------------[ cut here ]------------
refcount_t: saturated; leaking memory.
WARNING: lib/refcount.c:19 at refcount_warn_saturate+0x13a/0x1d0 lib/refcount.c:19, CPU#0: syz.5.1180/9891
Modules linked in:
CPU: 0 UID: 0 PID: 9891 Comm: syz.5.1180 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:refcount_warn_saturate+0x13a/0x1d0 lib/refcount.c:19
Code: 00 93 e0 8b e8 f7 03 eb fc 90 0f 0b 90 90 eb b7 e8 fb e8 28 fd c6 05 4c 72 10 0b 01 90 48 c7 c7 40 92 e0 8b e8 d7 03 eb fc 90 <0f> 0b 90 90 eb 97 e8 db e8 28 fd c6 05 30 72 10 0b 01 90 48 c7 c7
RSP: 0018:ffffc90004ecf528 EFLAGS: 00010246
RAX: 81fe1c57cdf66100 RBX: 0000000000000000 RCX: ffff888030783d00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000002
RBP: ffffc90004ecf648 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1c3a720 R12: ffff888029f191c0
R13: ffff888029f19140 R14: ffff888029f191c0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125a6e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdcd19a6e9c CR3: 000000005fb64000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __refcount_add_not_zero include/linux/refcount.h:187 [inline]
 refcount_add_not_zero include/linux/refcount.h:212 [inline]
 __vma_enter_locked+0x62e/0x6a0 mm/mmap_lock.c:69
 __vma_start_write+0x23/0x140 mm/mmap_lock.c:96
 vma_start_write include/linux/mmap_lock.h:213 [inline]
 free_pgtables+0x72d/0x9d0 mm/memory.c:413
 exit_mmap+0x431/0xb40 mm/mmap.c:1288
 __mmput+0x118/0x430 kernel/fork.c:1173
 exit_mm+0x1da/0x2c0 kernel/exit.c:581
 do_exit+0x658/0x2310 kernel/exit.c:959
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112
 get_signal+0x1285/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
 exit_to_user_mode_loop+0x87/0x4f0 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x2e9/0xfa0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f59c898f749
Code: Unable to access opcode bytes at 0x7f59c898f71f.
RSP: 002b:00007f59c9764038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: fffffffffffffffc RBX: 00007f59c8be5fa0 RCX: 00007f59c898f749
RDX: 0000200000000100 RSI: 00000000c028aa05 RDI: 0000000000000004
RBP: 00007f59c8a13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f59c8be6038 R14: 00007f59c8be5fa0 R15: 00007ffc7a480328
 </TASK>