[v6.1] INFO: rcu detected stall in vm_mmap_pgoff (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 1989cd3d56e2 Linux 6.1.167
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=160a08f2580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f0605c5af04d7603
dashboard link: https://syzkaller.appspot.com/bug?extid=3acb464e2992516d0500
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/814271465bd5/disk-1989cd3d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/bd559379c491/vmlinux-1989cd3d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/063c12bf8ba7/bzImage-1989cd3d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3acb46...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P13250/1:b..l
(detected by 1, t=10503 jiffies, g=78941, q=94 ncpus=2)
task:syz.0.2060 state:R running task stack:25232 pid:13250 ppid:4271 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0x11d1/0x40e0 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:lock_is_held_type+0x13a/0x190 kernel/locking/lockdep.c:5710
Code: 75 40 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 46 41 f7 c5 00 02 00 00 74 01 fb 65 48 8b 04 25 28 00 00 00 <48> 3b 44 24 08 75 3c 89 e8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f
RSP: 0018:ffffc90005c9f730 EFLAGS: 00000206
RAX: 73efb389c2b6db00 RBX: ffff88807d80d940 RCX: 73efb389c2b6db00
RDX: ffff88807d80d940 RSI: ffffffff8a8c2220 RDI: ffffffff8adf0d20
RBP: 0000000000000001 R08: ffff88807d80d940 R09: 0000000000000002
R10: 0000000000000003 R11: 0000000000000002 R12: 0000000000000001
R13: 0000000000000246 R14: ffffffff8cb2d5a0 R15: ffff88807d80e448
xa_entry include/linux/xarray.h:1198 [inline]
xas_descend+0x129/0x490 lib/xarray.c:204
xas_load lib/xarray.c:242 [inline]
xas_find+0x1e0/0xab0 lib/xarray.c:1252
first_map_page mm/filemap.c:3445 [inline]
filemap_map_pages+0x261/0x11c0 mm/filemap.c:3472
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+0x2991/0x3ee0 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: 0033:0x7fad2b39c819
RSP: 002b:00007fad2c20c028 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fad2b615fa0 RCX: 00007fad2b39c819
RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007fad2b432c91 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fad2b616038 R14: 00007fad2b615fa0 R15: 00007fffa1e83e98
</TASK>
rcu: rcu_preempt kthread starved for 10538 jiffies! g78941 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:26448 pid:16 ppid:2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0x11d1/0x40e0 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+0x303/0x1340 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: 1 PID: 13252 Comm: syz.6.2061 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:84 [inline]
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:102 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:128 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]
RIP: 0010:kasan_check_range+0x77/0x290 mm/kasan/generic.c:189
Code: df 4f 8d 1c 16 4c 8d 44 3e ff 4d 89 c1 49 c1 e9 03 4b 8d 1c 21 49 89 df 4d 29 df 49 83 ff 10 7f 29 4d 85 ff 0f 84 38 01 00 00 <4c> 89 cb 48 f7 d3 4c 01 f3 41 80 3b 00 0f 85 86 01 00 00 49 ff c3
RSP: 0018:ffffc9000cd5fba0 EFLAGS: 00000206
RAX: ffffffff84114301 RBX: fffff520019abf8f RCX: ffffffff84114387
RDX: 0000000000000001 RSI: 0000000000000018 RDI: ffffc9000cd5fc60
RBP: 0000000000000000 R08: ffffc9000cd5fc77 R09: 1ffff920019abf8e
R10: dffffc0000000000 R11: fffff520019abf8c R12: dffffc0000000001
R13: dffffc0000000000 R14: 1ffff920019abf8c R15: 0000000000000003
FS: 00007ff27fec16c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f23b8ac4d58 CR3: 0000000028ae5000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
instrument_copy_from_user_before include/linux/instrumented.h:137 [inline]
_copy_from_user+0xe7/0x170 lib/usercopy.c:22
copy_from_user include/linux/uaccess.h:161 [inline]
restore_altstack+0xa8/0x4c0 kernel/signal.c:4257
__ia32_sys_rt_sigreturn+0x619/0x760 arch/x86/kernel/signal.c:678
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: 0033:0x7ff27ef9c817
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:00007ff27fec10e8 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007ff27f215fa8 RCX: 00007ff27ef9c819
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007ff27f215fa8
RBP: 00007ff27f215fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff27f216038 R14: 00007fffe2409e60 R15: 00007fffe2409f48
</TASK>


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