From 6ade99ec6175ab2b54c227521e181e1c3c2bfc8a Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Fri, 24 Apr 2020 15:41:20 -0500 Subject: [PATCH] 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: 7bc3e6e55acf ("proc: Use a list of inodes to flush from proc") Reported-by: Oleg Nesterov Signed-off-by: "Eric W. Biederman" --- fs/proc/base.c | 1 - kernel/exit.c | 1 + 2 files changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 6042b646ab27..42f43c7b9669 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -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, diff --git a/kernel/exit.c b/kernel/exit.c index 389a88cb3081..ce2a75bc0ade 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -219,6 +219,7 @@ void release_task(struct task_struct *p) write_unlock_irq(&tasklist_lock); proc_flush_pid(thread_pid); + put_pid(thread_pid); release_thread(p); put_task_struct_rcu_user(p);