On Mon, Jun 6, 2016 at 1:08 AM, SeokHoon Yoon <iamyooon@xxxxxxxxx> wrote:
>
> 2016-06-05 21:49 GMT+09:00 Dmitry Vyukov <dvyukov@xxxxxxxxxx>:
>>
>> On Sun, Jun 5, 2016 at 1:11 PM, seokhoon.yoon <iamyooon@xxxxxxxxx> wrote:
>> > When Kasan tell memory access is write or not, use true or false.
>> > This expression is simple and convenient.
>> >
>> > But I think it is possible to more readable. and so change it.
>> >
>> > Signed-off-by: seokhoon.yoon <iamyooon@xxxxxxxxx>
>> > ---
>> > mm/kasan/kasan.c | 32 ++++++++++++++++----------------
>> > mm/kasan/kasan.h | 12 ++++++++++--
>> > mm/kasan/report.c | 16 ++++++++--------
>> > 3 files changed, 34 insertions(+), 26 deletions(-)
>> >
>> > diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
>> > index 18b6a2b..642d936 100644
>> > --- a/mm/kasan/kasan.c
>> > +++ b/mm/kasan/kasan.c
>> > @@ -274,7 +274,7 @@ static __always_inline bool
>> > memory_is_poisoned(unsigned long addr, size_t size)
>> > }
>> >
>> > static __always_inline void check_memory_region_inline(unsigned long
>> > addr,
>> > - size_t size, bool write,
>> > + size_t size, enum
>> > acc_type type,
>> > unsigned long ret_ip)
>> > {
>> > if (unlikely(size == 0))
>> > @@ -282,39 +282,39 @@ static __always_inline void
>> > check_memory_region_inline(unsigned long addr,
>> >
>> > if (unlikely((void *)addr <
>> > kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
>> > - kasan_report(addr, size, write, ret_ip);
>> > + kasan_report(addr, size, type, ret_ip);
>> > return;
>> > }
>> >
>> > if (likely(!memory_is_poisoned(addr, size)))
>> > return;
>> >
>> > - kasan_report(addr, size, write, ret_ip);
>> > + kasan_report(addr, size, type, ret_ip);
>> > }
>> >
>> > static void check_memory_region(unsigned long addr,
>> > - size_t size, bool write,
>> > + size_t size, enum acc_type type,
>> > unsigned long ret_ip)
>> > {
>> > - check_memory_region_inline(addr, size, write, ret_ip);
>> > + check_memory_region_inline(addr, size, type, ret_ip);
>> > }
>> >
>> > void kasan_check_read(const void *p, unsigned int size)
>> > {
>> > - check_memory_region((unsigned long)p, size, false, _RET_IP_);
>> > + check_memory_region((unsigned long)p, size, READ_MODE,
>> > _RET_IP_);
>> > }
>> > EXPORT_SYMBOL(kasan_check_read);
>> >
>> > void kasan_check_write(const void *p, unsigned int size)
>> > {
>> > - check_memory_region((unsigned long)p, size, true, _RET_IP_);
>> > + check_memory_region((unsigned long)p, size, WRITE_MODE,
>> > _RET_IP_);
>> > }
>> > EXPORT_SYMBOL(kasan_check_write);
>> >
>> > #undef memset
>> > void *memset(void *addr, int c, size_t len)
>> > {
>> > - check_memory_region((unsigned long)addr, len, true, _RET_IP_);
>> > + check_memory_region((unsigned long)addr, len, WRITE_MODE,
>> > _RET_IP_);
>> >
>> > return __memset(addr, c, len);
>> > }
>> > @@ -322,8 +322,8 @@ void *memset(void *addr, int c, size_t len)
>> > #undef memmove
>> > void *memmove(void *dest, const void *src, size_t len)
>> > {
>> > - check_memory_region((unsigned long)src, len, false, _RET_IP_);
>> > - check_memory_region((unsigned long)dest, len, true, _RET_IP_);
>> > + check_memory_region((unsigned long)src, len, READ_MODE,
>> > _RET_IP_);
>> > + check_memory_region((unsigned long)dest, len, WRITE_MODE,
>> > _RET_IP_);
>> >
