From: Philipp Rudo <prudo@linux.ibm.com>
Date: Mon, 13 Aug 2018 11:16:57 +0200
Subject: s390/kdump: Fix memleak in nt_vmcoreinfo
Git-commit: 2d2e7075b87181ed0c675e4936e20bdadba02e1f
Patch-mainline: v4.19-rc1
References: git-fixes bsc#1215028

The vmcoreinfo of a crashed system is potentially fragmented. Thus the
crash kernel has an intermediate step where the vmcoreinfo is copied into a
temporary, continuous buffer in the crash kernel memory. This temporary
buffer is never freed. Free it now to prevent the memleak.

While at it replace all occurrences of "VMCOREINFO" by its corresponding
macro to prevent potential renaming issues.

Signed-off-by: Philipp Rudo <prudo@linux.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Miroslav Franc <mfranc@suse.cz>
---
 arch/s390/kernel/crash_dump.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c
index 4b2773e1ddfe..27d2b7093ea0 100644
--- a/arch/s390/kernel/crash_dump.c
+++ b/arch/s390/kernel/crash_dump.c
@@ -451,11 +451,13 @@ static void *get_vmcoreinfo_old(unsigned long *size)
 	if (copy_oldmem_kernel(nt_name, addr + sizeof(note),
 			       sizeof(nt_name) - 1))
 		return NULL;
-	if (strcmp(nt_name, "VMCOREINFO") != 0)
+	if (strcmp(nt_name, VMCOREINFO_NOTE_NAME) != 0)
 		return NULL;
 	vmcoreinfo = kzalloc_panic(note.n_descsz);
-	if (copy_oldmem_kernel(vmcoreinfo, addr + 24, note.n_descsz))
+	if (copy_oldmem_kernel(vmcoreinfo, addr + 24, note.n_descsz)) {
+		kfree(vmcoreinfo);
 		return NULL;
+	}
 	*size = note.n_descsz;
 	return vmcoreinfo;
 }
@@ -465,15 +467,20 @@ static void *get_vmcoreinfo_old(unsigned long *size)
  */
 static void *nt_vmcoreinfo(void *ptr)
 {
+	const char *name = VMCOREINFO_NOTE_NAME;
 	unsigned long size;
 	void *vmcoreinfo;
 
 	vmcoreinfo = os_info_old_entry(OS_INFO_VMCOREINFO, &size);
-	if (!vmcoreinfo)
-		vmcoreinfo = get_vmcoreinfo_old(&size);
+	if (vmcoreinfo)
+		return nt_init_name(ptr, 0, vmcoreinfo, size, name);
+
+	vmcoreinfo = get_vmcoreinfo_old(&size);
 	if (!vmcoreinfo)
 		return ptr;
-	return nt_init_name(ptr, 0, vmcoreinfo, size, "VMCOREINFO");
+	ptr = nt_init_name(ptr, 0, vmcoreinfo, size, name);
+	kfree(vmcoreinfo);
+	return ptr;
 }
 
 static size_t nt_vmcoreinfo_size(void)