https://golang.org/cmd/go/#hdr-Build_and_test_caching says:
> If you have made changes to the C libraries on your system, you will
> need to clean the cache explicitly or else use the -a build flag
> (see 'go help build') to force rebuilding of packages that depend
> on the updated C libraries.
This means that:
1. We need to either 'go clean -cache' or 'go build -a' when building
the release binary. Adding '-a' seems less intrusive / more focused.
2. The check for existing libseccomp.a (added by commit d748280aa)
is no longer needed.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Instead of reconnecting to dbus after some failed operations, and
returning an error (so a caller has to retry), reconnect AND retry
in place for all such operations.
This should fix issues caused by a stale dbus connection after e.g.
a dbus daemon restart.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
[@kolyshkin: doc nits, use dbus.ErrClosed and isDbusError]
Signed-off-by: Shiming Zhang <wzshiming@foxmail.com>
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Generalize isUnitExists as isDbusError, and use errors.As while at it
(which can handle wrapped errors as well).
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Function (*FreezerGroup).Set has a few paths where in can return an
error. In any case, if an error is returned, we failed to freeze,
and we need to thaw to avoid leaving the cgroup in a stuck state.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This checks that in-container view of /sys/fs/cgroup does not
contain any extra cgroups (which was the case for rootless
before the previous commit).
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
In case of rootless, cgroup2 mount is not possible (see [1] for more
details), so since commit 9c81440fb5 runc bind-mounts the whole
/sys/fs/cgroup into container.
Problem is, if cgroupns is enabled, /sys/fs/cgroup inside the container
is supposed to show the cgroup files for this cgroup, not the root one.
The fix is to pass through and use the cgroup path in case cgroup2
mount failed, cgroupns is enabled, and the path is non-empty.
Surely this requires the /sys/fs/cgroup mount in the spec, so modify
runc spec --rootless to keep it.
Before:
$ ./runc run aaa
# find /sys/fs/cgroup/ -type d
/sys/fs/cgroup
/sys/fs/cgroup/user.slice
/sys/fs/cgroup/user.slice/user-1000.slice
/sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service
...
# ls -l /sys/fs/cgroup/cgroup.controllers
-r--r--r-- 1 nobody nogroup 0 Feb 24 02:22 /sys/fs/cgroup/cgroup.controllers
# wc -w /sys/fs/cgroup/cgroup.procs
142 /sys/fs/cgroup/cgroup.procs
# cat /sys/fs/cgroup/memory.current
cat: can't open '/sys/fs/cgroup/memory.current': No such file or directory
After:
# find /sys/fs/cgroup/ -type d
/sys/fs/cgroup/
# ls -l /sys/fs/cgroup/cgroup.controllers
-r--r--r-- 1 root root 0 Feb 24 02:43 /sys/fs/cgroup/cgroup.controllers
# wc -w /sys/fs/cgroup/cgroup.procs
2 /sys/fs/cgroup/cgroup.procs
# cat /sys/fs/cgroup/memory.current
577536
[1] https://github.com/opencontainers/runc/issues/2158
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
The code is already passing three parameters around from
mountToRootfs to mountCgroupV* to mountToRootfs again.
I am about to add another parameter, so let's introduce and
use struct mountConfig to pass around.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Per OCI runtime spec, mount destination MUST be absolute. Let's check
that and return an error if not.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This helps a lot to find out where the errors come from.
Before:
> level=warning msg="lstat /sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/test_hello: no such file or directory"
After:
> level=warning msg="lstat /sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/test_hello: no such file or directory" func=github.com/opencontainers/runc/libcontainer.destroy file="github.com/opencontainers/runc/libcontainer/state_linux.go:44"
Presumably this comes with an overhead, but I guess no one is using
--debug by default anyway.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Commit 5d0ffbf9c8 added OOM kill count checking and better container
start/run/exec error reporting in case we hit OOM.
It also introduced warnings like these:
> level=warning msg="unable to get oom kill count" error="openat2
> /sys/fs/cgroup/user.slice/user-1000.slice/user@1000.service/test_hello/memory.events:
> no such file or directory"
In case of rootless containers, unless cgroup is delegated or systemd is
used, runc can not create a cgroup and thus it fails to get OOM kill
count. This is expected, and the warning should not be shown in this
case.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
For fs, commit fc620fdf81 made rootless field private,
and for fs2, it was always private, and yet comments in both
mention it as m.Rootless.
Fix it.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
For the fix, see previous commit. Without the fix, this test case fails:
> container_linux.go:380: starting container process caused:
> process_linux.go:545: container init caused: readonly path /proc/bus:
> operation not permitted
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Currently, runc fails like this when used from rootless podman
with host PID namespace:
> $ podman --runtime=runc run --pid=host --rm -it busybox sh
> WARN[0000] additional gid=10 is not present in the user namespace, skip setting it
> Error: container_linux.go:380: starting container process caused:
> process_linux.go:545: container init caused: readonly path /proc/asound:
> operation not permitted: OCI permission denied
(Here /proc/asound is the first path from OCI spec's readonlyPaths).
The code uses MS_BIND|MS_REMOUNT flags that have a special meaning in
the kernel ("keep the flags like nodev, nosuid, noexec as is").
