| Message ID | 20240508075159.1646031-1-edumazet@google.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [v2,net-next] net: usb: smsc95xx: stop lying about skb->truesize | expand |
Hi Eric, kernel test robot noticed the following build warnings: [auto build test WARNING on net-next/main] url: https://github.com/intel-lab-lkp/linux/commits/Eric-Dumazet/net-usb-smsc95xx-stop-lying-about-skb-truesize/20240508-155316 base: net-next/main patch link: https://lore.kernel.org/r/20240508075159.1646031-1-edumazet%40google.com patch subject: [PATCH v2 net-next] net: usb: smsc95xx: stop lying about skb->truesize config: arc-randconfig-r132-20240509 (https://download.01.org/0day-ci/archive/20240509/202405091310.KvncIecx-lkp@intel.com/config) compiler: arceb-elf-gcc (GCC) 13.2.0 reproduce: (https://download.01.org/0day-ci/archive/20240509/202405091310.KvncIecx-lkp@intel.com/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202405091310.KvncIecx-lkp@intel.com/ sparse warnings: (new ones prefixed by >>) >> drivers/net/usb/smsc95xx.c:1815:19: sparse: sparse: incorrect type in assignment (different base types) @@ expected restricted __wsum [usertype] csum @@ got unsigned short x @@ drivers/net/usb/smsc95xx.c:1815:19: sparse: expected restricted __wsum [usertype] csum drivers/net/usb/smsc95xx.c:1815:19: sparse: got unsigned short x drivers/net/usb/smsc95xx.c: note: in included file (through include/net/checksum.h, include/linux/skbuff.h, include/net/net_namespace.h, ...): arch/arc/include/asm/checksum.h:27:26: sparse: sparse: restricted __wsum degrades to integer arch/arc/include/asm/checksum.h:27:36: sparse: sparse: restricted __wsum degrades to integer arch/arc/include/asm/checksum.h:29:11: sparse: sparse: bad assignment (-=) to restricted __wsum arch/arc/include/asm/checksum.h:30:16: sparse: sparse: restricted __wsum degrades to integer arch/arc/include/asm/checksum.h:30:18: sparse: sparse: incorrect type in return expression (different base types) @@ expected restricted __sum16 @@ got unsigned int @@ arch/arc/include/asm/checksum.h:30:18: sparse: expected restricted __sum16 arch/arc/include/asm/checksum.h:30:18: sparse: got unsigned int vim +1815 drivers/net/usb/smsc95xx.c 1810 1811 static void smsc95xx_rx_csum_offload(struct sk_buff *skb) 1812 { 1813 u16 *csum_ptr = (u16 *)(skb_tail_pointer(skb) - 2); 1814 > 1815 skb->csum = get_unaligned(csum_ptr); 1816 skb->ip_summed = CHECKSUM_COMPLETE; 1817 skb_trim(skb, skb->len - 2); /* remove csum */ 1818 } 1819
On Thu, May 9, 2024 at 8:01 AM kernel test robot <lkp@intel.com> wrote: > > Hi Eric, > > kernel test robot noticed the following build warnings: > > [auto build test WARNING on net-next/main] > > url: https://github.com/intel-lab-lkp/linux/commits/Eric-Dumazet/net-usb-smsc95xx-stop-lying-about-skb-truesize/20240508-155316 > base: net-next/main > patch link: https://lore.kernel.org/r/20240508075159.1646031-1-edumazet%40google.com > patch subject: [PATCH v2 net-next] net: usb: smsc95xx: stop lying about skb->truesize > config: arc-randconfig-r132-20240509 (https://download.01.org/0day-ci/archive/20240509/202405091310.KvncIecx-lkp@intel.com/config) > compiler: arceb-elf-gcc (GCC) 13.2.0 > reproduce: (https://download.01.org/0day-ci/archive/20240509/202405091310.KvncIecx-lkp@intel.com/reproduce) > > If you fix the issue in a separate patch/commit (i.e. not just a new version of > the same patch/commit), kindly add following tags > | Reported-by: kernel test robot <lkp@intel.com> > | Closes: https://lore.kernel.org/oe-kbuild-all/202405091310.KvncIecx-lkp@intel.com/ > > sparse warnings: (new ones prefixed by >>) > >> drivers/net/usb/smsc95xx.c:1815:19: sparse: sparse: incorrect type in assignment (different base types) @@ expected restricted __wsum [usertype] csum @@ got unsigned short x @@ > drivers/net/usb/smsc95xx.c:1815:19: sparse: expected restricted __wsum [usertype] csum > drivers/net/usb/smsc95xx.c:1815:19: sparse: got unsigned short x > drivers/net/usb/smsc95xx.c: