Subject: Re: [PATCH 2/7] kexec_file: print out debugging message if required

From: kernel test robot <[email-masked]>
Date: Thu, 16 Nov 2023 05:57:47 +0800

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/[email-masked]/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/[email-masked]/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 <[email-masked]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email-masked]/

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

   323	
   324	int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
   325				  void **addr, unsigned long *sz)
   326	{
   327		Elf64_Ehdr *ehdr;
   328		Elf64_Phdr *phdr;
   329		unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
   330		unsigned char *buf;
   331		unsigned int cpu, i;
   332		unsigned long long notes_addr;
   333		unsigned long mstart, mend;
   334	
   335		/* extra phdr for vmcoreinfo ELF note */
   336		nr_phdr = nr_cpus + 1;
   337		nr_phdr += mem->nr_ranges;
   338	
   339		/*
   340		 * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
   341		 * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).
   342		 * I think this is required by tools like gdb. So same physical
   343		 * memory will be mapped in two ELF headers. One will contain kernel
   344		 * text virtual addresses and other will have __va(physical) addresses.
   345		 */
   346	
   347		nr_phdr++;
   348		elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
   349		elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
   350	
   351		buf = vzalloc(elf_sz);
   352		if (!buf)
   353			return -ENOMEM;
   354	
   355		ehdr = (Elf64_Ehdr *)buf;
   356		phdr = (Elf64_Phdr *)(ehdr + 1);
   357		memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
   358		ehdr->e_ident[EI_CLASS] = ELFCLASS64;
   359		ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
   360		ehdr->e_ident[EI_VERSION] = EV_CURRENT;
   361		ehdr->e_ident[EI_OSABI] = ELF_OSABI;
   362		memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
   363		ehdr->e_type = ET_CORE;
   364		ehdr->e_machine = ELF_ARCH;
   365		ehdr->e_version = EV_CURRENT;
   366		ehdr->e_phoff = sizeof(Elf64_Ehdr);
   367		ehdr->e_ehsize = sizeof(Elf64_Ehdr);
   368		ehdr->e_phentsize = sizeof(Elf64_Phdr);
   369	
   370		/* Prepare one phdr of type PT_NOTE for each possible CPU */
   371		for_each_possible_cpu(cpu) {
   372			phdr->p_type = PT_NOTE;
   373			notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
   374			phdr->p_offset = phdr->p_paddr = notes_addr;
   375			phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
   376			(ehdr->e_phnum)++;
   377			phdr++;
   378		}
   379	
   380		/* Prepare one PT_NOTE header for vmcoreinfo */
   381		phdr->p_type = PT_NOTE;
   382		phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
   383		phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
   384		(ehdr->e_phnum)++;
   385		phdr++;
   386	
   387		/* Prepare PT_LOAD type program header for kernel text region */
   388		if (need_kernel_map) {
   389			phdr->p_type = PT_LOAD;
   390			phdr->p_flags = PF_R|PF_W|PF_X;
   391			phdr->p_vaddr = (unsigned long) _text;
   392			phdr->p_filesz = phdr->p_memsz = _end - _text;
   393			phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
   394			ehdr->e_phnum++;
   395			phdr++;
   396		}
   397	
   398		/* Go through all the ranges in mem->ranges[] and prepare phdr */
   399		for (i = 0; i < mem->nr_ranges; i++) {
   400			mstart = mem->ranges[i].start;
   401			mend = mem->ranges[i].end;
   402	
   403			phdr->p_type = PT_LOAD;
   404			phdr->p_flags = PF_R|PF_W|PF_X;
   405			phdr->p_offset  = mstart;
   406	
   407			phdr->p_paddr = mstart;
   408			phdr->p_vaddr = (unsigned long) __va(mstart);
   409			phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
   410			phdr->p_align = 0;
   411			ehdr->e_phnum++;
 > 412			kexec_dprintk("Crash PT_LOAD ELF header. phdr=%p vaddr=0x%llx, paddr=0x%llx, "
   413				"sz=0x%llx e_phnum=%d p_offset=0x%llx\n",
   414				phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
   415				ehdr->e_phnum, phdr->p_offset);
   416			phdr++;
   417		}
   418	
   419		*addr = buf;
   420		*sz = elf_sz;
   421		return 0;
   422	}
   423	

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https://github.com/intel/lkp-tests/wiki