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SubjectRe: [RFC PATCH 1/5] signal: Teach sigsuspend to use set_user_sigmask
David Laight <David.Laight@ACULAB.COM> writes:

> From: David Laight
>> Sent: 11 June 2019 10:52
> ...
>> If I have an application that has a loop with a pselect call that
>> enables SIGINT (without a handler) and, for whatever reason,
>> one of the fd is always 'ready' then I'd expect a SIGINT
>> (from ^C) to terminate the program.
>>
>> A quick test program:
>>
>> #include <sys/time.h>
>> #include <sys/types.h>
>> #include <unistd.h>
>>
>> #include <sys/select.h>
>> #include <signal.h>
>>
>> int main(int argc, char **argv)
>> {
>> fd_set readfds;
>> sigset_t sig_int;
>> struct timespec delay = {1, 0};
>>
>> sigfillset(&sig_int);
>> sigdelset(&sig_int, SIGINT);
>>
>> sighold(SIGINT);
>>
>> for (;;) {
>> FD_ZERO(&readfds);
>> FD_SET(0, &readfds);
>> pselect(1, &readfds, NULL, NULL, &delay, &sig_int);
>>
>> poll(0,0,1000);
>> }
>> }
>>
>> Run under strace to see what is happening and send SIGINT from a different terminal.
>> The program sleeps for a second in each of the pselect() and poll() calls.
>> Send a SIGINT and in terminates after pselect() returns ERESTARTNOHAND.
>>
>> Run again, this time press enter - making fd 0 readable.
>> pselect() returns 1, but the program still exits.
>> (Tested on a 5.1.0-rc5 kernel.)
>>
>> If a signal handler were defined it should be called instead.
>
> If I add a signal handler for SIGINT it is called when pselect()
> returns regardless of the return value.

That is odd. Is this with Oleg's fix applied?

Eric

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