note: in included file (through include/net/checksum.h, include/linux/skbuff.h, include/net/net_namespace.h, ...): > arch/arc/include/asm/checksum.h:27:26: sparse: sparse: restricted __wsum degrades to integer > arch/arc/include/asm/checksum.h:27:36: sparse: sparse: restricted __wsum degrades to integer > arch/arc/include/asm/checksum.h:29:11: sparse: sparse: bad assignment (-=) to restricted __wsum > arch/arc/include/asm/checksum.h:30:16: sparse: sparse: restricted __wsum degrades to integer > arch/arc/include/asm/checksum.h:30:18: sparse: sparse: incorrect type in return expression (different base types) @@ expected restricted __sum16 @@ got unsigned int @@ > arch/arc/include/asm/checksum.h:30:18: sparse: expected restricted __sum16 > arch/arc/include/asm/checksum.h:30:18: sparse: got unsigned int > > vim +1815 drivers/net/usb/smsc95xx.c > > 1810 > 1811 static void smsc95xx_rx_csum_offload(struct sk_buff *skb) > 1812 { > 1813 u16 *csum_ptr = (u16 *)(skb_tail_pointer(skb) - 2); > 1814 > > 1815 skb->csum = get_unaligned(csum_ptr); > 1816 skb->ip_summed = CHECKSUM_COMPLETE; > 1817 skb_trim(skb, skb->len - 2); /* remove csum */ > 1818 } > 1819 > > -- > 0-DAY CI Kernel Test Service > https://github.com/intel/lkp-tests/wiki Please note this is not a new warning. Prior to my change we had : drivers/net/usb/smsc95xx.c:1813:19: warning: incorrect type in assignment (different base types) drivers/net/usb/smsc95xx.c:1813:19: expected restricted __wsum [usertype] csum drivers/net/usb/smsc95xx.c:1813:19: got unsigned short [usertype] I will submit a v3, to _also_ fix the sparse warning.
diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c index 2fa46baa589e5e87e12e145fe46268bdaf9fc219..0311328797c345bfa9a117596c268757808828d1 100644 --- a/drivers/net/usb/smsc95xx.c +++ b/drivers/net/usb/smsc95xx.c @@ -1810,9 +1810,11 @@ static int smsc95xx_reset_resume(struct usb_interface *intf) static void smsc95xx_rx_csum_offload(struct sk_buff *skb) { - skb->csum = *(u16 *)(skb_tail_pointer(skb) - 2); + u16 *csum_ptr = (u16 *)(skb_tail_pointer(skb) - 2); + + skb->csum = get_unaligned(csum_ptr); skb->ip_summed = CHECKSUM_COMPLETE; - skb_trim(skb, skb->len - 2); + skb_trim(skb, skb->len - 2); /* remove csum */ } static int smsc95xx_rx_fixup(struct usbnet *dev, struct sk_buff *skb) @@ -1870,25 +1872,22 @@ static int smsc95xx_rx_fixup(struct usbnet *dev, struct sk_buff *skb) if (dev->net->features & NETIF_F_RXCSUM) smsc95xx_rx_csum_offload(skb); skb_trim(skb, skb->len - 4); /* remove fcs */ - skb->truesize = size + sizeof(struct sk_buff); return 1; } - ax_skb = skb_clone(skb, GFP_ATOMIC); + ax_skb = netdev_alloc_skb_ip_align(dev->net, size); if (unlikely(!ax_skb)) { netdev_warn(dev->net, "Error allocating skb\n"); return 0; } - ax_skb->len = size; - ax_skb->data = packet; - skb_set_tail_pointer(ax_skb, size); + skb_put(ax_skb, size); + memcpy(ax_skb->data, packet, size); if (dev->net->features & NETIF_F_RXCSUM) smsc95xx_rx_csum_offload(ax_skb); skb_trim(ax_skb, ax_skb->len - 4); /* remove fcs */ - ax_skb->truesize = size + sizeof(struct sk_buff); usbnet_skb_return(dev, ax_skb); }
Some usb drivers try to set small skb->truesize and break core networking stacks. In this patch, I removed one of the skb->truesize override. I also replaced one skb_clone() by an allocation of a fresh and small skb, to get minimally sized skbs, like we did in commit 1e2c61172342 ("net: cdc_ncm: reduce skb truesize in rx path") and 4ce62d5b2f7a ("net: usb: ax88179_178a: stop lying about skb->truesize") v2: leave the skb_trim() game because smsc95xx_rx_csum_offload() needs the csum part. (Jakub) While we are it, use get_unaligned() in smsc95xx_rx_csum_offload(). Fixes: 2f7ca802bdae ("net: Add SMSC LAN9500 USB2.0 10/100 ethernet adapter driver") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Steve Glendinning <steve.glendinning@shawell.net> Cc: UNGLinuxDriver@microchip.com --- drivers/net/usb/smsc95xx.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-)