Messages in this thread | | | Subject | Re: [PATCH v3 2/2] Bluetooth: fix inconsistent lock state in rfcomm_connect_ind | From | Desmond Cheong Zhi Xi <> | Date | Fri, 30 Jul 2021 17:06:09 +0800 |
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Hi Marcel,
On 30/7/21 3:53 am, Marcel Holtmann wrote: > Hi Desmond, > >> Commit fad003b6c8e3d ("Bluetooth: Fix inconsistent lock state with >> RFCOMM") fixed a lockdep warning due to sk->sk_lock.slock being >> acquired without disabling softirq while the lock is also used in >> softirq context. This was done by disabling interrupts before calling >> bh_lock_sock in rfcomm_sk_state_change. >> >> Later, this was changed in commit e6da0edc24ee ("Bluetooth: Acquire >> sk_lock.slock without disabling interrupts") to disable softirqs >> only. >> >> However, there is another instance of sk->sk_lock.slock being acquired >> without disabling softirq in rfcomm_connect_ind. This patch fixes this >> by disabling local bh before the call to bh_lock_sock. > > back in the days, the packet processing was done in a tasklet, but these days it is done in a workqueue. So shouldn’t this be just converted into a lock_sock(). Am I missing something? >
Thanks for the info. I think you're right, I just didn't understand very much when I wrote this patch.
If I'm understanding correctly, it seems that both the bh_lock_sock in rfcomm_connect_ind, and spin_lock_bh in rfcomm_sk_state_change need to be changed to lock_sock, otherwise they don't provide any synchronization with other functions in RFCOMM that use lock_sock.
If that sounds correct I can prepare the patch for that.
Best wishes, Desmond
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