From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Peter Zijlstra <peterz@infradead.org>,
the arch/x86 maintainers <x86@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Kees Cook <keescook@chromium.org>
Subject: Re: Remaining randconfig objtool warnings, linux-next-20200428
Date: Tue, 28 Apr 2020 11:10:44 -0500 [thread overview]
Message-ID: <20200428161044.caamvx67t2z4t6vd@treble> (raw)
In-Reply-To: <CAK8P3a2qLJkokMGt48JRky=WUeAbJRuNmoD1oqfWdrGSC6y1LA@mail.gmail.com>
On Tue, Apr 28, 2020 at 04:49:15PM +0200, Arnd Bergmann wrote:
> I noticed the number of objtool warnings in randconfig kernels have gone down
> recently, maybe it's possible to eliminate the remaining ones?
>
> Here are the ones I ran into recently, using gcc-9.3:
>
> ==> build/x86/0x3D2B5D6D_defconfig/log <==
> arch/x86/kvm/vmx/vmx.o: warning: objtool: vmx_handle_exit_irqoff()+0x24: unreachable instruction
This is a legit warning caused by CONFIG_UBSAN_TRAP +
CONFIG_UBSAN_ALIGNMENT, I think Kees is going to do a fix.
> ==> build/x86/0xFD7B7323_defconfig/log <==
> arch/x86/entry/entry_64.o: warning: objtool: .entry.text+0x991: unreachable instruction
This warning looks correct, did you make a change to entry_64.S?
> ==> build/x86/0x7942F24A_defconfig/log <==
> samples/ftrace/ftrace-direct.o: warning: objtool: .text+0x0: unreachable instruction
> samples/ftrace/ftrace-direct-too.o: warning: objtool: .text+0x0: unreachable instruction
> samples/ftrace/ftrace-direct-modify.o: warning: objtool: .text+0x0: unreachable instruction
I posted a fix for these a few days ago:
https://lkml.kernel.org/r/86c1cbca67cb353da9f335643ef5fd19bd82988f.1587761369.git.jpoimboe@redhat.com
> ==> build/x86/0xE0F2ACFF_defconfig/log <==
> kernel/time/posix-stubs.o: warning: objtool: __x64_sys_timer_create()+0x23: sibling call from callable instruction with modified stack frame
>
> ==> build/x86/0x2EA4CE4F_defconfig/log <==
> kernel/kcov.o: warning: objtool: write_comp_data()+0x1b: call to check_kcov_mode() with UACCESS enabled
> kernel/kcov.o: warning: objtool: __sanitizer_cov_trace_pc()+0x15: call to check_kcov_mode() with UACCESS enabled
>
> ==> build/x86/0x500B1B82_defconfig/log <==
> kernel/bpf/core.o: warning: objtool: ___bpf_prog_run()+0x1269: call
> without frame pointer save/setup
I'll look into these.
--
Josh
next prev parent reply other threads:[~2020-04-28 16:10 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-28 14:49 Arnd Bergmann
2020-04-28 16:10 ` Josh Poimboeuf [this message]
2020-04-28 19:11 ` Kees Cook
2020-04-28 20:19 ` Arnd Bergmann
2020-04-28 20:38 ` Josh Poimboeuf
2020-04-28 21:55 ` Peter Zijlstra
2020-04-28 22:03 ` Josh Poimboeuf
2020-04-28 22:33 ` Peter Zijlstra
2020-04-28 22:48 ` Josh Poimboeuf
2020-04-28 23:08 ` Josh Poimboeuf
2020-04-29 18:55 ` Josh Poimboeuf
2020-04-29 22:46 ` Arnd Bergmann
2020-04-29 23:01 ` Josh Poimboeuf
2020-04-29 23:11 ` Josh Poimboeuf
2020-04-29 23:28 ` Josh Poimboeuf
2020-04-30 13:41 ` Arnd Bergmann
2020-04-30 14:33 ` Josh Poimboeuf
2020-04-30 19:46 ` Josh Poimboeuf
2020-04-30 20:59 ` Arnd Bergmann
2020-04-30 21:10 ` Josh Poimboeuf
2020-04-30 21:08 ` Josh Poimboeuf
2020-04-30 23:02 ` Josh Poimboeuf
2020-04-29 19:18 ` Josh Poimboeuf
2020-05-01 12:23 ` Peter Zijlstra
2020-04-30 14:05 ` Arnd Bergmann
2020-05-01 0:28 ` Josh Poimboeuf
2020-05-01 11:41 ` Arnd Bergmann
2020-05-01 17:16 ` Peter Zijlstra
2020-05-01 12:27 ` Peter Zijlstra
2020-05-01 1:07 ` Josh Poimboeuf
2020-05-01 11:18 ` Arnd Bergmann
2020-05-01 12:33 ` Peter Zijlstra
2020-05-01 13:08 ` Arnd Bergmann
2020-05-01 15:49 ` Josh Poimboeuf
2020-05-01 17:21 ` Arnd Bergmann
2020-05-01 17:26 ` Peter Zijlstra
2020-05-01 17:50 ` Josh Poimboeuf
2020-05-01 19:47 ` Arnd Bergmann
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