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    SubjectPossible regression in "slab, slub: skip unnecessary kasan_cache_shutdown()"
    Hello Shakeel,

    It may be the case that f9e13c0a5a33d1eaec374d6d4dab53a4f72756a0 has
    introduced a regression. I've bisected a failing test to this commit,
    and after staring at the my code for a long time, I'm unable to find a
    bug that this commit might have unearthed. Rather, it looks like this
    commit introduces a performance optimization, rather than a
    correctness fix, so it seems that whatever test case is failing is
    likely an incorrect failure. Does that seem like an accurate
    possibility to you?

    Below is a stack trace when things go south. Let me know if you'd like
    to run my test suite, and I can send additional information.

    Regards,
    Jason


    [ 1.364686] kasan: GPF could be caused by NULL-ptr deref or user
    memory access
    [ 1.365258] general protection fault: 0000 [#1] PREEMPT SMP
    DEBUG_PAGEALLOC KASAN
    [ 1.365852] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.16.0 #19
    [ 1.366315] RIP: 0010:___cache_free+0x76/0x1e0
    [ 1.366667] RSP: 0000:ffff8800003af868 EFLAGS: 00010286
    [ 1.367079] RAX: ffffea0000cb04a0 RBX: ffff8800351f1958 RCX: ffff880035954900
    [ 1.367640] RDX: ffffea0000cb049f RSI: ffff8800351f1958 RDI: ffff880035954900
    [ 1.368014] RBP: ffffea0000d47c40 R08: ffff8800003a0870 R09: 0000000000000006
    [ 1.368014] R10: 0000000000000000 R11: 0000000000000000 R12: ffff880033314b98
    [ 1.368014] R13: ffff880035954900 R14: ffffea0000000000 R15: ffffffff826dfae0
    [ 1.368014] FS: 0000000000000000(0000) GS:ffff880036480000(0000)
    knlGS:00000000000
    [ 1.368014] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    [ 1.368014] CR2: 00000000ffffffff CR3: 0000000002220001 CR4: 00000000001606a0
    [ 1.368014] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
    [ 1.368014] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
    [ 1.368014] Call Trace:
    [ 1.368014] ? qlist_free_all+0x58/0x1c0
    [ 1.368014] qlist_free_all+0x70/0x1c0
    [ 1.368014] ? trace_hardirqs_on_caller+0x3d0/0x630
    [ 1.368014] quarantine_reduce+0x221/0x310
    [ 1.368014] kasan_kmalloc+0x95/0xc0
    [ 1.368014] kmem_cache_alloc+0x151/0x2b0
    [ 1.368014] create_object+0xa7/0xa70
    [ 1.368014] ? kmemleak_disable+0x90/0x90
    [ 1.368014] ? trace_hardirqs_on_caller+0x3d0/0x630
    [ 1.368014] ? fs_reclaim_acquire.part.14+0x30/0x30
    [ 1.368014] __kmalloc+0x200/0x340
    [ 1.368014] ? do_one_initcall+0x12c/0x212
    [ 1.368014] __register_sysctl_table+0xbe/0x11b0
    [ 1.368014] ipv4_sysctl_init_net+0x1cf/0x2d0
    [ 1.368014] ops_init+0x203/0x510
    [ 1.368014] ? proc_sys_setattr+0xe0/0xe0
    [ 1.368014] ? __peernet2id_alloc+0x180/0x180
    [ 1.368014] ? __rb_erase_color+0x1d90/0x1d90
    [ 1.368014] register_pernet_operations+0x38e/0x960
    [ 1.368014] ? setup_net+0x8b0/0x8b0
    [ 1.368014] ? register_pernet_subsys+0x10/0x40
    [ 1.368014] ? down_write+0x96/0x150
    [ 1.368014] ? register_pernet_subsys+0x10/0x40
    [ 1.368014] ? __register_sysctl_table+0x669/0x11b0
    [ 1.368014] ? gre_offload_init+0x44/0x44
    [ 1.368014] register_pernet_subsys+0x1f/0x40
    [ 1.368014] sysctl_ipv4_init+0x34/0x47
    [ 1.368014] do_one_initcall+0x12c/0x212
    [ 1.368014] ? start_kernel+0x60e/0x60e
    [ 1.368014] ? up_write+0x78/0x220
    [ 1.368014] ? up_read+0x130/0x130
    [ 1.368014] ? __asan_register_globals+0x53/0x80
    [ 1.368014] ? kasan_unpoison_shadow+0x30/0x40
    [ 1.368014] kernel_init_freeable+0x3b5/0x459
    [ 1.368014] ? rest_init+0x2bf/0x2bf
    [ 1.368014] kernel_init+0x7/0x11b
    [ 1.368014] ? rest_init+0x2bf/0x2bf
    [ 1.368014] ret_from_fork+0x24/0x30
    [ 1.368014] Code: 83 fd e0 0f 84 62 01 00 00 48 8b 45 20 49 c7 c7
    e0 fa 6d 82 48 8
    [ 1.368014] RIP: ___cache_free+0x76/0x1e0 RSP: ffff8800003af868
    [ 1.387680] ---[ end trace 975b7b250dd637de ]---
    [ 1.388098] Kernel panic - not syncing: Fatal exception
    [ 1.388655] Kernel Offset: disabled

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