From f6187769dae48234f3877df3c4d99294cc2254fa Mon Sep 17 00:00:00 2001 From: Fabian Frederick Date: Wed, 4 Jun 2014 16:11:12 -0700 Subject: sys_sgetmask/sys_ssetmask: add CONFIG_SGETMASK_SYSCALL sys_sgetmask and sys_ssetmask are obsolete system calls no longer supported in libc. This patch replaces architecture related __ARCH_WANT_SYS_SGETMAX by expert mode configuration.That option is enabled by default for those architectures. Signed-off-by: Fabian Frederick Cc: Steven Miao Cc: Mikael Starvik Cc: Jesper Nilsson Cc: David Howells Cc: Geert Uytterhoeven Cc: Michal Simek Cc: Ralf Baechle Cc: Koichi Yasutake Cc: "James E.J. Bottomley" Cc: Helge Deller Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: "David S. Miller" Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Greg Ungerer Cc: Heiko Carstens Cc: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/signal.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/signal.c') diff --git a/kernel/signal.c b/kernel/signal.c index 6ea13c09ae5..6e600aaa2af 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -3496,7 +3496,7 @@ COMPAT_SYSCALL_DEFINE3(sigaction, int, sig, } #endif -#ifdef __ARCH_WANT_SYS_SGETMASK +#ifdef CONFIG_SGETMASK_SYSCALL /* * For backwards compatibility. Functionality superseded by sigprocmask. @@ -3517,7 +3517,7 @@ SYSCALL_DEFINE1(ssetmask, int, newmask) return old; } -#endif /* __ARCH_WANT_SGETMASK */ +#endif /* CONFIG_SGETMASK_SYSCALL */ #ifdef __ARCH_WANT_SYS_SIGNAL /* -- cgit v1.2.3-70-g09d2 From 650226bd95817d727c9a388752d72ef292c4a668 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 6 Jun 2014 14:36:44 -0700 Subject: ptrace: task_clear_jobctl_trapping()->wake_up_bit() needs mb() __wake_up_bit() checks waitqueue_active() and thus the caller needs mb() as wake_up_bit() documents, fix task_clear_jobctl_trapping(). Signed-off-by: Oleg Nesterov Cc: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/signal.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel/signal.c') diff --git a/kernel/signal.c b/kernel/signal.c index 6e600aaa2af..9b5453ee5f5 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -277,6 +277,7 @@ void task_clear_jobctl_trapping(struct task_struct *task) { if (unlikely(task->jobctl & JOBCTL_TRAPPING)) { task->jobctl &= ~JOBCTL_TRAPPING; + smp_mb(); /* advised by wake_up_bit() */ wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT); } } -- cgit v1.2.3-70-g09d2 From 6114041aa7e79a28cee554450fc4a67442327c7f Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 6 Jun 2014 14:36:46 -0700 Subject: signals: s/siginitset/sigemptyset/ in do_sigtimedwait() Cosmetic, but siginitset(0) looks a bit strange, sigemptyset() is what do_sigtimedwait() needs. Signed-off-by: Oleg Nesterov Cc: Peter Zijlstra Cc: Al Viro Cc: David Woodhouse Cc: Frederic Weisbecker Cc: Geert Uytterhoeven Cc: Ingo Molnar Cc: Mathieu Desnoyers Cc: Richard Weinberger Cc: Steven Rostedt Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/signal.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/signal.c') diff --git a/kernel/signal.c b/kernel/signal.c index 9b5453ee5f5..251ca9c9d66 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2855,7 +2855,7 @@ int do_sigtimedwait(const sigset_t *which, siginfo_t *info, spin_lock_irq(&tsk->sighand->siglock); __set_task_blocked(tsk, &tsk->real_blocked); - siginitset(&tsk->real_blocked, 0); + sigemptyset(&tsk->real_blocked); sig = dequeue_signal(tsk, &mask, info); } spin_unlock_irq(&tsk->sighand->siglock); -- cgit v1.2.3-70-g09d2 From 9490592f2762320ac220f50d4459d9ea7bb797c8 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 6 Jun 2014 14:36:48 -0700 Subject: signals: kill rm_from_queue(), change prepare_signal() to use for_each_thread() rm_from_queue() doesn't make sense. The only caller, prepare_signal(), can use rm_from_queue_full() with the same effect. While at it, change