For some reason, this "special meaning" trick is not working for the
above use case (rootless podman + no PID namespace), and I don't know
how to reproduce this without podman.
Instead of relying on the kernel feature, let's just get the current
mount flags using fstatfs(2) and add those that needs to be preserved.
While at it, wrap errors from unix.Mount into os.PathError to make
errors a bit less cryptic.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
full diff: https://github.com/cilium/ebpf/compare/v0.4.0...v0.5.0
Breaking changes
------------------------------------------
All LoadPinned*() functions now take LoadPinOptions to control loader behaviour.
Simply pass nil to load with default options.
- LoadPinnedMap()
- LoadPinnedProgram()
- LoadPinnedCgroup()
- LoadPinnedIter()
- LoadPinnedRawLink()
- LoadPinnedNetNs()
Bug fixes
------------------------------------------
- Program.IsPinned() now behaves correctly on maps loaded from bpffs
- Map.Pin() no longer clobbers the destination file if it already exists
Features
------------------------------------------
- Attaching to k(ret)probes and tracepoints can now be done with link.Kprobe(),
link.Kretprobe() and link.Tracepoint()
- Programs of type Kprobe automatically get their KernelVersion fields populated
by detecting the kernel version at runtime
- MapOptions now contains a LoadPinOptions
- ProgSpec now contains a Flags field, adding support for BPF_F_SLEEPABLE
- Made BTF map loader more flexible by looping over Vars in a BTF data section
- Pinned Maps and Programs can now be loaded from bpffs in read-or write-only mode
- Added golangci-lint project configuration, running in CI
Examples
------------------------------------------
kprobe and tracepoint examples updated to use the new link.Kprobe() and link.Tracepoint() API
There is now an example for how to attach eBPF programs to uprobes
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Caught by golangci-lint when enabling golint:
libcontainer/cgroups/ebpf/ebpf.go:35:12: SA1019: prog.Attach is deprecated: use link.RawAttachProgram instead. (staticcheck)
if err := prog.Attach(dirFD, ebpf.AttachCGroupDevice, unix.BPF_F_ALLOW_MULTI); err != nil {
^
libcontainer/cgroups/ebpf/ebpf.go:39:13: SA1019: prog.Detach is deprecated: use link.RawDetachProgram instead. (staticcheck)
if err := prog.Detach(dirFD, ebpf.AttachCGroupDevice, unix.BPF_F_ALLOW_MULTI); err != nil {
^
Worth noting that we currently call prog.Detach() with unix.BPF_F_ALLOW_MULTI;
https://github.com/golang/sys/blob/22da62e12c0cd9c1da93581e1113ca4d82a5be14/unix/zerrors_linux.go#L178
BPF_F_ALLOW_MULTI = 0x2
Looking at the source code for prog.Detach(); https://github.com/cilium/ebpf/blob/v0.4.0/prog.go#L579-L581,
this would _always_ produce an error:
if flags != 0 {
return errors.New("flags must be zero")
}
Note that the flags parameter is not used (except for that validation)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Since the previous commit, some strings logged by write_log() contain a
literal newline, which leads to errors like this one:
> # time="2020-06-07T15:41:37Z" level=error msg="failed to decode \"{\\\"level\\\":\\\"debug\\\", \\\"msg\\\": \\\"nsexec-0[2265]: update /proc/2266/uid_map to '0 1000 1\\n\" to json: invalid character '\\n' in string literal"
The fix is to escape such characters.
Add a simple (as much as it can be) routine which implements JSON string
escaping as required by RFC4627, section 2.5, plus escaping of DEL (0x7f)
character (not required, but allowed by the standard, and usually done
by tools such as jq).
As much as I hate to code something like this, I was not able to find
a ready to consume and decent C implementation (not using glib).
Added a test case (and some additional asserts in C code, conditionally
enabled by the test case) to make sure the implementation is correct.
The test case have to live in a separate directory so we can use
different C flags to compile the test, and use C from go test.
[v2: try to simplify the code, add more tests]
[v3: don't do exit(1), try returning an error instead]
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This is somewhat radical approach to deal with kernel memory.
Per-cgroup kernel memory limiting was always problematic. A few
examples:
- older kernels had bugs and were even oopsing sometimes (best example
is RHEL7 kernel);
- kernel is unable to reclaim the kernel memory so once the limit is
hit a cgroup is toasted;
- some kernel memory allocations don't allow failing.
In addition to that,
- users don't have a clue about how to set kernel memory limits
(as the concept is much more complicated than e.g. [user] memory);
- different kernels might have different kernel memory usage,
which is sort of unexpected;
- cgroup v2 do not have a [dedicated] kmem limit knob, and thus
runc silently ignores kernel memory limits for v2;
- kernel v5.4 made cgroup v1 kmem.limit obsoleted (see
https://github.com/torvalds/linux/commit/0158115f702b).
In view of all this, and as the runtime-spec lists memory.kernel
and memory.kernelTCP as OPTIONAL, let's ignore kernel memory
limits (for cgroup v1, same as we're already doing for v2).
This should result in less bugs and better user experience.
The only bad side effect from it might be that stat can show kernel
memory usage as 0 (since the accounting is not enabled).
[v2: add a warning in specconv that limits are ignored]
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Kir Kolyshkin