Messages in this thread Patch in this message | | | Date | Fri, 12 May 2017 00:20:14 -0700 | From | Jessica Yu <> | Subject | Re: [PATCH] powerpc/modules: If mprofile-kernel is enabled add it to vermagic |
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+++ 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 <mpe@ellerman.id.au>
Looks good to me:
Acked-by: Jessica Yu <jeyu@redhat.com>
>--- > arch/powerpc/include/asm/module.h | 4 ++++ > 1 file changed, 4 insertions(+) > >diff --git a/arch/powerpc/include/asm/module.h b/arch/powerpc/include/asm/module.h >index 53885512b8d3..6c0132c7212f 100644 >--- a/arch/powerpc/include/asm/module.h >+++ b/arch/powerpc/include/asm/module.h >@@ -14,6 +14,10 @@ > #include <asm-generic/module.h> > > >+#ifdef CC_USING_MPROFILE_KERNEL >+#define MODULE_ARCH_VERMAGIC "mprofile-kernel" >+#endif >+ > #ifndef __powerpc64__ > /* > * Thanks to Paul M for explaining this. >-- >2.7.4 >
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