+ fat-allow-0xe9-near-jump-in-fat_read_static_bpb.patch added to mm-nonmm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: FAT: allow 0xE9 near jump in fat_read_static_bpb()
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     fat-allow-0xe9-near-jump-in-fat_read_static_bpb.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/fat-allow-0xe9-near-jump-in-fat_read_static_bpb.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Ziran Zhang <zhangcoder@yeah.net>
Subject: FAT: allow 0xE9 near jump in fat_read_static_bpb()
Date: Sun, 12 Apr 2026 14:59:41 +0800

fat_read_static_bpb() only accepts a short jump as a valid bootstrap code
signature for DOS 1.x volumes when the dos1xfloppy mount option is used.

However, according to the Microsoft fatgen103.doc, the BS_jmpBoot field
has two allowed forms: 0xEB 0x??  0x90 (short jump + NOP) and 0xE9 0x?? 
0x??  (near jump).  The specification explicitly states that either form
is acceptable.

This patch relaxes the check to also accept 0xE9 as the first byte of the
jump instruction.

Link: https://lore.kernel.org/20260412070109.5197-1-zhangcoder@yeah.net
Signed-off-by: Ziran Zhang <zhangcoder@yeah.net>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Christian Brauner <brauner@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/fat/inode.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/fs/fat/inode.c~fat-allow-0xe9-near-jump-in-fat_read_static_bpb
+++ a/fs/fat/inode.c
@@ -1479,8 +1479,9 @@ static int fat_read_static_bpb(struct su
 	int error = -EINVAL;
 	unsigned i;
 
-	/* 16-bit DOS 1.x reliably wrote bootstrap short-jmp code */
-	if (b->ignored[0] != 0xeb || b->ignored[2] != 0x90) {
+	/* 16-bit DOS 1.x reliably wrote bootstrap short-jmp or near-jmp code */
+	if ((b->ignored[0] != 0xeb || b->ignored[2] != 0x90) &&
+	    (b->ignored[0] != 0xe9)) {
 		if (!silent)
 			fat_msg(sb, KERN_ERR,
 				"%s; no bootstrapping code", notdos1x);
_

Patches currently in -mm which might be from zhangcoder@yeah.net are

fat-allow-0xe9-near-jump-in-fat_read_static_bpb.patch