------------[ cut here ]------------
refcount_t: saturated; leaking memory.
WARNING: lib/refcount.c:19 at 0x0, CPU#0: syz.5.4570/18962
Modules linked in:
CPU: 0 UID: 0 PID: 18962 Comm: syz.5.4570 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+0xc5/0x110 lib/refcount.c:19
Code: 91 0e 33 0b 67 48 0f b9 3a eb 37 e8 95 1c 2b fd 48 8d 3d 8e 0e 33 0b 67 48 0f b9 3a eb 24 e8 82 1c 2b fd 48 8d 3d 8b 0e 33 0b <67> 48 0f b9 3a eb 11 e8 6f 1c 2b fd 48 8d 3d 88 0e 33 0b 67 48 0f
RSP: 0000:ffffc9000bf37528 EFLAGS: 00010293
RAX: ffffffff8496c3fe RBX: 0000000000000000 RCX: ffff88802f3b0000
RDX: 0000000000000000 RSI: ffffffff8ea87240 RDI: ffffffff8fc9d290
RBP: ffffc9000bf37648 R08: ffff88802f3b0000 R09: 0000000000000005
R10: 0000000000000004 R11: 0000000000000000 R12: ffff888076e83d00
R13: ffff888076e83c80 R14: ffff888076e83d00 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125a41000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000001bc0c CR3: 0000000031316000 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+0x431/0xb10 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+0x2e3/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3c8c38f749
Code: Unable to access opcode bytes at 0x7f3c8c38f71f.
RSP: 002b:00007f3c8d178038 EFLAGS: 00000246 ORIG_RAX: 000000000000010f
RAX: fffffffffffffdfe RBX: 00007f3c8c5e6090 RCX: 00007f3c8c38f749
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000200000000080
RBP: 00007f3c8c413f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3c8c5e6128 R14: 00007f3c8c5e6090 R15: 00007ffe537cdbf8
 </TASK>
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	33 0b                	xor    (%rbx),%ecx
   2:	67 48 0f b9 3a       	ud1    (%edx),%rdi
   7:	eb 37                	jmp    0x40
   9:	e8 95 1c 2b fd       	call   0xfd2b1ca3
   e:	48 8d 3d 8e 0e 33 0b 	lea    0xb330e8e(%rip),%rdi        # 0xb330ea3
  15:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  1a:	eb 24                	jmp    0x40
  1c:	e8 82 1c 2b fd       	call   0xfd2b1ca3
  21:	48 8d 3d 8b 0e 33 0b 	lea    0xb330e8b(%rip),%rdi        # 0xb330eb3
* 28:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2d:	eb 11                	jmp    0x40
  2f:	e8 6f 1c 2b fd       	call   0xfd2b1ca3
  34:	48 8d 3d 88 0e 33 0b 	lea    0xb330e88(%rip),%rdi        # 0xb330ec3
  3b:	67                   	addr32
  3c:	48                   	rex.W
  3d:	0f                   	.byte 0xf