>> > return __memmove(dest, src, len);
>> > }
>> > @@ -331,8 +331,8 @@ void *memmove(void *dest, const void *src, size_t
>> > len)
>> > #undef memcpy
>> > void *memcpy(void *dest, const void *src, size_t len)
>> > {
>> > - check_memory_region((unsigned long)src, len, false, _RET_IP_);
>> > - check_memory_region((unsigned long)dest, len, true, _RET_IP_);
>> > + check_memory_region((unsigned long)src, len, READ_MODE,
>> > _RET_IP_);
>> > + check_memory_region((unsigned long)dest, len, WRITE_MODE,
>> > _RET_IP_);
>> >
>> > return __memcpy(dest, src, len);
>> > }
>> > @@ -709,7 +709,7 @@ EXPORT_SYMBOL(__asan_unregister_globals);
>> > #define DEFINE_ASAN_LOAD_STORE(size)
>> > \
>> > void __asan_load##size(unsigned long addr)
>> > \
>> > {
>> > \
>> > - check_memory_region_inline(addr, size, false,
>> > _RET_IP_);\
>> > + check_memory_region_inline(addr, size, READ_MODE,
>> > _RET_IP_);\
>> > }
>> > \
>> > EXPORT_SYMBOL(__asan_load##size);
>> > \
>> > __alias(__asan_load##size)
>> > \
>> > @@ -717,7 +717,7 @@ EXPORT_SYMBOL(__asan_unregister_globals);
>> > EXPORT_SYMBOL(__asan_load##size##_noabort);
>> > \
>> > void __asan_store##size(unsigned long addr)
>> > \
>> > {
>> > \
>> > - check_memory_region_inline(addr, size, true, _RET_IP_);
>> > \
>> > + check_memory_region_inline(addr, size, WRITE_MODE,
>> > _RET_IP_);\
>> > }
>> > \
>> > EXPORT_SYMBOL(__asan_store##size);
>> > \
>> > __alias(__asan_store##size)
>> > \
>> > @@ -732,7 +732,7 @@ DEFINE_ASAN_LOAD_STORE(16);
>> >
>> > void __asan_loadN(unsigned long addr, size_t size)
>> > {
>> > - check_memory_region(addr, size, false, _RET_IP_);
>> > + check_memory_region(addr, size, READ_MODE, _RET_IP_);
>> > }
>> > EXPORT_SYMBOL(__asan_loadN);
>> >
>> > @@ -742,7 +742,7 @@ EXPORT_SYMBOL(__asan_loadN_noabort);
>> >
>> > void __asan_storeN(unsigned long addr, size_t size)
>> > {
>> > - check_memory_region(addr, size, true, _RET_IP_);
>> > + check_memory_region(addr, size, WRITE_MODE, _RET_IP_);
>> > }
>> > EXPORT_SYMBOL(__asan_storeN);
>> >
>> > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
>> > index 7f7ac51..47cb58c 100644
>> > --- a/mm/kasan/kasan.h
>> > +++ b/mm/kasan/kasan.h
>> > @@ -27,11 +27,19 @@
>> > #define KASAN_ABI_VERSION 1
>> > #endif
>> >
>> > +/*
>> > + * Distinguish memory access
>> > + */
>> > +enum acc_type {
>> > + READ_MODE,
>> > + WRITE_MODE
>> > +};
>> > +
>> > struct kasan_access_info {
>> > const void *access_addr;
>> > const void *first_bad_addr;
>> > size_t access_size;
>> > - bool is_write;
>> > + enum acc_type access_type;
>> > unsigned long ip;
>> > };
>> >
>> > @@ -109,7 +117,7 @@ static inline bool kasan_report_enabled(void)
>> > }
>> >
>> > void kasan_report(unsigned long addr, size_t size,
>> > - bool is_write, unsigned long ip);
>> > + enum acc_type type, unsigned long ip);
>> >
>> > #ifdef CONFIG_SLAB
>> > void quarantine_put(struct kasan_free_meta *info, struct kmem_cache
>> > *cache);
>> > diff --git a/mm/kasan/report.c b/mm/kasan/report.c
>> > index b3c122d..e0bee22 100644
>> > --- a/mm/kasan/report.c
>> > +++ b/mm/kasan/report.c
>> > @@ -96,7 +96,7 @@ static void print_error_description(struct
>> > kasan_access_info *info)
>> > bug_type, (void *)info->ip,
>> > info->access_addr);
>> > pr_err("%s of size %zu by task %s/%d\n",
