Unverified Commit ee9955d6 authored by Christian Brauner's avatar Christian Brauner
Browse files

mm: use pidfd_get_task() 

Instead of duplicating the same code in two places use the newly added
pidfd_get_task() helper. This fixes an (unimportant for now) bug where
PIDTYPE_PID is used whereas PIDTYPE_TGID should have been used.

Link: https://lore.kernel.org/r/20211004125050.1153693-3-christian.brauner@ubuntu.com
Link: https://lore.kernel.org/r/20211011133245.1703103-3-brauner@kernel.org


Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Matthew Bobrowski <repnop@google.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Reviewed-by: default avatarMatthew Bobrowski <repnop@google.com>
Acked-by: default avatarDavid Hildenbrand <david@redhat.com>
Signed-off-by: default avatarChristian Brauner <christian.brauner@ubuntu.com>
parent e9bdcdbf

mm/madvise.c

+3 −12
Original line number Diff line number Diff line
@@ -1235,7 +1235,6 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec, 
	struct iovec iovstack[UIO_FASTIOV], iovec;

	struct iovec *iov = iovstack;

	struct iov_iter iter;

	struct pid *pid;

	struct task_struct *task;

	struct mm_struct *mm;

	size_t total_len;
@@ -1250,18 +1249,12 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec, 
	if (ret < 0)

		goto out;



	pid = pidfd_get_pid(pidfd, &f_flags);

	if (IS_ERR(pid)) {

		ret = PTR_ERR(pid);

	task = pidfd_get_task(pidfd, &f_flags);

	if (IS_ERR(task)) {

		ret = PTR_ERR(task);

		goto free_iov;

	}



	task = get_pid_task(pid, PIDTYPE_PID);

	if (!task) {

		ret = -ESRCH;

		goto put_pid;

	}



	if (!process_madvise_behavior_valid(behavior)) {

		ret = -EINVAL;

		goto release_task;
@@ -1301,8 +1294,6 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec, 
	mmput(mm);

release_task:

	put_task_struct(task);

put_pid:

	put_pid(pid);

free_iov:

	kfree(iov);

out:

mm/oom_kill.c

+3 −12
Original line number Diff line number Diff line
@@ -1151,21 +1151,14 @@ SYSCALL_DEFINE2(process_mrelease, int, pidfd, unsigned int, flags) 
	struct task_struct *p;

	unsigned int f_flags;

	bool reap = true;

	struct pid *pid;

	long ret = 0;



	if (flags)

		return -EINVAL;



	pid = pidfd_get_pid(pidfd, &f_flags);

	if (IS_ERR(pid))

		return PTR_ERR(pid);



	task = get_pid_task(pid, PIDTYPE_TGID);

	if (!task) {

		ret = -ESRCH;

		goto put_pid;

	}

	task = pidfd_get_task(pidfd, &f_flags);

	if (IS_ERR(task))

		return PTR_ERR(task);



	/*

	 * Make sure to choose a thread which still has a reference to mm
@@ -1204,8 +1197,6 @@ SYSCALL_DEFINE2(process_mrelease, int, pidfd, unsigned int, flags) 
	mmdrop(mm);

put_task:

	put_task_struct(task);

put_pid:

	put_pid(pid);

	return ret;

#else

	return -ENOSYS;