Messages in this thread |  | | Date | Tue, 2 Nov 2021 09:00:36 +0100 | From | Peter Zijlstra <> | Subject | Re: [GIT pull] objtool/core for v5.16-rc1 |
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On Mon, Nov 01, 2021 at 01:44:39PM -0700, Linus Torvalds wrote: > On Sun, Oct 31, 2021 at 6:16 PM Thomas Gleixner <tglx@linutronix.de> wrote: > > > > please pull the latest objtool/core branch from: > > Hmm. I've pulled this, but I'm not happy about the new warnings it > generates with an allmodconfig build:
Right, due to fixing the dependency on !PARAVIRT, allyesconfig now does a noinstr validation, and this is the result.
> vmlinux.o: warning: objtool: __do_fast_syscall_32()+0xa: call to > stackleak_track_stack() leaves .noinstr.text section > .. > mce_setup()+0x18: call to memset ...
Boris was having a poke at the MCE stuff.
> rcu_dynticks_eqs_enter()+0x0: call to rcu_dynticks_task_trace_enter ... > rcu_dynticks_eqs_exit()+0xe: call to rcu_dynticks_task_trace_exit ... > rcu_nmi_enter()+0x36: call to __kasan_check_read ...
Fixes for those ^ should be in the rcu tree.
There were also a bunch of Xen ones that should be fixed in the Xen tree, perhaps you've already pulled that.
> do_machine_check()+0x27: call to stackleak_track_stack ... > do_syscall_64()+0x9: call to stackleak_track_stack ... > do_int80_syscall_32()+0x9: call to stackleak_track_stack ... > exc_general_protection()+0x22: call to stackleak_track_stack ... > fixup_bad_iret()+0x20: call to stackleak_track_stack ... > .entry.text+0x10e6: call to stackleak_erase ... > .entry.text+0x143: call to stackleak_erase ... > .entry.text+0x17d9: call to stackleak_erase ... > > most seem to be about the stackleak thing,
Right, I recently ran into this and hacen't yet had time to look into it. I suspect my normal build box doesn't have the GCC plugin crud enabled or somesuch.
I think the GCC stackleak plugin needs fixing, specifically it needs a function attribute such that it will not emit instrumentation in noinstr functions. I'll go chase down the developer of that thing.
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