Introduce bpf_cgroup_read_xattr #5525
Closed
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
![kernel-patches-daemon-bpf-rc[bot]](https://avatars.githubusercontent.com/u/70728002?s=60&v=4){kind=small}
|
Upstream branch: 16f3c7a |
kernel-patches-daemon-bpf-rc
bot
force-pushed
the
bpf-net_base
branch
from
7345409 to
6117781
Compare
All allocations of struct kernfs_iattrs are serialized through a global mutex. Simply do a racy allocation and let the first one win. I bet most callers are under inode->i_rwsem anyway and it wouldn't be needed but let's not require that. Signed-off-by: Christian Brauner <[email protected]> Acked-by: Greg Kroah-Hartman <[email protected]> Acked-by: Tejun Heo <[email protected]> Signed-off-by: Song Liu <[email protected]>
BPF programs, such as LSM and sched_ext, would benefit from tags on cgroups. One common practice to apply such tags is to set xattrs on cgroupfs folders. Introduce kfunc bpf_cgroup_read_xattr, which allows reading cgroup's xattr. Note that, we already have bpf_get_[file|dentry]_xattr. However, these two APIs are not ideal for reading cgroupfs xattrs, because: 1) These two APIs only works in sleepable contexts; 2) There is no kfunc that matches current cgroup to cgroupfs dentry. bpf_cgroup_read_xattr is generic and can be useful for many program types. It is also safe, because it requires trusted or rcu protected argument (KF_RCU). Therefore, we make it available to all program types. Signed-off-by: Song Liu <[email protected]> Acked-by: Tejun Heo <[email protected]>
|
Upstream branch: 16f3c7a |
Mark struct cgroup_subsys_state->cgroup as safe under RCU read lock. This will enable accessing css->cgroup from a bpf css iterator. Signed-off-by: Song Liu <[email protected]>
Add tests for different scenarios with bpf_cgroup_read_xattr: 1. Read cgroup xattr from bpf_cgroup_from_id; 2. Read cgroup xattr from bpf_cgroup_ancestor; 3. Read cgroup xattr from css_iter; 4. Use bpf_cgroup_read_xattr in LSM hook security_socket_connect. 5. Use bpf_cgroup_read_xattr in cgroup program. Signed-off-by: Song Liu <[email protected]>
kernel-patches-daemon-bpf-rc
bot
force-pushed
the
series/973998=>bpf-net
branch
from
1f366fd to
2a13bff
Compare
|
At least one diff in series https://patchwork.kernel.org/project/netdevbpf/list/?series=974689 irrelevant now. Closing PR. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Pull request for series with
subject: Introduce bpf_cgroup_read_xattr
version: 3
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=974689