While running selftests: cgroup: test_kmem on FVP following kernel crash noticed on Linux next 6.6.0-rc4-next-20231006. Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx> Boot log: [ 0.000000] Booting Linux on physical CPU 0x0000000000 [0x410fd0f0] [ 0.000000] Linux version 6.6.0-rc4-next-20231006 (tuxmake@tuxmake) (aarch64-linux-gnu-gcc (Debian 13.2.0-2) 13.2.0, GNU ld (GNU Binutils for Debian) 2.41) #1 SMP PREEMPT @1696592107 [ 0.000000] KASLR enabled [ 0.000000] Machine model: FVP Base RevC ... Running selftests: cgroup # selftests: cgroup: test_kmem # ok 1 test_kmem_basic # not ok 2 selftests: cgroup: test_kmem # TIMEOUT 45 seconds # timeout set to 45 # selftests: cgroup: test_core # ok 1 test_cgcore_internal_process_constraint # ok 2 test_cgcore_top_down_constraint_enable # ok 3 test_cgcore_top_down_constraint_disable # ok 4 test_cgcore_no_internal_process_constraint_on_threads # ok 5 test_cgcore_parent_becomes_threaded # ok 6 test_cgcore_invalid_domain # ok 7 test_cgcore_populated # ok 8 test_cgcore_proc_migration # ok 9 test_cgcore_thread_migration # ok 10 test_cgcore_destroy # ok 11 test_cgcore_lesser_euid_open # ok 12 test_cgcore_lesser_ns_open [ 400.108176] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 [ 400.108404] Mem abort info: [ 400.108523] ESR = 0x0000000096000004 [ 400.108656] EC = 0x25: DABT (current EL), IL = 32 bits [ 400.108810] SET = 0, FnV = 0 [ 400.108942] EA = 0, S1PTW = 0 [ 400.109074] FSC = 0x04: level 0 translation fault [ 400.109219] Data abort info: [ 400.109338] ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 [ 400.109488] CM = 0, WnR = 0, TnD = 0, TagAccess = 0 ok 3 selftests: cgroup: test_core [ 400.109644] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [ 400.109802] user pgtable: 4k pages, 48-bit VAs, pgdp=00000008898f3000 [ 400.109969] [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 [ 400.110267] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP [ 400.110372] Modules linked in: pl111_drm drm_dma_helper arm_spe_pmu panel_simple crct10dif_ce drm_kms_helper fuse drm backlight dm_mod ip_tables x_tables [ 400.110872] CPU: 4 PID: 131 Comm: kworker/4:2 Not tainted 6.6.0-rc4-next-20231006 #1 [ 400.111010] Hardware name: FVP Base RevC (DT) [ 400.111093] Workqueue: cgroup_destroy css_free_rwork_fn [ 400.111238] pstate: 03402009 (nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--) [ 400.111380] pc : percpu_ref_put_many.constprop.0+0xa0/0xf0 [ 400.111540] lr : percpu_ref_put_many.constprop.0+0x18/0xf0 [ 400.111700] sp : ffff800080713ca0 [ 400.111774] x29: ffff800080713ca0 x28: 0000000000000000 x27: 0000000000000000 [ 400.111970] x26: ffff00087f779d28 x25: ffff000800a3f700 x24: ffff0008003c2205 [ 400.112173] x23: 0000000000000036 x22: ffffd7c64df6a000 x21: ffffd7c64df6cb70 [ 400.112373] x20: ffff0008094d2000 x19: ffff000806dfa4c0 x18: ffff800083893c48 [ 400.112575] x17: 0000000000000000 x16: 0000000000000001 x15: 0000000000000001 [ 400.112765] x14: 0000000000000004 x13: ffffd7c64df87258 x12: 0000000000000000 [ 400.112964] x11: ffff000800402e60 x10: ffff000800402da0 x9 : ffffd7c64b786a90 [ 400.113166] x8 : ffff800080713b68 x7 : 0000000000000000 x6 : 0000000000000001 [ 400.113360] x5 : ffffd7c64df6a000 x4 : ffffd7c64df6a288 x3 : 0000000000000000 [ 400.113558] x2 : ffff0008044e0000 x1 : 0000000000000000 x0 : ffffffffffffffff [ 400.113756] Call trace: [ 400.113819] percpu_ref_put_many.constprop.0+0xa0/0xf0 [ 400.113980] __mem_cgroup_free+0x2c/0xe8 [ 400.114129] mem_cgroup_css_free+0x16c/0x1e8 [ 400.114281] css_free_rwork_fn+0x54/0x370 [ 400.114408] process_one_work+0x148/0x3b8 [ 400.114530] worker_thread+0x32c/0x450 [ 400.114650] kthread+0x104/0x118 [ 400.114797] ret_from_fork+0x10/0x20 [ 400.114954] Code: d65f03c0 f9400661 d503201f 92800000 (f8e00020) [ 400.115051] ---[ end trace 0000000000000000 ]--- Links: - https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20231006/testrun/20279395/suite/log-parser-test/test/check-kernel-oops/log - https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20231006/testrun/20279395/suite/log-parser-test/tests/ - https://tuxapi.tuxsuite.com/v1/groups/linaro/projects/lkft/tests/2WO7SlYRh87RbfNXUbvVZx2HBL8 - https://storage.tuxsuite.com/public/linaro/lkft/builds/2WO7RIllBsiwSAbiLChz9w6KXn8/ - https://storage.tuxsuite.com/public/linaro/lkft/builds/2WO7RIllBsiwSAbiLChz9w6KXn8/config https://storage.tuxsuite.com/public/linaro/lkft/builds/2WO7RIllBsiwSAbiLChz9w6KXn8/tuxmake_reproducer.sh -- Linaro LKFT https://lkft.linaro.org