| commit | f71ad62a264a89cb1952df0c92b167005de8d1b0 | |
| author | Michael Holzheu <holzheu@de.ibm.com> | |
| Fri, 30 May 2008 08:03:25 +0000 (30 10:03 +0200) | ||
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | |
| Fri, 30 May 2008 08:03:33 +0000 (30 10:03 +0200) | ||
| tree | de173ab5f138204d5ba5458de249c39e5faecdbd | treesnapshot (tar.gz zip) |
| parent | 97195d6b411fec8e33aa55b6a7c3dde7984d65ca | commitdiff |
[S390] tape: Fix race condition in tape block device driver
Due to incorrect function call sequence it can happen that a tape block
request is finished before the request is taken from the block request queue.
The following sequence leads to that condition:
* tapeblock_start_request() -> start CCW program
* Request finishes -> IO interrupt
* tapeblock_end_request()
* end_that_request_last()
If blkdev_dequeue_request() has not been called before end_that_request_last(),
a kernel bug is triggered in end_that_request_last() because the request is
still queued. To solve that problem blkdev_dequeue_request() has to be called
before starting the CCW program.
Signed-off-by: Michael Holzheu <holzheu@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Due to incorrect function call sequence it can happen that a tape block
request is finished before the request is taken from the block request queue.
The following sequence leads to that condition:
* tapeblock_start_request() -> start CCW program
* Request finishes -> IO interrupt
* tapeblock_end_request()
* end_that_request_last()
If blkdev_dequeue_request() has not been called before end_that_request_last(),
a kernel bug is triggered in end_that_request_last() because the request is
still queued. To solve that problem blkdev_dequeue_request() has to be called
before starting the CCW program.
Signed-off-by: Michael Holzheu <holzheu@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
| drivers/s390/char/tape_block.c | diffblobblamehistory |