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| author | Jan Höppner <hoeppner@linux.vnet.ibm.com> | 2016-10-18 17:54:49 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2016-10-28 10:09:04 +0200 |
| commit | 0f57c97f241b4fc18251fb2b1c499e9f71e93c78 (patch) | |
| tree | d4a852d838aa62ad6fc28ce183730646b8bbc3c3 /drivers/s390/block/dasd_eer.c | |
| parent | s390/dasd: Make use of dasd_set_feature() more often (diff) | |
| download | linux-0f57c97f241b4fc18251fb2b1c499e9f71e93c78.tar.xz linux-0f57c97f241b4fc18251fb2b1c499e9f71e93c78.zip | |
s390/dasd: Eliminate race condition in dasd_generic_set_offline()
Before we set a device offline, the open_count for the block device is
checked and certain flags are checked and set as well.
However, this is all done without holding any lock. Potentially, if the
open_count was checked but the DASD_FLAG_OFFLINE wasn't set yet, a
different process might want to increase the open_count depending on
whether DASD_FLAG_OFFLINE is set or not in the meanwhile.
This is quite racy and can lead to the loss of the device for that
process and subsequently lead to a panic.
Fix this by checking the open_count and setting the offline flags while
holding the ccwdev lock.
Reviewed-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'drivers/s390/block/dasd_eer.c')
0 files changed, 0 insertions, 0 deletions