rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P13250/1:b..l (detected by 1, t=10503 jiffies, g=78941, q=94 ncpus=2) task:syz.0.2060 state:R running task stack:25232 pid:13250 ppid:4271 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5245 [inline] __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6874 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:lock_is_held_type+0x13a/0x190 kernel/locking/lockdep.c:5710 Code: 75 40 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 46 41 f7 c5 00 02 00 00 74 01 fb 65 48 8b 04 25 28 00 00 00 <48> 3b 44 24 08 75 3c 89 e8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f RSP: 0018:ffffc90005c9f730 EFLAGS: 00000206 RAX: 73efb389c2b6db00 RBX: ffff88807d80d940 RCX: 73efb389c2b6db00 RDX: ffff88807d80d940 RSI: ffffffff8a8c2220 RDI: ffffffff8adf0d20 RBP: 0000000000000001 R08: ffff88807d80d940 R09: 0000000000000002 R10: 0000000000000003 R11: 0000000000000002 R12: 0000000000000001 R13: 0000000000000246 R14: ffffffff8cb2d5a0 R15: ffff88807d80e448 xa_entry include/linux/xarray.h:1198 [inline] xas_descend+0x129/0x490 lib/xarray.c:204 xas_load lib/xarray.c:242 [inline] xas_find+0x1e0/0xab0 lib/xarray.c:1252 first_map_page mm/filemap.c:3445 [inline] filemap_map_pages+0x261/0x11c0 mm/filemap.c:3472 do_fault_around mm/memory.c:4598 [inline] do_read_fault mm/memory.c:4624 [inline] do_fault mm/memory.c:4758 [inline] handle_pte_fault mm/memory.c:5029 [inline] __handle_mm_fault mm/memory.c:5171 [inline] handle_mm_fault+0x2991/0x3ee0 mm/memory.c:5292 faultin_page mm/gup.c:1026 [inline] __get_user_pages+0x40d/0xec0 mm/gup.c:1250 populate_vma_page_range+0x214/0x2b0 mm/gup.c:1607 __mm_populate+0x25c/0x380 mm/gup.c:1721 mm_populate include/linux/mm.h:2891 [inline] vm_mmap_pgoff+0x212/0x2d0 mm/util.c:525 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fad2b39c819 RSP: 002b:00007fad2c20c028 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007fad2b615fa0 RCX: 00007fad2b39c819 RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000 RBP: 00007fad2b432c91 R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fad2b616038 R14: 00007fad2b615fa0 R15: 00007fffa1e83e98 rcu: rcu_preempt kthread starved for 10538 jiffies! g78941 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:26448 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5245 [inline] __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562 schedule+0xb9/0x180 kernel/sched/core.c:6638 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x303/0x1340 kernel/rcu/tree.c:1706 rcu_gp_kthread+0x99/0x3b0 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: 13252 Comm: syz.6.2061 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:84 [inline] RIP: 0010:memory_is_nonzero mm/kasan/generic.c:102 [inline] RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:128 [inline] RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline] RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline] RIP: 0010:kasan_check_range+0x77/0x290 mm/kasan/generic.c:189 Code: df 4f 8d 1c 16 4c 8d 44 3e ff 4d 89 c1 49 c1 e9 03 4b 8d 1c 21 49 89 df 4d 29 df 49 83 ff 10 7f 29 4d 85 ff 0f 84 38 01 00 00 <4c> 89 cb 48 f7 d3 4c 01 f3 41 80 3b 00 0f 85 86 01 00 00 49 ff c3 RSP: 0018:ffffc9000cd5fba0 EFLAGS: 00000206 RAX: ffffffff84114301 RBX: fffff520019abf8f RCX: ffffffff84114387 RDX: 0000000000000001 RSI: 0000000000000018 RDI: ffffc9000cd5fc60 RBP: 0000000000000000 R08: ffffc9000cd5fc77 R09: 1ffff920019abf8e R10: dffffc0000000000 R11: fffff520019abf8c R12: dffffc0000000001 R13: dffffc0000000000 R14: 1ffff920019abf8c R15: 0000000000000003 FS: 00007ff27fec16c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f23b8ac4d58 CR3: 0000000028ae5000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: instrument_copy_from_user_before include/linux/instrumented.h:137 [inline] _copy_from_user+0xe7/0x170 lib/usercopy.c:22 copy_from_user include/linux/uaccess.h:161 [inline] restore_altstack+0xa8/0x4c0 kernel/signal.c:4257 __ia32_sys_rt_sigreturn+0x619/0x760 arch/x86/kernel/signal.c:678 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7ff27ef9c817 Code: 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 RSP: 002b:00007ff27fec10e8 EFLAGS: 00000246 RAX: 00000000000000ca RBX: 00007ff27f215fa8 RCX: 00007ff27ef9c819 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007ff27f215fa8 RBP: 00007ff27f215fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff27f216038 R14: 00007fffe2409e60 R15: 00007fffe2409f48