* [PATCH] io_uring: fix bug of wrong BUILD_BUG_ON check
@ 2021-09-06 15:12 Hao Xu
2021-09-06 15:22 ` Pavel Begunkov
0 siblings, 1 reply; 5+ messages in thread
From: Hao Xu @ 2021-09-06 15:12 UTC (permalink / raw)
To: Jens Axboe; +Cc: io-uring, Pavel Begunkov, Joseph Qi
Some check should be large than not equal or large than.
Signed-off-by: Hao Xu <[email protected]>
---
fs/io_uring.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 2bde732a1183..3a833037af43 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -10637,13 +10637,13 @@ static int __init io_uring_init(void)
sizeof(struct io_uring_rsrc_update2));
/* ->buf_index is u16 */
- BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16));
+ BUILD_BUG_ON(IORING_MAX_REG_BUFFERS > (1u << 16));
/* should fit into one byte */
- BUILD_BUG_ON(SQE_VALID_FLAGS >= (1 << 8));
+ BUILD_BUG_ON(SQE_VALID_FLAGS > (1 << 8));
BUILD_BUG_ON(ARRAY_SIZE(io_op_defs) != IORING_OP_LAST);
- BUILD_BUG_ON(__REQ_F_LAST_BIT >= 8 * sizeof(int));
+ BUILD_BUG_ON(__REQ_F_LAST_BIT > 8 * sizeof(int));
req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC |
SLAB_ACCOUNT);
--
2.24.4
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] io_uring: fix bug of wrong BUILD_BUG_ON check
2021-09-06 15:12 [PATCH] io_uring: fix bug of wrong BUILD_BUG_ON check Hao Xu
@ 2021-09-06 15:22 ` Pavel Begunkov
2021-09-06 17:03 ` Hao Xu
0 siblings, 1 reply; 5+ messages in thread
From: Pavel Begunkov @ 2021-09-06 15:22 UTC (permalink / raw)
To: Hao Xu, Jens Axboe; +Cc: io-uring, Joseph Qi
On 9/6/21 4:12 PM, Hao Xu wrote:
> Some check should be large than not equal or large than.
>
> Signed-off-by: Hao Xu <[email protected]>
> ---
> fs/io_uring.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index 2bde732a1183..3a833037af43 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -10637,13 +10637,13 @@ static int __init io_uring_init(void)
> sizeof(struct io_uring_rsrc_update2));
>
> /* ->buf_index is u16 */
> - BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16));
> + BUILD_BUG_ON(IORING_MAX_REG_BUFFERS > (1u << 16));
>
> /* should fit into one byte */
> - BUILD_BUG_ON(SQE_VALID_FLAGS >= (1 << 8));
> + BUILD_BUG_ON(SQE_VALID_FLAGS > (1 << 8));
0xff = 255 is the largest number fitting in u8,
1<<8 = 256.
let SQE_VALID_FLAGS = 256,
(256 > (1<<8)) == (256 > 256) == false, even though it can't
be represented by u8.
> BUILD_BUG_ON(ARRAY_SIZE(io_op_defs) != IORING_OP_LAST);
> - BUILD_BUG_ON(__REQ_F_LAST_BIT >= 8 * sizeof(int));
> + BUILD_BUG_ON(__REQ_F_LAST_BIT > 8 * sizeof(int));
>
> req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC |
> SLAB_ACCOUNT);
>
--
Pavel Begunkov
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] io_uring: fix bug of wrong BUILD_BUG_ON check
2021-09-06 15:22 ` Pavel Begunkov
@ 2021-09-06 17:03 ` Hao Xu
2021-09-06 19:15 ` Pavel Begunkov
0 siblings, 1 reply; 5+ messages in thread
From: Hao Xu @ 2021-09-06 17:03 UTC (permalink / raw)
To: Pavel Begunkov, Jens Axboe; +Cc: io-uring, Joseph Qi
在 2021/9/6 下午11:22, Pavel Begunkov 写道:
> On 9/6/21 4:12 PM, Hao Xu wrote:
>> Some check should be large than not equal or large than.
>>
>> Signed-off-by: Hao Xu <[email protected]>
>> ---
>> fs/io_uring.c | 6 +++---
>> 1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/io_uring.c b/fs/io_uring.c
>> index 2bde732a1183..3a833037af43 100644
>> --- a/fs/io_uring.c
>> +++ b/fs/io_uring.c
>> @@ -10637,13 +10637,13 @@ static int __init io_uring_init(void)
>> sizeof(struct io_uring_rsrc_update2));
>>
>> /* ->buf_index is u16 */
>> - BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16));
>> + BUILD_BUG_ON(IORING_MAX_REG_BUFFERS > (1u << 16));
>>
>> /* should fit into one byte */
>> - BUILD_BUG_ON(SQE_VALID_FLAGS >= (1 << 8));
>> + BUILD_BUG_ON(SQE_VALID_FLAGS > (1 << 8));
>
> 0xff = 255 is the largest number fitting in u8,
> 1<<8 = 256.
>
> let SQE_VALID_FLAGS = 256,
> (256 > (1<<8)) == (256 > 256) == false, even though it can't
> be represented by u8.
Isn't SQE_VALID_FLAGS = 256 a valid value for it?
