[PATCH 06/10] cachefiles, erofs: Fix NULL deref in when cachefiles is not doing ondemand-mode

[Gao Xiang]

On 2024/1/22 20:38, David Howells wrote:
> cachefiles_ondemand_init_object() as called from cachefiles_open_file() and
> cachefiles_create_tmpfile() does not check if object->ondemand is set
> before dereferencing it, leading to an oops something like:
> 
> 	RIP: 0010:cachefiles_ondemand_init_object+0x9/0x41
> 	...
> 	Call Trace:
> 	 <TASK>
> 	 cachefiles_open_file+0xc9/0x187
> 	 cachefiles_lookup_cookie+0x122/0x2be
> 	 fscache_cookie_state_machine+0xbe/0x32b
> 	 fscache_cookie_worker+0x1f/0x2d
> 	 process_one_work+0x136/0x208
> 	 process_scheduled_works+0x3a/0x41
> 	 worker_thread+0x1a2/0x1f6
> 	 kthread+0xca/0xd2
> 	 ret_from_fork+0x21/0x33
> 
> Fix this by making the calls to cachefiles_ondemand_init_object()
> conditional.
> 
> Fixes: 3c5ecfe16e76 ("cachefiles: extract ondemand info field from cachefiles_object")
> Reported-by: Marc Dionne <marc.dionne at auristor.com>
> Signed-off-by: David Howells <dhowells at redhat.com>
> cc: Gao Xiang <xiang at kernel.org>
> cc: Chao Yu <chao at kernel.org>
> cc: Yue Hu <huyue2 at coolpad.com>
> cc: Jeffle Xu <jefflexu at linux.alibaba.com>
> cc: linux-erofs at lists.ozlabs.org
> cc: netfs at lists.linux.dev
> cc: linux-fsdevel at vger.kernel.org

Looks good to me, thanks for fixing this:

Reviewed-by: Gao Xiang <hsiangkao at linux.alibaba.com>

Thanks,
Gao Xiang