rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4272/1:b..l P4686/1:b..l (detected by 1, t=10503 jiffies, g=11501, q=108 ncpus=2) task:syz.3.67 state:R running task stack:27584 pid:4686 ppid:4280 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873 irqentry_exit+0x63/0x70 kernel/entry/common.c:439 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:mte_parent_slot lib/maple_tree.c:-1 [inline] RIP: 0010:mas_validate_parent_slot lib/maple_tree.c:7037 [inline] RIP: 0010:mt_validate+0xd6e/0x4c90 lib/maple_tree.c:7240 Code: 84 c0 0f 85 45 30 00 00 8b 1b 4c 89 ee 48 83 e6 02 31 ff e8 d4 64 7b f7 4c 89 e8 48 83 e0 02 0f 84 4b 2f 00 00 b9 03 00 00 00 <83> e3 01 45 89 ee 41 81 e6 fc 00 00 00 49 d3 ee 31 ff 89 de e8 29 RSP: 0018:ffffc90004bdf880 EFLAGS: 00000202 RAX: 0000000000000002 RBX: 000000000000030b RCX: 0000000000000003 RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000 RBP: ffffc90004bdfa50 R08: ffff88802c64d940 R09: 0000000000000003 R10: 0000000000000003 R11: 0000000000000000 R12: dffffc0000000000 R13: ffff888026b86e0e R14: 0000000000000006 R15: 000000000000000b validate_mm_mt+0xcd/0x420 mm/mmap.c:295 validate_mm+0xcc/0x2b0 mm/mmap.c:332 do_mmap+0xc7/0xfd0 mm/mmap.c:1270 vm_mmap_pgoff+0x1b2/0x2b0 mm/util.c:520 ksys_mmap_pgoff+0x516/0x6f0 mm/mmap.c:1482 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f503258f003 RSP: 002b:00007fff88796a18 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 0000001b2f364000 RCX: 00007f503258f003 RDX: 0000000000000003 RSI: 00000000005c0000 RDI: 0000001b2f364000 RBP: 0000000000600000 R08: 0000000000000004 R09: 0000000000040000 R10: 0000000000100001 R11: 0000000000000246 R12: 000000000000000a R13: 00000000000927c0 R14: 000000000001f9a6 R15: 00007fff88796d00 task:udevd state:R running task stack:23040 pid:4272 ppid:3638 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873 irqentry_exit+0x63/0x70 kernel/entry/common.c:439 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:696 RIP: 0010:__sanitizer_cov_trace_pc+0x58/0x60 kernel/kcov.c:234 Code: f8 15 00 00 83 fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 48 8d 7e 01 8b 89 fc 15 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 08 0f 1f 80 00 00 00 00 48 8b 04 24 65 48 8b 15 74 98 81 7e 65 8b RSP: 0018:ffffc90003cd7800 EFLAGS: 00000293 RAX: ffffffff81aa81ec RBX: ffffea0001dde734 RCX: ffff88807c105940 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffc90003cd78a0 RBP: dffffc0000000000 R08: dffffc0000000000 R09: fffff940003bbce7 R10: fffff940003bbce7 R11: 1ffffd40003bbce6 R12: ffffc90003cd78a0 R13: ffffea0001dde700 R14: 0000000000000201 R15: ffffc90003cd78a0 xas_reload+0x1c/0x470 include/linux/xarray.h:1574 filemap_get_read_batch+0x2b3/0xa60 mm/filemap.c:2454 filemap_get_pages mm/filemap.c:2667 [inline] filemap_read+0x61a/0x2f80 mm/filemap.c:2759 blkdev_read_iter+0x3d5/0x500 block/fops.c:614 call_read_iter include/linux/fs.h:2259 [inline] new_sync_read fs/read_write.c:389 [inline] vfs_read+0x434/0x920 fs/read_write.c:470 ksys_read+0x143/0x240 fs/read_write.c:613 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fc5932a7407 RSP: 002b:00007fffd0d5a3b0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007fc593a92880 RCX: 00007fc5932a7407 RDX: 0000000000000200 RSI: 00007fc593a7c000 RDI: 0000000000000009 RBP: 000055c17693cf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000018 R13: 0000000000200000 R14: 000055c17693b778 R15: 00007fc593bb939c rcu: rcu_preempt kthread starved for 10568 jiffies! g11501 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task stack:27392 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 schedule+0xb9/0x180 kernel/sched/core.c:6637 schedule_timeout+0x15c/0x280 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 PID: 4675 Comm: syz.0.63 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202 Code: f5 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 8e 8f 41 f7 48 89 df e8 e6 54 42 f7 e8 31 48 65 f7 fb bf 01 00 00 00 76 cd 35 f7 65 8b 05 f7 84 e0 75 85 c0 74 02 5b c3 e8 44 96 de RSP: 0018:ffffc90004b7fb98 EFLAGS: 00000282 RAX: 67ebe1a702669500 RBX: ffff888023c35c80 RCX: 67ebe1a702669500 RDX: dffffc0000000000 RSI: ffffffff8a8c0580 RDI: 0000000000000001 RBP: ffff888023c36118 R08: dffffc0000000000 R09: ffffed1004786b91 R10: ffffed1004786b91 R11: 1ffff11004786b90 R12: 1ffff11004786c23 R13: 0000000000000021 R14: dffffc0000000000 R15: 0000000000000000 FS: 00007f1a9fe996c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc593a7d000 CR3: 0000000054b2b000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: spin_unlock_irq include/linux/spinlock.h:401 [inline] get_signal+0x1163/0x1350 kernel/signal.c:2874 arch_do_signal_or_restart+0xb7/0x1240 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f1a9ef8efc7 Code: ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 <0f> 05 48 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 RSP: 002b:00007f1a9fe990e8 EFLAGS: 00000246 RAX: 00000000000000ca RBX: 00007f1a9f1e5fa8 RCX: 00007f1a9ef8efc9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f1a9f1e5fa8 RBP: 00007f1a9f1e5fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1a9f1e6038 R14: 00007ffd4a07eeb0 R15: 00007ffd4a07ef98