Re: [GIT PULL] execve updates for v6.13-rc1

[Al Viro]

On Thu, Nov 21, 2024 at 02:36:19AM +0000, Al Viro wrote:
> On Wed, Nov 20, 2024 at 02:50:39PM -0800, Linus Torvalds wrote:
> > So you probably want to do something like
> > 
> >         const char *name = smp_load_acquire(&dentry->d_name.name);
> > 
> > under the RCU read lock before then copying it with strscpy(). It
> > should always be NULL-terminated.
> > 
> > If you want to be extra careful, you might surround it with a
> > 
> >         read_seqbegin_or_lock(&rename_lock, &seq);
> 
> What for?
> 
> 	char name[something];
> 
> 	sprintf(name, "%*pD", sizeof(name) - 1, file);
> 
> and be done with that...

... or

	struct name_snapshot n;

	take_dentry_name_snapshot(&n, file->f_path.dentry);

	do_something(n.name.name);

	release_dentry_name_snapshot(&n);