan_init_shadow(void) @@ -338,6 +354,14 @@ static inline void kmsan_unpoison_entry_regs(const struct pt_regs *regs) { } +static inline void kmsan_enable_current(void) +{ +} + +static inline void kmsan_disable_current(void) +{ +} + #endif #endif /* _LINUX_KMSAN_H */ diff --git a/include/linux/kmsan_types.h b/include/linux/kmsan_types.h index 929287981afe..dfc59918b3c0 100644 --- a/include/linux/kmsan_types.h +++ b/include/linux/kmsan_types.h @@ -31,7 +31,7 @@ struct kmsan_context_state { struct kmsan_ctx { struct kmsan_context_state cstate; int kmsan_in_runtime; - bool allow_reporting; + unsigned int depth; }; #endif /* _LINUX_KMSAN_TYPES_H */ diff --git a/mm/kmsan/core.c b/mm/kmsan/core.c index 95f859e38c53..81b22220711a 100644 --- a/mm/kmsan/core.c +++ b/mm/kmsan/core.c @@ -43,7 +43,6 @@ void kmsan_internal_task_create(struct task_struct *task) struct thread_info *info = current_thread_info(); __memset(ctx, 0, sizeof(*ctx)); - ctx->allow_reporting = true; kmsan_internal_unpoison_memory(info, sizeof(*info), false); } diff --git a/mm/kmsan/hooks.c b/mm/kmsan/hooks.c index b408714f9ba3..267d0afa2e8b 100644 --- a/mm/kmsan/hooks.c +++ b/mm/kmsan/hooks.c @@ -39,12 +39,10 @@ void kmsan_task_create(struct task_struct *task) void kmsan_task_exit(struct task_struct *task) { - struct kmsan_ctx *ctx = &task->kmsan_ctx; - if (!kmsan_enabled || kmsan_in_runtime()) return; - ctx->allow_reporting = false; + kmsan_disable_current(); } void kmsan_slab_alloc(struct kmem_cache *s, void *object, gfp_t flags) @@ -424,3 +422,17 @@ void kmsan_check_memory(const void *addr, size_t size) REASON_ANY); } EXPORT_SYMBOL(kmsan_check_memory); + +void kmsan_enable_current(void) +{ + KMSAN_WARN_ON(current->kmsan_ctx.depth == 0); + current->kmsan_ctx.depth--; +} +EXPORT_SYMBOL(kmsan_enable_current); + +void kmsan_disable_current(void) +{ + current->kmsan_ctx.depth++; + KMSAN_WARN_ON(current->kmsan_ctx.depth == 0); +} +EXPORT_SYMBOL(kmsan_disable_current); diff --git a/mm/kmsan/report.c b/mm/kmsan/report.c index c79d3b0d2d0d..92e73ec61435 100644 --- a/mm/kmsan/report.c +++ b/mm/kmsan/report.c @@ -8,6 +8,7 @@ */ #include <linux/console.h> +#include <linux/kmsan.h> #include <linux/moduleparam.h> #include <linux/stackdepot.h> #include <linux/stacktrace.h> @@ -158,12 +159,12 @@ void kmsan_report(depot_stack_handle_t origin, void *address, int size, if (!kmsan_enabled) return; - if (!current->kmsan_ctx.allow_reporting) + if (current->kmsan_ctx.depth) return; if (!origin) return; - current->kmsan_ctx.allow_reporting = false; + kmsan_disable_current(); ua_flags = user_access_save(); raw_spin_lock(&kmsan_report_lock); pr_err("=====================================================\n"); @@ -216,5 +217,5 @@ void kmsan_report(depot_stack_handle_t origin, void *address, int size, if (panic_on_kmsan) panic("kmsan.panic set ...\n"); user_access_restore(ua_flags); - current->kmsan_ctx.allow_reporting = true; + kmsan_enable_current(); } diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 0a33d9195b7a..01237d167223 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1202,6 +1202,8 @@ static const char *uaccess_safe_builtin[] = { "__sanitizer_cov_trace_switch", /* KMSAN */ "kmsan_copy_to_user", + "kmsan_disable_current", + "kmsan_enable_current", "kmsan_report", "kmsan_unpoison_entry_regs", "kmsan_unpoison_memory", |