linux-kernel - Re: [PATCH 2/7] kexec_file: print out debugging message if required

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Message-ID: <ZVcikWw9lYN9SucO@MiWiFi-R3L-srv>
Date:   Fri, 17 Nov 2023 16:21:37 +0800
From:   Baoquan He <bhe@...hat.com>
To:     kernel test robot <lkp@...el.com>
Cc:     linux-kernel@...r.kernel.org, oe-kbuild-all@...ts.linux.dev,
        kexec@...ts.infradead.org, x86@...nel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-riscv@...ts.infradead.org, linuxppc-dev@...ts.ozlabs.org,
        linux-parisc@...r.kernel.org
Subject: Re: [PATCH 2/7] kexec_file: print out debugging message if required

On 11/16/23 at 05:57am, kernel test robot wrote:
> Hi Baoquan,
> 
> kernel test robot noticed the following build errors:
> 
> [auto build test ERROR on arm64/for-next/core]
> [also build test ERROR on tip/x86/core powerpc/next powerpc/fixes linus/master v6.7-rc1 next-20231115]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:    https://github.com/intel-lab-lkp/linux/commits/Baoquan-He/kexec_file-add-kexec_file-flag-to-control-debug-printing/20231114-234003
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/core
> patch link:    https://lore.kernel.org/r/20231114153253.241262-3-bhe%40redhat.com
> patch subject: [PATCH 2/7] kexec_file: print out debugging message if required
> config: x86_64-randconfig-002-20231115 (https://download.01.org/0day-ci/archive/20231116/202311160502.jnu7b8KF-lkp@intel.com/config)
> compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231116/202311160502.jnu7b8KF-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@...el.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202311160502.jnu7b8KF-lkp@intel.com/
> 
> All errors (new ones prefixed by >>):
> 
>    kernel/crash_core.c: In function 'crash_prepare_elf64_headers':
> >> kernel/crash_core.c:412:17: error: implicit declaration of function 'kexec_dprintk'; did you mean '_dev_printk'? [-Werror=implicit-function-declaration]
>      412 |                 kexec_dprintk("Crash PT_LOAD ELF header. phdr=%p vaddr=0x%llx, paddr=0x%llx, "
>          |                 ^~~~~~~~~~~~~
>          |                 _dev_printk
>    cc1: some warnings being treated as errors
> 
> 
> vim +412 kernel/crash_core.c

Thanks for reporting this.

Below code can fix it.

crash_prepare_elf64_headers() could be used by kexec_load interface for
cpu/memory hotplug updating elfcoreheader, or by kexec_file_load
interface for elfcoreheader composing or updating. Only print out the
debugging message about ELF core header when kexec_file_load interface
is taken.

diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 41001ffbaa99..1485fd7bb67f 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -551,10 +551,12 @@ int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
 		phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
 		phdr->p_align = 0;
 		ehdr->e_phnum++;
+#ifdef CONFIG_KEXEC_FILE
 		kexec_dprintk("Crash PT_LOAD ELF header. phdr=%p vaddr=0x%llx, paddr=0x%llx, "
 			"sz=0x%llx e_phnum=%d p_offset=0x%llx\n",
 			phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
 			ehdr->e_phnum, phdr->p_offset);
+#endif
 		phdr++;
 	}