google/gvisor

Failed to stop overwriting a running binary

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#1005 opened on Oct 14, 2019

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area: compatibilityarea: filesystemgood first issuepriority: p2type: bug

Description

runsc result:

$ stress -c 1 &
$ which stress
/usr/bin/stress
$ cp /bin/ls /usr/bin/stress
[1]+  Bus error               stress -c 1

Expected result in vanilla Linux:

$ stress -c 1 &
$ which stress
/usr/bin/stress
$ cp /bin/ls /usr/bin/stress
cp: cannot create regular file '/usr/bin/stress': Text file busy

Contributor guide

Tech stack
go
Domain
backendsecurity
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
GoLinux file system
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
25
Research direction
Investigate how gVisor's runsc handles file writes to running binaries. The issue shows that runsc does not prevent overwriting an executing file, which should be blocked by the kernel. Look into the file operation implementations in the gVisor kernel, possibly in the pkg/sentry/fs/ directory. Check if there are any existing tests for ETXTBUSY behavior. Also review the comment thread for any clues from maintainers.