1inject(8)                   System Manager's Manual                  inject(8)
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NAME

6       inject  -  injects  appropriate error into function if input call chain
7       and predicates are satisfied. Uses Linux eBPF/bcc.
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SYNOPSIS

12       inject -h [-I header] [-P probability] [-v] [-c count] <mode> <spec>
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DESCRIPTION

17       inject injects errors into specified kernel functionality when a  given
18       call chain and associated predicates are satisfied.
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20       WARNING:  This  tool injects failures into key kernel functions and may
21       crash the kernel. You should know what you're  doing  if  you're  using
22       this tool.
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24       This makes use of a Linux 4.16 feature (bpf_override_return())
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26       Since this uses BPF, only the root user can use this tool.
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OPTIONS

31       -h     Print usage message.
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33       -v     Display  the  generated  BPF program, for debugging or modifica‐
34              tion.
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36       -I header
37              Necessary headers to be included.
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39       -P probability
40              Optional probability of failure, default 1.
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42       -c count
43              Number of errors to inject before stopping, default never stops.
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MODE

48       kmalloc
49              Make the following function indicate failure
50                     int should_failslab(struct kmem_cache *s, gfp_t gfpflags)
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53       bio    Make the following function indicate failure
54                     int should_fail_bio(struct bio *bio)
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57       alloc_page
58              Make the following function indicate failure
59                     bool should_fail_alloc_page(gfp_t gfp_mask, unsigned  int
60                     order)
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SPEC

65       FUNCTION([ARGS])[(TEST)] [=> ...]
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67       A  list of predicates separated by "=>". A predicate is a function sig‐
68       nature (name and arguments) in a call stack and a  test  on  the  func‐
69       tion's arguments.
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71       Missing  predicates  are  implicitly true. Missing tests are implicitly
72       true.  Specifying the function arguments is optional if the  test  does
73       not  use  them.   If  the error injection function is not listed as the
74       first predicate, it is implicitly added.
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76       Functions are listed in the reverse order that they are called, ie.  if
77       a() calls b(), the spec would be "b() => a()".
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REQUIREMENTS

82       CONFIG_BPF, CONFIG_BPF_KPROBE_OVERRIDE, bcc
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EXAMPLES

87       inject kmalloc -v 'SyS_mount()'
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89       inject kmalloc -v 'mount_subtree() => btrfs_mount()'
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91       inject -P 0.5 -c 100 alloc_page "should_fail_alloc_page(gfp_t gfp_mask, unsigned int order) (order == 1) => qlge_refill_bq()"
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93       Please  see  the  output  of '-h' and tools/inject_example.txt for more
94       examples.
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SOURCE

99       This is from bcc.
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101              https://github.com/iovisor/bcc
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103       Also look in the bcc distribution for a  companion  _examples.txt  file
104       containing example usage, output, and commentary for this tool.
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OS

109       Linux
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STABILITY

114       Unstable - in development.
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AUTHOR

119       Howard McLauchlan
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123USER COMMANDS                     2018-03-16                         inject(8)