This is the first patch removing several categories of use cases of the list iterator variable past the loop. This is follow up to the discussion in: https://lore.kernel.org/all/20220217184829.1991035-1-jakobkoschel@xxxxxxxxx/ As concluded in: https://lore.kernel.org/all/YhdfEIwI4EdtHdym@xxxxxxxxx/ the correct use should be using a separate variable after the loop and using a 'tmp' variable as the list iterator. The list iterator will not point to a valid structure after the loop if no break/goto was hit. Invalid uses of the list iterator variable can be avoided altogether by simply using a separate pointer to iterate the list. Linus and Greg agreed on the following pattern: - struct gr_request *req; + struct gr_request *req = NULL; + struct gr_request *tmp; struct gr_ep *ep; int ret = 0; - list_for_each_entry(req, &ep->queue, queue) { - if (&req->req == _req) + list_for_each_entry(tmp, &ep->queue, queue) { + if (&tmp->req == _req) { + req = tmp; break; + } } - if (&req->req != _req) { + if (!req) { ret = -EINVAL; goto out; } With gnu89 the list iterator variable cannot yet be declared within the for loop of the list iterator. Moving to a more modern version of C would allow defining the list iterator variable within the macro, limiting the scope to the loop. This avoids any incorrect usage past the loop altogether. This are around 30% of the cases where the iterator variable is used past the loop (identified with a slightly modified version of use_after_iter.cocci). I've decided to split it into at a few patches separated by similar use cases. Because the output of get_maintainer.pl was too big, I included all the found lists and everyone from the previous discussion. Jakob Koschel (6): drivers: usb: remove usage of list iterator past the loop body treewide: remove using list iterator after loop body as a ptr treewide: fix incorrect use to determine if list is empty drivers: remove unnecessary use of list iterator variable treewide: remove dereference of list iterator after loop body treewide: remove check of list iterator against head past the loop body arch/arm/mach-mmp/sram.c | 9 ++-- arch/arm/plat-pxa/ssp.c | 28 +++++------- arch/powerpc/sysdev/fsl_gtm.c | 4 +- arch/x86/kernel/cpu/sgx/encl.c | 6 ++- drivers/block/drbd/drbd_req.c | 45 ++++++++++++------- drivers/counter/counter-chrdev.c | 26 ++++++----- drivers/crypto/cavium/nitrox/nitrox_main.c | 11 +++-- drivers/dma/dw-edma/dw-edma-core.c | 4 +- drivers/dma/ppc4xx/adma.c | 11 +++-- drivers/firewire/core-transaction.c | 32 +++++++------ drivers/firewire/sbp2.c | 14 +++--- drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 19 +++++--- drivers/gpu/drm/drm_memory.c | 15 ++++--- drivers/gpu/drm/drm_mm.c | 17 ++++--- drivers/gpu/drm/drm_vm.c | 13 +++--- drivers/gpu/drm/gma500/oaktrail_lvds.c | 9 ++-- drivers/gpu/drm/i915/gem/i915_gem_context.c | 14 +++--- .../gpu/drm/i915/gem/i915_gem_execbuffer.c | 15 ++++--- drivers/gpu/drm/i915/gt/intel_ring.c | 15 ++++--- .../gpu/drm/nouveau/nvkm/subdev/clk/base.c | 11 +++-- .../gpu/drm/nouveau/nvkm/subdev/fb/ramgk104.c | 13 +++--- drivers/gpu/drm/scheduler/sched_main.c | 14 +++--- drivers/gpu/drm/ttm/ttm_bo.c | 19 ++++---- drivers/gpu/drm/vmwgfx/vmwgfx_kms.c | 22 +++++---- drivers/infiniband/hw/hfi1/tid_rdma.c | 16 ++++--- drivers/infiniband/hw/mlx4/main.c | 12 ++--- drivers/media/dvb-frontends/mxl5xx.c | 11 +++-- drivers/media/pci/saa7134/saa7134-alsa.c | 4 +- drivers/media/v4l2-core/v4l2-ctrls-api.c | 31 +++++++------ drivers/misc/mei/interrupt.c | 12 ++--- .../net/ethernet/intel/i40e/i40e_ethtool.c | 3 +- .../net/ethernet/qlogic/qede/qede_filter.c | 11 +++-- drivers/net/wireless/ath/ath6kl/htc_mbox.c | 2 +- .../net/wireless/intel/ipw2x00/libipw_rx.c | 15 ++++--- drivers/perf/xgene_pmu.c | 13 +++--- drivers/power/supply/cpcap-battery.c | 11 +++-- drivers/scsi/lpfc/lpfc_bsg.c | 16 ++++--- drivers/scsi/scsi_transport_sas.c | 17 ++++--- drivers/scsi/wd719x.c | 12 +++-- drivers/staging/rtl8192e/rtl819x_TSProc.c | 17 +++---- drivers/staging/rtl8192e/rtllib_rx.c | 17 ++++--- .../staging/rtl8192u/ieee80211/ieee80211_rx.c | 15 ++++--- .../rtl8192u/ieee80211/rtl819x_TSProc.c | 19 ++++---- drivers/thermal/thermal_core.c | 38 ++++++++++------ drivers/usb/gadget/composite.c | 9 ++-- drivers/usb/gadget/configfs.c | 22 +++++---- drivers/usb/gadget/udc/aspeed-vhub/epn.c | 11 +++-- drivers/usb/gadget/udc/at91_udc.c | 26 ++++++----- drivers/usb/gadget/udc/atmel_usba_udc.c | 11 +++-- drivers/usb/gadget/udc/bdc/bdc_ep.c | 11 +++-- drivers/usb/gadget/udc/fsl_qe_udc.c | 11 +++-- drivers/usb/gadget/udc/fsl_udc_core.c | 11 +++-- drivers/usb/gadget/udc/goku_udc.c | 11 +++-- drivers/usb/gadget/udc/gr_udc.c | 11 +++-- drivers/usb/gadget/udc/lpc32xx_udc.c | 11 +++-- drivers/usb/gadget/udc/max3420_udc.c | 11 +++-- drivers/usb/gadget/udc/mv_u3d_core.c | 11 +++-- drivers/usb/gadget/udc/mv_udc_core.c | 11 +++-- drivers/usb/gadget/udc/net2272.c | 12 ++--- drivers/usb/gadget/udc/net2280.c | 11 +++-- drivers/usb/gadget/udc/omap_udc.c | 11 +++-- drivers/usb/gadget/udc/pxa25x_udc.c | 11 +++-- drivers/usb/gadget/udc/s3c-hsudc.c | 11 +++-- drivers/usb/gadget/udc/tegra-xudc.c | 11 +++-- drivers/usb/gadget/udc/udc-xilinx.c | 11 +++-- drivers/usb/mtu3/mtu3_gadget.c | 11 +++-- drivers/usb/musb/musb_gadget.c | 11 +++-- drivers/vfio/mdev/mdev_core.c | 11 +++-- fs/cifs/smb2misc.c | 10 +++-- fs/f2fs/segment.c | 9 ++-- fs/proc/kcore.c | 13 +++--- kernel/debug/kdb/kdb_main.c | 36 +++++++++------ kernel/power/snapshot.c | 10 +++-- kernel/trace/ftrace.c | 22 +++++---- kernel/trace/trace_eprobe.c | 15 ++++--- kernel/trace/trace_events.c | 11 ++--- net/9p/trans_xen.c | 11 +++-- net/ipv4/udp_tunnel_nic.c | 10 +++-- net/tipc/name_table.c | 11 +++-- net/tipc/socket.c | 11 +++-- net/xfrm/xfrm_ipcomp.c | 11 +++-- sound/soc/intel/catpt/pcm.c | 13 +++--- sound/soc/sprd/sprd-mcdt.c | 13 +++--- 83 files changed, 708 insertions(+), 465 deletions(-) base-commit: 7ee022567bf9e2e0b3cd92461a2f4986ecc99673 -- 2.25.1