prepare_signal() to use for_each_thread() instead of do/while_each_thread. Signed-off-by: Oleg Nesterov Cc: Peter Zijlstra Cc: Al Viro Cc: David Woodhouse Cc: Frederic Weisbecker Cc: Geert Uytterhoeven Cc: Ingo Molnar Cc: Mathieu Desnoyers Cc: Richard Weinberger Cc: Steven Rostedt Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/signal.c | 43 ++++++++++--------------------------------- 1 file changed, 10 insertions(+), 33 deletions(-) (limited to 'kernel/signal.c') diff --git a/kernel/signal.c b/kernel/signal.c index 251ca9c9d66..19316dc3eb0 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -728,29 +728,6 @@ static int rm_from_queue_full(sigset_t *mask, struct sigpending *s) } return 1; } -/* - * Remove signals in mask from the pending set and queue. - * Returns 1 if any signals were found. - * - * All callers must be holding the siglock. - */ -static int rm_from_queue(unsigned long mask, struct sigpending *s) -{ - struct sigqueue *q, *n; - - if (!sigtestsetmask(&s->signal, mask)) - return 0; - - sigdelsetmask(&s->signal, mask); - list_for_each_entry_safe(q, n, &s->list, list) { - if (q->info.si_signo < SIGRTMIN && - (mask & sigmask(q->info.si_signo))) { - list_del_init(&q->list); - __sigqueue_free(q); - } - } - return 1; -} static inline int is_si_special(const struct siginfo *info) { @@ -862,6 +839,7 @@ static bool prepare_signal(int sig, struct task_struct *p, bool force) { struct signal_struct *signal = p->signal; struct task_struct *t; + sigset_t flush; if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) { if (signal->flags & SIGNAL_GROUP_COREDUMP) @@ -873,26 +851,25 @@ static bool prepare_signal(int sig, struct task_struct *p, bool force) /* * This is a stop signal. Remove SIGCONT from all queues. */ - rm_from_queue(sigmask(SIGCONT), &signal->shared_pending); - t = p; - do { - rm_from_queue(sigmask(SIGCONT), &t->pending); - } while_each_thread(p, t); + siginitset(&flush, sigmask(SIGCONT)); + rm_from_queue_full(&flush, &signal->shared_pending); + for_each_thread(p, t) + rm_from_queue_full(&flush, &t->pending); } else if (sig == SIGCONT) { unsigned int why; /* * Remove all stop signals from all queues, wake all threads. */ - rm_from_queue(SIG_KERNEL_STOP_MASK, &signal->shared_pending); - t = p; - do { + siginitset(&flush, SIG_KERNEL_STOP_MASK); + rm_from_queue_full(&flush, &signal->shared_pending); + for_each_thread(p, t) { + rm_from_queue_full(&flush, &t->pending); task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING); - rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending); if (likely(!(t->ptrace & PT_SEIZED))) wake_up_state(t, __TASK_STOPPED); else ptrace_trap_notify(t); - } while_each_thread(p, t); + } /* * Notify the parent with CLD_CONTINUED if we were stopped. -- cgit v1.2.3-70-g09d2 From c09c144139f227de13330111adcafa1659ebd008 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 6 Jun 2014 14:36:50 -0700 Subject: signals: rename rm_from_queue_full() to flush_sigqueue_mask() "rm_from_queue_full" looks ugly and misleading, especially now that rm_from_queue() has gone away. Rename it to flush_sigqueue_mask(), this matches flush_sigqueue() we already have. Also remove the obsolete comment which explains the difference with rm_from_queue() we already killed. Signed-off-by: Oleg Nesterov Cc: Peter Zijlstra Cc: Al Viro Cc: David Woodhouse Cc: Frederic Weisbecker Cc: Geert Uytterhoeven Cc: Ingo Molnar Cc: Mathieu Desnoyers Cc: Richard Weinberger Cc: Steven Rostedt Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/signal.