Hi,
On 2020/12/1 16:53, Greg Kroah-Hartman wrote:
From: Jens Axboe <axboe@xxxxxxxxx>
[ Upstream commit 8d4c3e76e3be11a64df95ddee52e99092d42fc19 ]
If this is attempted by a kthread, then return -EOPNOTSUPP as we don't
currently support that. Once we can get task_pid_ptr() doing the right
thing, then this can go away again.
https://www.spinics.net/lists/io-uring/msg05297.html
This patch seems used for io-wq worker which is merged in
v5.5-rc1, why we need this in linux-4.19.y ?
Thanks,
Yang
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
fs/proc/self.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/fs/proc/self.c b/fs/proc/self.c
index cc6d4253399d1..7922edf70ce1a 100644
--- a/fs/proc/self.c
+++ b/fs/proc/self.c
@@ -16,6 +16,13 @@ static const char *proc_self_get_link(struct dentry *dentry,
pid_t tgid = task_tgid_nr_ns(current, ns);
char *name;
+ /*
+ * Not currently supported. Once we can inherit all of struct pid,
+ * we can allow this.
+ */
+ if (current->flags & PF_KTHREAD)
+ return ERR_PTR(-EOPNOTSUPP);
+
if (!tgid)
return ERR_PTR(-ENOENT);
/* max length of unsigned int in decimal + NULL term */
