rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5844/1:b.el
rcu: (detected by 1, t=10504 jiffies, g=12913, q=1381 ncpus=2)
task:udevd state:R running task stack:25864 pid:5844 tgid:5844 ppid:5215 task_flags:0x40014c flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5382 [inline]
__schedule+0x1b88/0x5240 kernel/sched/core.c:6767
preempt_schedule_irq+0xfe/0x1c0 kernel/sched/core.c:7090
irqentry_exit+0x5e/0x90 kernel/entry/common.c:354
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:99 [inline]
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:227 [inline]
RIP: 0010:unwind_next_frame+0x7aa/0x23b0 arch/x86/kernel/unwind_orc.c:494
Code: 0f b6 04 08 84 c0 75 27 48 63 03 48 01 d8 48 8d 4b 04 4c 39 e0 4c 0f 46 f1 48 8d 43 fc 48 0f 47 e8 4c 0f 46 eb 49 39 ee 76 a9 28 fb ff ff 89 d9 80 e1 07 80 c1 03 38 c1 7c cd 48 89 df 48 89
RSP: 0018:ffffc90003e07488 EFLAGS: 00000202
RAX: ffffffff90737540 RBX: ffffffff90737544 RCX: ffffffff90737548
RDX: ffffffff90eb8a92 RSI: ffffffff8ca1b680 RDI: ffffffff8ca1b640
RBP: ffffffff90737544 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff81818484
R13: ffffffff90737544 R14: ffffffff90737548 R15: ffffffff90737544
arch_stack_walk+0x11e/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x11a/0x1d0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
__kasan_kmalloc+0x9d/0xb0 mm/kasan/common.c:394
kasan_kmalloc include/linux/kasan.h:260 [inline]
__kmalloc_cache_noprof+0x236/0x370 mm/slub.c:4362
kmalloc_noprof include/linux/slab.h:905 [inline]
slab_free_hook mm/slub.c:2341 [inline]
slab_free mm/slub.c:4646 [inline]
kmem_cache_free+0x16e/0x410 mm/slub.c:4748
exit_mmap+0x73e/0xde0 mm/mmap.c:1309
__mmput+0x115/0x420 kernel/fork.c:1379
exit_mm+0x221/0x310 kernel/exit.c:589
do_exit+0x994/0x27f0 kernel/exit.c:940
do_group_exit+0x207/0x2c0 kernel/exit.c:1102
__do_sys_exit_group kernel/exit.c:1113 [inline]
__se_sys_exit_group kernel/exit.c:1111 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1111
x64_sys_call+0x26c3/0x26d0 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7feaee2fca90
RSP: 002b:00007ffc1b808c88 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007feaee2fca90
RDX: 00000000000000e7 RSI: 000000000000003c RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000007 R09: 2bbb3691b7eba5eb
R10: 00000000ffffffff R11: 0000000000000202 R12: 000056392eaeaa30
R13: 00007ffc1b808cc8 R14: 0000000000000001 R15: 000056392eab5910
rcu: rcu_preempt kthread starved for 4592 jiffies! g12913 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:26376 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5382 [inline]
__schedule+0x1b88/0x5240 kernel/sched/core.c:6767
__schedule_loop kernel/sched/core.c:6845 [inline]
schedule+0x163/0x360 kernel/sched/core.c:6860
schedule_timeout+0x15b/0x2b0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x2e1/0x1340 kernel/rcu/tree.c:2046
rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2248
kthread+0x7b7/0x940 kernel/kthread.c:464
ret_from_fork+0x4b/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: 1 UID: 0 PID: 770 Comm: kworker/u8:5 Not tainted 6.15.0-rc1-syzkaller-00178-gf0433eea4688 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline]
RIP: 0010:smp_call_function_many_cond+0x1bac/0x2d40 kernel/smp.c:885
Code: 03 84 c0 75 7e 45 8b 65 00 44 89 e6 83 e6 01 31 ff e8 18 e3 0b 00 41 83 e4 01 4c 8b 64 24 68 75 07 e8 c8 de 0b 00 eb 41 f3 90 <48> b8 00 00 00 00 00 fc ff df 0f b6 04 03 84 c0 75 11 41 f7 45 00
RSP: 0018:ffffc90002f9dee0 EFLAGS: 00000293
RAX: ffffffff81b786cd RBX: 1ffff110170c823d RCX: ffff8880255dbc00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90002f9e0e0 R08: ffffffff81b78698 R09: 1ffffffff20bfc4e
R10: dffffc0000000000 R11: ffffffff816b7a80 R12: ffff8880b873ad08
R13: ffff8880b86411e8 R14: ffff8880b873ad00 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125094000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2fc8912bd0 CR3: 000000005d024000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
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:1275 [inline]
flush_tlb_mm_range+0xb8d/0x13f0 arch/x86/mm/tlb.c:1365
flush_tlb_page arch/x86/include/asm/tlbflush.h:324 [inline]
ptep_clear_flush+0x11a/0x170 mm/pgtable-generic.c:101
page_vma_mkclean_one+0x5c6/0xa10 mm/rmap.c:1059
page_mkclean_one+0x270/0x360 mm/rmap.c:1100
__rmap_walk_file+0x422/0x5f0 mm/rmap.c:2897
rmap_walk mm/rmap.c:2941 [inline]
folio_mkclean+0x257/0x380 mm/rmap.c:1132
folio_clear_dirty_for_io+0x22d/0x9b0 mm/page-writeback.c:2987
mpage_submit_folio+0x84/0x340 fs/ext4/inode.c:1917
mpage_process_page_bufs+0x6d3/0x9d0 fs/ext4/inode.c:2049
mpage_prepare_extent_to_map+0xed0/0x1870 fs/ext4/inode.c:2550
ext4_do_writepages+0xc9f/0x3e50 fs/ext4/inode.c:2691
ext4_writepages+0x26f/0x450 fs/ext4/inode.c:2828
do_writepages+0x364/0x890 mm/page-writeback.c:2656
__writeback_single_inode+0x14f/0x10d0 fs/fs-writeback.c:1680
writeback_sb_inodes+0x822/0x1360 fs/fs-writeback.c:1976
__writeback_inodes_wb+0x11b/0x260 fs/fs-writeback.c:2047
wb_writeback+0x429/0xb90 fs/fs-writeback.c:2158
wb_check_old_data_flush fs/fs-writeback.c:2262 [inline]
wb_do_writeback fs/fs-writeback.c:2315 [inline]
wb_workfn+0xbbc/0x10b0 fs/fs-writeback.c:2343
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0xac3/0x18e0 kernel/workqueue.c:3319
worker_thread+0x870/0xd50 kernel/workqueue.c:3400
kthread+0x7b7/0x940 kernel/kthread.c:464
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245