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authorDavid Jeffery <djeffery@redhat.com>2017-08-28 18:52:44 +0200
committerJens Axboe <axboe@kernel.dk>2017-08-28 18:52:44 +0200
commite9a823fb34a8b0fcba6e112aa1003258a1a5af50 (patch)
treedd6507e25c254a6aa569b0f5c5451bba04b415d4 /drivers/ata/pata_octeon_cf.c
parentblock, scheduler: convert xxx_var_store to void (diff)
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block: fix warning when I/O elevator is changed as request_queue is being removed
There is a race between changing I/O elevator and request_queue removal which can trigger the warning in kobject_add_internal. A program can use sysfs to request a change of elevator at the same time another task is unregistering the request_queue the elevator would be attached to. The elevator's kobject will then attempt to be connected to the request_queue in the object tree when the request_queue has just been removed from sysfs. This triggers the warning in kobject_add_internal as the request_queue no longer has a sysfs directory: kobject_add_internal failed for iosched (error: -2 parent: queue) ------------[ cut here ]------------ WARNING: CPU: 3 PID: 14075 at lib/kobject.c:244 kobject_add_internal+0x103/0x2d0 To fix this warning, we can check the QUEUE_FLAG_REGISTERED flag when changing the elevator and use the request_queue's sysfs_lock to serialize between clearing the flag and the elevator testing the flag. Signed-off-by: David Jeffery <djeffery@redhat.com> Tested-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/ata/pata_octeon_cf.c')
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