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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

NetBSD 11.99                    January 7, 2019                   NetBSD 11.99