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Vladimir Oltean
10b6bb62ae
Ido Schimmel points out that since commit52cff74eef("dcbnl : Disable software interrupts before taking dcb_lock"), the DCB API can be called by drivers from softirq context. One such in-tree example is the chelsio cxgb4 driver: dcb_rpl -> cxgb4_dcb_handle_fw_update -> dcb_ieee_setapp If the firmware for this driver happened to send an event which resulted in a call to dcb_ieee_setapp() at the exact same time as another DCB-enabled interface was unregistering on the same CPU, the softirq would deadlock, because the interrupted process was already holding the dcb_lock in dcbnl_flush_dev(). Fix this unlikely event by using spin_lock_bh() in dcbnl_flush_dev() as in the rest of the dcbnl code. Fixes:91b0383fef("net: dcb: flush lingering app table entries for unregistered devices") Reported-by: Ido Schimmel <[email protected]> Signed-off-by: Vladimir Oltean <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Jakub Kicinski <[email protected]>