syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P13938/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=62985, q=124 ncpus=2)
task:syz.5.2114      state:R  running task     stack:25384 pid:13938 tgid:13937 ppid:7874   task_flags:0x400140 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6785
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7108
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:307
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:unwind_next_frame+0xc89/0x2390 arch/x86/kernel/unwind_orc.c:592
Code: af 00 49 89 1f 48 8b 44 24 58 80 3c 28 00 48 8b 5c 24 70 4c 8b 6c 24 50 4c 8b 64 24 10 74 08 48 89 df e8 ba 0f af 00 4c 89 23 <ba> 10 00 00 00 4c 89 ef 31 f6 e8 88 11 af 00 48 8b 14 24 e9 c5 04
RSP: 0018:ffffc9000418eef8 EFLAGS: 00000246
RAX: 1ffff92000831e00 RBX: ffffc9000418f000 RCX: 1ffff92000831d01
RDX: ffffffff903bd65e RSI: 0000000000000002 RDI: ffffc9000418f368
RBP: dffffc0000000000 R08: 000000000000000a R09: ffffffff81728af5
R10: ffffc9000418f018 R11: ffffffff81ace5d0 R12: ffffc9000418f370
R13: ffffc9000418f018 R14: ffffc9000418efc8 R15: ffffc9000418f010
 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
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4328 [inline]
 __kmalloc_node_track_caller_noprof+0x271/0x4e0 mm/slub.c:4347
 __kmemdup_nul mm/util.c:63 [inline]
 kstrdup+0x42/0x100 mm/util.c:83
 __kernfs_new_node+0x9c/0x7e0 fs/kernfs/dir.c:633
 kernfs_new_node+0x102/0x210 fs/kernfs/dir.c:713
 __kernfs_create_file+0x4b/0x2e0 fs/kernfs/file.c:1039
 sysfs_add_file_mode_ns+0x238/0x300 fs/sysfs/file.c:319
 create_files fs/sysfs/group.c:76 [inline]
 internal_create_group+0x66d/0x1110 fs/sysfs/group.c:183
 internal_create_groups fs/sysfs/group.c:223 [inline]
 sysfs_create_groups+0x59/0x120 fs/sysfs/group.c:249
 setup_gid_attrs drivers/infiniband/core/sysfs.c:1162 [inline]
 ib_setup_port_attrs+0x1407/0x2070 drivers/infiniband/core/sysfs.c:1439
 add_one_compat_dev+0x3d6/0x5c0 drivers/infiniband/core/device.c:968
 rdma_dev_init_net+0x1dd/0x270 drivers/infiniband/core/device.c:1184
 ops_init+0x35c/0x5c0 net/core/net_namespace.c:138
 setup_net+0x219/0x4b0 net/core/net_namespace.c:442
 copy_net_ns+0x31b/0x4d0 net/core/net_namespace.c:574
 create_new_namespaces+0x3f3/0x720 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x11c/0x170 kernel/nsproxy.c:218
 ksys_unshare+0x4c8/0x8c0 kernel/fork.c:3121
 __do_sys_unshare kernel/fork.c:3192 [inline]
 __se_sys_unshare kernel/fork.c:3190 [inline]
 __x64_sys_unshare+0x38/0x50 kernel/fork.c:3190
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f246af8e929
RSP: 002b:00007f246bd1f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007f246b1b5fa0 RCX: 00007f246af8e929
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000006a040000
RBP: 00007f246b010b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f246b1b5fa0 R15: 00007ffee1dc7168
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g62985 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=52988
rcu: rcu_preempt kthread starved for 10502 jiffies! g62985 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:26464 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6785
 __schedule_loop kernel/sched/core.c:6863 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6878
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 13960 Comm: syz.6.2120 Not tainted 6.16.0-rc4-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x70 kernel/kcov.c:216
Code: 8b 3d a4 e6 f8 0b 48 89 de 5b e9 13 91 56 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0c 25 08 c0 99 92 65 8b 15 88 72 d9 10 81 e2 00 01 ff 00
RSP: 0000:ffffc90000007c68 EFLAGS: 00000002
RAX: ffffffff897f6f78 RBX: 0000000000000001 RCX: 0000000000010000
RDX: ffff8880306c1e00 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000000f7c R12: ffff88807d543340
R13: ffff88807d543000 R14: dffffc0000000000 R15: ffff8880798dbc00
FS:  00007fe63dba36c0(0000) GS:ffff888125c84000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe63dba0f70 CR3: 0000000024516000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 advance_sched+0x178/0xc90 net/sched/sch_taprio.c:927
 __run_hrtimer kernel/time/hrtimer.c:1761 [inline]
 __hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1825
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
 __sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1056
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:unwind_next_frame+0x395/0x2390 arch/x86/kernel/unwind_orc.c:505
Code: e0 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 6d 19 00 00 4c 89 e8 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 80 19 00 00 41 0f b6 44 24 01 <83> e0 07 0f 84 75 15 00 00 83 f8 01 4c 8b 7c 24 48 48 bd 00 00 00
RSP: 0000:ffffc9000473f2b8 EFLAGS: 00000246
RAX: 000000000000000b RBX: ffffffff8fada984 RCX: ffffffff8fada988
RDX: ffffffff9025e64c RSI: ffffffff9025e5e6 RDI: ffffffff8be1b8a0
RBP: dffffc0000000000 R08: 000000000000001c R09: ffffffff81728af5
R10: ffffc9000473f3d8 R11: ffffffff81ace5d0 R12: ffffffff9025e650
R13: ffffffff9025e651 R14: ffffc9000473f388 R15: ffffffff8fada984
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 save_stack+0xf7/0x1f0 mm/page_owner.c:156
 __set_page_owner+0x8d/0x4a0 mm/page_owner.c:329
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x21d5/0x22b0 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4959
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419
 folio_alloc_mpol_noprof mm/mempolicy.c:2438 [inline]
 vma_alloc_folio_noprof+0xe4/0x200 mm/mempolicy.c:2473
 folio_prealloc+0x30/0x180 mm/memory.c:-1
 alloc_anon_folio mm/memory.c:5014 [inline]
 do_anonymous_page mm/memory.c:5071 [inline]
 do_pte_missing mm/memory.c:4249 [inline]
 handle_pte_fault mm/memory.c:6069 [inline]
 __handle_mm_fault+0x2c88/0x5620 mm/memory.c:6212
 handle_mm_fault+0x2d5/0x7f0 mm/memory.c:6381
 do_user_addr_fault+0xa81/0x1390 arch/x86/mm/fault.c:1336
 handle_page_fault arch/x86/mm/fault.c:1476 [inline]
 exc_page_fault+0x76/0xf0 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7fe63cc5ffb6
Code: 00 00 00 00 41 57 31 c0 41 56 49 89 d6 41 55 49 89 f5 48 89 d6 41 54 49 89 fc 48 8d 3d 8e 1f 1b 00 55 53 48 81 ec 88 20 00 00 <48> 89 0c 24 4c 89 44 24 08 e8 5c e0 fe ff 4d 85 f6 0f 84 46 0a 00
RSP: 002b:00007fe63dba0f70 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 00007fe63cfb6160 RCX: 0000000000000000
RDX: 0000200000000200 RSI: 0000200000000200 RDI: 00007fe63ce11f3b
RBP: 00007fe63ce10b39 R08: 00007fe63cc4e3a0 R09: 0000000000000000
R10: 0000000000000004 R11: 0000200000000200 R12: 0000000000000004
R13: 0000000000000024 R14: 0000200000000200 R15: 00007ffc34de0928
 </TASK>