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Biederman" , Tycho Andersen , linux-api@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] pidfd: change pidfd_send_signal() to respect PIDFD_THREAD Message-ID: <20240207114549.GA12697@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 10.11.54.7 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1790240567578243134 X-GMAIL-MSGID: 1790240567578243134 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 --- 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 #include #include +#include #define CREATE_TRACE_POINTS #include @@ -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;