* [linux-stable-rc:linux-5.10.y 6996/7120] arch/x86/kernel/ftrace_64.o: warning: objtool: ftrace_epilogue()+0x10: unreachable instruction
@ 2022-07-12 19:57 kernel test robot
2022-07-13 23:41 ` Ben Hutchings
0 siblings, 1 reply; 4+ messages in thread
From: kernel test robot @ 2022-07-12 19:57 UTC (permalink / raw)
To: Josh Poimboeuf
Cc: kbuild-all, linux-kernel, Greg Kroah-Hartman, Ben Hutchings
tree: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.10.y
head: ba398a0e54049bb6a1c102245ae84103f103ff2c
commit: 8ca9dceaa17983afec1cc8e1a6e76d6bd142447a [6996/7120] objtool: Assume only ELF functions do sibling calls
config: x86_64-rhel-8.3-syz (https://download.01.org/0day-ci/archive/20220713/202207130344.dwXyDmTk-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.3.0-3) 11.3.0
reproduce (this is a W=1 build):
# https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git/commit/?id=8ca9dceaa17983afec1cc8e1a6e76d6bd142447a
git remote add linux-stable-rc https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
git fetch --no-tags linux-stable-rc linux-5.10.y
git checkout 8ca9dceaa17983afec1cc8e1a6e76d6bd142447a
# save the config file
mkdir build_dir && cp config build_dir/.config
make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash arch/x86/
If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>
All warnings (new ones prefixed by >>):
>> arch/x86/kernel/ftrace_64.o: warning: objtool: ftrace_epilogue()+0x10: unreachable instruction
objdump-func vmlinux.o ftrace_epilogue:
0000 000000000008ca70 <ftrace_epilogue>:
0000 8ca70: e9 00 00 00 00 jmp 8ca75 <ftrace_epilogue+0x5> 8ca71: R_X86_64_PLT32 ftrace_stub-0x4
0005 8ca75: 66 66 2e 0f 1f 84 00 00 00 00 00 data16 cs nopw 0x0(%rax,%rax,1)
--
0-DAY CI Kernel Test Service
https://01.org/lkp
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [linux-stable-rc:linux-5.10.y 6996/7120] arch/x86/kernel/ftrace_64.o: warning: objtool: ftrace_epilogue()+0x10: unreachable instruction
2022-07-12 19:57 [linux-stable-rc:linux-5.10.y 6996/7120] arch/x86/kernel/ftrace_64.o: warning: objtool: ftrace_epilogue()+0x10: unreachable instruction kernel test robot
@ 2022-07-13 23:41 ` Ben Hutchings
2022-07-14 0:18 ` Josh Poimboeuf
0 siblings, 1 reply; 4+ messages in thread
From: Ben Hutchings @ 2022-07-13 23:41 UTC (permalink / raw)
To: kernel test robot, Josh Poimboeuf, Steven Rostedt (VMware)
Cc: kbuild-all, linux-kernel, Greg Kroah-Hartman
[-- Attachment #1: Type: text/plain, Size: 1945 bytes --]
On Wed, 2022-07-13 at 03:57 +0800, kernel test robot wrote:
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.10.y
> head: ba398a0e54049bb6a1c102245ae84103f103ff2c
> commit: 8ca9dceaa17983afec1cc8e1a6e76d6bd142447a [6996/7120] objtool: Assume only ELF functions do sibling calls
> config: x86_64-rhel-8.3-syz (https://download.01.org/0day-ci/archive/20220713/202207130344.dwXyDmTk-lkp@intel.com/config)
> compiler: gcc-11 (Debian 11.3.0-3) 11.3.0
> reproduce (this is a W=1 build):
> # https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git/commit/?id=8ca9dceaa17983afec1cc8e1a6e76d6bd142447a
> git remote add linux-stable-rc https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
> git fetch --no-tags linux-stable-rc linux-5.10.y
> git checkout 8ca9dceaa17983afec1cc8e1a6e76d6bd142447a
> # save the config file
> mkdir build_dir && cp config build_dir/.config
> make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash arch/x86/
>
> If you fix the issue, kindly add following tag where applicable
> Reported-by: kernel test robot <lkp@intel.com>
>
> All warnings (new ones prefixed by >>):
>
> > > arch/x86/kernel/ftrace_64.o: warning: objtool: ftrace_epilogue()+0x10: unreachable instruction
>
>
> objdump-func vmlinux.o ftrace_epilogue:
> 0000 000000000008ca70 <ftrace_epilogue>:
> 0000 8ca70: e9 00 00 00 00 jmp 8ca75 <ftrace_epilogue+0x5> 8ca71: R_X86_64_PLT32 ftrace_stub-0x4
> 0005 8ca75: 66 66 2e 0f 1f 84 00 00 00 00 00 data16 cs nopw 0x0(%rax,%rax,1)
>
I don't know what's going on here. There's a jump to a ret (now
potentialy a rethunk), and nothing obviously unreachable.
