From: Baokun Li <libaokun1@xxxxxxxxxx> Hi all! This is the third version of this patch series, in which another patch set is subsumed into this one to avoid confusing the two patch sets. (https://patchwork.kernel.org/project/linux-fsdevel/list/?series=854914) Thank you, Jia Zhu, Gao Xiang, Jeff Layton, for the feedback in the previous version. We've been testing ondemand mode for cachefiles since January, and we're almost done. We hit a lot of issues during the testing period, and this patch series fixes some of the issues. The patches have passed internal testing without regression. The following is a brief overview of the patches, see the patches for more details. Patch 1-2: Add fscache_try_get_volume() helper function to avoid fscache_volume use-after-free on cache withdrawal. Patch 3: Fix cachefiles_lookup_cookie() and cachefiles_withdraw_cache() concurrency causing cachefiles_volume use-after-free. Patch 4: Propagate error codes returned by vfs_getxattr() to avoid endless loops. Patch 5-7: A read request waiting for reopen could be closed maliciously before the reopen worker is executing or waiting to be scheduled. So ondemand_object_worker() may be called after the info and object and even the cache have been freed and trigger use-after-free. So use cancel_work_sync() in cachefiles_ondemand_clean_object() to cancel the reopen worker or wait for it to finish. Since it makes no sense to wait for the daemon to complete the reopen request, to avoid this pointless operation blocking cancel_work_sync(), Patch 1 avoids request generation by the DROPPING state when the request has not been sent, and Patch 2 flushes the requests of the current object before cancel_work_sync(). Patch 8: Cyclic allocation of msg_id to avoid msg_id reuse misleading the daemon to cause hung. Patch 9: Hold xas_lock during polling to avoid dereferencing reqs causing use-after-free. This issue was triggered frequently in our tests, and we found that anolis 5.10 had fixed it. So to avoid failing the test, this patch is pushed upstream as well. Comments and questions are, as always, welcome. Please let me know what you think. Thanks, Baokun Changes since v2: * Collect Acked-by from Jeff Layton.(Thanks for your ack!) * Collect RVB from Gao Xiang.(Thanks for your review!) * Patch 1-4 from another patch set. * Pathch 4,6,7: Optimise commit messages and subjects. Changes since v1: * Collect RVB from Jia Zhu and Gao Xiang.(Thanks for your review!) * Pathch 1,2：Add more commit messages. * Pathch 3：Add Fixes tag as suggested by Jia Zhu. * Pathch 4：No longer changing "do...while" to "retry" to focus changes and optimise commit messages. * Pathch 5: Drop the internal RVB tag. v1: https://lore.kernel.org/all/20240424033409.2735257-1-libaokun@xxxxxxxxxxxxxxx v2: https://lore.kernel.org/all/20240515125136.3714580-1-libaokun@xxxxxxxxxxxxxxx Baokun Li (7): netfs, fscache: export fscache_put_volume() and add fscache_try_get_volume() cachefiles: fix slab-use-after-free in fscache_withdraw_volume() cachefiles: fix slab-use-after-free in cachefiles_withdraw_cookie() cachefiles: propagate errors from vfs_getxattr() to avoid infinite loop cachefiles: stop sending new request when dropping object cachefiles: cancel all requests for the object that is being dropped cachefiles: cyclic allocation of msg_id to avoid reuse Hou Tao (1): cachefiles: wait for ondemand_object_worker to finish when dropping object Jingbo Xu (1): cachefiles: add missing lock protection when polling fs/cachefiles/cache.c | 45 ++++++++++++++++++++++++++++- fs/cachefiles/daemon.c | 4 +-- fs/cachefiles/internal.h | 3 ++ fs/cachefiles/ondemand.c | 52 ++++++++++++++++++++++++++++++---- fs/cachefiles/volume.c | 1 - fs/cachefiles/xattr.c | 5 +++- fs/netfs/fscache_volume.c | 14 +++++++++ fs/netfs/internal.h | 2 -- include/linux/fscache-cache.h | 6 ++++ include/trace/events/fscache.h | 4 +++ 10 files changed, 123 insertions(+), 13 deletions(-) -- 2.39.2
