On Mon, Oct 30, 2017 at 04:10:09PM +0100, Peter Zijlstra wrote: > I can indeed confirm it's running old code; cpuhp_state is no more. > > However, that splat translates like: > > __cpuhp_setup_state() > #0 cpus_read_lock() > __cpuhp_setup_state_cpuslocked() > #1 mutex_lock(&cpuhp_state_mutex) > > > > __cpuhp_state_add_instance() > #2 mutex_lock(&cpuhp_state_mutex) > cpuhp_issue_call() > cpuhp_invoke_ap_callback() > #3 wait_for_completion() > > msr_device_create() > ... > #4 filename_create() > #3 complete() > So all this you can get in a single callchain when you do something shiny like: modprobe msr > do_splice() > #4 file_start_write() > do_splice_from() > iter_file_splice_write() > #5 pipe_lock() > vfs_iter_write() > ... > #6 inode_lock() > > This is a splice into a devtmpfs file > sys_fcntl() > do_fcntl() > shmem_fcntl() > #5 inode_lock() #6 (obviously) > shmem_wait_for_pins() > if (!scan) > lru_add_drain_all() > #0 cpus_read_lock() > Is the right fcntl() So 3 different callchains, and *splat*.. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
