How is `SIGSEGV` an example of “signals related to the current state of the process be delivered before other signals”? [closed]

-1

APUE says

What happens if more than one signal is ready to be delivered to a process?
POSIX.1 does not specify the order in which the signals are delivered to the process.
The Rationale for POSIX.1 does suggest, however, that signals related to the current
state of the process be delivered before other signals. (SIGSEGV is one such signal.)

How is SIGSEGV an example of "signals related to the current
state of the process be delivered before other signals"?

Thanks.

edited Dec 25 '18 at 19:16

asked Dec 25 '18 at 17:01

Tim

26.3k74246455

closed as unclear what you're asking by Stephen Harris, icarus, Rui F Ribeiro, Volker Siegel, msp9011 Dec 27 '18 at 6:35

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

add a comment |

-1

APUE says

What happens if more than one signal is ready to be delivered to a process?
POSIX.1 does not specify the order in which the signals are delivered to the process.
The Rationale for POSIX.1 does suggest, however, that signals related to the current
state of the process be delivered before other signals. (SIGSEGV is one such signal.)

How is SIGSEGV an example of "signals related to the current
state of the process be delivered before other signals"?

Thanks.

edited Dec 25 '18 at 19:16

asked Dec 25 '18 at 17:01

Tim

26.3k74246455

closed as unclear what you're asking by Stephen Harris, icarus, Rui F Ribeiro, Volker Siegel, msp9011 Dec 27 '18 at 6:35

add a comment |

-1

APUE says

What happens if more than one signal is ready to be delivered to a process?
POSIX.1 does not specify the order in which the signals are delivered to the process.
The Rationale for POSIX.1 does suggest, however, that signals related to the current
state of the process be delivered before other signals. (SIGSEGV is one such signal.)

How is SIGSEGV an example of "signals related to the current
state of the process be delivered before other signals"?

Thanks.

edited Dec 25 '18 at 19:16

asked Dec 25 '18 at 17:01

Tim

26.3k74246455

APUE says

What happens if more than one signal is ready to be delivered to a process?
POSIX.1 does not specify the order in which the signals are delivered to the process.
The Rationale for POSIX.1 does suggest, however, that signals related to the current
state of the process be delivered before other signals. (SIGSEGV is one such signal.)

How is SIGSEGV an example of "signals related to the current
state of the process be delivered before other signals"?

Thanks.

linux signals segmentation-fault

edited Dec 25 '18 at 19:16

asked Dec 25 '18 at 17:01

Tim

26.3k74246455

edited Dec 25 '18 at 19:16

asked Dec 25 '18 at 17:01

Tim

26.3k74246455

edited Dec 25 '18 at 19:16

asked Dec 25 '18 at 17:01

Tim

26.3k74246455

asked Dec 25 '18 at 17:01

Tim

26.3k74246455

asked Dec 25 '18 at 17:01

Tim

26.3k74246455

closed as unclear what you're asking by Stephen Harris, icarus, Rui F Ribeiro, Volker Siegel, msp9011 Dec 27 '18 at 6:35

add a comment |

1 Answer
1

active

oldest

votes

SEGV is usually delivered when the state of a process is corrupt (memory is not mapped where it should be or is mapped with different permissions than expected, the program logic is trying to access memory that it shouldn't be accessing, etc).

In that case, it helps to dump core and die as soon as possible so that subsequent changes don't mess up everything further and render any post-mortem debugging futile.

edited Dec 25 '18 at 18:11

answered Dec 25 '18 at 17:35

Uncle Billy

3845

Thanks. The question is how SIGSEGV is an example of "What happens if more than one signal is ready to be delivered to a process?"
– Tim
Dec 25 '18 at 19:16

