On Mon, Jun 08, 2015 at 10:33:14AM +0200, Ludovic Desroches wrote: > Using _bh variant for spin locks causes this kind of warning: > Starting logging: ------------[ cut here ]------------ > WARNING: CPU: 0 PID: 3 at /ssd_drive/linux/kernel/softirq.c:151 > __local_bh_enable_ip+0xe8/0xf4() > Modules linked in: > CPU: 0 PID: 3 Comm: ksoftirqd/0 Not tainted 4.1.0-rc2+ #94 > Hardware name: Atmel SAMA5 > [<c0013c04>] (unwind_backtrace) from [<c00118a4>] (show_stack+0x10/0x14) > [<c00118a4>] (show_stack) from [<c001bbcc>] > (warn_slowpath_common+0x80/0xac) > [<c001bbcc>] (warn_slowpath_common) from [<c001bc14>] > (warn_slowpath_null+0x1c/0x24) > [<c001bc14>] (warn_slowpath_null) from [<c001e28c>] > (__local_bh_enable_ip+0xe8/0xf4) > [<c001e28c>] (__local_bh_enable_ip) from [<c01fdbd0>] > (at_xdmac_device_terminate_all+0xf4/0x100) > [<c01fdbd0>] (at_xdmac_device_terminate_all) from [<c02221a4>] > (atmel_complete_tx_dma+0x34/0xf4) > [<c02221a4>] (atmel_complete_tx_dma) from [<c01fe4ac>] > (at_xdmac_tasklet+0x14c/0x1ac) > [<c01fe4ac>] (at_xdmac_tasklet) from [<c001de58>] > (tasklet_action+0x68/0xb4) > [<c001de58>] (tasklet_action) from [<c001dfdc>] > (__do_softirq+0xfc/0x238) > [<c001dfdc>] (__do_softirq) from [<c001e140>] (run_ksoftirqd+0x28/0x34) > [<c001e140>] (run_ksoftirqd) from [<c0033a3c>] > (smpboot_thread_fn+0x138/0x18c) > [<c0033a3c>] (smpboot_thread_fn) from [<c0030e7c>] (kthread+0xdc/0xf0) > [<c0030e7c>] (kthread) from [<c000f480>] (ret_from_fork+0x14/0x34) > ---[ end trace b57b14a99c1d8812 ]--- > > It comes from the fact that devices can called some code from the DMA > controller with irq disabled. _bh variant is not intended to be used in > this case since it can enable irqs. Switch to irqsave/irqrestore variant to > avoid this situation. Applied, thanks -- ~Vinod -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
