Subject: Re: [PATCH v2 4/7] kexec_file, arm64: print out debugging message if required

From: Baoquan He <[email-masked]>
Date: Sun, 26 Nov 2023 19:55:40 +0800

On 11/26/23 at 05:26am, 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-rc2 next-20231124]
> [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/20231124-113942
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/core
> patch link:    https://lore.kernel.org/r/20231124033642.520686-5-bhe%40redhat.com
> patch subject: [PATCH v2 4/7] kexec_file, arm64: print out debugging message if required
> config: arm64-randconfig-001-20231126 (https://download.01.org/0day-ci/archive/20231126/[email-masked]/config)
> compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project.git f28c006a5895fc0e329fe15fead81e37457cb1d1)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231126/[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 >>):
> 
> >> arch/arm64/kernel/machine_kexec.c:35:2: error: implicit declaration of function 'kexec_dprintk' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
>            kexec_dprintk("%s:%d:\n", func, line);
>            ^
>    1 error generated.

Thanks for reporting. It has below kexec related config items, whereas
the kexec_drpintk() is only defined in CONFIG_KEXEC_FILE ifdeffery
scope, moving it to CONFIG_KEXEC_CORE iddeffery scope in <linux/kexec.h>
can fix it as below draft code. Will update patch 1 to include the code
change.

===
CONFIG_CRASH_CORE=y
CONFIG_KEXEC_CORE=y
CONFIG_KEXEC=y
# CONFIG_KEXEC_FILE is not set
CONFIG_CRASH_DUMP=y
===

diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 66997efe36f1..b457b0d70f3f 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -265,13 +265,6 @@ arch_kexec_apply_relocations(struct purgatory_info *pi, Elf_Shdr *section,
 }
 #endif
 
-extern bool kexec_file_dbg_print;
-
-#define kexec_dprintk(fmt, ...)					\
-	printk("%s" fmt,					\
-	       kexec_file_dbg_print ? KERN_INFO : KERN_DEBUG,	\
-	       ##__VA_ARGS__)
-
 #endif /* CONFIG_KEXEC_FILE */
 
 #ifdef CONFIG_KEXEC_ELF
@@ -508,6 +501,13 @@ static inline int crash_hotplug_memory_support(void) { return 0; }
 static inline unsigned int crash_get_elfcorehdr_size(void) { return 0; }
 #endif
 
+extern bool kexec_file_dbg_print;
+
+#define kexec_dprintk(fmt, ...)					\
+	printk("%s" fmt,					\
+	       kexec_file_dbg_print ? KERN_INFO : KERN_DEBUG,	\
+	       ##__VA_ARGS__)
+
 #else /* !CONFIG_KEXEC_CORE */
 struct pt_regs;
 struct task_struct;
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index be5642a4ec49..bddba29a1557 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -52,6 +52,8 @@ atomic_t __kexec_lock = ATOMIC_INIT(0);
 /* Flag to indicate we are going to kexec a new kernel */
 bool kexec_in_progress = false;
 
+bool kexec_file_dbg_print;
+
 int kexec_should_crash(struct task_struct *p)
 {
 	/*
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 7ae1b0901aa4..8f87644b4eec 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -38,8 +38,6 @@ void set_kexec_sig_enforced(void)
 }
 #endif
 
-bool kexec_file_dbg_print;
-
 static int kexec_calculate_store_digests(struct kimage *image);
 
 /* Maximum size in bytes for kernel/initrd files. */