Commit 6ade99ec authored Apr 24, 2020 by Eric W. Biederman

proc: Put thread_pid in release_task not proc_flush_pid



Oleg pointed out that in the unlikely event the kernel is compiled
with CONFIG_PROC_FS unset that release_task will now leak the pid.

Move the put_pid out of proc_flush_pid into release_task to fix this
and to guarantee I don't make that mistake again.

When possible it makes sense to keep get and put in the same function
so it can easily been seen how they pair up.

Fixes: 7bc3e6e5 ("proc: Use a list of inodes to flush from proc")
Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

parent 61e713bd

fs/proc/base.c

+0 −1

Original line number	Diff line number	Diff line
		@@ -3274,7 +3274,6 @@ static const struct inode_operations proc_tgid_base_inode_operations = {
		void proc_flush_pid(struct pid *pid)
		{
		proc_invalidate_siblings_dcache(&pid->inodes, &pid->lock);
		put_pid(pid);
		}

		static struct dentry proc_pid_instantiate(struct dentry dentry,

kernel/exit.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -219,6 +219,7 @@ repeat:

		write_unlock_irq(&tasklist_lock);
		proc_flush_pid(thread_pid);
		put_pid(thread_pid);
		release_thread(p);
		put_task_struct_rcu_user(p);

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