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) (limited to 'kernel/signal.c') diff --git a/kernel/signal.c b/kernel/signal.c index 19316dc3eb0..c088011f873 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -706,11 +706,8 @@ void signal_wake_up_state(struct task_struct *t, unsigned int state) * Returns 1 if any signals were found. * * All callers must be holding the siglock. - * - * This version takes a sigset mask and looks at all signals, - * not just those in the first mask word. */ -static int rm_from_queue_full(sigset_t *mask, struct sigpending *s) +static int flush_sigqueue_mask(sigset_t *mask, struct sigpending *s) { struct sigqueue *q, *n; sigset_t m; @@ -852,18 +849,18 @@ static bool prepare_signal(int sig, struct task_struct *p, bool force) * This is a stop signal. Remove SIGCONT from all queues. */ siginitset(&flush, sigmask(SIGCONT)); - rm_from_queue_full(&flush, &signal->shared_pending); + flush_sigqueue_mask(&flush, &signal->shared_pending); for_each_thread(p, t) - rm_from_queue_full(&flush, &t->pending); + flush_sigqueue_mask(&flush, &t->pending); } else if (sig == SIGCONT) { unsigned int why; /* * Remove all stop signals from all queues, wake all threads. */ siginitset(&flush, SIG_KERNEL_STOP_MASK); - rm_from_queue_full(&flush, &signal->shared_pending); + flush_sigqueue_mask(&flush, &signal->shared_pending); for_each_thread(p, t) { - rm_from_queue_full(&flush, &t->pending); + flush_sigqueue_mask(&flush, &t->pending); task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING); if (likely(!(t->ptrace & PT_SEIZED))) wake_up_state(t, __TASK_STOPPED); @@ -3102,9 +3099,9 @@ int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) if (sig_handler_ignored(sig_handler(t, sig), sig)) { sigemptyset(&mask); sigaddset(&mask, sig); - rm_from_queue_full(&mask, &t->signal->shared_pending); + flush_sigqueue_mask(&mask, &t->signal->shared_pending); do { - rm_from_queue_full(&mask, &t->pending); + flush_sigqueue_mask(&mask, &t->pending); } while_each_thread(current, t); } } @@ -3113,7 +3110,7 @@ int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) return 0; } -static int +static int do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp) { stack_t oss; -- cgit v1.2.3-70-g09d2 From afe2b0386ac22b6a189a2067b25282cade3fbb4d Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 6 Jun 2014 14:36:51 -0700 Subject: signals: cleanup the usage of t/current in do_sigaction() The usage of "task_struct *t" and "current" in do_sigaction() looks really annoying and chaotic. Initially "t" is used as a cached value of current but not consistently, then it is reused as a loop variable and we have to use "current" again. Clean up this mess and also convert the code to use for_each_thread(). Signed-off-by: Oleg Nesterov Cc: Peter Zijlstra Cc: Al Viro Cc: David Woodhouse Cc: Frederic Weisbecker Cc: Geert Uytterhoeven Cc: Ingo Molnar Cc: Mathieu Desnoyers Cc: Richard Weinberger Cc: Steven Rostedt Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/signal.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) (limited to 'kernel/signal.c') diff --git a/kernel/signal.c b/kernel/signal.c index c088011f873..a6d8c3af0ad 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -3068,16 +3068,16 @@ COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo, int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) { - struct task_struct *t = current; + struct task_struct *p = current, *t; struct k_sigaction *k; sigset_t mask; if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) return -EINVAL; - k = &t->sighand->action[sig-1]; + k = &p->sighand->action[sig-1]; - spin_lock_irq(¤t->sighand->siglock); + spin_lock_irq(&p->sighand->siglock); if (oact) *oact = *k; @@ -3096,17 +3096,16 @@ int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) * (for example, SIGCHLD), shall cause the pending signal to * be discarded, whether or not it is blocked" */ - if (sig_handler_ignored(sig_handler(t, sig), sig)) { + if (sig_handler_ignored(sig_handler(p, sig), sig)) { sigemptyset(&mask); sigaddset(&mask, sig); - flush_sigqueue_mask(&mask, &t->signal->shared_pending); - do { + flush_sigqueue_mask(&mask, &p->signal->shared_pending); + for_each_thread(p, t) flush_sigqueue_mask(&mask, &t->pending); - } while_each_thread(current, t); } } - spin_unlock_irq(¤t->sighand->siglock); + spin_unlock_irq(&p->sighand->siglock); return 0; } -- cgit v1.2.3-70-g09d2 From 0341729b4b832e753c5e745c6ba0e797f6198be0 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 6 Jun 2014 14:36:53 -0700 Subject: signals: mv {dis,}allow_signal() from sched.h/exit.c to signal.