On Mon, Jun 03, 2024 at 09:53:26AM +0800, Gao Xiang wrote: > Hi Al, > > On 2024/6/3 08:11, Al Viro wrote: > > fd_install() can't be undone by close_fd(). Just delay it > > until the last failure exit - have cachefiles_ondemand_get_fd() > > return the file on success (and ERR_PTR() on error) and let the > > caller do fd_install() after successful copy_to_user() > > > > Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx> > > It's a straight-forward fix to me, yet it will have a conflict with > https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git/commit/fs/cachefiles?h=vfs.fixes&id=4b4391e77a6bf24cba2ef1590e113d9b73b11039 > https://lore.kernel.org/all/20240522114308.2402121-10-libaokun@xxxxxxxxxxxxxxx/ > > It also moves fd_install() to the end of the daemon_read() and tends > to fix it for months, does it look good to you? Looks sane (and my variant lacks put_unused_fd(), so it leaks the descriptor). OTOH, I suspect that my variant of calling conventions makes for less churn - fd is available anyway, so you just need error or file reference, and for that struct file * with ERR_PTR() for errors works fine. Anyway, your variant seems to be correct; feel free to slap my ACKed-by on it.
