initramfs: debug detected compression method

This can greatly aid in narrowing down the real source of initramfs problems such as failures related to the compression of the in-kernel initramfs when an external initramfs is in use as well. Existing errors are ambiguous as to which initramfs is a problem and why. [[email protected]: use pr_debug()] Signed-off-by: Daniel M. Weeks <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
niw · Apr 7, 2014 · 6aa7a29 · 6aa7a29
1 parent 16caed3
commit 6aa7a29
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diff --git a/init/initramfs.c b/init/initramfs.c
@@ -455,6 +455,7 @@ static char * __init unpack_to_rootfs(char *buf, unsigned len)
 		}
 		this_header = 0;
 		decompress = decompress_method(buf, len, &compress_name);
+		pr_debug("Detected %s compressed data\n", compress_name);
 		if (decompress) {
 			res = decompress(buf, len, NULL, flush_buffer, NULL,
 				   &my_inptr, error);

diff --git a/lib/decompress.c b/lib/decompress.c
@@ -16,6 +16,7 @@
 #include <linux/types.h>
 #include <linux/string.h>
 #include <linux/init.h>
+#include <linux/printk.h>
 
 #ifndef CONFIG_DECOMPRESS_GZIP
 # define gunzip NULL
@@ -61,6 +62,8 @@ decompress_fn __init decompress_method(const unsigned char *inbuf, int len,
 	if (len < 2)
 		return NULL;	/* Need at least this much... */
 
+	pr_debug("Compressed data magic: %#.2x %#.2x\n", inbuf[0], inbuf[1]);
+
 	for (cf = compressed_formats; cf->name; cf++) {
 		if (!memcmp(inbuf, cf->magic, 2))
 			break;