[PATCH v4] proc/vmcore: fix potential memory leak in vmcore_init()

[Jianglei Nie]

elfcorehdr_alloc() allocates a memory chunk for elfcorehdr_addr with
kzalloc(). If is_vmcore_usable() returns false, elfcorehdr_addr is a
predefined value. If parse_crash_elf_headers() occurs some error and
returns a negetive value, the elfcorehdr_addr should be released with
elfcorehdr_free().

We can fix by calling elfcorehdr_free() when parse_crash_elf_headers()
fails.

Signed-off-by: Jianglei Nie <niejianglei2021 at 163.com>
---
 fs/proc/vmcore.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index 4eaeb645e759..390515c249dd 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -1569,15 +1569,16 @@ static int __init vmcore_init(void)
 	rc = parse_crash_elf_headers();
 	if (rc) {
 		pr_warn("Kdump: vmcore not initialized\n");
-		return rc;
+		goto fail;
 	}
-	elfcorehdr_free(elfcorehdr_addr);
 	elfcorehdr_addr = ELFCORE_ADDR_ERR;
 
 	proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &vmcore_proc_ops);
 	if (proc_vmcore)
 		proc_vmcore->size = vmcore_size;
-	return 0;
+fail:
+	elfcorehdr_free(elfcorehdr_addr);
+	return rc;
 }
 fs_initcall(vmcore_init);
 
-- 
2.25.1