From: SeokHoon Yoon <iamyooon@gmail.com>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>,
kasan-dev <kasan-dev@googlegroups.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"sh.yoon@lge.com" <sh.yoon@lge.com>
Subject: Re: [PATCH 1/1] mm/kasan: use {READ,WRITE}_MODE not true,false
Date: Mon, 6 Jun 2016 08:08:14 +0900 [thread overview]
Message-ID: <CAPjZS4qnmc5zPG==2PB0yPjGPZ6SKc31aT1d0u+PoO1c0uYMVw@mail.gmail.com> (raw)
In-Reply-To: <CACT4Y+b8aCV9-8Qg6oxmOKHWvNsPeDyhz=x0GAtWzyYEC6Z2FA@mail.gmail.com>
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2016-06-05 21:49 GMT+09:00 Dmitry Vyukov <dvyukov@google.com>:
> On Sun, Jun 5, 2016 at 1:11 PM, seokhoon.yoon <iamyooon@gmail.com> 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@gmail.com>
> > ---
> > 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? :)
> 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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next prev parent reply other threads:[~2016-06-05 23:08 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-05 11:11 seokhoon.yoon
2016-06-05 12:49 ` Dmitry Vyukov
2016-06-05 23:08 ` SeokHoon Yoon [this message]
2016-06-06 14:33 ` Dmitry Vyukov
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