Following kernel BUG noticed on qemu_i386 while testing selftests: net: pmtu.sh with kselftest merge config build image [1] & [2] and after this BUG test hung.

metadata: git_ref: master git_repo: https://gitlab.com/Linaro/lkft/mirrors/torvalds/linux-mainline git_sha: 672c0c5173427e6b3e2a9bbb7be51ceeec78093a git_describe: v5.18-rc5 kernel_version: 5.18.0-rc5 kernel-config: https://builds.tuxbuild.com/28a2wrzQ62tLypUV7bgCOXEGKig/config build-url: https://gitlab.com/Linaro/lkft/mirrors/torvalds/linux-mainline/-/pipelines/5... artifact-location: https://builds.tuxbuild.com/28a2wrzQ62tLypUV7bgCOXEGKig toolchain: gcc-11

Test log: --------- # selftests: net: pmtu.sh [ 468.730000] ip (15022) used greatest stack depth: 4232 bytes left

<trim>

# TEST: ipv6: cleanup of cached exceptions [ OK ] [ 587.633640] IPv6: ADDRCONF(NETDEV_CHANGE): veth_A-R1: link becomes ready [ 587.695867] IPv6: ADDRCONF(NETDEV_CHANGE): veth_A-R2: link becomes ready [ 587.758384] IPv6: ADDRCONF(NETDEV_CHANGE): veth_B-R1: link becomes ready [ 587.821528] IPv6: ADDRCONF(NETDEV_CHANGE): veth_B-R2: link becomes ready # TEST: ipv6: cleanup of cached exceptions - nexthop objects [ OK ] [ 591.442819] BUG: unable to handle page fault for address: 2509c000 [ 591.444468] #PF: supervisor read access in kernel mode [ 591.445810] #PF: error_code(0x0000) - not-present page [ 591.447175] *pde = 00000000 [ 591.448121] Oops: 0000 [#1] PREEMPT SMP [ 591.449350] CPU: 3 PID: 0 Comm: swapper/3 Not tainted 5.18.0-rc5 #1 [ 591.451373] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 [ 591.453404] EIP: percpu_counter_add_batch+0x2e/0xe0 [ 591.454134] Code: ec 20 89 5d f4 89 c3 b8 01 00 00 00 89 75 f8 89 7d fc 89 55 ec 89 4d f0 e8 3f f0 a3 ff b8 5f c4 c7 cf e8 e5 43 bd 00 8b 4b 34 <64> 8b 39 89 7d e0 89 fe 8b 45 08 c1 ff 1f 03 75 ec 13 7d f0 89 45 [ 591.456840] EAX: 00000003 EBX: c60fd540 ECX: 00000000 EDX: cfc7c45f [ 591.457755] ESI: 00000000 EDI: c11a92c0 EBP: c1251f40 ESP: c1251f20 [ 591.458686] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 EFLAGS: 00210202 [ 591.459688] CR0: 80050033 CR2: 2509c000 CR3: 05401000 CR4: 003506d0 [ 591.460628] Call Trace: [ 591.461009] <SOFTIRQ> [ 591.461366] dst_destroy+0xac/0xe0 [ 591.461879] dst_destroy_rcu+0x10/0x20 [ 591.462438] rcu_core+0x354/0xa50 [ 591.462942] ? rcu_core+0x2fd/0xa50 [ 591.463462] rcu_core_si+0xd/0x10 [ 591.463962] __do_softirq+0x14f/0x4ae [ 591.464509] ? __entry_text_end+0x8/0x8 [ 591.465108] call_on_stack+0x4c/0x60 [ 591.465637] </SOFTIRQ> [ 591.466010] ? __irq_exit_rcu+0xca/0x130 [ 591.466588] ? irq_exit_rcu+0xd/0x20 [ 591.467132] ? sysvec_apic_timer_interrupt+0x36/0x50 [ 591.467868] ? handle_exception+0x133/0x133 [ 591.468481] ? __sched_text_end+0x2/0x2 [ 591.469079] ? sysvec_call_function_single+0x50/0x50 [ 591.469804] ? default_idle+0x13/0x20 [ 591.470346] ? sysvec_call_function_single+0x50/0x50 [ 591.471068] ? default_idle+0x13/0x20 [ 591.471605] ? arch_cpu_idle+0x12/0x20 [ 591.472164] ? default_idle_call+0x52/0xa0 [ 591.472788] ? do_idle+0x20a/0x270 [ 591.473289] ? cpu_startup_entry+0x20/0x30 [ 591.473890] ? cpu_startup_entry+0x25/0x30 [ 591.474489] ? start_secondary+0x10f/0x140 [ 591.475098] ? startup_32_smp+0x161/0x164 [ 591.475687] Modules linked in: sit xt_policy iptable_filter ip_tables x_tables veth fuse [last unloaded: test_blackhole_dev] [ 591.477321] CR2: 000000002509c000 [ 591.477818] ---[ end trace 0000000000000000 ]--- [ 591.478500] EIP: percpu_counter_add_batch+0x2e/0xe0 [ 591.479218] Code: ec 20 89 5d f4 89 c3 b8 01 00 00 00 89 75 f8 89 7d fc 89 55 ec 89 4d f0 e8 3f f0 a3 ff b8 5f c4 c7 cf e8 e5 43 bd 00 8b 4b 34 <64> 8b 39 89 7d e0 89 fe 8b 45 08 c1 ff 1f 03 75 ec 13 7d f0 89 45 [ 591.481915] EAX: 00000003 EBX: c60fd540 ECX: 00000000 EDX: cfc7c45f [ 591.482829] ESI: 00000000 EDI: c11a92c0 EBP: c1251f40 ESP: c1251f20 [ 591.483739] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 EFLAGS: 00210202 [ 591.484744] CR0: 80050033 CR2: 2509c000 CR3: 05401000 CR4: 003506d0 [ 591.485656] Kernel panic - not syncing: Fatal exception in interrupt [ 591.486680] Kernel Offset: disabled [ 591.487215] ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---

Reported-by: Linux Kernel Functional Testing lkft@linaro.org

-- Linaro LKFT https://lkft.linaro.org

[1] https://lkft.validation.linaro.org/scheduler/job/4976107#L4726 [2] https://qa-reports.linaro.org/lkft/linux-mainline-master/build/v5.18-rc5/tes...