From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings
Date: Mon, 10 Oct 2016 15:23:22 -0500 [thread overview]
Message-ID: <20161010202322.labiotb5dsf4oyfi@treble> (raw)
In-Reply-To: <20161010125709.1870563-1-arnd@arndb.de>
On Mon, Oct 10, 2016 at 02:56:56PM +0200, Arnd Bergmann wrote:
> I have no idea what is actually going on here, but building an x86 kernel
> with CONFIG_MATOM results in countless warnings from objtool, such as
>
> arch/x86/events/intel/ds.o: warning: objtool: intel_pmu_pebs_del()+0x43: call without frame pointer save/setup
> security/keys/keyring.o: warning: objtool: keyring_read()+0x59: call without frame pointer save/setup
> kernel/signal.o: warning: objtool: __dequeue_signal()+0xd8: call without frame pointer save/setup
> kernel/signal.o: warning: objtool: kill_pid()+0x15: call without frame pointer save/setup
> kernel/signal.o: warning: objtool: SyS_signal()+0x27: call without frame pointer save/setup
> mm/page_alloc.o: warning: objtool: zone_watermark_ok_safe()+0x27: call without frame pointer save/setup
> fs/exec.o: warning: objtool: read_code()+0x18: call without frame pointer save/setup
> mm/swap.o: warning: objtool: get_kernel_page()+0x24: call without frame pointer save/setup
> mm/swap.o: warning: objtool: pagevec_move_tail.constprop.25()+0x26: call without frame pointer save/setup
> block/bio.o: warning: objtool: bio_map_kern()+0x47: call without frame pointer save/setup
> arch/x86/crypto/poly1305_glue.o: warning: objtool: poly1305_simd_mult()+0x2d: call without frame pointer save/setup
> crypto/skcipher.o: warning: objtool: skcipher_encrypt_ablkcipher()+0x58: call without frame pointer save/setup
> crypto/skcipher.o: warning: objtool: skcipher_decrypt_ablkcipher()+0x58: call without frame pointer save/setup
> fs/inode.o: warning: objtool: ilookup()+0x5d: call without frame pointer save/setup
> fs/inode.o: warning: objtool: proc_nr_inodes()+0x3e: call without frame pointer save/setup
> fs/namei.o: warning: objtool: lookup_one_len_unlocked()+0x21: call without frame pointer save/setup
> block/elevator.o: warning: objtool: elv_rb_add()+0x5b: call without frame pointer save/setup
> crypto/shash.o: warning: objtool: shash_async_init()+0x1e: call without frame pointer save/setup
> crypto/shash.o: warning: objtool: shash_async_import()+0x1e: call without frame pointer save/setup
> mm/vmscan.o: warning: objtool: pfmemalloc_watermark_ok()+0xb9: call without frame pointer save/setup
>
> I have not looked at whether this is a bug in gcc or in objtool, however
> I found that not using -mtune=atom reliably avoids the problem. I could
> reproduce the problem with gcc versions 4.7 through 6.1.
Thanks for reporting it. It looks like 'mtune=atom' sometimes makes a
slight change to one of the stack frame setup instructions. Instead of:
move rsp, rbp
It sometimes does:
lea (%rsp),%rbp
They're two different instructions, but they have the same result. It's
an easy fix for objtool. I'll post a patch soon.
--
Josh
next prev parent reply other threads:[~2016-10-10 20:30 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-10 12:56 [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Arnd Bergmann
2016-10-10 20:23 ` Josh Poimboeuf [this message]
2016-10-11 8:08 ` Arnd Bergmann
2016-10-11 12:20 ` Josh Poimboeuf
2016-10-11 13:30 ` Arnd Bergmann
2016-10-11 15:05 ` Josh Poimboeuf
2016-10-11 15:51 ` Josh Poimboeuf
2016-10-11 20:38 ` Arnd Bergmann
2016-10-12 13:01 ` Josh Poimboeuf
2016-10-13 12:46 ` Another gcc corruption bug (was Re: [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings) Josh Poimboeuf
2016-10-13 17:57 ` Denys Vlasenko
2016-10-13 20:15 ` Josh Poimboeuf
2017-03-01 9:34 ` [PATCH] [RFC] x86: avoid -mtune=atom for objtool warnings Arnd Bergmann
2017-03-01 9:45 ` Arnd Bergmann
2017-03-01 14:40 ` Josh Poimboeuf
2017-03-01 15:27 ` Arnd Bergmann
2017-03-01 16:53 ` Josh Poimboeuf
2017-03-01 22:05 ` Arnd Bergmann
2017-03-01 22:42 ` Arnd Bergmann
2017-03-02 1:03 ` Josh Poimboeuf
2017-03-02 6:31 ` Ingo Molnar
2017-03-02 12:49 ` Josh Poimboeuf
2017-03-02 13:46 ` Ingo Molnar
2017-03-02 14:08 ` Josh Poimboeuf
2017-03-02 14:46 ` Ingo Molnar
2017-03-02 22:49 ` Arnd Bergmann
2017-03-02 23:05 ` Josh Poimboeuf
2017-03-03 8:58 ` Arnd Bergmann
2017-03-03 11:27 ` Arnd Bergmann
2017-03-01 14:31 ` Josh Poimboeuf
2017-03-01 15:21 ` Arnd Bergmann
2017-03-02 18:25 ` Josh Poimboeuf
2017-03-02 22:43 ` Arnd Bergmann
2017-03-02 22:57 ` [PATCH] objtool: fix another gcc jump table detection issue Josh Poimboeuf
2017-03-02 23:01 ` Arnd Bergmann
2016-10-11 1:53 ` [PATCH] objtool: support '-mtune=atom' stack frame setup instruction Josh Poimboeuf
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