On 08/15/2016 05:54 PM, Jonathan Cameron wrote: > On 09/08/16 01:19, Brian Norris wrote: >> When using CONFIG_DEBUG_ATOMIC_SLEEP, the scheduler nicely points out >> that we're calling sleeping primitives within the wait_event loop, which >> means we might clobber the task state: >> >> [ 10.831289] do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffc00026b610>] >> [ 10.845531] ------------[ cut here ]------------ >> [ 10.850161] WARNING: at kernel/sched/core.c:7630 >> ... >> [ 12.164333] ---[ end trace 45409966a9a76438 ]--- >> [ 12.168942] Call trace: >> [ 12.171391] [<ffffffc00024ed44>] __might_sleep+0x64/0x90 >> [ 12.176699] [<ffffffc000954774>] mutex_lock_nested+0x50/0x3fc >> [ 12.182440] [<ffffffc0007b9424>] iio_kfifo_buf_data_available+0x28/0x4c >> [ 12.189043] [<ffffffc0007b76ac>] iio_buffer_ready+0x60/0xe0 >> [ 12.194608] [<ffffffc0007b7834>] iio_buffer_read_first_n_outer+0x108/0x1a8 >> [ 12.201474] [<ffffffc000370d48>] __vfs_read+0x58/0x114 >> [ 12.206606] [<ffffffc000371740>] vfs_read+0x94/0x118 >> [ 12.211564] [<ffffffc0003720f8>] SyS_read+0x64/0xb4 >> [ 12.216436] [<ffffffc000203cb4>] el0_svc_naked+0x24/0x28 >> >> To avoid this, we should (a la https://lwn.net/Articles/628628/) use the >> wait_woken() function, which avoids the nested sleeping while still >> handling races between waiting / wake-events. >> >> Signed-off-by: Brian Norris <briannorris@xxxxxxxxxxxx> > Looks good to me, but given Lars' involvement in the discussion I'd > like his review before applying this. Looks good. Thanks Brian for fixing this. Reviewed-by: Lars-Peter Clausen <lars@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
