On 05/02/24 08:41, Baoquan He wrote:

On 01/11/24 at 04:21pm, Sourabh Jain wrote:

quoted

In the event of memory hotplug or online/offline events, the crash
memory hotplug notifier `crash_memhp_notifier()` receives a
`memory_notify` object but doesn't forward that object to the
generic and architecture-specific crash hotplug handler.

The `memory_notify` object contains the starting PFN (Page Frame Number)
and the number of pages in the hot-removed memory. This information is
necessary for architectures like PowerPC to update/recreate the kdump
image, specifically `elfcorehdr`.

So update the function signature of `crash_handle_hotplug_event()` and
`arch_crash_handle_hotplug_event()` to accept the `memory_notify` object
as an argument from crash memory hotplug notifier.

Since no such object is available in the case of CPU hotplug event, the
crash CPU hotplug notifier `crash_cpuhp_online()` passes NULL to the
crash hotplug handler.

......

quoted

---
  arch/x86/include/asm/kexec.h |  2 +-
  arch/x86/kernel/crash.c      |  3 ++-
  include/linux/kexec.h        |  2 +-
  kernel/crash_core.c          | 14 +++++++-------
  4 files changed, 11 insertions(+), 10 deletions(-)

LGTM,

Acked-by: Baoquan He <bhe@redhat.com>

Thanks Baoquan He

- Sourabh

quoted

diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index c9f6a6c5de3c..9bb6607e864e 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h

@@ -208,7 +208,7 @@ int arch_kimage_file_post_load_cleanup(struct kimage *image);
  extern void kdump_nmi_shootdown_cpus(void);
  
  #ifdef CONFIG_CRASH_HOTPLUG
-void arch_crash_handle_hotplug_event(struct kimage *image);
+void arch_crash_handle_hotplug_event(struct kimage *image, void *arg);
  #define arch_crash_handle_hotplug_event arch_crash_handle_hotplug_event
  
  #ifdef CONFIG_HOTPLUG_CPU

diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index b6b044356f1b..44744e9c68ec 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c

@@ -428,10 +428,11 @@ unsigned int arch_crash_get_elfcorehdr_size(void)
  /**
   * arch_crash_handle_hotplug_event() - Handle hotplug elfcorehdr changes
   * @image: a pointer to kexec_crash_image
+ * @arg: struct memory_notify handler for memory hotplug case and NULL for CPU hotplug case.
   *
   * Prepare the new elfcorehdr and replace the existing elfcorehdr.
   */
-void arch_crash_handle_hotplug_event(struct kimage *image)
+void arch_crash_handle_hotplug_event(struct kimage *image, void *arg)
  {
  	void *elfbuf = NULL, *old_elfcorehdr;
  	unsigned long nr_mem_ranges;

diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 400cb6c02176..802052d9c64b 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h

@@ -483,7 +483,7 @@ static inline void arch_kexec_pre_free_pages(void *vaddr, unsigned int pages) {
  #endif
  
  #ifndef arch_crash_handle_hotplug_event
-static inline void arch_crash_handle_hotplug_event(struct kimage *image) { }
+static inline void arch_crash_handle_hotplug_event(struct kimage *image, void *arg) { }
  #endif
  
  int crash_check_update_elfcorehdr(void);

diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index d48315667752..ab1c8e79759d 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c

@@ -914,7 +914,7 @@ int crash_check_update_elfcorehdr(void)
   * list of segments it checks (since the elfcorehdr changes and thus
   * would require an update to purgatory itself to update the digest).
   */
-static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu)
+static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu, void *arg)
  {
  	struct kimage *image;
  

@@ -976,7 +976,7 @@ static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu)
  	image->hp_action = hp_action;
  
  	/* Now invoke arch-specific update handler */
-	arch_crash_handle_hotplug_event(image);
+	arch_crash_handle_hotplug_event(image, arg);
  
  	/* No longer handling a hotplug event */
  	image->hp_action = KEXEC_CRASH_HP_NONE;

@@ -992,17 +992,17 @@ static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu)
  	crash_hotplug_unlock();
  }
  
-static int crash_memhp_notifier(struct notifier_block *nb, unsigned long val, void *v)
+static int crash_memhp_notifier(struct notifier_block *nb, unsigned long val, void *arg)
  {
  	switch (val) {
  	case MEM_ONLINE:
  		crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_MEMORY,
-			KEXEC_CRASH_HP_INVALID_CPU);
+			KEXEC_CRASH_HP_INVALID_CPU, arg);
  		break;
  
  	case MEM_OFFLINE:
  		crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_MEMORY,
-			KEXEC_CRASH_HP_INVALID_CPU);
+			KEXEC_CRASH_HP_INVALID_CPU, arg);
  		break;
  	}
  	return NOTIFY_OK;

@@ -1015,13 +1015,13 @@ static struct notifier_block crash_memhp_nb = {
  
  static int crash_cpuhp_online(unsigned int cpu)
  {
-	crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_CPU, cpu);
+	crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_CPU, cpu, NULL);
  	return 0;
  }
  
  static int crash_cpuhp_offline(unsigned int cpu)
  {
-	crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_CPU, cpu);
+	crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_CPU, cpu, NULL);
  	return 0;
  }
  

-- 
2.41.0