cgroup: fork rejected by pids controller in /syz1 BUG: unable to handle page fault for address: ffff88801bab3050 #PF: supervisor write access in kernel mode #PF: error_code(0x0003) - permissions violation PGD 1b689067 P4D 1b689067 PUD 1b68a067 PMD 1d2a0063 PTE 800000001bab3121 Oops: Oops: 0003 [#1] SMP KASAN NOPTI CPU: 2 UID: 0 PID: 14016 Comm: syz.1.2912 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:arch_clear_bit arch/x86/include/asm/bitops.h:79 [inline] RIP: 0010:clear_bit include/asm-generic/bitops/instrumented-atomic.h:42 [inline] RIP: 0010:mm_drop_cid kernel/sched/sched.h:3801 [inline] RIP: 0010:mm_cid_schedout kernel/sched/sched.h:3984 [inline] RIP: 0010:mm_cid_switch_to kernel/sched/sched.h:3991 [inline] RIP: 0010:context_switch kernel/sched/core.c:5284 [inline] RIP: 0010:__schedule+0x3eb9/0x60e0 kernel/sched/core.c:6907 Code: 00 e9 7b cf ff ff 4c 89 e0 4c 8d ae 90 0b 00 00 be 08 00 00 00 48 89 8d 68 ff ff ff 48 c1 f8 06 49 8d 7c c5 00 e8 b7 99 e5 f6 4d 0f b3 65 00 48 8b 8d 68 ff ff ff 48 b8 00 00 00 00 00 fc ff RSP: 0000:ffffc9000f7f7678 EFLAGS: 00010046 RAX: 0000000000000001 RBX: ffff888026c64e80 RCX: ffffffff8b8dce69 RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff88801bab3050 RBP: ffffc9000f7f77d0 R08: 0000000000000001 R09: ffffed100375660a R10: ffff88801bab3057 R11: 0000000000000002 R12: 0000000040000001 R13: ffff888013ab3050 R14: ffff888026c64900 R15: ffff88802b43b280 FS: 0000000000000000(0000) GS:ffff888097351000(0063) knlGS:00000000f5446b40 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: ffff88801bab3050 CR3: 0000000055299000 CR4: 0000000000352ef0 Call Trace: preempt_schedule_common+0x42/0xc0 kernel/sched/core.c:7091 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:188 [inline] _raw_spin_unlock_irq+0x44/0x50 kernel/locking/spinlock.c:202 spin_unlock_irq include/linux/spinlock.h:401 [inline] copy_process+0x402/0x7a10 kernel/fork.c:2044 create_io_thread+0xc2/0x110 kernel/fork.c:2602 create_worker_cont+0xe5/0x420 io_uring/io-wq.c:852 task_work_run+0x150/0x240 kernel/task_work.c:233 get_signal+0x1bd/0x21e0 kernel/signal.c:2807 arch_do_signal_or_restart+0x91/0x770 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x86/0x4a0 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_int80_emulation+0x4b8/0x6b0 arch/x86/entry/syscall_32.c:175 asm_int80_emulation+0x1a/0x20 arch/x86/include/asm/idtentry.h:621 RIP: 0023:0xf7f82f6c Code: d2 74 05 c1 e8 0c 89 02 8b 5d fc 31 c0 c9 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 58 b8 77 00 00 00 cd 80 0f 0b 8d b6 00 00 00 00 b8 ad RSP: 002b:00000000f54465bc EFLAGS: 00000292 ORIG_RAX: 00000000000000f0 RAX: fffffffffffffe00 RBX: 00000000f7444f88 RCX: 0000000000000080 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000f7444f8c RBP: 0000000000000081 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Modules linked in: CR2: ffff88801bab3050 ---[ end trace 0000000000000000 ]--- RIP: 0010:arch_clear_bit arch/x86/include/asm/bitops.h:79 [inline] RIP: 0010:clear_bit include/asm-generic/bitops/instrumented-atomic.h:42 [inline] RIP: 0010:mm_drop_cid kernel/sched/sched.h:3801 [inline] RIP: 0010:mm_cid_schedout kernel/sched/sched.h:3984 [inline] RIP: 0010:mm_cid_switch_to kernel/sched/sched.h:3991 [inline] RIP: 0010:context_switch kernel/sched/core.c:5284 [inline] RIP: 0010:__schedule+0x3eb9/0x60e0 kernel/sched/core.c:6907 Code: 00 e9 7b cf ff ff 4c 89 e0 4c 8d ae 90 0b 00 00 be 08 00 00 00 48 89 8d 68 ff ff ff 48 c1 f8 06 49 8d 7c c5 00 e8 b7 99 e5 f6 4d 0f b3 65 00 48 8b 8d 68 ff ff ff 48 b8 00 00 00 00 00 fc ff RSP: 0000:ffffc9000f7f7678 EFLAGS: 00010046 RAX: 0000000000000001 RBX: ffff888026c64e80 RCX: ffffffff8b8dce69 RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff88801bab3050 RBP: ffffc9000f7f77d0 R08: 0000000000000001 R09: ffffed100375660a R10: ffff88801bab3057 R11: 0000000000000002 R12: 0000000040000001 R13: ffff888013ab3050 R14: ffff888026c64900 R15: ffff88802b43b280 FS: 0000000000000000(0000) GS:ffff888097351000(0063) knlGS:00000000f5446b40 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: ffff88801bab3050 CR3: 0000000055299000 CR4: 0000000000352ef0 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: e9 7b cf ff ff jmp 0xffffcf80 5: 4c 89 e0 mov %r12,%rax 8: 4c 8d ae 90 0b 00 00 lea 0xb90(%rsi),%r13 f: be 08 00 00 00 mov $0x8,%esi 14: 48 89 8d 68 ff ff ff mov %rcx,-0x98(%rbp) 1b: 48 c1 f8 06 sar $0x6,%rax 1f: 49 8d 7c c5 00 lea 0x0(%r13,%rax,8),%rdi 24: e8 b7 99 e5 f6 call 0xf6e599e0 * 29: f0 4d 0f b3 65 00 lock btr %r12,0x0(%r13) <-- trapping instruction 2f: 48 8b 8d 68 ff ff ff mov -0x98(%rbp),%rcx 36: 48 rex.W 37: b8 00 00 00 00 mov $0x0,%eax 3c: 00 fc add %bh,%ah 3e: ff .byte 0xff