* Linus Torvalds <torva...@linux-foundation.org> wrote: > On Sat, Apr 28, 2018 at 2:18 AM Ingo Molnar <mi...@kernel.org> wrote: > > > I just tried the MPX testcases with the latest kernel: > > > deimos:~/tip/tools/testing/selftests/x86> ./mpx-mini-test_64 > > They need to be run as root. They try to access > > /sys/kernel/debug/tracing/set_ftrace_pid > /sys/kernel/debug/tracing/trace > > and that's root-only.
Indeed - but note that they are crashing as root as well here: root@deimos:/home/mingo/tip/tools/testing/selftests/x86# ./mpx-mini-test_64 [...] Aborted (core dumped) ... because I don't even have /sys/kernel/debug/tracing/set_ftrace_pid... :-/ That's despite having ftrace enabled. After some digging I found out that 'set_ftrace_pid' is dependent on CONFIG_FUNCTION_TRACING=y (not just CONFIG_TRACING=y), which I didn't have enabled on this kernel. After enabling it I got the 64-bit testcase to work: # ... ./mpx-mini-test_64 completed successfully But the 32-bit testcase is erroring out: root@deimos:/home/mingo/tip/tools/testing/selftests/x86# ./mpx-mini-test_32 XSAVE is supported by HW & OS XSAVE processor supported state mask: 0x21f XSAVE OS supported state mask: 0x21f BNDREGS: size: 64 user: 1 supervisor: 0 aligned: 0 BNDCSR: size: 64 user: 1 supervisor: 0 aligned: 0 executing unmaptest mpx dig ( 1) complete, SUCCESS ( 0 / 0) #BR status == 2, missing bounds table,kernel should have handled!! v4.17-rc2 based kernel, so it should have the latest MPX code. Thanks, Ingo