[syzbot] [jfs?] [fat?] general protection fault in txEnd

[Rafael Alejandro Diaz Cruz <rafad900@gmail.com>]

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#syz test

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From da93920ddc6ccfe238f98e6e060700566f4052c0 Mon Sep 17 00:00:00 2001
From: rafad900 <19312533+rafad900@users.noreply.github.com>
Date: Mon, 30 Mar 2026 13:33:13 -0700
Subject: [PATCH]     jfs: prevent null log deference from superblock during
 read only mode

    Clearing the inode pointer is necessary to ensure no memory leaks
    after txBegin fails to initialize the superblock during read only
    mode.

Signed-off-by: rafad900 <19312533+rafad900@users.noreply.github.com>
---
 fs/jfs/namei.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/fs/jfs/namei.c b/fs/jfs/namei.c
index 60c4a0e0fca5..3a5f45cdeae0 100644
--- a/fs/jfs/namei.c
+++ b/fs/jfs/namei.c
@@ -97,7 +97,13 @@ static int jfs_create(struct mnt_idmap *idmap, struct inode *dip,
 	}
 
 	tid = txBegin(dip->i_sb, 0);
-
+	if (tid == 0) {
+		jfs_err("jfs_create: unable to create tblk due to read only filesystem");
+		free_ea_wmap(ip);
+		clear_nlink(ip);
+		discard_new_inode(ip);
+		return -EROFS;
+	}
 	mutex_lock_nested(&JFS_IP(dip)->commit_mutex, COMMIT_MUTEX_PARENT);
 	mutex_lock_nested(&JFS_IP(ip)->commit_mutex, COMMIT_MUTEX_CHILD);
 
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2.43.0