On 2021/05/18 6:21, Romain Naour wrote: > Hello, > > Recently in Buildroot the option BR2_PIC_PIE has been enabled by default along > with other hardening features [1]. Since then some ppc defconfig such > qemu_ppc_e500mc_defconfig are failing to boot due to a segfault in init > program.
Note that I am seeing similar problems on RISC-V NOMMU builds with the latest buildroot/busybox 1.33. I had no time to explore the reason for it yet though. It sounds like it may be a similar problem as yours. > > The segfault appear very early in __uClibc_main while starting any binaries, > an issue located in crt1.S (powerpc)[2]. Same early segfault I am seeing on init shell startup (used as init process in my case). > > After some trial and error, removing HAVE_ASM_PPC_REL16 from CFLAGS [3] > allow to generate a working system again. But this is actually wrong since > instead we should consider HAVE_ASM_PPC_REL16 always true nowadays. > > Indeed, Glibc removed HAVE_ASM_PPC_REL16 since version 2.22 [4] since "the > minimum binutils supports rel16 relocs". Binutils 2.22 supports R_PPC_REL16 as > default. > > uClibc-ng should remove HAVE_ASM_PPC_REL16 but keep the code as it was > defined. > But this doesn't fix the initial issue. > > Any idea ? > > [1] > https://git.buildroot.net/buildroot/commit/?id=810ba387bec3c5b6904e8893fb4cb6f9d3717466 > [2] > https://cgit.uclibc-ng.org/cgi/cgit/uclibc-ng.git/tree/libc/sysdeps/linux/powerpc/crt1.S?id=2bf4991c4dd7b50b74656011dea9c40464ff390c#n47 > [3] > https://cgit.uclibc-ng.org/cgi/cgit/uclibc-ng.git/tree/Rules.mak?id=2bf4991c4dd7b50b74656011dea9c40464ff390c#n486 > [4] > https://sourceware.org/git/?p=glibc.git;a=commit;h=59261ad3eb345e0d7b9f5c73e1a09d046991cea5 > > Best regards, > Romain > _______________________________________________ > devel mailing list > devel@uclibc-ng.org > https://mailman.uclibc-ng.org/cgi-bin/mailman/listinfo/devel > -- Damien Le Moal Western Digital Research _______________________________________________ devel mailing list devel@uclibc-ng.org https://mailman.uclibc-ng.org/cgi-bin/mailman/listinfo/devel
