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From: Nick Desaulniers <ndesaulniers@google.com>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Sami Tolvanen <samitolvanen@google.com>, X86 ML <x86@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Sedat Dilek <sedat.dilek@gmail.com>,
	Kees Cook <keescook@chromium.org>,
	clang-built-linux <clang-built-linux@googlegroups.com>,
	Miroslav Benes <mbenes@suse.cz>
Subject: Re: [PATCH 00/21] objtool: vmlinux.o and CLANG LTO support
Date: Tue, 19 Jan 2021 13:29:16 -0800	[thread overview]
Message-ID: <CAKwvOd=tRwOvLdQXDRYo00P3vLAnwnb1SXtaHPVkXTnfjMst+g@mail.gmail.com> (raw)
In-Reply-To: <20210118172255.hirr6qpquxgq2vr6@treble>

On Mon, Jan 18, 2021 at 9:23 AM Josh Poimboeuf <jpoimboe@redhat.com> wrote:
>
> On Thu, Jan 14, 2021 at 04:41:28PM -0800, Sami Tolvanen wrote:
> > I can confirm that all the warnings I previously saw are now fixed,
> > but I'm seeing a few new ones:
> >
> > vmlinux.o: warning: objtool: balance_leaf_when_delete()+0x17d4: stack state mismatch: cfa1=7+192 cfa2=7+176
> > vmlinux.o: warning: objtool: internal_move_pointers_items()+0x9f7: stack state mismatch: cfa1=7+160 cfa2=7+176
>
> These seem legit stack state mismatches (compiler bug).  Two code
> blocks, with different stack sizes, transfer control to the same
> noreturn block (violating DWARF/ORC expectation that each instruction
> has a deterministic stack layout).  In both cases the noreturn block has
> a call to __reiserfs_panic().
>
> https://paste.centos.org/view/081cbfc1
> https://paste.centos.org/view/265968a6
>

Sorry, I think all of the pastes linked here expired before I had a
chance to grab them.

> > vmlinux.o: warning: objtool: strncpy_from_user()+0x181: call to do_strncpy_from_user() with UACCESS enabled
> > vmlinux.o: warning: objtool: strnlen_user()+0x12b: call to do_strnlen_user() with UACCESS enabled
>
> It's odd that Clang wouldn't inline these static single-called
> functions.  I could '__always_inline' them, but is this expected
> behavior?
>
> > vmlinux.o: warning: objtool: i915_gem_execbuffer2_ioctl()+0x390: call to __ubsan_handle_negate_overflow() with UACCESS enabled
>
> PeterZ, have you seen this one?
>
> https://paste.centos.org/view/b4723113
>
> > vmlinux.o: warning: objtool: .text.snd_trident_free_voice: unexpected end of section
>
> Another weird compiler issue.  It generates obviously dead code which
> jumps off the end of the function:
>
>   f7:   b0 01                   mov    $0x1,%al
>   f9:   84 c0                   test   %al,%al
>   fb:   0f 84 79 05 00 00       je     67a <snd_trident_free_voice+0x67a>
>
> https://paste.centos.org/view/a1887ae3
>
> --
> Josh
>


-- 
Thanks,
~Nick Desaulniers

  reply	other threads:[~2021-01-19 21:31 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-14 19:39 [PATCH 00/21] objtool: vmlinux.o and CLANG LTO support Josh Poimboeuf
2021-01-14 19:39 ` [PATCH 01/21] objtool: Fix seg fault in BT_FUNC() with fake jump Josh Poimboeuf
2021-01-14 20:04   ` Josh Poimboeuf
2021-01-14 19:39 ` [PATCH 02/21] objtool: Fix error handling for STD/CLD warnings Josh Poimboeuf
2021-01-14 19:39 ` [PATCH 03/21] objtool: Fix retpoline detection in asm code Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 04/21] objtool: Fix ".cold" section suffix check for newer versions of GCC Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 05/21] objtool: Support retpoline jump detection for vmlinux.o Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 06/21] x86/ftrace: Add UNWIND_HINT_FUNC annotation for ftrace_stub Josh Poimboeuf
2021-01-14 20:42   ` Steven Rostedt
2021-01-14 19:40 ` [PATCH 07/21] objtool: Assume only ELF functions do sibling calls Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 08/21] objtool: Add asm version of STACK_FRAME_NON_STANDARD Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 09/21] objtool: Combine UNWIND_HINT_RET_OFFSET and UNWIND_HINT_FUNC Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 10/21] objtool: Add xen_start_kernel() to noreturn list Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 11/21] objtool: Move unsuffixed symbol conversion to a helper function Josh Poimboeuf
2021-01-14 20:55   ` [PATCH v1.1 " Josh Poimboeuf
2021-01-14 21:30     ` Sedat Dilek
2021-01-14 19:40 ` [PATCH 12/21] objtool: Add CONFIG_CFI_CLANG support Josh Poimboeuf
2021-01-14 20:49   ` Sami Tolvanen
2021-01-14 20:52     ` Josh Poimboeuf
2021-01-14 20:56   ` [PATCH v1.1 " Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 13/21] x86/xen: Support objtool validation in xen-asm.S Josh Poimboeuf
2021-01-15  0:31   ` boris.ostrovsky
2021-01-14 19:40 ` [PATCH 14/21] x86/xen: Support objtool vmlinux.o validation in xen-head.S Josh Poimboeuf
2021-01-15  0:32   ` boris.ostrovsky
2021-01-15  5:17   ` Jürgen Groß
2021-01-15 19:46     ` Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 15/21] x86/xen/pvh: Convert indirect jump to retpoline Josh Poimboeuf
2021-01-15  0:33   ` boris.ostrovsky
2021-01-15  5:24   ` Jürgen Groß
2021-01-15 15:08     ` Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 16/21] x86/ftrace: Support objtool vmlinux.o validation in ftrace_64.S Josh Poimboeuf
2021-01-14 20:42   ` Steven Rostedt
2021-01-14 19:40 ` [PATCH 17/21] x86/acpi: Convert indirect jump to retpoline Josh Poimboeuf
2021-01-14 22:59   ` Andrew Cooper
2021-01-14 23:47     ` Josh Poimboeuf
2021-01-15  0:54       ` Andrew Cooper
2021-01-14 19:40 ` [PATCH 18/21] x86/acpi: Support objtool validation in wakeup_64.S Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 19/21] x86/power: Convert indirect jumps to retpolines Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 20/21] x86/power: Move restore_registers() to top of the file Josh Poimboeuf
2021-01-14 19:40 ` [PATCH 21/21] x86/power: Support objtool validation in hibernate_asm_64.S Josh Poimboeuf
2021-01-15  0:41 ` [PATCH 00/21] objtool: vmlinux.o and CLANG LTO support Sami Tolvanen
2021-01-15  0:49   ` Nick Desaulniers
2021-01-15 19:52   ` Josh Poimboeuf
2021-01-15 20:19     ` Sedat Dilek
2021-01-15 20:59       ` Josh Poimboeuf
2021-01-15 21:01         ` Sedat Dilek
2021-01-18 17:22   ` Josh Poimboeuf
2021-01-19 21:29     ` Nick Desaulniers [this message]
2021-01-20 15:37       ` Josh Poimboeuf
2021-01-15  4:51 ` Sedat Dilek
2021-01-15  5:18   ` Sedat Dilek
2021-01-15 15:30   ` Sedat Dilek
2021-01-15 18:54     ` Sedat Dilek
2021-01-15 19:28       ` Josh Poimboeuf

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