syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P20053/1:b..l P20081/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=129825, q=440 ncpus=2)
task:sed             state:R  running task     stack:24232 pid:20081 ppid:20079  flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:check_region_inline mm/kasan/generic.c:169 [inline]
RIP: 0010:kasan_check_range+0x12/0x290 mm/kasan/generic.c:187
Code: 0f 0b b8 ea ff ff ff c3 0f 0b b8 ea ff ff ff c3 cc cc cc cc cc cc cc cc 66 0f 1f 00 b0 01 48 85 f6 0f 84 b8 01 00 00 55 41 57 <41> 56 41 55 41 54 53 4c 8d 04 37 49 39 f8 0f 82 5a 02 00 00 49 89
RSP: 0018:ffffc9000da8f4e8 EFLAGS: 00000202
RAX: ffffffff8a5c6301 RBX: ffff8880655fb200 RCX: ffffffff8a5c6367
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff972c05e0
RBP: ffffc9000da8f6d0 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff2e580b8 R12: 0000000000000003
R13: ffff8880655fb400 R14: 0000000000000001 R15: 0000000000000050
 instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
 atomic_inc include/linux/atomic/atomic-instrumented.h:435 [inline]
 mas_validate_parent_slot lib/maple_tree.c:7034 [inline]
 mt_validate+0x667/0x4530 lib/maple_tree.c:7228
 validate_mm+0xb1/0x420 mm/mmap.c:288
 do_vmi_align_munmap+0x148a/0x1660 mm/mmap.c:2597
 do_vmi_munmap+0x252/0x2d0 mm/mmap.c:2660
 __mmap_region mm/mmap.c:2710 [inline]
 mmap_region+0x741/0x2020 mm/mmap.c:2941
 do_mmap+0x92f/0x10a0 mm/mmap.c:1385
 vm_mmap_pgoff+0x1c0/0x400 mm/util.c:556
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fe56777f242
RSP: 002b:00007ffc9d167c28 EFLAGS: 00000206 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fe56748e000 RCX: 00007fe56777f242
RDX: 0000000000000003 RSI: 00000000000016d0 RDI: 00007fe56748e000
RBP: 0000000000000032 R08: 00000000ffffffff R09: 0000000000000000
R10: 0000000000000032 R11: 0000000000000206 R12: 00007ffc9d167ce8
R13: 00007fe56775cab0 R14: 00007ffc9d1680a0 R15: 00007fe56748e000
 </TASK>
task:syz.8.3532      state:R  running task     stack:26856 pid:20053 ppid:19206  flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:get_stack_info+0x74/0x170 arch/x86/kernel/dumpstack_64.c:208
Code: 00 00 00 4d 8b 2e 44 8b 23 bf 40 00 00 00 44 89 e6 e8 20 cc 56 00 49 83 fc 3f 0f 87 c9 00 00 00 e8 61 c8 56 00 bd 01 00 00 00 <44> 89 e1 48 d3 e5 48 89 ee 4c 21 ee 31 ff e8 89 cc 56 00 4c 21 ed
RSP: 0018:ffffc9000c3df208 EFLAGS: 00000293
RAX: ffffffff812ec72f RBX: ffffc9000c3df2a8 RCX: ffff88802c7b8000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000040
RBP: 0000000000000001 R08: ffffc9000c3df301 R09: 0000000000000000
R10: ffffc9000c3df2a8 R11: fffff5200187be61 R12: 0000000000000001
R13: 0000000000000000 R14: ffffc9000c3df2c8 R15: ffff88802c7b8000
 __unwind_start+0x48b/0x7e0 arch/x86/kernel/unwind_orc.c:729
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0xf8/0x190 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 save_stack+0xf7/0x1f0 mm/page_owner.c:128
 __reset_page_owner+0x4e/0x190 mm/page_owner.c:149
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1154 [inline]
 free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336
 free_unref_page_list+0xbe/0x860 mm/page_alloc.c:2475
 release_pages+0x1fa0/0x2220 mm/swap.c:1022
 tlb_batch_pages_flush mm/mmu_gather.c:98 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:293 [inline]
 tlb_flush_mmu+0x368/0x4f0 mm/mmu_gather.c:300
 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:392
 exit_mmap+0x3f0/0xb50 mm/mmap.c:3315
 __mmput+0x118/0x3c0 kernel/fork.c:1355
 exit_mm+0x1da/0x2c0 kernel/exit.c:569
 do_exit+0x88e/0x23c0 kernel/exit.c:870
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1024
 get_signal+0x12fc/0x1400 kernel/signal.c:2902
 arch_do_signal_or_restart+0x9c/0x7b0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f045518f6c9
RSP: 002b:00007f04560110e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f04553e5fa8 RCX: 00007f045518f6c9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f04553e5fa8
RBP: 00007f04553e5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f04553e6038 R14: 00007fffdb054540 R15: 00007fffdb054628
 </TASK>
rcu: rcu_preempt kthread starved for 10553 jiffies! g129825 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
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:26888 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_timeout+0x160/0x280 kernel/time/timer.c:2167
 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:148
Code: cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d c3 64 39 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 66 0f 1f 00 55 41 57 41 56
RSP: 0000:ffffffff8ca07d80 EFLAGS: 000002c2
RAX: eb38a282d2750f00 RBX: ffffffff816187ab RCX: eb38a282d2750f00
RDX: 0000000000000001 RSI: ffffffff8aaabce0 RDI: ffffffff8afc6b00
RBP: ffffffff8ca07eb8 R08: ffff8880b8e36b2b R09: 1ffff110171c6d65
R10: dffffc0000000000 R11: ffffed10171c6d66 R12: ffffffff8e4a8d68
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1952688
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe56748d068 CR3: 0000000065a96000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:753
 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97
 cpuidle_idle_call kernel/sched/idle.c:170 [inline]
 do_idle+0x1eb/0x510 kernel/sched/idle.c:282
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380
 rest_init+0x2e2/0x300 init/main.c:744
 arch_call_rest_init+0xe/0x10 init/main.c:841
 start_kernel+0x459/0x4e0 init/main.c:1086
 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555
 x86_64_start_kernel+0x60/0x60 arch/x86/kernel/head64.c:536
 secondary_startup_64_no_verify+0x179/0x17b
 </TASK>