1

@Tim I think you misquoted your own question.
– undercat
Dec 25 '18 at 19:34

Well you could just try it. Run sh -c 'echo $$; read f' in a terminal, stop it with ^Z, attach to it with strace -p <echoed pid>, and then from another window run kill -HUP <pid>; kill -INT <pid>; kill -SEGV <pid>; kill -CONT <pid> and see which of INT, HUP or SEGV will get it first. Does this make it an example?
– Uncle Billy
Dec 25 '18 at 19:50

@Tim. In case it isn't clear, SEGV will always be delivered before HUP, INT or WINCH, if all of them are pending. This is an example of ""signals related to the current state of the process (SEGV, BUS, ILL) be delivered before other signals (USR1, WINCH, INT, etc)"
– Uncle Billy
Dec 25 '18 at 20:19

Thanks. What are the reason and purpose that SEGV will always be delivered before HUP, INT or WINCH?
– Tim
Dec 26 '18 at 14:30

add a comment |

1 Answer
1

active

oldest

votes

1 Answer
1

active

oldest

votes

In that case, it helps to dump core and die as soon as possible so that subsequent changes don't mess up everything further and render any post-mortem debugging futile.

edited Dec 25 '18 at 18:11

answered Dec 25 '18 at 17:35

Uncle Billy

3845

Thanks. The question is how SIGSEGV is an example of "What happens if more than one signal is ready to be delivered to a process?"
– Tim
Dec 25 '18 at 19:16

1

@Tim I think you misquoted your own question.
– undercat
Dec 25 '18 at 19:34

Well you could just try it. Run sh -c 'echo $$; read f' in a terminal, stop it with ^Z, attach to it with strace -p <echoed pid>, and then from another window run kill -HUP <pid>; kill -INT <pid>; kill -SEGV <pid>; kill -CONT <pid> and see which of INT, HUP or SEGV will get it first. Does this make it an example?
– Uncle Billy
Dec 25 '18 at 19:50

@Tim. In case it isn't clear, SEGV will always be delivered before HUP, INT or WINCH, if all of them are pending. This is an example of ""signals related to the current state of the process (SEGV, BUS, ILL) be delivered before other signals (USR1, WINCH, INT, etc)"
– Uncle Billy
Dec 25 '18 at 20:19

Thanks. What are the reason and purpose that SEGV will always be delivered before HUP, INT or WINCH?
– Tim
Dec 26 '18 at 14:30

add a comment |

In that case, it helps to dump core and die as soon as possible so that subsequent changes don't mess up everything further and render any post-mortem debugging futile.

edited Dec 25 '18 at 18:11

answered Dec 25 '18 at 17:35

Uncle Billy

3845

Thanks. The question is how SIGSEGV is an example of "What happens if more than one signal is ready to be delivered to a process?"
– Tim
Dec 25 '18 at 19:16

1

@Tim I think you misquoted your own question.
– undercat
Dec 25 '18 at 19:34

Well you could just try it. Run sh -c 'echo $$; read f' in a terminal, stop it with ^Z, attach to it with strace -p <echoed pid>, and then from another window run kill -HUP <pid>; kill -INT <pid>; kill -SEGV <pid>; kill -CONT <pid> and see which of INT, HUP or SEGV will get it first. Does this make it an example?
– Uncle Billy
Dec 25 '18 at 19:50

@Tim. In case it isn't clear, SEGV will always be delivered before HUP, INT or WINCH, if all of them are pending. This is an example of ""signals related to the current state of the process (SEGV, BUS, ILL) be delivered before other signals (USR1, WINCH, INT, etc)"
– Uncle Billy
Dec 25 '18 at 20:19

Thanks. What are the reason and purpose that SEGV will always be delivered before HUP, INT or WINCH?
– Tim
Dec 26 '18 at 14:30

add a comment |

In that case, it helps to dump core and die as soon as possible so that subsequent changes don't mess up everything further and render any post-mortem debugging futile.

edited Dec 25 '18 at 18:11

answered Dec 25 '18 at 17:35

Uncle Billy

3845

In that case, it helps to dump core and die as soon as possible so that subsequent changes don't mess up everything further and render any post-mortem debugging futile.

