Hi, On 15.12.2016 10:45, Pavel Machek wrote: > Hi! > >> The driver uses a private lock for synchronization of the xmit function and >> the xmit completion handler, but since the NETIF_F_LLTX flag is not set, >> the xmit function is also called with the xmit_lock held. >> >> On the other hand the completion handler uses the reverse locking order by >> first taking the private lock and (in case that the tx queue had been >> stopped) then the xmit_lock. >> >> Improve the locking by removing the private lock and using only the >> xmit_lock for synchronization instead. > > Do you have stmmac hardware to test on? >
Unfortunately not (I mentioned that the patch I send was only compile tested in the first version but I think I forgot to do so in the last version). > I believe something is very wrong with the locking there. In > particular... scheduling the stmmac_tx_timer() function to run often > should not do anything bad if locking is correct... but it breaks the > driver rather quickly. [Example patch below, needs applying to two > places in net-next.] > Do you get this result only after the private lock is removed? Or has this problem been there before? And how exactly does the failure look like? Regards, Lino