>> > - info->is_write ? "Write" : "Read",
>> > + info->access_type == WRITE_MODE ? "Write" : "Read",
>> > info->access_size, current->comm, task_pid_nr(current));
>> > }
>> >
>> > @@ -267,7 +267,7 @@ static void kasan_report_error(struct
>> > kasan_access_info *info)
>> > pr_err("BUG: KASAN: %s on address %p\n",
>> > bug_type, info->access_addr);
>> > pr_err("%s of size %zu by task %s/%d\n",
>> > - info->is_write ? "Write" : "Read",
>> > + info->access_type == WRITE_MODE ? "Write" :
>> > "Read",
>> > info->access_size, current->comm,
>> > task_pid_nr(current));
>> > dump_stack();
>> > @@ -283,7 +283,7 @@ static void kasan_report_error(struct
>> > kasan_access_info *info)
>> > }
>> >
>> > void kasan_report(unsigned long addr, size_t size,
>> > - bool is_write, unsigned long ip)
>> > + enum acc_type type, unsigned long ip)
>> > {
>> > struct kasan_access_info info;
>> >
>> > @@ -292,7 +292,7 @@ void kasan_report(unsigned long addr, size_t size,
>> >
>> > info.access_addr = (void *)addr;
>> > info.access_size = size;
>> > - info.is_write = is_write;
>> > + info.access_type = type;
>> > info.ip = ip;
>> >
>> > kasan_report_error(&info);
>> > @@ -302,14 +302,14 @@ void kasan_report(unsigned long addr, size_t size,
>> > #define DEFINE_ASAN_REPORT_LOAD(size) \
>> > void __asan_report_load##size##_noabort(unsigned long addr) \
>> > { \
>> > - kasan_report(addr, size, false, _RET_IP_); \
>> > + kasan_report(addr, size, READ_MODE, _RET_IP_); \
>> > } \
>> > EXPORT_SYMBOL(__asan_report_load##size##_noabort)
>> >
>> > #define DEFINE_ASAN_REPORT_STORE(size) \
>> > void __asan_report_store##size##_noabort(unsigned long addr) \
>> > { \
>> > - kasan_report(addr, size, true, _RET_IP_); \
>> > + kasan_report(addr, size, WRITE_MODE, _RET_IP_); \
>> > } \
>> > EXPORT_SYMBOL(__asan_report_store##size##_noabort)
>> >
>> > @@ -326,12 +326,12 @@ DEFINE_ASAN_REPORT_STORE(16);
>> >
>> > void __asan_report_load_n_noabort(unsigned long addr, size_t size)
>> > {
>> > - kasan_report(addr, size, false, _RET_IP_);
>> > + kasan_report(addr, size, READ_MODE, _RET_IP_);
>> > }
>> > EXPORT_SYMBOL(__asan_report_load_n_noabort);
>> >
>> > void __asan_report_store_n_noabort(unsigned long addr, size_t size)
>> > {
>> > - kasan_report(addr, size, true, _RET_IP_);
>> > + kasan_report(addr, size, WRITE_MODE, _RET_IP_);
>> > }
>> > EXPORT_SYMBOL(__asan_report_store_n_noabort);
>>
>>
>> Hello seokhoon.yoon,
>>
> Hi Dmitry,
> thanks for your replies.
>
>>
>>
>> Where exactly do you hit readability problems?
>
>
> I don`t hit readablity problem,but kasan need to abstract this expression.
> I think more abstraction give us more readablity. isn't it? :)
Keeping it simple also gives readability.
>> I would say that the only problematic place is where we initialize the
>> value:
>>
>> kasan_report(addr, size, true, _RET_IP_);
>> check_memory_region(addr, size, true, _RET_IP_);
>>
>> Here it is really difficult to say what true/false mean. Even if you
>> know that it is access type, you don't necessary remember if true
>>
>> means write or read. That could be solved by adding comments:
>>
>> kasan_report(addr, size, /* write = */ true, _RET_IP_);
>>
>> In all other places one sees that we are talking about "write".
>
>
> thanks.
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