[ch] Move the declaration/definition of allow_signal/disallow_signal to signal.h/signal.c. The new place is more logical and allows to use the static helpers in signal.c (see the next changes). While at it, make them return void and remove the valid_signal() check. Nobody checks the returned value, and in-kernel users must not pass the wrong signal number. Signed-off-by: Oleg Nesterov Cc: Peter Zijlstra Cc: Al Viro Cc: David Woodhouse Cc: Frederic Weisbecker Cc: Geert Uytterhoeven Cc: Ingo Molnar Cc: Mathieu Desnoyers Cc: Richard Weinberger Cc: Steven Rostedt Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/sched.h | 3 --- include/linux/signal.h | 2 ++ kernel/exit.c | 39 --------------------------------------- kernel/signal.c | 29 +++++++++++++++++++++++++++++ 4 files changed, 31 insertions(+), 42 deletions(-) (limited to 'kernel/signal.c') diff --git a/include/linux/sched.h b/include/linux/sched.h index 8fcd0e6098d..ea74596014a 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2414,9 +2414,6 @@ extern void flush_itimer_signals(void); extern void do_group_exit(int); -extern int allow_signal(int); -extern int disallow_signal(int); - extern int do_execve(struct filename *, const char __user * const __user *, const char __user * const __user *); diff --git a/include/linux/signal.h b/include/linux/signal.h index ae744c31463..ac83c593f4b 100644 --- a/include/linux/signal.h +++ b/include/linux/signal.h @@ -284,6 +284,8 @@ extern int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, extern void signal_setup_done(int failed, struct ksignal *ksig, int stepping); extern void signal_delivered(int sig, siginfo_t *info, struct k_sigaction *ka, struct pt_regs *regs, int stepping); extern void exit_signals(struct task_struct *tsk); +extern void allow_signal(int); +extern void disallow_signal(int); /* * Eventually that'll replace get_signal_to_deliver(); macro for now, diff --git a/kernel/exit.c b/kernel/exit.c index 750c2e59461..e5c4668f179 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -313,45 +313,6 @@ kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent) } } -/* - * Let kernel threads use this to say that they allow a certain signal. - * Must not be used if kthread was cloned with CLONE_SIGHAND. - */ -int allow_signal(int sig) -{ - if (!valid_signal(sig) || sig < 1) - return -EINVAL; - - spin_lock_irq(¤t->sighand->siglock); - /* This is only needed for daemonize()'ed kthreads */ - sigdelset(¤t->blocked, sig); - /* - * Kernel threads handle their own signals. Let the signal code - * know it'll be handled, so that they don't get converted to - * SIGKILL or just silently dropped. - */ - current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2; - recalc_sigpending(); - spin_unlock_irq(¤t->sighand->siglock); - return 0; -} - -EXPORT_SYMBOL(allow_signal); - -int disallow_signal(int sig) -{ - if (!valid_signal(sig) || sig < 1) - return -EINVAL; - - spin_lock_irq(¤t->sighand->siglock); - current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN; - recalc_sigpending(); - spin_unlock_irq(¤t->sighand->siglock); - return 0; -} - -EXPORT_SYMBOL(disallow_signal); - #ifdef CONFIG_MEMCG /* * A task is exiting. If it owned this mm, find a new owner for the mm. diff --git a/kernel/signal.c b/kernel/signal.c index a6d8c3af0ad..7d6ff8b1850 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -3066,6 +3066,35 @@ COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo, } #endif +/* + * Let