Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
signal: Refactor send_sigqueue()
To handle posix timers which have their signal ignored via SIG_IGN properly
it is required to requeue a ignored signal for delivery when SIG_IGN is
lifted so the timer gets rearmed.
Split the required code out of send_sigqueue() so it can be reused in
context of sigaction().
While at it rename send_sigqueue() to posixtimer_send_sigqueue() so its
clear what this is about.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.586453412@linutronix.de
+47
-39
+1
include/linux/posix-timers.h
+1
include/linux/posix-timers.h
···
109
109
110
110
void posixtimer_rearm_itimer(struct task_struct *p);
111
111
bool posixtimer_init_sigqueue(struct sigqueue *q);
112
+
int posixtimer_send_sigqueue(struct k_itimer *tmr);
112
113
bool posixtimer_deliver_signal(struct kernel_siginfo *info);
113
114
void posixtimer_free_timer(struct k_itimer *timer);
114
115
-1
include/linux/sched/signal.h
-1
include/linux/sched/signal.h
···
340
340
extern int zap_other_threads(struct task_struct *p);
341
341
extern struct sigqueue *sigqueue_alloc(void);
342
342
extern void sigqueue_free(struct sigqueue *);
343
-
extern int send_sigqueue(struct sigqueue *, struct pid *, enum pid_type, int si_private);
344
343
extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *);
345
344
346
345
static inline void clear_notify_signal(void)
+45
-37
kernel/signal.c
+45
-37
kernel/signal.c
···
1947
1947
__sigqueue_free(q);
1948
1948
}
1949
1949
1950
-
int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type, int si_private)
1950
+
static void posixtimer_queue_sigqueue(struct sigqueue *q, struct task_struct *t, enum pid_type type)
1951
1951
{
1952
-
int sig = q->info.si_signo;
1953
1952
struct sigpending *pending;
1953
+
int sig = q->info.si_signo;
1954
+
1955
+
signalfd_notify(t, sig);
1956
+
pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
1957
+
list_add_tail(&q->list, &pending->list);
1958
+
sigaddset(&pending->signal, sig);
1959
+
complete_signal(sig, t, type);
1960
+
}
1961
+
1962
+
/*
1963
+
* This function is used by POSIX timers to deliver a timer signal.
1964
+
* Where type is PIDTYPE_PID (such as for timers with SIGEV_THREAD_ID
1965
+
* set), the signal must be delivered to the specific thread (queues
1966
+
* into t->pending).
1967
+
*
1968
+
* Where type is not PIDTYPE_PID, signals must be delivered to the
1969
+
* process. In this case, prefer to deliver to current if it is in
1970
+
* the same thread group as the target process, which avoids
1971
+
* unnecessarily waking up a potentially idle task.
1972
+
*/
1973
+
static inline struct task_struct *posixtimer_get_target(struct k_itimer *tmr)
1974
+
{
1975
+
struct task_struct *t = pid_task(tmr->it_pid, tmr->it_pid_type);
1976
+
1977
+
if (t && tmr->it_pid_type != PIDTYPE_PID && same_thread_group(t, current))
1978
+
t = current;
1979
+
return t;
1980
+
}
1981
+
1982
+
int posixtimer_send_sigqueue(struct k_itimer *tmr)
1983
+
{
1984
+
struct sigqueue *q = tmr->sigq;
1985
+
int sig = q->info.si_signo;
1954
1986
struct task_struct *t;
1955
1987
unsigned long flags;
1956
1988
int ret, result;
1957
1989
1958
-
if (WARN_ON_ONCE(!(q->flags & SIGQUEUE_PREALLOC)))
1959
-
return 0;
1960
-
if (WARN_ON_ONCE(q->info.si_code != SI_TIMER))
1961
-
return 0;
1990
+
guard(rcu)();
1962
1991
1963
-
ret = -1;
1964
-
rcu_read_lock();
1965
-
1966
-
/*
1967
-
* This function is used by POSIX timers to deliver a timer signal.
1968
-
* Where type is PIDTYPE_PID (such as for timers with SIGEV_THREAD_ID
1969
-
* set), the signal must be delivered to the specific thread (queues
1970
-
* into t->pending).
1971
-
*
1972
-
* Where type is not PIDTYPE_PID, signals must be delivered to the
1973
-
* process. In this case, prefer to deliver to current if it is in
1974
-
* the same thread group as the target process, which avoids
1975
-
* unnecessarily waking up a potentially idle task.
1976
-
*/
1977
-
t = pid_task(pid, type);
1992
+
t = posixtimer_get_target(tmr);
1978
1993
if (!t)
1979
-
goto ret;
1980
-
if (type != PIDTYPE_PID && same_thread_group(t, current))
1981
-
t = current;
1994
+
return -1;
1995
+
1982
1996
if (!likely(lock_task_sighand(t, &flags)))
1983
-
goto ret;
1997
+
return -1;
1984
1998
1985
1999
/*
1986
2000
* Update @q::info::si_sys_private for posix timer signals with
···
2002
1988
* decides based on si_sys_private whether to invoke
2003
1989
* posixtimer_rearm() or not.
2004
1990
*/
2005
-
q->info.si_sys_private = si_private;
1991
+
q->info.si_sys_private = tmr->it_signal_seq;
2006
1992
2007
1993
ret = 1; /* the signal is ignored */
2008
-
result = TRACE_SIGNAL_IGNORED;
2009
-
if (!prepare_signal(sig, t, false))
1994
+
if (!prepare_signal(sig, t, false)) {
1995
+
result = TRACE_SIGNAL_IGNORED;
2010
1996
goto out;
1997
+
}
2011
1998
2012
1999
ret = 0;
2013
2000
if (unlikely(!list_empty(&q->list))) {
2014
2001
result = TRACE_SIGNAL_ALREADY_PENDING;
2015
2002
goto out;
2016
2003
}
2017
-
2018
-
signalfd_notify(t, sig);
2019
-
pending = (type != PIDTYPE_PID) ? &t->signal->shared_pending : &t->pending;
2020
-
list_add_tail(&q->list, &pending->list);
2021
-
sigaddset(&pending->signal, sig);
2022
-
complete_signal(sig, t, type);
2004
+
posixtimer_queue_sigqueue(q, t, tmr->it_pid_type);
2023
2005
result = TRACE_SIGNAL_DELIVERED;
2024
2006
out:
2025
-
trace_signal_generate(sig, &q->info, t, type != PIDTYPE_PID, result);
2007
+
trace_signal_generate(sig, &q->info, t, tmr->it_pid_type != PIDTYPE_PID, result);
2026
2008
unlock_task_sighand(t, &flags);
2027
-
ret:
2028
-
rcu_read_unlock();
2029
2009
return ret;
2030
2010
}
2031
2011
#endif /* CONFIG_POSIX_TIMERS */
+1
-1
kernel/time/posix-timers.c
+1
-1
kernel/time/posix-timers.c