Hello,
with the rbp2-image-4.3.0-10-osmc kernel image, and the hifiberry dac+ pro, I get the following backtrace.
The problem seems to be that i2s audio devices are not yet stable with kernel 4.3 (see: https://github.com/raspberrypi/linux/pull/1178)
[ 73.987013] WARNING: CPU: 0 PID: 0 at include/asm-generic/dma-mapping-common.h:274 bcm2835_dma_desc_free+0xc8/0xcc()
[ 73.987022] Modules linked in: sg 8021q garp stp llc uas evdev joydev hid_logitech_hidpp snd_soc_bcm2835_i2s snd_soc_hifiberry_dacplus regmap_mmio snd_soc_hifiberry_dac snd_soc_pcm512x_i2c hid_logitech_dj snd_soc_pcm512x snd_soc_core bcm2835_thermal snd_compress snd_pcm_dmaengine i2c_bcm2708 bcm2835_wdt bcm2835_gpiomem snd_pcm snd_timer snd uio_pdrv_genirq uio fuse ipv6
[ 73.987144] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.3.0-10-osmc #1
[ 73.987153] Hardware name: BCM2709
[ 73.987184] [<8001f730>] (unwind_backtrace) from [<8001afdc>] (show_stack+0x20/0x24)
[ 73.987205] [<8001afdc>] (show_stack) from [<80400b7c>] (dump_stack+0x9c/0xdc)
[ 73.987226] [<80400b7c>] (dump_stack) from [<80031380>] (warn_slowpath_null+0x88/0xdc)
[ 73.987243] [<80031380>] (warn_slowpath_null) from [<804594cc>] (bcm2835_dma_desc_free+0xc8/0xcc)
[ 73.987259] [<804594cc>] (bcm2835_dma_desc_free) from [<80459618>] (bcm2835_dma_terminate_all+0x7c/0x1e4)
[ 73.987284] [<80459618>] (bcm2835_dma_terminate_all) from [<7f1360f8>] (snd_dmaengine_pcm_trigger+0x70/0x188 [snd_pcm_dmaengine])
[ 73.987368] [<7f1360f8>] (snd_dmaengine_pcm_trigger [snd_pcm_dmaengine]) from [<7f1582bc>] (soc_pcm_trigger+0xac/0x12c [snd_soc_core])
[ 73.987445] [<7f1582bc>] (soc_pcm_trigger [snd_soc_core]) from [<7f103530>] (snd_pcm_do_stop+0x64/0x68 [snd_pcm])
[ 73.987499] [<7f103530>] (snd_pcm_do_stop [snd_pcm]) from [<7f109dd8>] (snd_pcm_drain_done+0x44/0x8c [snd_pcm])
[ 73.987556] [<7f109dd8>] (snd_pcm_drain_done [snd_pcm]) from [<7f10e038>] (snd_pcm_update_state+0xf8/0x1b0 [snd_pcm])
[ 73.987614] [<7f10e038>] (snd_pcm_update_state [snd_pcm]) from [<7f10e2a8>] (snd_pcm_update_hw_ptr0+0x1b8/0x42c [snd_pcm])
[ 73.987671] [<7f10e2a8>] (snd_pcm_update_hw_ptr0 [snd_pcm]) from [<7f10e5cc>] (snd_pcm_period_elapsed+0xb0/0xd8 [snd_pcm])
[ 73.987712] [<7f10e5cc>] (snd_pcm_period_elapsed [snd_pcm]) from [<7f136404>] (dmaengine_pcm_dma_complete+0x54/0x58 [snd_pcm_dmaengine])
[ 73.987735] [<7f136404>] (dmaengine_pcm_dma_complete [snd_pcm_dmaengine]) from [<804588b0>] (vchan_complete+0x98/0x100)
[ 73.987755] [<804588b0>] (vchan_complete) from [<800362a0>] (tasklet_action+0x78/0x108)
[ 73.987771] [<800362a0>] (tasklet_action) from [<80036c88>] (__do_softirq+0x1d4/0x4dc)
[ 73.987785] [<80036c88>] (__do_softirq) from [<8003748c>] (irq_exit+0x120/0x168)
[ 73.987801] [<8003748c>] (irq_exit) from [<8009e9a8>] (__handle_domain_irq+0x94/0xe8)
[ 73.987818] [<8009e9a8>] (__handle_domain_irq) from [<80009374>] (asm_do_IRQ+0x2c/0x30)
[ 73.987836] [<80009374>] (asm_do_IRQ) from [<8073cb74>] (__irq_svc+0x34/0x14c)
[ 73.987845] Exception stack(0x80b3ff08 to 0x80b3ff50)
[ 73.987857] ff00: 00000001 00000000 00000000 00000000 80b3e000 80b5cdd8
[ 73.987870] ff20: 80b5cd78 80bc02d8 00000000 00000000 80741f2c 80b3ff64 80b5dce4 80b3ff58
[ 73.987880] ff40: 800178cc 800178d0 60000013 ffffffff
[ 73.987898] [<8073cb74>] (__irq_svc) from [<800178d0>] (arch_cpu_idle+0x34/0x4c)
[ 73.987916] [<800178d0>] (arch_cpu_idle) from [<80086e34>] (cpu_startup_entry+0x33c/0x424)
[ 73.987935] [<80086e34>] (cpu_startup_entry) from [<80736038>] (rest_init+0x98/0x9c)
[ 73.987954] [<80736038>] (rest_init) from [<80981d4c>] (start_kernel+0x3f4/0x400)