adfs: fix memory leak in sb->s_fs_info

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Syzbot reported a memory leak in adfs during the mount process. The issue
arises because the ownership of the allocated (struct adfs_sb_info) is
transferred from the filesystem context to the superblock via sget_fc().
This function sets fc->s_fs_info to NULL after the transfer.

The ADFS filesystem previously used the default kill_block_super for
superblock destruction. This helper performs generic cleanup but does not
free the private sb->s_fs_info data. Since fc->s_fs_info is set to
NULL during the transfer, the standard context cleanup (adfs_free_fc)
also skips freeing this memory. As a result, if the superblock is
destroyed, the allocated struct adfs_sb_info is leaked.

Fix this by implementing a custom .kill_sb callback (adfs_kill_sb)
that explicitly frees sb->s_fs_info before invoking the generic
kill_block_super.

Reported-by: syzbot+1c70732df5fd4f0e4fbb@syzkaller.appspotmail.com
Signed-off-by: Ahmet Eray Karadag <eraykrdg1@gmail.com>
Link: https://patch.msgid.link/20251215031433.182205-2-eraykrdg1@gmail.com
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>

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Ahmet Eray Karadag 2025-12-15 06:14:34 +03:00 • committed by Christian Brauner

parent fe967191e5

commit b12e20c6ac

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1 changed files with 12 additions and 12 deletions

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fs/adfs/super.c

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