kernel threads use this to say that they allow a certain signal. + * Must not be used if kthread was cloned with CLONE_SIGHAND. + */ +void allow_signal(int sig) +{ + spin_lock_irq(¤t->sighand->siglock); + /* This is only needed for daemonize()'ed kthreads */ + sigdelset(¤t->blocked, sig); + /* + * Kernel threads handle their own signals. Let the signal code + * know it'll be handled, so that they don't get converted to + * SIGKILL or just silently dropped. + */ + current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2; + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); +} +EXPORT_SYMBOL(allow_signal); + +void disallow_signal(int sig) +{ + spin_lock_irq(¤t->sighand->siglock); + current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN; + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); +} +EXPORT_SYMBOL(disallow_signal); + int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) { struct task_struct *p = current, *t; -- cgit v1.2.3-70-g09d2 From ec5955b8fdc1b0bc62495e13869769be732cc6c3 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 6 Jun 2014 14:36:57 -0700 Subject: signals: kill the obsolete sigdelset() and recalc_sigpending() in allow_signal() allow_signal() does sigdelset(current->blocked) due to historic reason, previously it could be called by a daemonize()'ed kthread, and daemonize() played with current->blocked. Now that daemonize() has gone away we can remove sigdelset() and recalc_sigpending(). If a user really wants to unblock a signal, it must use sigprocmask() or set_current_block() explicitely. Signed-off-by: Oleg Nesterov Cc: Peter Zijlstra Cc: Al Viro Cc: David Woodhouse Cc: Frederic Weisbecker Cc: Geert Uytterhoeven Cc: Ingo Molnar Cc: Mathieu Desnoyers Cc: Richard Weinberger Cc: Steven Rostedt Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/signal.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'kernel/signal.c') diff --git a/kernel/signal.c b/kernel/signal.c index 7d6ff8b1850..c64c891ca0a 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -3072,16 +3072,13 @@ COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo, */ void allow_signal(int sig) { - spin_lock_irq(¤t->sighand->siglock); - /* This is only needed for daemonize()'ed kthreads */ - sigdelset(¤t->blocked, sig); /* * Kernel threads handle their own signals. Let the signal code * know it'll be handled, so that they don't get converted to * SIGKILL or just silently dropped. */ + spin_lock_irq(¤t->sighand->siglock); current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2; - recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); } EXPORT_SYMBOL(allow_signal); -- cgit v1.2.3-70-g09d2 From 580d34e42ad621736a3c53c9c11a2152c18a4068 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 6 Jun 2014 14:36:58 -0700 Subject: signals: disallow_signal() should flush the potentially pending signal disallow_signal() simply sets SIG_IGN, this is not enough and recalc_sigpending() is simply pointless because in can never change the state of TIF_SIGPENDING. If we ignore a signal, we also need to do flush_sigqueue_mask() for the case when this signal is pending, this way recalc_sigpending() can actually clear TIF_SIGPENDING and we do not "leak" the allocated siginfo's. Signed-off-by: Oleg Nesterov Cc: Peter Zijlstra Cc: Al Viro Cc: David Woodhouse Cc: Frederic Weisbecker Cc: Geert Uytterhoeven Cc: Ingo Molnar Cc: Mathieu Desnoyers Cc: Richard Weinberger Cc: Steven Rostedt Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/signal.