On Tue 30-07-24 11:49:37, Christian Brauner wrote:
> On Tue, Jul 30, 2024 at 10:58:13AM GMT, Olaf Hering wrote:
> > If no page could be allocated, an error pointer was used as format
> > string in pr_warn.
> >
> > Rearrange the code to return early in case of OOM. Also add a check
> > for the return value of d_path. The API of that function is not
> > documented. It currently returns only ERR_PTR values, but may return
> > also NULL in the future. Use PTR_ERR_OR_ZERO to cover both cases.
> >
> > Fixes: f8b92ba67c5d ("mount: Add mount warning for impending timestamp expiry")
> >
> > Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>
> > ---
> > fs/namespace.c | 12 ++++++++++--
> > 1 file changed, 10 insertions(+), 2 deletions(-)
> >
> > diff --git a/fs/namespace.c b/fs/namespace.c
> > index 328087a4df8a..539d4f203a20 100644
> > --- a/fs/namespace.c
> > +++ b/fs/namespace.c
> > @@ -2922,7 +2922,14 @@ static void mnt_warn_timestamp_expiry(struct path *mountpoint, struct vfsmount *
> > (!(sb->s_iflags & SB_I_TS_EXPIRY_WARNED)) &&
> > (ktime_get_real_seconds() + TIME_UPTIME_SEC_MAX > sb->s_time_max)) {
> > char *buf = (char *)__get_free_page(GFP_KERNEL);
> > - char *mntpath = buf ? d_path(mountpoint, buf, PAGE_SIZE) : ERR_PTR(-ENOMEM);
> > + char *mntpath;
> > +
> > + if (!buf)
> > + return;
> > +
> > + mntpath = d_path(mountpoint, buf, PAGE_SIZE);
> > + if (PTR_ERR_OR_ZERO(mntpath))
>
> This needs to be IS_ERR_OR_NULL().
>
> > + goto err;
>
> We should still warn when decoding the mountpoint fails. I'll just amend
> your patch to something like:
Looks good to me. Feel free to add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
>
> diff --git a/fs/namespace.c b/fs/namespace.c
> index 328087a4df8a..0f2f140aaf05 100644
> --- a/fs/namespace.c
> +++ b/fs/namespace.c
> @@ -2921,16 +2921,21 @@ static void mnt_warn_timestamp_expiry(struct path *mountpoint, struct vfsmount *
> if (!__mnt_is_readonly(mnt) &&
> (!(sb->s_iflags & SB_I_TS_EXPIRY_WARNED)) &&
> (ktime_get_real_seconds() + TIME_UPTIME_SEC_MAX > sb->s_time_max)) {
> - char *buf = (char *)__get_free_page(GFP_KERNEL);
> - char *mntpath = buf ? d_path(mountpoint, buf, PAGE_SIZE) : ERR_PTR(-ENOMEM);
> + char *buf, *mntpath = NULL;
> +
> + buf = (char *)__get_free_page(GFP_KERNEL);
> + if (buf)
> + mntpath = d_path(mountpoint, buf, PAGE_SIZE);
> + if (IS_ERR_OR_NULL(mntpath))
> + mntpath = "(unknown)";
>
> pr_warn("%s filesystem being %s at %s supports timestamps until %ptTd (0x%llx)\n",
> sb->s_type->name,
> is_mounted(mnt) ? "remounted" : "mounted",
> mntpath, &sb->s_time_max,
> (unsigned long long)sb->s_time_max);
> -
> - free_page((unsigned long)buf);
> + if (buf)
> + free_page((unsigned long)buf);
> sb->s_iflags |= SB_I_TS_EXPIRY_WARNED;
> }
> }
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
