Jessica Yu <j...@redhat.com> writes: > +++ Michael Ellerman [10/05/17 16:57 +1000]: >>On powerpc we can build the kernel with two different ABIs for mcount(), which >>is used by ftrace. Kernels built with one ABI do not know how to load modules >>built with the other ABI. The new style ABI is called "mprofile-kernel", for >>want of a better name. >> >>Currently if we build a module using the old style ABI, and the kernel with >>mprofile-kernel, when we load the module we'll oops something like: >> >> # insmod autofs4-no-mprofile-kernel.ko >> ftrace-powerpc: Unexpected instruction f8810028 around bl _mcount >> ------------[ cut here ]------------ >> WARNING: CPU: 6 PID: 3759 at ../kernel/trace/ftrace.c:2024 >> ftrace_bug+0x2b8/0x3c0 >> CPU: 6 PID: 3759 Comm: insmod Not tainted >> 4.11.0-rc3-gcc-5.4.1-00017-g5a61ef74f269 #11 >> ... >> NIP [c0000000001eaa48] ftrace_bug+0x2b8/0x3c0 >> LR [c0000000001eaff8] ftrace_process_locs+0x4a8/0x590 >> Call Trace: >> alloc_pages_current+0xc4/0x1d0 (unreliable) >> ftrace_process_locs+0x4a8/0x590 >> load_module+0x1c8c/0x28f0 >> SyS_finit_module+0x110/0x140 >> system_call+0x38/0xfc >> ... >> ftrace failed to modify >> [<d000000002a31024>] 0xd000000002a31024 >> actual: 35:65:00:48 >> >>We can avoid this by including in the vermagic whether the kernel/module was >>built with mprofile-kernel. Which results in: >> >> # insmod autofs4-pg.ko >> autofs4: version magic >> '4.11.0-rc3-gcc-5.4.1-00017-g5a61ef74f269 SMP mod_unload modversions ' >> should be >> '4.11.0-rc3-gcc-5.4.1-00017-g5a61ef74f269-dirty SMP mod_unload modversions >> mprofile-kernel' >> insmod: ERROR: could not insert module autofs4-pg.ko: Invalid module format >> >>Signed-off-by: Michael Ellerman <m...@ellerman.id.au> > > Looks good to me: > > Acked-by: Jessica Yu <j...@redhat.com>
Thanks. cheers
