summaryrefslogtreecommitdiff
path: root/kernel/signal.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/signal.c')
-rw-r--r--kernel/signal.c96
1 files changed, 54 insertions, 42 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index a4077e90f19f..16a305295256 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1263,6 +1263,10 @@ struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
struct sighand_struct *sighand;
for (;;) {
+ /*
+ * Disable interrupts early to avoid deadlocks.
+ * See rcu_read_unlock() comment header for details.
+ */
local_irq_save(*flags);
rcu_read_lock();
sighand = rcu_dereference(tsk->sighand);
@@ -1271,7 +1275,17 @@ struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
local_irq_restore(*flags);
break;
}
-
+ /*
+ * This sighand can be already freed and even reused, but
+ * we rely on SLAB_DESTROY_BY_RCU and sighand_ctor() which
+ * initializes ->siglock: this slab can't go away, it has
+ * the same object type, ->siglock can't be reinitialized.
+ *
+ * We need to ensure that tsk->sighand is still the same
+ * after we take the lock, we can race with de_thread() or
+ * __exit_signal(). In the latter case the next iteration
+ * must see ->sighand == NULL.
+ */
spin_lock(&sighand->siglock);
if (likely(sighand == tsk->sighand)) {
rcu_read_unlock();
@@ -1327,23 +1341,21 @@ int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
int error = -ESRCH;
struct task_struct *p;
- rcu_read_lock();
-retry:
- p = pid_task(pid, PIDTYPE_PID);
- if (p) {
- error = group_send_sig_info(sig, info, p);
- if (unlikely(error == -ESRCH))
- /*
- * The task was unhashed in between, try again.
- * If it is dead, pid_task() will return NULL,
- * if we race with de_thread() it will find the
- * new leader.
- */
- goto retry;
- }
- rcu_read_unlock();
+ for (;;) {
+ rcu_read_lock();
+ p = pid_task(pid, PIDTYPE_PID);
+ if (p)
+ error = group_send_sig_info(sig, info, p);
+ rcu_read_unlock();
+ if (likely(!p || error != -ESRCH))
+ return error;
- return error;
+ /*
+ * The task was unhashed in between, try again. If it
+ * is dead, pid_task() will return NULL, if we race with
+ * de_thread() it will find the new leader.
+ */
+ }
}
int kill_proc_info(int sig, struct siginfo *info, pid_t pid)
@@ -2166,8 +2178,7 @@ static int ptrace_signal(int signr, siginfo_t *info)
return signr;
}
-int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka,
- struct pt_regs *regs, void *cookie)
+int get_signal(struct ksignal *ksig)
{
struct sighand_struct *sighand = current->sighand;
struct signal_struct *signal = current->signal;
@@ -2237,13 +2248,13 @@ relock:
goto relock;
}
- signr = dequeue_signal(current, &current->blocked, info);
+ signr = dequeue_signal(current, &current->blocked, &ksig->info);
if (!signr)
break; /* will return 0 */
if (unlikely(current->ptrace) && signr != SIGKILL) {
- signr = ptrace_signal(signr, info);
+ signr = ptrace_signal(signr, &ksig->info);
if (!signr)
continue;
}
@@ -2251,13 +2262,13 @@ relock:
ka = &sighand->action[signr-1];
/* Trace actually delivered signals. */
- trace_signal_deliver(signr, info, ka);
+ trace_signal_deliver(signr, &ksig->info, ka);
if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
continue;
if (ka->sa.sa_handler != SIG_DFL) {
/* Run the handler. */
- *return_ka = *ka;
+ ksig->ka = *ka;
if (ka->sa.sa_flags & SA_ONESHOT)
ka->sa.sa_handler = SIG_DFL;
@@ -2307,7 +2318,7 @@ relock:
spin_lock_irq(&sighand->siglock);
}
- if (likely(do_signal_stop(info->si_signo))) {
+ if (likely(do_signal_stop(ksig->info.si_signo))) {
/* It released the siglock. */
goto relock;
}
@@ -2328,7 +2339,7 @@ relock:
if (sig_kernel_coredump(signr)) {
if (print_fatal_signals)
- print_fatal_signal(info->si_signo);
+ print_fatal_signal(ksig->info.si_signo);
proc_coredump_connector(current);
/*
* If it was able to dump core, this kills all
@@ -2338,34 +2349,32 @@ relock:
* first and our do_group_exit call below will use
* that value and ignore the one we pass it.
*/
- do_coredump(info);
+ do_coredump(&ksig->info);
}
/*
* Death signals, no core dump.
*/
- do_group_exit(info->si_signo);
+ do_group_exit(ksig->info.si_signo);
/* NOTREACHED */
}
spin_unlock_irq(&sighand->siglock);
- return signr;
+
+ ksig->sig = signr;
+ return ksig->sig > 0;
}
/**
* signal_delivered -
- * @sig: number of signal being delivered
- * @info: siginfo_t of signal being delivered
- * @ka: sigaction setting that chose the handler
- * @regs: user register state
+ * @ksig: kernel signal struct
* @stepping: nonzero if debugger single-step or block-step in use
*
* This function should be called when a signal has successfully been
- * delivered. It updates the blocked signals accordingly (@ka->sa.sa_mask
+ * delivered. It updates the blocked signals accordingly (@ksig->ka.sa.sa_mask
* is always blocked, and the signal itself is blocked unless %SA_NODEFER
- * is set in @ka->sa.sa_flags. Tracing is notified.
+ * is set in @ksig->ka.sa.sa_flags. Tracing is notified.
*/
-void signal_delivered(int sig, siginfo_t *info, struct k_sigaction *ka,
- struct pt_regs *regs, int stepping)
+static void signal_delivered(struct ksignal *ksig, int stepping)
{
sigset_t blocked;
@@ -2375,11 +2384,11 @@ void signal_delivered(int sig, siginfo_t *info, struct k_sigaction *ka,
simply clear the restore sigmask flag. */
clear_restore_sigmask();
- sigorsets(&blocked, &current->blocked, &ka->sa.sa_mask);
- if (!(ka->sa.sa_flags & SA_NODEFER))
- sigaddset(&blocked, sig);
+ sigorsets(&blocked, &current->blocked, &ksig->ka.sa.sa_mask);
+ if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
+ sigaddset(&blocked, ksig->sig);
set_current_blocked(&blocked);
- tracehook_signal_handler(sig, info, ka, regs, stepping);
+ tracehook_signal_handler(stepping);
}
void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
@@ -2387,8 +2396,7 @@ void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
if (failed)
force_sigsegv(ksig->sig, current);
else
- signal_delivered(ksig->sig, &ksig->info, &ksig->ka,
- signal_pt_regs(), stepping);
+ signal_delivered(ksig, stepping);
}
/*
@@ -2748,6 +2756,10 @@ int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from)
if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)
err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
#endif
+#ifdef SEGV_BNDERR
+ err |= __put_user(from->si_lower, &to->si_lower);
+ err |= __put_user(from->si_upper, &to->si_upper);
+#endif
break;
case __SI_CHLD:
err |= __put_user(from->si_pid, &to->si_pid);
generated by cgit v1.2.3 (git 2.39.0) at 2025-02-20 14:04:45 +0300