Messages in this thread | | | Date | Fri, 8 Oct 2021 15:58:16 +0200 | From | Andrew Lunn <> | Subject | Re: [PATCH net] net: dsa: microchip: Added the condition for scheduling ksz_mib_read_work |
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On Fri, Oct 08, 2021 at 02:13:48PM +0530, Arun Ramadoss wrote: > When the ksz module is installed and removed using rmmod, kernel crashes > with null pointer dereferrence error. During rmmod, ksz_switch_remove > function tries to cancel the mib_read_workqueue using > cancel_delayed_work_sync routine. > > At the end of mib_read_workqueue execution, it again reschedule the > workqueue unconditionally. Due to which queue rescheduled after > mib_interval, during this execution it tries to access dp->slave. But > the slave is unregistered in the ksz_switch_remove function. Hence > kernel crashes.
Something not correct here.
https://www.kernel.org/doc/html/latest/core-api/workqueue.html?highlight=delayed_work#c.cancel_delayed_work_sync
This is cancel_work_sync() for delayed works.
and
https://www.kernel.org/doc/html/latest/core-api/workqueue.html?highlight=delayed_work#c.cancel_work_sync
This function can be used even if the work re-queues itself or migrates to another workqueue.
Maybe the real problem is a missing call to destroy_worker()?
Andrew
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