2020-04-25 16:05:13

by Eric W. Biederman

[permalink] [raw]
Subject: [GIT PULL] Please pull proc_flush_pid fix for v5.7-rc3


Linus,

Please pull the for-linus branch from the git tree:

git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace.git for-linus

HEAD: 6ade99ec6175ab2b54c227521e181e1c3c2bfc8a proc: Put thread_pid in release_task not proc_flush_pid

Oleg noticed that put_pid(thread_pid) was not getting called when proc
was not compiled in. Let's get that fixed before 5.7 is released and
causes problems for anyone.

Eric

---

From: "Eric W. Biederman" <[email protected]>
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")
Signed-off-by: "Eric W. Biederman" <[email protected]>
---
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);

--
2.20.1





2020-04-25 19:34:27

by pr-tracker-bot

[permalink] [raw]
Subject: Re: [GIT PULL] Please pull proc_flush_pid fix for v5.7-rc3

The pull request you sent on Sat, 25 Apr 2020 10:58:35 -0500:

> git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace.git for-linus

has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/b2768df24ec400dd4f7fa79542f797e904812053

Thank you!

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