On Wed, 2013-07-24 at 22:46 -0700, Steve Hodgson wrote: > No, nothing so complicated. > > I added symbols from a kernel module into > /sys/kernel/debug/tracing/set_ftrace_filter, enabled tracing, then > unloaded the kernel module. > > Which I'll admit is a stupid thing to do. I was then punished for my > stupidity by being unable to use ftrace until the next reboot.
It's not stupid. ftrace should be robust enough to handle this. Anyway, thank you, I found a reproducer. Removing the module isn't good enough. You need to load it again. # cd /sys/kernel/debug/tracing # cat set_ftrace_filter #### all functions enabled #### # modprobe uinput # echo uniput_release > set_ftrace_filter # cat set_ftrace_filter uinput_release [uinput] # rmmod uinput # cat set_ftrace_filter # # note this is empty # modprobe uinput # cat set_ftrace_filter uinput_release [uinput] # # '<it magically appeared>' # echo > set_ftrace_filter [BOOM] Now that I know what's the problem, it shouldn't be too hard to fix. Thanks! -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
