mountinfo: linux: use /proc/thread-self/mountinfo #128
Conversation
This file contains 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
This comment was marked as resolved.
This comment was marked as resolved.
cyphar
force-pushed
the
mountinfo-linux-thread-self
branch
from
7049be0
to
da2df1c
Compare
This comment was marked as resolved.
This comment was marked as resolved.
I guess this was not backported in the RHEL 3.10 kernels? I think RHEL 7 reaches EOL June next year, so ... it's getting closer. |
|
(For future reference, this was motivated by opencontainers/runc#3985.) |
cyphar
force-pushed
the
mountinfo-linux-thread-self
branch
from
da2df1c
to
170c9be
Compare
|
Wdyt @kolyshkin? |
kolyshkin
reviewed
Oct 26, 2023
In a Go program with many threads, which goroutine is running on the thread-group leader thread is not something programs can controls. Thus, even if you use runtime.LockOSThread() for threads that have different mount namespaces, it's possible that /proc/self will refer to the "wrong" thread. The solution is to simply use /proc/thread-self, which will always provide the correct result for the calling thread. For pre-3.17 kernels we use /proc/self/task/<tid> as a fallback. The usage of /proc/self/mountinfo caused isuses for a patch to runc which creates a thread to create id-mapped mounts (which requires joining the container mount namespace). Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
cyphar
force-pushed
the
mountinfo-linux-thread-self
branch
from
170c9be
to
12c61a3
Compare
|
@thaJeztah ptal |
|
Merging as this doesn't seem like a breaking change, and we need it in runc (#3985). |
|
Ah, it seems that we need the |
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Outdated suggestions cannot be applied.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.
In a Go program with many threads, which goroutine is running on the thread-group leader thread is not something programs can controls. Thus, even if you use runtime.LockOSThread() for threads that have different mount namespaces, it's possible that /proc/self will refer to the "wrong" thread.
The solution is to simply use /proc/thread-self, which will always provide the correct result for the calling thread.
The usage of /proc/self/mountinfo caused isuses for a patch to runc which creates a thread to create id-mapped mounts (which requires joining the container mount namespace).
Signed-off-by: Aleksa Sarai cyphar@cyphar.com