On Tue, Jun 15, 2021 at 09:26:19AM -0700, Linus Torvalds wrote:
> On Tue, Jun 15, 2021 at 9:21 AM Leon Romanovsky <leon@xxxxxxxxxx> wrote:
> >
> > The commit 591a22c14d3f ("proc: Track /proc/$pid/attr/ opener mm_struct")
> > that we got in v5.13-rc6 broke our regression to pieces. The NIC interfaces
> > fail to start when using NetworkManager.
>
> Does the attached patch fix it?
Yes, this patch fixed the issue.
Tested-by: Leon Romanovsky <leonro@xxxxxxxxxx>
Thanks
>
> It just makes the open always succeed, and then the private_data that
> the open did (that may or may not then have been filled in) is only
> used on write.
>
> Linus
> fs/proc/base.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/proc/base.c b/fs/proc/base.c
> index 7118ebe38fa6..9cbd915025ad 100644
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -2676,7 +2676,9 @@ static int proc_pident_readdir(struct file *file, struct dir_context *ctx,
> #ifdef CONFIG_SECURITY
> static int proc_pid_attr_open(struct inode *inode, struct file *file)
> {
> - return __mem_open(inode, file, PTRACE_MODE_READ_FSCREDS);
> + file->private_data = NULL;
> + __mem_open(inode, file, PTRACE_MODE_READ_FSCREDS);
> + return 0;
> }
>
> static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
