Bug in AIO (Asynchronous I/O) functions in Linux!

[balat.raju]

 

Hi,

      I am working with open POSIX test suite in Linux. I found aio_xxx related functions are not returned with an appropriate error in a given execution condition. I analyzed the source code and it seems that there is no problem with that. So, I think the problem may be due to glibc. Just I would like to know the present glibc is fully complaint with the AIO functions or not?

 

      I have given below the detailed analysis of the failed test cases. I used Linux kernel version 2.6.8 and the glibc version : 2.3.4. The latest published result for Open POSIX test suite is also available in http://tslogparser.sourceforge.net/run-browse.php.

 

 

 

TEST CASE FAILURE ANALYSIS REPORT ON AIO (Asynchronous Input and Output)

 

 

 

Conclusion:

1. aio_error, aio_return, aio_read, aio_write and lio_listio functions are not returned correctly with an appropriate error if some invalid value is passed as an argument.  Even without initializing aiocb structure, calling aio_read and aio_write are returned 0.

 

2. aio_read and aio_write functions are not accepted NULL as an argument. It generated Segmentation Fault.

 

These test cases are taken from posixtestsuite-1.5.0.tar.gz ( http://prdownloads.sourceforge.net/posixtest/posixtestsuite-1.5.0.tar.gz?use_mirror=unc). The path of the each file is posixtestsuite/conformance/interfaces/aio_xxx.c

 

1.aio_error: 3-1.c [error message: bad aio_error return value ]

Test: Call aio_error() with an invalid aiocbp, i.e passed an un initialized address of aiocb structure as an argumrnt.

Expected: aio_error function is expected to return an appropriate error number. If the return value of the function is equal to -1  and errno is equal to EINVAL(22) then the test case will be passed.

Output: The aio_error function returns 1. The corresponding error (according to errno.h) is Operation is not permitted.

Analysis: aio_error function is not returned correctly if a dummy structure is passed as an argument.

        

2. aio_return:3-2.c [ error message: aio_return/3-1.c aio_return() should fail]

Test: Call aio_return function two times consecutively after aio_write.

Expected:  First time it should be returned with the given buffer size and the next time it should be returned -1 and the EINVAL error.

Output: The aio_return function returns correctly when it was executing first time. But in second time, still the aio_return returns again the buf size. So the test case was failed.

Analysis: aio_return should return with an appropriate error, when it is called second time. i.e)called second time after I/O operation completes.

 

3.aio_write: 2-1.c [error message:aio_write/2-1.c Error at read(): No such file

or directory ]

Test: Call three times aio_write function with corresponding buffer size 400, 200 and 300.

Expected: It writes in three times with different buffer and wants to read all the data.

Output: Able to read only the first write data not the remaining two.

Analysis: So the expected return value of the read system call is 900 but it returns 400, which is equivalent to the first write buffer size. So the test case is failed.

 

4&5. aio_write: 6-1.c and aio_read: 8-1.c[error message: Segmentation Fault]

Test: Call aio_read /aio_write function with NULL as an argument.

Expected: -1 is the return value

Output: created Segmentation Fault.

Analysis: In general aio_write/aio_read will accept address of the aiocb structure but in these test cases NULL is passed as an argument. aio_write/aio_read didn't accept NULL as the argument. It has generated segmentation fault.

 

6.  aio_write: 8-2.c [error message: aio_write/8-2.c bad aio_write return value()]

Test: Call aio_write but file is open in read only mode.

Expected: aio_write function should be returned -1 and EBADF error

Ouptut: Function is returned with zero and error no is 2 (ENOENT).

Analysis: aio_write return value is not handled properly even if it is failed.

 

7.  aio_write: 8-1.c [ error message: bad aio_write return value]

Test: assign  aiocb.aio_fildes = -1; and call aio_write

Expected: function should be returned -1 and EBADF error

Output: Function is returned with zero and the error number is 0.

Analysis: aio_write function is not returned with an appropriate error even if some of the invalid value is assigned in aiocb structure, which is passed as an argument of the function.

 

8. aio_write: 9-1.c [ error message: aio_write/9-1.c bad aio_write return value()]

Test: assign  aiocb.aio_offset = -1; and call aio_write

Expected: function should be returned -1 and EBADF error

Output: Function is returned with zero and the error number is 2 (ENOENT).

Analysis: aio_write function is not returned with an appropriate error even if some of the invalid value is assigned in aiocb structure, which is passed as an argument of the function.

 

9. aio_read: 10-1.c [error message: aio_read/10-1.c bad aio_read return value()]

Test: assign  aiocb.aio_fildes = -1; and call aio_read without writing

Expected: function should be returned -1 and EBADF error

Output: Function is returned with zero and the error number is 0.

Analysis: aio_read function is not returned with an appropriate error even if some of the invalid value is assigned in aiocb structure, which is passed as an argument of the function.

 

10. aio_read: 11-1.c [error message: aio_read/11-1.c bad aio_read return value()]

Test: assign  aiocb.aio_offset = -1; and call aio_read after writing

Expected: function should be returned -1 and EBADF error

Output: Function is returned with zero and the error number is 2 (ENOENT).

Analysis: aio_read function is not returned with an appropriate error even if some of the invalid value is assigned in aiocb structure, which is passed as an argument of the function.

 

11. lio_listio: 5-1.c [error message: lio_listio/5-1.c lio_listio() accepts invalid opcode]

Test: assign  aiocb.aio_lio_opcode = -1; and call lio_litio

Expected: function should be returned -1.

Output: Function is returned with zero.

Analysis: lio_litio function is not returned with an appropriate error even if some of the invalid value is assigned in aiocb structure, which is passed as an argument of the function.

 

 

With best regards,

B. Thangaraju