rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (1 GPs behind) idle=ed0c/1/0x4000000000000000 softirq=88058/88060 fqs=6
rcu: (detected by 0, t=10506 jiffies, g=88429, q=108 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 18968 Comm: syz.6.5316 Not tainted 6.15.0-rc6-syzkaller-00052-g9f35e33144ae #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:trace_hrtimer_expire_exit include/trace/events/timer.h:306 [inline]
RIP: 0010:__run_hrtimer kernel/time/hrtimer.c:1764 [inline]
RIP: 0010:__hrtimer_run_queues+0x5c7/0xc60 kernel/time/hrtimer.c:1825
Code: c7 40 0f 92 c6 bf 02 00 00 00 e8 d4 9a 11 00 45 84 ff 74 1f e8 5a bf f8 ff 84 c0 49 bd 00 00 00 00 00 fc ff df 4c 8b 7c 24 60 <74> 1d e8 b2 97 11 00 eb 28 e8 ab 97 11 00 49 bd 00 00 00 00 00 fc
RSP: 0018:ffffc90000a08d40 EFLAGS: 00000002
RAX: 0000000000000001 RBX: ffff8880b8927908 RCX: 5c423dd92b314b00
RDX: ffff888069ecda00 RSI: ffffffff8bc1d800 RDI: ffffffff8bc1d7c0
RBP: ffffc90000a08e90 R08: ffffffff8f7efb77 R09: 1ffffffff1efdf6e
R10: dffffc0000000000 R11: fffffbfff1efdf6f R12: ffff888059ec3340
R13: dffffc0000000000 R14: 0000000000000001 R15: ffff8880b89278c0
FS: 00007f56462116c0(0000) GS:ffff8881261c7000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2ff1eff8 CR3: 000000004b69d000 CR4: 0000000000350ef0
Call Trace:
hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline]
__sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1055
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:127 [inline]
RIP: 0010:lock_release+0xa6/0x3e0 kernel/locking/lockdep.c:5883
Code: 25 08 90 75 92 41 83 bf ec 0a 00 00 00 0f 85 1e 02 00 00 49 81 3e f0 26 39 93 0f 84 11 02 00 00 48 c7 44 24 20 00 00 00 00 9c <8f> 44 24 20 48 8b 5c 24 20 fa 48 c7 c7 4b f5 75 8d e8 c4 11 b8 09
RSP: 0018:ffffc9000b73f188 EFLAGS: 00000206
RAX: 0000000000000000 RBX: ffffffff90363e01 RCX: 5c423dd92b314b00
RDX: ffffc9000b73f301 RSI: ffffffff8bc1d800 RDI: ffffffff8bc1d7c0
RBP: dffffc0000000000 R08: ffffc9000b73fd68 R09: ffffc9000b73f318
R10: dffffc0000000000 R11: fffff520016e7e65 R12: ffffc9000b73fd78
R13: ffffffff8171ca05 R14: ffffffff8df3dce0 R15: ffff888069ecda00
rcu_lock_release include/linux/rcupdate.h:341 [inline]
rcu_read_unlock include/linux/rcupdate.h:871 [inline]
class_rcu_destructor include/linux/rcupdate.h:1155 [inline]
unwind_next_frame+0x19a9/0x2390 arch/x86/kernel/unwind_orc.c:680
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
unpoison_slab_object mm/kasan/common.c:319 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:345
kasan_slab_alloc include/linux/kasan.h:250 [inline]
slab_post_alloc_hook mm/slub.c:4147 [inline]
slab_alloc_node mm/slub.c:4196 [inline]
kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4203
radix_tree_node_alloc+0x19c/0x3a0 lib/radix-tree.c:253
__radix_tree_create lib/radix-tree.c:624 [inline]
radix_tree_insert+0x1fd/0x660 lib/radix-tree.c:712
btrfs_insert_fs_root+0xf7/0x4c0 fs/btrfs/disk-io.c:1207
btrfs_get_root_ref+0x69e/0xaf0 fs/btrfs/disk-io.c:1381
btrfs_get_fs_root fs/btrfs/disk-io.c:1413 [inline]
open_ctree+0x1fef/0x2800 fs/btrfs/disk-io.c:3603
btrfs_fill_super+0x19d/0x2e0 fs/btrfs/super.c:972
btrfs_get_tree_super fs/btrfs/super.c:1897 [inline]
btrfs_get_tree+0x107c/0x1620 fs/btrfs/super.c:2092
vfs_get_tree+0x92/0x2b0 fs/super.c:1759
fc_mount+0x1c/0xb0 fs/namespace.c:1289
btrfs_get_tree_subvol fs/btrfs/super.c:2050 [inline]
btrfs_get_tree+0x67d/0x1620 fs/btrfs/super.c:2093
vfs_get_tree+0x92/0x2b0 fs/super.c:1759