ftrace_epilogue got simplified by commit 0c0593b45c9b "x86/ftrace: Make
function graph use ftrace directly" which maybe avoids the warning in
the mainline.
Ben.
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [linux-stable-rc:linux-5.10.y 6996/7120] arch/x86/kernel/ftrace_64.o: warning: objtool: ftrace_epilogue()+0x10: unreachable instruction
2022-07-13 23:41 ` Ben Hutchings
@ 2022-07-14 0:18 ` Josh Poimboeuf
2022-07-14 9:17 ` Greg Kroah-Hartman
0 siblings, 1 reply; 4+ messages in thread
From: Josh Poimboeuf @ 2022-07-14 0:18 UTC (permalink / raw)
To: Ben Hutchings
Cc: kernel test robot, Josh Poimboeuf, Steven Rostedt (VMware),
kbuild-all, linux-kernel, Greg Kroah-Hartman
On Thu, Jul 14, 2022 at 01:41:58AM +0200, Ben Hutchings wrote:
> On Wed, 2022-07-13 at 03:57 +0800, kernel test robot wrote:
> > tree: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.10.y
> > head: ba398a0e54049bb6a1c102245ae84103f103ff2c
> > commit: 8ca9dceaa17983afec1cc8e1a6e76d6bd142447a [6996/7120] objtool: Assume only ELF functions do sibling calls
> > config: x86_64-rhel-8.3-syz (https://download.01.org/0day-ci/archive/20220713/202207130344.dwXyDmTk-lkp@intel.com/config)
> > compiler: gcc-11 (Debian 11.3.0-3) 11.3.0
> > reproduce (this is a W=1 build):
> > # https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git/commit/?id=8ca9dceaa17983afec1cc8e1a6e76d6bd142447a
> > git remote add linux-stable-rc https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
> > git fetch --no-tags linux-stable-rc linux-5.10.y
> > git checkout 8ca9dceaa17983afec1cc8e1a6e76d6bd142447a
> > # save the config file
> > mkdir build_dir && cp config build_dir/.config
> > make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash arch/x86/
> >
> > If you fix the issue, kindly add following tag where applicable
> > Reported-by: kernel test robot <lkp@intel.com>
> >
> > All warnings (new ones prefixed by >>):
> >
> > > > arch/x86/kernel/ftrace_64.o: warning: objtool: ftrace_epilogue()+0x10: unreachable instruction
> >
> >
> > objdump-func vmlinux.o ftrace_epilogue:
> > 0000 000000000008ca70 <ftrace_epilogue>:
> > 0000 8ca70: e9 00 00 00 00 jmp 8ca75 <ftrace_epilogue+0x5> 8ca71: R_X86_64_PLT32 ftrace_stub-0x4
> > 0005 8ca75: 66 66 2e 0f 1f 84 00 00 00 00 00 data16 cs nopw 0x0(%rax,%rax,1)
> >
>
> I don't know what's going on here. There's a jump to a ret (now
> potentialy a rethunk), and nothing obviously unreachable.
> ftrace_epilogue got simplified by commit 0c0593b45c9b "x86/ftrace: Make
> function graph use ftrace directly" which maybe avoids the warning in
> the mainline.
