On Friday, November 1, 2019 10:15 PM, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote: > On Fri, 1 Nov 2019 15:08:03 -0600 > dann frazier dann.frazier@xxxxxxxxxxxxx wrote: > > > hey, > > fyi, I'm seeing a bunch of errors from tracefs when booting 5.4-rc5 in > > lockdown=confidentiality mode: > > [ 1.763630] Lockdown: swapper/0: use of tracefs is restricted; see man kernel_lockdown.7 > > [ 1.772332] Could not create tracefs 'available_events' entry > > [ 1.778633] Lockdown: swapper/0: use of tracefs is restricted; see man kernel_lockdown.7 > > [ 1.787095] Could not create tracefs 'set_event' entry > > [ 1.792412] Lockdown: swapper/0: use of tracefs is restricted; see man kernel_lockdown.7 > > (...) > > [ 2.899481] Could not create tracefs 'set_graph_notrace' entry > > [ 2.905671] Lockdown: swapper/0: use of tracefs is restricted; see man kernel_lockdown.7 > > [ 2.913934] ------------[ cut here ]------------ > > [ 2.918435] Could not register function stat for cpu 0 > > [ 2.923717] WARNING: CPU: 1 PID: 1 at kernel/trace/ftrace.c:987 ftrace_init_tracefs_toplevel+0x168/0x1bc > > [ 2.933939] Modules linked in: > > [ 2.937290] CPU: 1 PID: 1 Comm: > > Looks to me that it's working as designed ;-) > > I'm guessing we could quiet these warnings for boot up though. :-/ > > But there should be at least one message that states that the tracefs > files are not being created due to lockdown. > > -- Steve Could you clarify what functionality is lost here and if it affects system stability? I agree that triggering WARNING on every boot with supported kernel configuration isn't optimal experience for users. Jordan