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'kernel/signal.c') diff --git a/kernel/signal.c b/kernel/signal.c index c64c891ca0a..3ec405132c7 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -3085,8 +3085,15 @@ EXPORT_SYMBOL(allow_signal); void disallow_signal(int sig) { + sigset_t mask; + + sigemptyset(&mask); + sigaddset(&mask, sig); + spin_lock_irq(¤t->sighand->siglock); current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN; + flush_sigqueue_mask(&mask, ¤t->signal->shared_pending); + flush_sigqueue_mask(&mask, ¤t->pending); recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); } -- cgit v1.2.3-70-g09d2 From b4e74264eb0b03f42097fa70a0766312156244a0 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 6 Jun 2014 14:37:00 -0700 Subject: signals: introduce kernel_sigaction() Now that allow_signal() is really trivial we can unify it with disallow_signal(). Add the new helper, kernel_sigaction(), and reimplement allow_signal/disallow_signal as a trivial wrappers. This saves one EXPORT_SYMBOL() and the new helper can have more users. Signed-off-by: Oleg Nesterov Cc: Peter Zijlstra Cc: Al Viro Cc: David Woodhouse Cc: Frederic Weisbecker Cc: Geert Uytterhoeven Cc: Ingo Molnar Cc: Mathieu Desnoyers Cc: Richard Weinberger Cc: Steven Rostedt Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/signal.h | 18 ++++++++++++++++-- kernel/signal.c | 36 ++++++++++++------------------------ 2 files changed, 28 insertions(+), 26 deletions(-) (limited to 'kernel/signal.c') diff --git a/include/linux/signal.h b/include/linux/signal.h index ac83c593f4b..c9e65360c49 100644 --- a/include/linux/signal.h +++ b/include/linux/signal.h @@ -284,8 +284,22 @@ extern int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, extern void signal_setup_done(int failed, struct ksignal *ksig, int stepping); extern void signal_delivered(int sig, siginfo_t *info, struct k_sigaction *ka, struct pt_regs *regs, int stepping); extern void exit_signals(struct task_struct *tsk); -extern void allow_signal(int); -extern void disallow_signal(int); +extern void kernel_sigaction(int, __sighandler_t); + +static inline void allow_signal(int sig) +{ + /* + * Kernel threads handle their own signals. Let the signal code + * know it'll be handled, so that they don't get converted to + * SIGKILL or just silently dropped. + */ + kernel_sigaction(sig, (__force __sighandler_t)2); +} + +static inline void disallow_signal(int sig) +{ + kernel_sigaction(sig, SIG_IGN); +} /* * Eventually that'll replace get_signal_to_deliver(); macro for now, diff --git a/kernel/signal.c b/kernel/signal.c index 3ec405132c7..a4077e90f19 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -3067,37 +3067,25 @@ COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo, #endif /* - * Let kernel threads use this to say that they allow a certain signal. - * Must not be used if kthread was cloned with CLONE_SIGHAND. + * For kthreads only, must not be used if cloned with CLONE_SIGHAND */ -void allow_signal(int sig) +void kernel_sigaction(int sig, __sighandler_t action) { - /* - * Kernel threads handle their own signals. Let the signal code - * know it'll be handled, so that they don't get converted to - * SIGKILL or just silently dropped. - */ spin_lock_irq(¤t->sighand->siglock); - current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2; - spin_unlock_irq(¤t->sighand->siglock); -} -EXPORT_SYMBOL(allow_signal); + current->sighand->action[sig - 1].sa.sa_handler = action; + if (action == SIG_IGN) { + sigset_t mask; -void disallow_signal(int sig) -{ - sigset_t mask; + sigemptyset(&mask); + sigaddset(&mask, sig); - sigemptyset(&mask); - sigaddset(&mask, sig); - - spin_lock_irq(¤t->sighand->siglock); - current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN; - flush_sigqueue_mask(&mask, ¤t->signal->shared_pending); - flush_sigqueue_mask(&mask, ¤t->pending); - recalc_sigpending(); + flush_sigqueue_mask(&mask, ¤t->signal->shared_pending); + flush_sigqueue_mask(&mask, ¤t->pending); + recalc_sigpending(); + } spin_unlock_irq(¤t->sighand->siglock); } -EXPORT_SYMBOL(disallow_signal); +EXPORT_SYMBOL(kernel_sigaction); int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) { -- cgit v1.2.3-70-g09d2