On Thu, Mar 19, 2026 at 06:02:12PM -0700, Rosen Penev wrote: > There's no need to allocate these separately. > > Add __counted_by for extra runtime analysis. Moved counting variable > allocation to right after allocation as required by __counted_by. > > Signed-off-by: Rosen Penev <[email protected]>
This looks reasonable to me. One thought I've had while reviewing your flex-array patches is that I want to make sure you're doing your test builds with KCFLAGS=-Wflexible-array-member-not-at-end so that you can validate there's no new uses of the target structures being composed within other structures while making these changes. That looks clear here, but I think going forward, it would be worth mentioning it as part of the commit log. Something like: This structure is not composed within other structures, confirmed with builds using -Wflexible-array-member-not-at-end. or similar. Reviewed-by: Kees Cook <[email protected]> -Kees > --- > drivers/media/usb/em28xx/em28xx-cards.c | 18 ++---------------- > drivers/media/usb/em28xx/em28xx.h | 3 ++- > 2 files changed, 4 insertions(+), 17 deletions(-) > > diff --git a/drivers/media/usb/em28xx/em28xx-cards.c > b/drivers/media/usb/em28xx/em28xx-cards.c > index d7075ebabceb..c278e48b3428 100644 > --- a/drivers/media/usb/em28xx/em28xx-cards.c > +++ b/drivers/media/usb/em28xx/em28xx-cards.c > @@ -3567,9 +3567,6 @@ void em28xx_free_device(struct kref *ref) > if (!dev->disconnected) > em28xx_release_resources(dev); > > - if (dev->ts == PRIMARY_TS) > - kfree(dev->alt_max_pkt_size_isoc); > - > kfree(dev); > } > EXPORT_SYMBOL_GPL(em28xx_free_device); > @@ -3912,21 +3909,13 @@ static int em28xx_usb_probe(struct usb_interface > *intf, > } > > /* allocate memory for our device state and initialize it */ > - dev = kzalloc_obj(*dev); > + dev = kzalloc_flex(*dev, alt_max_pkt_size_isoc, intf->num_altsetting); > if (!dev) { > retval = -ENOMEM; > goto err; > } > > - /* compute alternate max packet sizes */ > - dev->alt_max_pkt_size_isoc = kcalloc(intf->num_altsetting, > - > sizeof(dev->alt_max_pkt_size_isoc[0]), > - GFP_KERNEL); > - if (!dev->alt_max_pkt_size_isoc) { > - kfree(dev); > - retval = -ENOMEM; > - goto err; > - } > + dev->num_alt = intf->num_altsetting; > > /* Get endpoints */ > for (i = 0; i < intf->num_altsetting; i++) { > @@ -4028,8 +4017,6 @@ static int em28xx_usb_probe(struct usb_interface *intf, > dev->dvb_ep_bulk ? " bulk" : "", > dev->dvb_ep_isoc ? " isoc" : ""); > > - dev->num_alt = intf->num_altsetting; > - > if ((unsigned int)card[nr] < em28xx_bcount) > dev->model = card[nr]; > > @@ -4163,7 +4150,6 @@ static int em28xx_usb_probe(struct usb_interface *intf, > return 0; > > err_free: > - kfree(dev->alt_max_pkt_size_isoc); > kfree(dev); > > err: > diff --git a/drivers/media/usb/em28xx/em28xx.h > b/drivers/media/usb/em28xx/em28xx.h > index f3449c240d21..1c2f92927889 100644 > --- a/drivers/media/usb/em28xx/em28xx.h > +++ b/drivers/media/usb/em28xx/em28xx.h > @@ -730,7 +730,6 @@ struct em28xx { > int packet_multiplier; // multiplier for wMaxPacketSize, used for > // URB buffer size definition > int num_alt; // number of alternative settings > - unsigned int *alt_max_pkt_size_isoc; // array of isoc wMaxPacketSize > unsigned int analog_xfer_bulk:1; // use bulk instead of isoc > // transfers for analog > int dvb_alt_isoc; // alternate setting for DVB isoc transfers > @@ -772,6 +771,8 @@ struct em28xx { > > struct em28xx *dev_next; > int ts; > + > + unsigned int alt_max_pkt_size_isoc[] __counted_by(num_alt); // array of > isoc wMaxPacketSize > }; > > #define kref_to_dev(d) container_of(d, struct em28xx, ref) > -- > 2.53.0 > > -- Kees Cook