edited Dec 25 '18 at 18:11

answered Dec 25 '18 at 17:35

Uncle Billy

3845

edited Dec 25 '18 at 18:11

answered Dec 25 '18 at 17:35

Uncle Billy

3845

answered Dec 25 '18 at 17:35

Uncle Billy

3845

answered Dec 25 '18 at 17:35

Uncle Billy

3845

Thanks. The question is how SIGSEGV is an example of "What happens if more than one signal is ready to be delivered to a process?"
– Tim
Dec 25 '18 at 19:16

1

@Tim I think you misquoted your own question.
– undercat
Dec 25 '18 at 19:34

Well you could just try it. Run sh -c 'echo $$; read f' in a terminal, stop it with ^Z, attach to it with strace -p <echoed pid>, and then from another window run kill -HUP <pid>; kill -INT <pid>; kill -SEGV <pid>; kill -CONT <pid> and see which of INT, HUP or SEGV will get it first. Does this make it an example?
– Uncle Billy
Dec 25 '18 at 19:50

@Tim. In case it isn't clear, SEGV will always be delivered before HUP, INT or WINCH, if all of them are pending. This is an example of ""signals related to the current state of the process (SEGV, BUS, ILL) be delivered before other signals (USR1, WINCH, INT, etc)"
– Uncle Billy
Dec 25 '18 at 20:19

Thanks. What are the reason and purpose that SEGV will always be delivered before HUP, INT or WINCH?
– Tim
Dec 26 '18 at 14:30

add a comment |

Thanks. The question is how SIGSEGV is an example of "What happens if more than one signal is ready to be delivered to a process?"
– Tim
Dec 25 '18 at 19:16

1

@Tim I think you misquoted your own question.
– undercat
Dec 25 '18 at 19:34

Well you could just try it. Run sh -c 'echo $$; read f' in a terminal, stop it with ^Z, attach to it with strace -p <echoed pid>, and then from another window run kill -HUP <pid>; kill -INT <pid>; kill -SEGV <pid>; kill -CONT <pid> and see which of INT, HUP or SEGV will get it first. Does this make it an example?
– Uncle Billy
Dec 25 '18 at 19:50

@Tim. In case it isn't clear, SEGV will always be delivered before HUP, INT or WINCH, if all of them are pending. This is an example of ""signals related to the current state of the process (SEGV, BUS, ILL) be delivered before other signals (USR1, WINCH, INT, etc)"
– Uncle Billy
Dec 25 '18 at 20:19

Thanks. What are the reason and purpose that SEGV will always be delivered before HUP, INT or WINCH?
– Tim
Dec 26 '18 at 14:30

Thanks. The question is how SIGSEGV is an example of "What happens if more than one signal is ready to be delivered to a process?"
– Tim
Dec 25 '18 at 19:16

@Tim I think you misquoted your own question.
– undercat
Dec 25 '18 at 19:34

Well you could just try it. Run sh -c 'echo $$; read f' in a terminal, stop it with ^Z, attach to it with strace -p <echoed pid>, and then from another window run kill -HUP <pid>; kill -INT <pid>; kill -SEGV <pid>; kill -CONT <pid> and see which of INT, HUP or SEGV will get it first. Does this make it an example?
– Uncle Billy
Dec 25 '18 at 19:50

@Tim. In case it isn't clear, SEGV will always be delivered before HUP, INT or WINCH, if all of them are pending. This is an example of ""signals related to the current state of the process (SEGV, BUS, ILL) be delivered before other signals (USR1, WINCH, INT, etc)"
– Uncle Billy
Dec 25 '18 at 20:19

Thanks. What are the reason and purpose that SEGV will always be delivered before HUP, INT or WINCH?
– Tim
Dec 26 '18 at 14:30

add a comment |

搜尋此網誌

mjhjmtu