View source for Fault injection

Fault injection testing is used to validate error paths in CRIU. Faults are artificially generated in peeked places of the code to check for particular roll-backs.

Faults are enforced by setting the <code>CRIU_FAULT</code> [[environment variables|env]] before executing CRIU binary. Values are described in <code>criu/include/fault-injection.h</code> header file.

== Fatal faults ==

These make CRIU abort the current operation and exit with error.

=== Abort dump early ===

<code>FI_DUMP_EARLY == 1</code>. Makes CRIU abort duming right after infecting the task with [[parasite code]]. Checks that parasite unloading on error works OK.

=== Abort restore early ===

<code>FI_RESTORE_ROOT_ONLY == 2</code>. Makes CRIU stop restoring right after spawning (and pre-restoring) the root task. Checks that early preparations (such as [[invisible files]] pre-creation) doesn't leave garbage in the system.

=== Abort link-remap file opening ===

<code>FI_RESTORE_OPEN_LINK_REMAP == 3</code>. Make CRIU fail the very first attempt opening the [[invisible files|link remap]] file. Additional check for invisible files cleanup.

=== Abort connection to parasite code ===

<code>FI_PARASITE_CONNECT == 4</code>. Makes CRIU simulate impossibility for [[parasite code]] to connect back to CRIU.

== Non fatal faults ==

These just make CRIU chose different paths on dump/restore, trying harder to get work done.

=== Abort open-by-handle ===

<code>FI_CHECK_OPEN_HANDLE == 128</code>. Simulates failure of the <code>open_by_handle_at</code> system call. Forces the [[irmap]] engine to work.

=== Abort memfd creation ===

<code>FI_NO_MEMFD == 129</code>. Forces [[parasite code]] use shmem-based blob instead of memfd-based. Used for older kernels (not having the <code>memfd_create()</code> system call) to work.

=== Abort breakpoints injectioin ===

<code>FI_NO_BREAKPOINTS == 130</code>. Disables breakpoints and makes CRIU unload [[code blobs]] by step-by-step tracing.


[[Category:Testing]]