The unreachable warning is actually pointing to ftrace_stub(). I think
you need
18660698a3d3 ("x86/ftrace: Add UNWIND_HINT_FUNC annotation for ftrace_stub")
--
Josh
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [linux-stable-rc:linux-5.10.y 6996/7120] arch/x86/kernel/ftrace_64.o: warning: objtool: ftrace_epilogue()+0x10: unreachable instruction
2022-07-14 0:18 ` Josh Poimboeuf
@ 2022-07-14 9:17 ` Greg Kroah-Hartman
0 siblings, 0 replies; 4+ messages in thread
From: Greg Kroah-Hartman @ 2022-07-14 9:17 UTC (permalink / raw)
To: Josh Poimboeuf
Cc: Ben Hutchings, kernel test robot, Josh Poimboeuf,
Steven Rostedt (VMware), kbuild-all, linux-kernel
On Wed, Jul 13, 2022 at 05:18:42PM -0700, Josh Poimboeuf wrote:
> On Thu, Jul 14, 2022 at 01:41:58AM +0200, Ben Hutchings wrote:
> > On Wed, 2022-07-13 at 03:57 +0800, kernel test robot wrote:
> > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.10.y
> > > head: ba398a0e54049bb6a1c102245ae84103f103ff2c
> > > commit: 8ca9dceaa17983afec1cc8e1a6e76d6bd142447a [6996/7120] objtool: Assume only ELF functions do sibling calls
> > > config: x86_64-rhel-8.3-syz (https://download.01.org/0day-ci/archive/20220713/202207130344.dwXyDmTk-lkp@intel.com/config)
> > > compiler: gcc-11 (Debian 11.3.0-3) 11.3.0
> > > reproduce (this is a W=1 build):
> > > # https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git/commit/?id=8ca9dceaa17983afec1cc8e1a6e76d6bd142447a
> > > git remote add linux-stable-rc https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
> > > git fetch --no-tags linux-stable-rc linux-5.10.y
> > > git checkout 8ca9dceaa17983afec1cc8e1a6e76d6bd142447a
> > > # save the config file
> > > mkdir build_dir && cp config build_dir/.config
> > > make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash arch/x86/
> > >
> > > If you fix the issue, kindly add following tag where applicable
> > > Reported-by: kernel test robot <lkp@intel.com>
> > >
> > > All warnings (new ones prefixed by >>):
> > >
> > > > > arch/x86/kernel/ftrace_64.o: warning: objtool: ftrace_epilogue()+0x10: unreachable instruction
> > >
> > >
> > > objdump-func vmlinux.o ftrace_epilogue:
> > > 0000 000000000008ca70 <ftrace_epilogue>:
> > > 0000 8ca70: e9 00 00 00 00 jmp 8ca75 <ftrace_epilogue+0x5> 8ca71: R_X86_64_PLT32 ftrace_stub-0x4
> > > 0005 8ca75: 66 66 2e 0f 1f 84 00 00 00 00 00 data16 cs nopw 0x0(%rax,%rax,1)
> > >
> >
> > I don't know what's going on here. There's a jump to a ret (now
> > potentialy a rethunk), and nothing obviously unreachable.
> > ftrace_epilogue got simplified by commit 0c0593b45c9b "x86/ftrace: Make
> > function graph use ftrace directly" which maybe avoids the warning in
> > the mainline.
>
> The unreachable warning is actually pointing to ftrace_stub(). I think
> you need
>
> 18660698a3d3 ("x86/ftrace: Add UNWIND_HINT_FUNC annotation for ftrace_stub")
Thanks for the hint, now queued up!
greg k-h
^ permalink raw reply [flat|nested] 4+ messages in thread
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2022-07-12 19:57 [linux-stable-rc:linux-5.10.y 6996/7120] arch/x86/kernel/ftrace_64.o: warning: objtool: ftrace_epilogue()+0x10: unreachable instruction kernel test robot
2022-07-13 23:41 ` Ben Hutchings
2022-07-14 0:18 ` Josh Poimboeuf
2022-07-14 9:17 ` Greg Kroah-Hartman
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