| inject(8) | System Manager's Manual | inject(8) |
inject - injects appropriate error into function if input call chain and predicates are satisfied. Uses Linux eBPF/bcc.
inject -h [-I header] [-P probability] [-v] [-c count] <mode> <spec>
inject injects errors into specified kernel functionality when a given call chain and associated predicates are satisfied.
WARNING: This tool injects failures into key kernel functions and may crash the kernel. You should know what you're doing if you're using this tool.
This makes use of a Linux 4.16 feature (bpf_override_return())
Since this uses BPF, only the root user can use this tool.
FUNCTION([ARGS])[(TEST)] [=> ...]
A list of predicates separated by "=>". A predicate is a function signature (name and arguments) in a call stack and a test on the function's arguments.
Missing predicates are implicitly true. Missing tests are implicitly true. Specifying the function arguments is optional if the test does not use them. If the error injection function is not listed as the first predicate, it is implicitly added.
Functions are listed in the reverse order that they are called, ie. if a() calls b(), the spec would be "b() => a()".
CONFIG_BPF, CONFIG_BPF_KPROBE_OVERRIDE, bcc
inject kmalloc -v 'SyS_mount()'
inject kmalloc -v 'mount_subtree() => btrfs_mount()'
inject -P 0.5 -c 100 alloc_page "should_fail_alloc_page(gfp_t gfp_mask, unsigned int order) (order == 1) => qlge_refill_bq()"
Please see the output of '-h' and tools/inject_example.txt for more examples.
This is from bcc.
Also look in the bcc distribution for a companion _examples.txt file containing example usage, output, and commentary for this tool.
Linux
Unstable - in development.
Howard McLauchlan
| 2018-03-16 | USER COMMANDS |