d/freebsd-nq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Add an option to have a fail point term only execute when run by a

Browse Source 
specified pid.  This is helpful for automated testing involving a global
knob that would otherwise be executed by many other threads.

MFC after: 1 week
This commit is contained in:
Matthew D Fleming 2011-07-08 20:41:12 +00:00
parent 0894a9bca6
commit b5bd50ae40
2 changed files with 26 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
share/man/man9/fail.9
View File

@ -116,6 +116,7 @@ The sysctl variable may be set using the following grammar:
( (<float> "%") | (<integer> "*" ) )*
<type>
[ "(" <integer> ")" ]
[ "[pid " <integer> "]" ]
<float> ::
<integer> [ "." <integer> ] |
@ -161,6 +162,10 @@ For the purpose of this operator, the return() and print() operators
are the only types that cascade.
A return() term only cascades if the code executes, and a print()
term only cascades when passed a non-zero argument.
A pid can optionally be specified.
The fail point term is only executed when invoked by a process with a
matching p_pid.
.Pp
.Sh EXAMPLES
.Bl -tag
.It Sy sysctl debug.fail_point.foobar="2.1%return(5)"
@ -181,6 +186,8 @@ After that, 1/1000th of the time, return 22.
Return 5 for 1 in 1000 executions, but only 5 times total.
.It Sy sysctl debug.fail_point.foobar="1%*sleep(50)"
1/100th of the time, sleep 50ms.
.It Sy sysctl debug.fail_point.foobar="1*return(5)[pid 1234]"
Return 5 once, when pid 1234 executes the fail point.
.El
.Sh AUTHORS
.An -nosplit

20
sys/kern/kern_fail.c
View File

@ -60,6 +60,7 @@ __FBSDID("$FreeBSD$");
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/sbuf.h>
#include <machine/stdarg.h>
@ -114,7 +115,7 @@ struct fail_point_entry {
int fe_arg; /**< argument to type (e.g. return value) */
int fe_prob; /**< likelihood of firing in millionths */
int fe_count; /**< number of times to fire, 0 means always */
pid_t fe_pid; /**< only fail for this process */
TAILQ_ENTRY(fail_point_entry) fe_entries; /**< next entry in fail point */
};
@ -227,6 +228,8 @@ fail_point_eval_nontrivial(struct fail_point *fp, int *return_value)
if (ent->fe_prob < PROB_MAX &&
ent->fe_prob < random() % PROB_MAX)
continue;
if (ent->fe_pid != NO_PID && ent->fe_pid != curproc->p_pid)
continue;
switch (ent->fe_type) {
case FAIL_POINT_PANIC:
@ -315,6 +318,8 @@ fail_point_get(struct fail_point *fp, struct sbuf *sb)
sbuf_printf(sb, "%s", fail_type_strings[ent->fe_type].name);
if (ent->fe_arg)
sbuf_printf(sb, "(%d)", ent->fe_arg);
if (ent->fe_pid != NO_PID)
sbuf_printf(sb, "[pid %d]", ent->fe_pid);
if (TAILQ_NEXT(ent, fe_entries))
sbuf_printf(sb, "->");
}
@ -451,6 +456,7 @@ parse_term(struct fail_point_entries *ents, char *p)
ent = fp_malloc(sizeof *ent, M_WAITOK | M_ZERO);
ent->fe_prob = PROB_MAX;
ent->fe_pid = NO_PID;
TAILQ_INSERT_TAIL(ents, ent, fe_entries);
/*
@ -458,6 +464,7 @@ parse_term(struct fail_point_entries *ents, char *p)
* ( (<float> "%") | (<integer> "*" ) )*
* <type>
* [ "(" <integer> ")" ]
* [ "[pid " <integer> "]" ]
*/
/* ( (<float> "%") | (<integer> "*" ) )* */
@ -500,6 +507,17 @@ parse_term(struct fail_point_entries *ents, char *p)
if (*p++ != ')')
return (NULL);
/* [ "[pid " <integer> "]" ] */
#define PID_STRING "[pid "
if (strncmp(p, PID_STRING, sizeof(PID_STRING) - 1) != 0)
return (p);
p += sizeof(PID_STRING) - 1;
if (!isdigit(*p))
return (NULL);
ent->fe_pid = strtol(p, &p, 0);
if (*p++ != ']')
return (NULL);
return (p);
}