On Mon, Jul 06, 2020 at 09:09:55AM +0200, Sedat Dilek wrote: > [ Please CC me I am not subscribed to this mailing-list ] > > Hi Josh and Peter, > > today I switched over from Linux v5.7.y to Linux v5.8-rc4 and built > the first time with GCC version 10 on Debian/testing AMD64. > > $ cat /proc/version > Linux version 5.8.0-rc4-1-amd64-gcc10 ([email protected]@iniza) > (gcc-10 (Debian 10.1.0-4) 10.1.0, GNU ld (GNU Binutils for Debian) > 2.34) #1~bullseye+dileks1 SMP 2020-07-06 > > I see these objtool warnings (which are new to me): > > $ grep warning: build-log_5.8.0-rc4-1-amd64-gcc10.txt | sort > arch/x86/kernel/cpu/mce/core.o: warning: objtool: mce_panic()+0x118: > unreachable instruction > drivers/atm/horizon.o: warning: objtool: interrupt_handler()+0x19f: > unreachable instruction > drivers/message/fusion/mptbase.o: warning: objtool: > mpt_Soft_Hard_ResetHandler()+0x33a: unreachable instruction > drivers/scsi/aic7xxx/aic79xx_core.o: warning: objtool: > ahd_intr.part.0()+0x10f: unreachable instruction > drivers/scsi/pcmcia/aha152x_core.o: warning: objtool: run()+0x4c0: > unreachable instruction > fs/btrfs/backref.o: warning: objtool: > btrfs_backref_finish_upper_links()+0x309: unreachable instruction > fs/btrfs/extent_io.o: warning: objtool: __set_extent_bit.cold()+0xc: > unreachable instruction > fs/btrfs/relocation.o: warning: objtool: update_backref_cache.part.0()+0x1de: > unreachable instruction > kernel/exit.o: warning: objtool: __x64_sys_exit_group()+0x14: unreachable > instruction > net/core/skbuff.o: warning: objtool: skb_push.cold()+0x15: unreachable > instruction
That's more CONFIG_LIVEPATCH=y wreckage I expect. The problem is that GCC -flive-patching= thing wreck the propagation of the noreturn. This really is a compiler issue and we've not managed a sensible work-around in objtool.
