Turn kill_pid_info() into kill_pid_info_type(), this allows to pass any
pid_type to group_send_sig_info(), despite its name it should work fine
even if type = PIDTYPE_PID.
Change pidfd_send_signal() to use PIDTYPE_PID or PIDTYPE_TGID depending
on PIDFD_THREAD.
While at it kill another TODO comment in pidfd_show_fdinfo(). As Christian
expains fdinfo reports f_flags, userspace can already detect PIDFD_THREAD.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
---
kernel/fork.c | 2 --
kernel/signal.c | 18 ++++++++++++------
2 files changed, 12 insertions(+), 8 deletions(-)
diff --git a/kernel/fork.c b/kernel/fork.c
index cd61ca87d0e6..47b565598063 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2051,8 +2051,6 @@ static void pidfd_show_fdinfo(struct seq_file *m, struct file *f)
seq_put_decimal_ll(m, "Pid:\t", nr);
- /* TODO: report PIDFD_THREAD */
-
#ifdef CONFIG_PID_NS
seq_put_decimal_ll(m, "\nNSpid:\t", nr);
if (nr > 0) {
diff --git a/kernel/signal.c b/kernel/signal.c
index c3fac06937e2..e3edcd784e45 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -47,6 +47,7 @@
#include <linux/cgroup.h>
#include <linux/audit.h>
#include <linux/sysctl.h>
+#include <uapi/linux/pidfd.h>
#define CREATE_TRACE_POINTS
#include <trace/events/signal.h>
@@ -1478,7 +1479,8 @@ int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp)
return ret;
}
-int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
+static int kill_pid_info_type(int sig, struct kernel_siginfo *info,
+ struct pid *pid, enum pid_type type)
{
int error = -ESRCH;
struct task_struct *p;
@@ -1487,11 +1489,10 @@ int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
rcu_read_lock();
p = pid_task(pid, PIDTYPE_PID);
if (p)
- error = group_send_sig_info(sig, info, p, PIDTYPE_TGID);
+ error = group_send_sig_info(sig, info, p, type);
rcu_read_unlock();
if (likely(!p || error != -ESRCH))
return error;
-
/*
* The task was unhashed in between, try again. If it
* is dead, pid_task() will return NULL, if we race with
@@ -1500,6 +1501,11 @@ int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
}
}
+int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
+{
+ return kill_pid_info_type(sig, info, pid, PIDTYPE_TGID);
+}
+
static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid)
{
int error;
@@ -3890,6 +3896,7 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
struct fd f;
struct pid *pid;
kernel_siginfo_t kinfo;
+ enum pid_type type;
/* Enforce flags be set to 0 until we add an extension. */
if (flags)
@@ -3928,9 +3935,8 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
prepare_kill_siginfo(sig, &kinfo);
}
- /* TODO: respect PIDFD_THREAD */
- ret = kill_pid_info(sig, &kinfo, pid);
-
+ type = (f.file->f_flags & PIDFD_THREAD) ? PIDTYPE_PID : PIDTYPE_TGID;
+ ret = kill_pid_info_type(sig, &kinfo, pid, type);
err:
fdput(f);
return ret;
--
2.25.1.362.g51ebf55
