[ipv4] f3f6f46e79: kernel-selftests.net.pmtu.sh.fail

FYI, we noticed the following commit (built with gcc-7):

commit: f3f6f46e7935c5fe707b4a88124556d8b9f10c92 ("[PATCH] ipv4: fix a RCU-list bug in inet_dump_fib()")
url: https://github.com/0day-ci/linux/commits/Qian-Cai/ipv4-fix-a-RCU-list-bug-in-inet_dump_fib/20200320-061342


in testcase: kernel-selftests
with following parameters:

	group: kselftests-02
	ucode: 0xd6

test-description: The kernel contains a set of "self tests" under the tools/testing/selftests/ directory. These are intended to be small unit tests to exercise individual code paths in the kernel.
test-url: https://www.kernel.org/doc/Documentation/kselftest.txt


on test machine: 8 threads Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz with 16G memory

caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):


If you fix the issue, kindly add following tag
Reported-by: kernel test robot <redacted>



# selftests: net: pmtu.sh
# TEST: ipv4: PMTU exceptions                                         [ OK ]
# TEST: ipv4: PMTU exceptions - nexthop objects                       [ OK ]
# TEST: ipv6: PMTU exceptions                                         [ OK ]
# TEST: ipv6: PMTU exceptions - nexthop objects                       [ OK ]
# TEST: IPv4 over vxlan4: PMTU exceptions                             [ OK ]
# TEST: IPv4 over vxlan4: PMTU exceptions - nexthop objects           [ OK ]
# TEST: IPv6 over vxlan4: PMTU exceptions                             [ OK ]
# TEST: IPv6 over vxlan4: PMTU exceptions - nexthop objects           [ OK ]
# TEST: IPv4 over vxlan6: PMTU exceptions                             [ OK ]
# TEST: IPv4 over vxlan6: PMTU exceptions - nexthop objects           [ OK ]
# TEST: IPv6 over vxlan6: PMTU exceptions                             [ OK ]
# TEST: IPv6 over vxlan6: PMTU exceptions - nexthop objects           [ OK ]
# TEST: IPv4 over geneve4: PMTU exceptions                            [ OK ]
# TEST: IPv4 over geneve4: PMTU exceptions - nexthop objects          [ OK ]
# TEST: IPv6 over geneve4: PMTU exceptions                            [ OK ]
# TEST: IPv6 over geneve4: PMTU exceptions - nexthop objects          [ OK ]
# TEST: IPv4 over geneve6: PMTU exceptions                            [ OK ]
# TEST: IPv4 over geneve6: PMTU exceptions - nexthop objects          [ OK ]
# TEST: IPv6 over geneve6: PMTU exceptions                            [ OK ]
# TEST: IPv6 over geneve6: PMTU exceptions - nexthop objects          [ OK ]
# TEST: IPv4 over fou4: PMTU exceptions                               [ OK ]
# TEST: IPv4 over fou4: PMTU exceptions - nexthop objects             [ OK ]
# TEST: IPv6 over fou4: PMTU exceptions                               [ OK ]
# TEST: IPv6 over fou4: PMTU exceptions - nexthop objects             [ OK ]
# TEST: IPv4 over fou6: PMTU exceptions                               [ OK ]
# TEST: IPv4 over fou6: PMTU exceptions - nexthop objects             [ OK ]
# TEST: IPv6 over fou6: PMTU exceptions                               [ OK ]
# TEST: IPv6 over fou6: PMTU exceptions - nexthop objects             [ OK ]
# TEST: IPv4 over gue4: PMTU exceptions                               [ OK ]
# TEST: IPv4 over gue4: PMTU exceptions - nexthop objects             [ OK ]
# TEST: IPv6 over gue4: PMTU exceptions                               [ OK ]
# TEST: IPv6 over gue4: PMTU exceptions - nexthop objects             [ OK ]
# TEST: IPv4 over gue6: PMTU exceptions                               [ OK ]
# TEST: IPv4 over gue6: PMTU exceptions - nexthop objects             [ OK ]
# TEST: IPv6 over gue6: PMTU exceptions                               [ OK ]
# TEST: IPv6 over gue6: PMTU exceptions - nexthop objects             [ OK ]
# TEST: vti6: PMTU exceptions                                         [ OK ]
# TEST: vti4: PMTU exceptions                                         [ OK ]
# TEST: vti4: default MTU assignment                                  [ OK ]
# TEST: vti6: default MTU assignment                                  [ OK ]
# TEST: vti4: MTU setting on link creation                            [ OK ]
# TEST: vti6: MTU setting on link creation                            [ OK ]
# TEST: vti6: MTU changes on link changes                             [ OK ]
# TEST: ipv4: cleanup of cached exceptions                            [ OK ]
# TEST: ipv4: cleanup of cached exceptions - nexthop objects          [ OK ]
# TEST: ipv6: cleanup of cached exceptions                            [ OK ]
# TEST: ipv6: cleanup of cached exceptions - nexthop objects          [ OK ]
# Segmentation fault
# Segmentation fault
# TEST: ipv4: list and flush cached exceptions                        [FAIL]
#   can't list cached exceptions
# Segmentation fault
# Segmentation fault
# TEST: ipv4: list and flush cached exceptions - nexthop objects      [FAIL]
#   can't list cached exceptions
# TEST: ipv6: list and flush cached exceptions                        [ OK ]
# TEST: ipv6: list and flush cached exceptions - nexthop objects      [ OK ]
not ok 16 selftests: net: pmtu.sh # exit=1

To reproduce:

        git clone https://github.com/intel/lkp-tests.git
        cd lkp-tests
        bin/lkp install job.yaml  # job file is attached in this email
        bin/lkp run     job.yaml



Thanks,
Rong Chen