>
>
>> BUILD_BUG_ON(ARRAY_SIZE(io_op_defs) != IORING_OP_LAST);
>> - BUILD_BUG_ON(__REQ_F_LAST_BIT >= 8 * sizeof(int));
>> + BUILD_BUG_ON(__REQ_F_LAST_BIT > 8 * sizeof(int));
>>
>> req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC |
>> SLAB_ACCOUNT);
>>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] io_uring: fix bug of wrong BUILD_BUG_ON check
2021-09-06 17:03 ` Hao Xu
@ 2021-09-06 19:15 ` Pavel Begunkov
2021-09-07 3:02 ` Hao Xu
0 siblings, 1 reply; 5+ messages in thread
From: Pavel Begunkov @ 2021-09-06 19:15 UTC (permalink / raw)
To: Hao Xu, Jens Axboe; +Cc: io-uring, Joseph Qi
On 9/6/21 6:03 PM, Hao Xu wrote:
> 在 2021/9/6 下午11:22, Pavel Begunkov 写道:
>> On 9/6/21 4:12 PM, Hao Xu wrote:
>>> Some check should be large than not equal or large than.
>>>
>>> Signed-off-by: Hao Xu <[email protected]>
>>> ---
>>> fs/io_uring.c | 6 +++---
>>> 1 file changed, 3 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/fs/io_uring.c b/fs/io_uring.c
>>> index 2bde732a1183..3a833037af43 100644
>>> --- a/fs/io_uring.c
>>> +++ b/fs/io_uring.c
>>> @@ -10637,13 +10637,13 @@ static int __init io_uring_init(void)
>>> sizeof(struct io_uring_rsrc_update2));
>>> /* ->buf_index is u16 */
>>> - BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16));
>>> + BUILD_BUG_ON(IORING_MAX_REG_BUFFERS > (1u << 16));
>>> /* should fit into one byte */
>>> - BUILD_BUG_ON(SQE_VALID_FLAGS >= (1 << 8));
>>> + BUILD_BUG_ON(SQE_VALID_FLAGS > (1 << 8));
>>
>> 0xff = 255 is the largest number fitting in u8,
>> 1<<8 = 256.
>>
>> let SQE_VALID_FLAGS = 256,
>> (256 > (1<<8)) == (256 > 256) == false, even though it can't
>> be represented by u8.
> Isn't SQE_VALID_FLAGS = 256 a valid value for it?
SQE_VALID_FLAGS is a "bitwise OR" combination of valid flags, so
can't be go beyond 0xff
>>
>>
>>> BUILD_BUG_ON(ARRAY_SIZE(io_op_defs) != IORING_OP_LAST);
>>> - BUILD_BUG_ON(__REQ_F_LAST_BIT >= 8 * sizeof(int));
>>> + BUILD_BUG_ON(__REQ_F_LAST_BIT > 8 * sizeof(int));
>>> req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC |
>>> SLAB_ACCOUNT);
>>>
>>
>
--
Pavel Begunkov
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] io_uring: fix bug of wrong BUILD_BUG_ON check
2021-09-06 19:15 ` Pavel Begunkov
@ 2021-09-07 3:02 ` Hao Xu
0 siblings, 0 replies; 5+ messages in thread
From: Hao Xu @ 2021-09-07 3:02 UTC (permalink / raw)
To: Pavel Begunkov, Jens Axboe; +Cc: io-uring, Joseph Qi
在 2021/9/7 上午3:15, Pavel Begunkov 写道:
> On 9/6/21 6:03 PM, Hao Xu wrote:
>> 在 2021/9/6 下午11:22, Pavel Begunkov 写道:
>>> On 9/6/21 4:12 PM, Hao Xu wrote:
>>>> Some check should be large than not equal or large than.
>>>>
>>>> Signed-off-by: Hao Xu <[email protected]>
>>>> ---
>>>> fs/io_uring.c | 6 +++---
>>>> 1 file changed, 3 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/fs/io_uring.c b/fs/io_uring.c
>>>> index 2bde732a1183..3a833037af43 100644
>>>> --- a/fs/io_uring.c
>>>> +++ b/fs/io_uring.c
>>>> @@ -10637,13 +10637,13 @@ static int __init io_uring_init(void)
>>>> sizeof(struct io_uring_rsrc_update2));
>>>> /* ->buf_index is u16 */
>>>> - BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16));
>>>> + BUILD_BUG_ON(IORING_MAX_REG_BUFFERS > (1u << 16));
>>>> /* should fit into one byte */
>>>> - BUILD_BUG_ON(SQE_VALID_FLAGS >= (1 << 8));
>>>> + BUILD_BUG_ON(SQE_VALID_FLAGS > (1 << 8));
>>>
>>> 0xff = 255 is the largest number fitting in u8,
>>> 1<<8 = 256.
>>>
>>> let SQE_VALID_FLAGS = 256,
>>> (256 > (1<<8)) == (256 > 256) == false, even though it can't
>>> be represented by u8.
>> Isn't SQE_VALID_FLAGS = 256 a valid value for it?
>
> SQE_VALID_FLAGS is a "bitwise OR" combination of valid flags, so
> can't be go beyond 0xff
I see, don't know why I mix it with __REQ_F_LAST_BIT in my mind..
>
>>>
>>>
>>>> BUILD_BUG_ON(ARRAY_SIZE(io_op_defs) != IORING_OP_LAST);
>>>> - BUILD_BUG_ON(__REQ_F_LAST_BIT >= 8 * sizeof(int));
>>>> + BUILD_BUG_ON(__REQ_F_LAST_BIT > 8 * sizeof(int));
>>>> req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC |
>>>> SLAB_ACCOUNT);
>>>>
>>>
>>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2021-09-07 3:02 UTC | newest]
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2021-09-06 15:12 [PATCH] io_uring: fix bug of wrong BUILD_BUG_ON check Hao Xu
2021-09-06 15:22 ` Pavel Begunkov
2021-09-06 17:03 ` Hao Xu
2021-09-06 19:15 ` Pavel Begunkov
2021-09-07 3:02 ` Hao Xu
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