Hi, Kernel 4.1.3 : there is some troubling kernel message that shows up after enabling CONFIG_DEBUG_ATOMIC_SLEEP and testing DMA XOR acceleration for raid5: BUG: sleeping function called from invalid context at mm/mempool.c:320 in_atomic(): 1, irqs_disabled(): 0, pid: 1048, name: md127_raid5 INFO: lockdep is turned off. CPU: 1 PID: 1048 Comm: md127_raid5 Not tainted 4.1.15.alpine.1-dirty #1 Hardware name: Annapurna Labs Alpine [<c00169d8>] (unwind_backtrace) from [<c0012a78>] (show_stack+0x10/0x14) [<c0012a78>] (show_stack) from [<c07462ec>] (dump_stack+0x80/0xb4) [<c07462ec>] (dump_stack) from [<c00bf2f0>] (mempool_alloc+0x68/0x13c) [<c00bf2f0>] (mempool_alloc) from [<c041c9b4>] (dmaengine_get_unmap_data+0x24/0x4c) [<c041c9b4>] (dmaengine_get_unmap_data) from [<c03a8084>] (async_xor_val+0x60/0x3a0) [<c03a8084>] (async_xor_val) from [<c058e4c0>] (raid_run_ops+0xb70/0x1248) [<c058e4c0>] (raid_run_ops) from [<c05915d4>] (handle_stripe+0x1068/0x22a8) [<c05915d4>] (handle_stripe) from [<c0592ae4>] (handle_active_stripes+0x2d0/0x3dc) [<c0592ae4>] (handle_active_stripes) from [<c059300c>] (raid5d+0x384/0x5b0) [<c059300c>] (raid5d) from [<c059db6c>] (md_thread+0x114/0x138) [<c059db6c>] (md_thread) from [<c0042d54>] (kthread+0xe4/0x104) [<c0042d54>] (kthread) from [<c000f658>] (ret_from_fork+0x14/0x3c) The reason is that async_xor_val() in crypto/async_tx/async_xor.c is called in atomic context (preemption disabled) by raid_run_ops(). Then it calls dmaengine_get_unmap_data() an then mempool_alloc() with GFP_NOIO flag - this allocation type might sleep under some condition. Checked latest kernel 4.3 and it has exactly same flow. Any advice regarding this issue? Thanks, Slava Samsonov -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
