Ksh (ksh93) Can Lead to a Fork Bomb and Make the System Unresponsive (Doc ID 1986326.1)

Last updated on APRIL 26, 2023

Applies to:

Symptoms

A system running Solaris 11.x can be affected by this. Should it happen, it behaves with a typical fork bomb exposure:

• The number of processes is rapidly increasing; this could be reported by monitoring software.
• The system responds slowly and later on stops responding at all.
• No possibility to log in, neither on the console nor via network (e.g. via ssh).

A kernel crash dump can be created in that situation by sending a break signal. The crash dump will then show that a ksh shell has one ksh child, and that child has one ksh child and so on:

Note that this tree has many more entries with exactly one ksh child on each level of that sub tree.

Cause

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