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Version: latest

deadlock

Use uprobe to trace pthread_mutex_lock and pthread_mutex_unlock in libc.so and detect potential deadlocks.

Getting started​

Running the gadget:

$ kubectl gadget run ghcr.io/inspektor-gadget/gadget/deadlock:latest [flags]

Flags​

--pid​

Show only events generated by processes with this pid

Default value: ""

Guide​

To generate mutex lock/unlock events, you can run a test program in another container.

For this example, we use a test C++ program (from BCC) with lock inversions that can cause a potential deadlock.

The deadlock gadget traces all potential deadlocks:

$ sudo ig run ghcr.io/inspektor-gadget/gadget/deadlock:latest
RUNTIME.CONTAINERNAME                                  PID NODES   STACK_IDS                                           COMM
hungry_montalcini                                    39046 3       [77, 13], [149, 42], [11, 109]                      test
hungry_montalcini                                    39046 4       [51, 208], [87, 52], [239, 71], [175, 35]           test

Notes​

  • This gadget detects "potential" deadlocks and not just actual deadlocks as a deadlock that didn't happen during the trace could happen in the future. A deadlock occurring depends on various factors such as thread scheduling and order of mutex acquisitions/releases, and hence it makes sense to report mutex lock order inversions as potentially unsafe resource management.
  • Tracing with --host will slow down the gadget due to too many events.