Em Mon, Sep 25, 2017 at 11:49:49AM -0300, Arnaldo Carvalho de Melo escreveu: > I'm trying to get an Infiniband test case working with the RT > kernel, and ended over tripping over this case: > > In drivers/infiniband/hw/hfi1/pio.c sc_buffer_alloc() disables > preemption that will be reenabled by either pio_copy() or > seg_pio_copy_end(). > > But before disabling preemption it grabs a spin lock that will > be dropped after it disables preemption, which ends up triggering a > warning in migrate_disable() later on. > > spin_lock_irqsave(&sc->alloc_lock) > migrate_disable() ++p->migrate_disable -> 2 > preempt_disable() > spin_unlock_irqrestore(&sc->alloc_lock) > migrate_enable() in_atomic(), so just returns, migrate_disable stays at 2 > spin_lock_irqsave(some other lock) -> b00m Sebastian, perhaps use local locks like you did for the random.c case? I'll study to see if that is possible... I mean this patch: https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git/commit/drivers/char/random.c?h=linux-4.11.y-rt&id=4bed11300e24d5178829758e535cc4996490b7c8 ------------- random: avoid preempt_disable()ed section extract_crng() will use sleeping locks while in a preempt_disable() section due to get_cpu_var(). Work around it with local_locks. Cc: stable-rt@xxxxxxxxxxxxxxx # where it applies to Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> ------------- - Arnaldo -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
