Commits on May 28, 2020

1. datapath: Fix back-edge in bpf_sock for older kernels …

   The commit 4fa26a4 ("datapath: Enable sessionAffinity for older
   kernels") enabled the session affinity feature in bpf_sock when running
   on older kernels (e.g. 4.19.57). However, the feature was broken on such
   kernels due to the back-edge detected by the BPF verifier:
   
   msg="+ tc exec bpf pin /sys/fs/bpf/tc/globals/cilium_cgroups_connect6 obj
   bpf_sock.o type sockaddr attach_type connect6 sec connect6" subsys=datapath-loader
   subsys=datapath-loader
   msg="Prog section 'connect6' rejected: Invalid argument (22)!" subsys=datapath-loader
   msg=" - Type:         18" subsys=datapath-loader
   msg=" - Attach Type:  11" subsys=datapath-loader
   msg=" - Instructions: 740 (0 over limit)" subsys=datapath-loader
   msg=" - License:      GPL" subsys=datapath-loader
   subsys=datapath-loader
   msg="Verifier analysis:" subsys=datapath-loader
   subsys=datapath-loader
   msg="back-edge from insn 624 to 570" subsys=datapath-loader
   subsys=datapath-loader
   msg="Error fetching program/map!" subsys=datapath-loader
   
   This was happening, as in the backend reselection case (when a backend from
   affinity cannot be found) we goto to previous lines in the code.
   
   Fix it by immediately checking whether the backend from affinity exists.
   
   Fixes: 4fa26a4 ("datapath: Enable sessionAffinity for older kernels")
   Reported-by: Paul Chaignon <paul@cilium.io>
   Signed-off-by: Martynas Pumputis <m@lambda.lt>

   

   brb committed May 28, 2020
   Copy the full SHA

   2b5f3b2 View commit details

   Browse the repository at this point in the history