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Stefan Haberland
d3a67c21b1
commitdb7ba07108upstream. Fix Oops in dasd_alias_get_start_dev() function caused by the pavgroup pointer being NULL. The pavgroup pointer is checked on the entrance of the function but without the lcu->lock being held. Therefore there is a race window between dasd_alias_get_start_dev() and _lcu_update() which sets pavgroup to NULL with the lcu->lock held. Fix by checking the pavgroup pointer with lcu->lock held. Cc: <stable@vger.kernel.org> # 2.6.25+ Fixes:8e09f21574("[S390] dasd: add hyper PAV support to DASD device driver, part 1") Signed-off-by: Stefan Haberland <sth@linux.ibm.com> Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com> Link: https://lore.kernel.org/r/20220919154931.4123002-2-sth@linux.ibm.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>