Commit f919b923 authored by Neil Armstrong's avatar Neil Armstrong Committed by Linus Torvalds

init/do_mounts_rd.c: fix ramdisk identification for padded cramfs

When a cramfs ramdisk padded with 512 bytes is given to the kernel, the
current identify_ramdisk_image function fails to identify it.

Tested with a padded cramfs image on an ARM based board.
Signed-off-by: default avatarNeil Armstrong <>
Cc: Namhyung Kim <>
Cc: Davidlohr Bueso <>
Cc: Al Viro <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 0620d919
......@@ -119,6 +119,20 @@ identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
goto done;
* Read 512 bytes further to check if cramfs is padded
sys_lseek(fd, start_block * BLOCK_SIZE + 0x200, 0);
sys_read(fd, buf, size);
if (cramfsb->magic == CRAMFS_MAGIC) {
"RAMDISK: cramfs filesystem found at block %d\n",
nblocks = (cramfsb->size + BLOCK_SIZE - 1) >> BLOCK_SIZE_BITS;
goto done;
* Read block 1 to test for minix and ext2 superblock
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