CRASHME(9)

CRASHME(9) | Kernel Developer's Manual | CRASHME(9)

# NAME

`crashme`, `crashme_add`, `crashme_remove` — in-kernel testing of crash handling

# SYNOPSIS

`#include <sys/crashme.h>`

int
`crashme_add`(crashme_node *cn);

int
`crashme_remove`(crashme_node *cn);

# DESCRIPTION

The `crashme` functions provide access to dynamically add and remove crashme nodes. These nodes are simply named callbacks that are expected to cause the system to crash.

The crashme functionality is only available in kernels with the `options DEBUG` set in the kernel config(5) file.

Each crashme node is maintained in a crashme_node structure which has the following public members:

    typedef int (*crashme_fn)(int /* flags */);

    typedef struct crashme_node {
            const char     *cn_name;
            const char     *cn_longname;
            crashme_fn      cn_fn;
    } crashme_node;

The caller must fill in the cn_name, cn_longname, and cn_fn members.

The cn_fn function is passed flags parameter from sysctl. It shall return 0 upon success or non zero on failure.

# SYSCTL SUPPORT

The following sysctl(8) variables are provided by the `crashme` subsystem:

debug.crashme_enable
  Must be set to 1 for any `crashme` node to be executed.

The following sysctl(8) variables trigger crashes in different ways when written to:

debug.crashme.panic
  Call panic(9).
debug.crashme.null_deref
  Dereference a null pointer.
debug.crashme.null_jump
  Call a null function pointer, i.e., jump to the instruction address zero.
debug.crashme.ddb
  Enter ddb(4) directly by calling `Debugger`(). Requires `options DDB`.

# SEE ALSO

ddb(4), options(4), sysctl(8), panic(9).

# HISTORY

The `crashme` driver appeared in NetBSD 9.0.

# AUTHORS

Matthew R. Green

January 7, 2019 | NetBSD 11.0