Re: [PATCH 5.4 00/51] 5.4.217-rc1 review

[Thadeu Lima de Souza Cascardo]

On Wed, Oct 05, 2022 at 02:12:46PM -0500, Daniel Díaz wrote:
> Hello!
> 
> On 05/10/22 06:31, Greg Kroah-Hartman wrote:
> > This is the start of the stable review cycle for the 5.4.217 release.
> > There are 51 patches in this series, all will be posted as a response
> > to this one.  If anyone has any issues with these being applied, please
> > let me know.
> > 
> > Responses should be made by Fri, 07 Oct 2022 11:31:56 +0000.
> > Anything received after that time might be too late.
> > 
> > The whole patch series can be found in one patch at:
> > 	https://www.kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.4.217-rc1.gz
> > or in the git tree and branch at:
> > 	git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.4.y
> > and the diffstat can be found below.
> > 
> > thanks,
> > 
> > greg k-h
> 
> We are seeing a new warning on x86_64:
> 
>   /builds/linux/arch/x86/entry/entry_64.S: Assembler messages:
>   /builds/linux/arch/x86/entry/entry_64.S:1756: Warning: no instruction mnemonic suffix given and no register operands; using default for `sysret'
>   arch/x86/entry/entry_64.o: warning: objtool: .entry.text+0x151: unsupported intra-function call
>   x86_64-linux-gnu-ld: arch/x86/boot/compressed/head_64.o: warning: relocation in read-only section `.head.text'
>   x86_64-linux-gnu-ld: warning: creating DT_TEXTREL in a PIE

You mean only the third line here with objtool complaining about unsupported
intra-function call, right? The other warnings were likely there before.

> 
> This started happening after 984b78c4ecea49b0b4b5729a502b689a623fde27 ("x86/speculation: Fix RSB filling with CONFIG_RETPOLINE=n").

This is, in fact, introduced by the previous commit, 65e5a1959296e16a3566ff75e527f211f0bf5a26 ("x86/speculation: Change FILL_RETURN_BUFFER to work with objtool").

You see it once 984b78c4ecea is applied because your configs do not have
CONFIG_RETPOLINE.

Notice that I note in 65e5a1959296 that intra-function validation is
missing in objtool in 5.4, which is why you are seeing this warning.

Cascardo.

> 
> The following configurations are affected:
> 
> * x86_64, build
>   - gcc-8-allnoconfig-warnings
>   - gcc-8-tinyconfig-warnings
>   - gcc-8-x86_64_defconfig-warnings
>   - gcc-9-allnoconfig-warnings
>   - gcc-9-tinyconfig-warnings
>   - gcc-9-x86_64_defconfig-warnings
>   - gcc-10-allnoconfig-warnings
>   - gcc-10-defconfig-warnings
>   - gcc-10-tinyconfig-warnings
>   - gcc-11-allnoconfig-warnings
>   - gcc-11-defconfig-warnings
>   - gcc-11-lkftconfig-debug-kmemleak-warnings
>   - gcc-11-lkftconfig-debug-warnings
>   - gcc-11-lkftconfig-kasan-warnings
>   - gcc-11-lkftconfig-kselftest-kernel-warnings
>   - gcc-11-lkftconfig-kselftest-warnings
>   - gcc-11-lkftconfig-kunit-warnings
>   - gcc-11-lkftconfig-libgpiod-warnings
>   - gcc-11-lkftconfig-perf-warnings
>   - gcc-11-lkftconfig-rcutorture-warnings
>   - gcc-11-lkftconfig-warnings
>   - gcc-11-tinyconfig-warnings
>   - gcc-12-allnoconfig-warnings
>   - gcc-12-defconfig-warnings
>   - gcc-12-tinyconfig-warnings
>   - clang-11-allnoconfig-warnings
>   - clang-11-tinyconfig-warnings
>   - clang-11-x86_64_defconfig-warnings
>   - clang-12-allnoconfig-warnings
>   - clang-12-lkftconfig-warnings
>   - clang-12-tinyconfig-warnings
>   - clang-12-x86_64_defconfig-warnings
>   - clang-13-allnoconfig-warnings
>   - clang-13-lkftconfig-warnings
>   - clang-13-tinyconfig-warnings
>   - clang-13-x86_64_defconfig-warnings
>   - clang-14-allnoconfig-warnings
>   - clang-14-lkftconfig-kcsan-warnings
>   - clang-14-lkftconfig-warnings
>   - clang-14-tinyconfig-warnings
>   - clang-14-x86_64_defconfig-warnings
>   - clang-nightly-lkftconfig-warnings
>   - clang-nightly-tinyconfig-warnings
>   - clang-nightly-x86_64_defconfig-warnings
> 
> 
> Greetings!
> 
> Daniel Díaz
> daniel.diaz@xxxxxxxxxx