core/mount.test: should not call removeLoop when set autoclear#12561
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fuweid merged 1 commit intocontainerd:mainfrom Nov 25, 2025
Merged
core/mount.test: should not call removeLoop when set autoclear#12561fuweid merged 1 commit intocontainerd:mainfrom
fuweid merged 1 commit intocontainerd:mainfrom
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In CI we run make root-test via gotestsum, which executes multiple
package tests concurrently. TestAutoclearTrueLoop attempts to invoke
LOOP_CLR_FD using a device name, which introduces a race condition.
Example race:
Process P1 represents mount.test which runs TestAutoclearTrueLoop
Process P2 represents manager.test which runs TestLoopbackMount
T1: P1 closes fd of loop-device (loop3) (kernel unsets backing-file on close)
T2: P2 gets loop3 from /dev/loop-control
T3: P2 configures loop3 with backing file successfully
T4: P1 invokes removeLoop to clear backing file for loop3
You might see that failure like this
```
=== FAIL: core/mount/manager TestLoopbackMount (0.05s)
log_hook.go:47: time="2025-10-23T21:49:22.532811960Z" level=debug msg="activating mount" func="manager.(*mountManager).Activate" file="/home/runner/work/containerd/containerd/core/mount/manager/manager.go:134" mounts="[{loop /tmp/TestLoopbackMount989607109/001/fs-1621892597 []} {format/ext4 {{ mount 0 }} []}]" name=id1 testcase=TestLoopbackMount
helpers.go:100: unmount /tmp/TestLoopbackMount989607109/001/test-mount-3030342351
manager_linux_test.go:80:
Error Trace: /home/runner/work/containerd/containerd/core/mount/manager/manager_linux_test.go:80
/home/runner/work/containerd/containerd/core/mount/manager/manager_linux_test.go:105
Error: Received unexpected error:
failed to get loop device info: no such device or address
Test: TestLoopbackMount
```
To fix this, the test now compares backing-file's inode directly and does
not call removeLoop when autoclear is set.
Signed-off-by: Wei Fu <[email protected]>
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| return dev | ||
| }() | ||
| for range 10 { | ||
| if err := removeLoop(dev); err != nil { |
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yeah, that can introduce a race since another loop user could reuse it after loop fd is closed with autoclear on.
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ping @containerd/reviewers could you please approve this one? It's trying to deflake that test case. thanks |
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Nov 25, 2025
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/cherry-pick release/2.2 |
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@fuweid: new pull request created: #12577 DetailsIn response to this:
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In CI we run make root-test via gotestsum, which executes multiple package tests concurrently. TestAutoclearTrueLoop attempts to invoke LOOP_CLR_FD using a device name, which introduces a race condition.
Example race:
Process P1 represents mount.test which runs TestAutoclearTrueLoop Process P2 represents manager.test which runs TestLoopbackMount
T1: P1 closes fd of loop-device (loop3) (kernel unsets backing-file on close)
T2: P2 gets loop3 from /dev/loop-control
T3: P2 configures loop3 with backing file successfully
T4: P1 invokes removeLoop to clear backing file for loop3
You might see that failure like this
To fix this, the test now compares backing-file's inode directly and does not call removeLoop when autoclear is set.