do_new_mount+0x24a/0xa40 fs/namespace.c:3881
do_mount fs/namespace.c:4221 [inline]
__do_sys_mount fs/namespace.c:4432 [inline]
__se_sys_mount+0x317/0x410 fs/namespace.c:4409
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f564539010a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5646210e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f5646210ef0 RCX: 00007f564539010a
RDX: 0000200000005100 RSI: 0000200000000040 RDI: 00007f5646210eb0
RBP: 0000200000005100 R08: 00007f5646210ef0 R09: 0000000000000810
R10: 0000000000000810 R11: 0000000000000246 R12: 0000200000000040
R13: 00007f5646210eb0 R14: 00000000000050f3 R15: 00002000000001c0
rcu: rcu_preempt kthread starved for 10475 jiffies! g88429 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:27032 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5382 [inline]
__schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767
__schedule_loop kernel/sched/core.c:6845 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6860
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2046
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2248
kthread+0x711/0x8a0 kernel/kthread.c:464
ret_from_fork+0x4e/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 19013 Comm: syz.7.5342 Not tainted 6.15.0-rc6-syzkaller-00052-g9f35e33144ae #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline]
RIP: 0010:smp_call_function_many_cond+0xe6e/0x11c0 kernel/smp.c:885
Code: 89 ee 83 e6 01 31 ff e8 80 6d 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 2b 69 0b 00 eb 37 f3 90 43 0f b6 04 2c <84> c0 75 10 41 f7 07 01 00 00 00 74 1e e8 10 69 0b 00 eb e5 44 89
RSP: 0018:ffffc9000436f4e0 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff8880b883ad40 RCX: ffff888032d29e00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000436f640 R08: ffffffff8f7efb77 R09: 1ffffffff1efdf6e
R10: dffffc0000000000 R11: fffffbfff1efdf6f R12: 1ffff11017127e99
R13: dffffc0000000000 R14: 0000000000000001 R15: ffff8880b893f4c8
FS: 0000000000000000(0000) GS:ffff8881260c7000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3f439bd000 CR3: 0000000031cf8000 CR4: 0000000000350ef0
Call Trace:
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052
__flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
flush_tlb_multi arch/x86/mm/tlb.c:1291 [inline]
flush_tlb_mm_range+0x6ae/0x12b0 arch/x86/mm/tlb.c:1381
tlb_flush arch/x86/include/asm/tlb.h:23 [inline]
tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:480 [inline]
tlb_flush_mmu+0x1a7/0x680 mm/mmu_gather.c:403
tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:496
exit_mmap+0x474/0xba0 mm/mmap.c:1297
__mmput+0x118/0x420 kernel/fork.c:1379
exit_mm+0x1da/0x2c0 kernel/exit.c:589
do_exit+0x859/0x2550 kernel/exit.c:940
do_group_exit+0x21c/0x2d0 kernel/exit.c:1102
get_signal+0x125e/0x1310 kernel/signal.c:3034
arch_do_signal_or_restart+0x95/0x780 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0x8b/0x120 kernel/entry/common.c:218
do_syscall_64+0x103/0x210 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1eddf8e969
Code: Unable to access opcode bytes at 0x7f1eddf8e93f.
RSP: 002b:00007f1ededd60e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f1ede1b5fa8 RCX: 00007f1eddf8e969
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f1ede1b5fa8
RBP: 00007f1ede1b5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f1ede1b5fac
R13: 0000000000000000 R14: 00007fff30ad3560 R15: 00007fff30ad3648