linux/fs/cachefiles
Baokun Li 85e833cd72
cachefiles: flush all requests after setting CACHEFILES_DEAD
In ondemand mode, when the daemon is processing an open request, if the
kernel flags the cache as CACHEFILES_DEAD, the cachefiles_daemon_write()
will always return -EIO, so the daemon can't pass the copen to the kernel.
Then the kernel process that is waiting for the copen triggers a hung_task.

Since the DEAD state is irreversible, it can only be exited by closing
/dev/cachefiles. Therefore, after calling cachefiles_io_error() to mark
the cache as CACHEFILES_DEAD, if in ondemand mode, flush all requests to
avoid the above hungtask. We may still be able to read some of the cached
data before closing the fd of /dev/cachefiles.

Note that this relies on the patch that adds reference counting to the req,
otherwise it may UAF.

Fixes: c838305450 ("cachefiles: notify the user daemon when looking up cookie")
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Link: https://lore.kernel.org/r/20240522114308.2402121-12-libaokun@huaweicloud.com
Acked-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-05-29 13:03:31 +02:00
..
cache.c cachefiles: fix memory leak in cachefiles_add_cache() 2024-02-20 09:46:07 +01:00
daemon.c cachefiles: flush all requests after setting CACHEFILES_DEAD 2024-05-29 13:03:31 +02:00
error_inject.c cachefiles: Remove the now superfluous sentinel element from ctl_table array 2023-12-28 04:57:57 -08:00
interface.c cachefiles: extract ondemand info field from cachefiles_object 2023-11-25 16:03:57 +01:00
internal.h cachefiles: flush all requests after setting CACHEFILES_DEAD 2024-05-29 13:03:31 +02:00
io.c vfs-6.8.netfs 2024-01-19 09:10:23 -08:00
Kconfig netfs, fscache: Combine fscache with netfs 2023-12-24 15:08:46 +00:00
key.c cachefiles: Implement key to filename encoding 2022-01-07 13:42:16 +00:00
main.c cachefiles: Implement object lifecycle funcs 2022-01-07 13:42:08 +00:00
Makefile cachefiles: notify the user daemon when looking up cookie 2022-05-18 00:11:17 +08:00
namei.c rename(): avoid a deadlock in the case of parents having no common ancestor 2023-11-25 02:54:14 -05:00
ondemand.c cachefiles: Set object to close if ondemand_id < 0 in copen 2024-05-29 13:03:30 +02:00
security.c cachefiles: Add security derivation 2022-01-07 13:41:14 +00:00
volume.c fscache, cachefiles: Store the volume coherency data 2022-01-07 13:43:03 +00:00
xattr.c fs: port ->permission() to pass mnt_idmap 2023-01-19 09:24:28 +01:00