[v6.1] INFO: rcu detected stall in vm_mmap_pgoff (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 090666d3cc90 Linux 6.1.177
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=16638746580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f5aae664b2df43c2
dashboard link: https://syzkaller.appspot.com/bug?extid=091b593b7226bb6f1373
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/0b218516a5e9/disk-090666d3.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3239ad568bdf/vmlinux-090666d3.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a8b19cfbec3e/bzImage-090666d3.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+091b59...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P22841/1:b..l
(detected by 0, t=10502 jiffies, g=128517, q=108 ncpus=2)
task:syz.3.4114 state:R running task stack:25360 pid:22841 ppid:10797 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0x107f/0x4030 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:filemap_map_pages+0x78e/0x11e0 mm/filemap.c:3481
Code: e6 e8 66 70 d5 ff 49 83 fc 43 0f 85 c1 07 00 00 4c 8b 6c 24 60 4c 89 e8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 <4c> 8b 64 24 18 74 12 4c 89 ef e8 43 92 26 00 48 b9 00 00 00 00 00
RSP: 0018:ffffc9000d99f840 EFLAGS: 00000246
RAX: 1ffff1100482e95f RBX: ffffea0000d3d100 RCX: dffffc0000000000
RDX: 0000000000000002 RSI: 0000000000000043 RDI: 0000000000000043
RBP: ffffc9000d99f9d0 R08: ffffea0000d3d107 R09: 1ffffd40001a7a20
R10: dffffc0000000000 R11: fffff940001a7a21 R12: 0000000000000043
R13: ffff888024174af8 R14: 1ffff92001b33f5e R15: 0000000000000001
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+0x25e5/0x3d40 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: 0033:0x7fb68b79de99
RSP: 002b:00007fb68c6d2028 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fb68ba25fa0 RCX: 00007fb68b79de99
RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007fb68b833eaf R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb68ba26038 R14: 00007fb68ba25fa0 R15: 00007ffcc4c95528
</TASK>
rcu: rcu_preempt kthread starved for 10528 jiffies! g128517 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:27600 pid:16 ppid:2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0x107f/0x4030 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+0x303/0x1350 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
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 22848 Comm: syz.4.4115 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: 00 00 00 66 90 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 de 0d 2a f7 48 89 df e8 66 d5 2a f7 e8 41 1f 4e f7 fb bf 01 00 00 00 <e8> c6 56 1e f7 65 8b 05 c7 07 c8 75 85 c0 74 02 5b c3 e8 d4 1b c6
RSP: 0018:ffffc9000dd8fb98 EFLAGS: 00000282
RAX: de74482d25ef8b00 RBX: ffff8880763e9bc0 RCX: de74482d25ef8b00
RDX: dffffc0000000000 RSI: ffffffff8a8c17a0 RDI: 0000000000000001
RBP: 0000000000000000 R08: ffff8880763e9bc3 R09: 1ffff1100ec7d378
R10: dffffc0000000000 R11: ffffed100ec7d379 R12: 0000000000000021
R13: ffff8880763ea058 R14: dffffc0000000000 R15: 000000001c000004
FS: 00007f44b4a216c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f56a438dff8 CR3: 0000000063e88000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
spin_unlock_irq include/linux/spinlock.h:401 [inline]
get_signal+0x114a/0x1340 kernel/signal.c:2875
arch_do_signal_or_restart+0xc4/0x1310 arch/x86/kernel/signal.c:871
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f44b3b9de97
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:00007f44b4a21028 EFLAGS: 00000246
RAX: 0000000000000048 RBX: 00007f44b3e25fa0 RCX: 00007f44b3b9de99
RDX: 0000200000000280 RSI: 0000000000000026 RDI: 0000000000000005
RBP: 00007f44b3c33eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f44b3e26038 R14: 00007f44b3e25fa0 R15: 00007ffe4ff24ca8
</TASK>


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