FYI, we noticed the below changes on https://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git work.misc commit d0cc075bf99c8b9a108655dc4ff4869bac3dd3b4 ("kernel/*: switch to memdup_user_nul()") +------------------------------------------+------------+------------+ | | 28242757db | d0cc075bf9 | +------------------------------------------+------------+------------+ | boot_successes | 15 | 1 | | boot_failures | 0 | 9 | | kernel_BUG_at_mm/slab.c | 0 | 9 | | invalid_opcode:#[##] | 0 | 1 | | RIP:__cache_free | 0 | 9 | | Kernel_panic-not_syncing:Fatal_exception | 0 | 9 | | backtrace:vfs_write | 0 | 9 | | backtrace:SyS_write | 0 | 9 | | invalid_opcode:#[##]SMP_DEBUG_PAGEALLOC | 0 | 7 | | invalid_opcode:#[##]SMP | 0 | 1 | +------------------------------------------+------------+------------+ [ 13.600611] init: Failed to create pty - disabling logging for job [ 13.601677] init: Temporary process spawn error: No such file or directory [ 13.605602] ------------[ cut here ]------------ [ 13.606392] kernel BUG at mm/slab.c:2735! [ 13.607283] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC [ 13.608379] Modules linked in: [ 13.609024] CPU: 1 PID: 342 Comm: sysctl Not tainted 4.4.0-rc4-00029-gd0cc075 #171 [ 13.610269] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014 [ 13.611671] task: ffff88001c580f00 ti: ffff88001c7fc000 task.ti: ffff88001c7fc000 [ 13.612906] RIP: 0010:[] [] __cache_free+0x154/0x46c [ 13.614314] RSP: 0018:ffff88001c7ffce0 EFLAGS: 00010002 [ 13.615145] RAX: ffff88001c776800 RBX: ffff880033000140 RCX: 0000000000000004 [ 13.616202] RDX: 0000000000000020 RSI: 0000000000000000 RDI: ffff880033000140 [ 13.617262] RBP: ffff88001c7ffd40 R08: 0000000000000000 R09: 0000000000000001 [ 13.618316] R10: 0000000000000000 R11: 000000000000000a R12: ffff88001c776808 [ 13.619371] R13: ffff8800349dd220 R14: ffffffff810df09b R15: ffff88001c776080 [ 13.620429] FS: 00007fc12a383700(0000) GS:ffff880034800000(0000) knlGS:0000000000000000 [ 13.621736] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 13.622631] CR2: 00007fc12a385000 CR3: 000000001c7f0000 CR4: 00000000000006e0 [ 13.623691] Stack: [ 13.624136] ffffffff81111c40 ffff88001c776808 ffffea000063a1d0 ffff88001c7ffd08 [ 13.625666] ffffffff81111cb8 ffff88001c7ffd40 ffffffff81114ec2 0000000000000282 [ 13.627188] ffff88001c776808 ffff880033000140 0000000000000000 ffff88001c7fff20 [ 13.628716] Call Trace: [ 13.629212] [] ? trace_hardirqs_off_caller+0x3f/0xaa [ 13.630204] [] ? trace_hardirqs_off+0xd/0xf [ 13.631108] [] ? debug_check_no_locks_freed+0x114/0x13b [ 13.632131] [] kfree+0xe8/0x15c [ 13.632915] [] __do_proc_dointvec+0x22f/0x250 [ 13.633846] [] proc_dointvec+0x27/0x29 [ 13.634700] [] ? proc_skip_spaces+0x21/0x21 [ 13.635601] [] proc_sys_call_handler+0xa4/0xca [ 13.636534] [] proc_sys_write+0x14/0x16 [ 13.637395] [] __vfs_write+0x26/0xa5 [ 13.638216] [] ? percpu_down_read+0x53/0x7f [ 13.639113] [] ? __sb_start_write+0x5f/0xb0 [ 13.640016] [] ? __sb_start_write+0x5f/0xb0 [ 13.640914] [] vfs_write+0xa0/0xeb [ 13.641725] [] SyS_write+0x50/0x7e [ 13.642543] [] entry_SYSCALL_64_fastpath+0x12/0x76 [ 13.643520] Code: 48 8b 45 b0 4c 89 e2 48 89 df 4c 8b 78 08 4c 89 fe e8 90 ee ff ff 3b 43 24 72 02 0f 0b 8b 53 14 0f af c2 4c 01 f8 49 39 c4 74 02 <0f> 0b 8b 43 20 f6 c4 08 0f 84 da 00 00 00 81 e2 ff 0f 00 00 0f [ 13.651176] RIP [] __cache_free+0x154/0x46c [ 13.652160] RSP [ 13.652785] ---[ end trace d8e0316b6de6c109 ]--- [ 13.653542] Kernel panic - not syncing: Fatal exception Thanks, Kernel Test Robot