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Biederman" , Tycho Andersen , linux-kernel@vger.kernel.org Subject: [PATCH v3 0/1] pidfd: implement PIDFD_THREAD flag for pidfd_open() Message-ID: <20240131132541.GA23632@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.2 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1789612803862687629 X-GMAIL-MSGID: 1789612803862687629 Please see the interdiff below. Also, I updated the changelog to document that the behaviour of pidfd_poll(PIDFD_THREAD, pid-of-group-leader) is not well defined if a sub-thread execs. Do you agree with this semantics? Oleg. diff --git a/fs/exec.c b/fs/exec.c index 73e4045df271..0fd7e668c477 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1143,7 +1143,11 @@ static int de_thread(struct task_struct *tsk) BUG_ON(leader->exit_state != EXIT_ZOMBIE); leader->exit_state = EXIT_DEAD; - + /* + * leader and tsk exhanged their pids, the old pid dies, + * wake up the PIDFD_THREAD waiters. + */ + do_notify_pidfd(leader); /* * We are going to release_task()->ptrace_unlink() silently, * the tracer can sleep in do_wait(). EXIT_DEAD guarantees diff --git a/include/linux/pid.h b/include/linux/pid.h index e6a041cb8bac..8124d57752b9 100644 --- a/include/linux/pid.h +++ b/include/linux/pid.h @@ -70,10 +70,11 @@ extern const struct file_operations pidfd_fops; struct file; -extern struct pid *pidfd_pid(const struct file *file); +struct pid *pidfd_pid(const struct file *file); struct pid *pidfd_get_pid(unsigned int fd, unsigned int *flags); struct task_struct *pidfd_get_task(int pidfd, unsigned int *flags); int pidfd_prepare(struct pid *pid, unsigned int flags, struct file **ret); +void do_notify_pidfd(struct task_struct *task); static inline struct pid *get_pid(struct pid *pid) { diff --git a/kernel/signal.c b/kernel/signal.c index 5f48d2c4b409..9b40109f0c56 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2019,7 +2019,7 @@ int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type) return ret; } -static void do_notify_pidfd(struct task_struct *task) +void do_notify_pidfd(struct task_struct *task) { struct pid *pid;