------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 0 PID: 5598 at lib/refcount.c:25 refcount_warn_saturate+0x17c/0x1f0 lib/refcount.c:25 Modules linked in: CPU: 0 PID: 5598 Comm: syz-executor.0 Not tainted 6.2.0-rc3-next-20230112-syzkaller-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 RIP: 0010:refcount_warn_saturate+0x17c/0x1f0 lib/refcount.c:25 Code: 0a 31 ff 89 de e8 d4 13 78 fd 84 db 0f 85 2e ff ff ff e8 57 17 78 fd 48 c7 c7 60 87 a6 8a c6 05 60 d0 54 0a 01 e8 98 a7 b2 05 <0f> 0b e9 0f ff ff ff e8 38 17 78 fd 0f b6 1d 4a d0 54 0a 31 ff 89 RSP: 0018:ffffc90005befb68 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff88807d2f57c0 RSI: ffffffff8166972c RDI: fffff52000b7df5f RBP: ffff88807d2f3aa8 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffff8880764ee300 R13: ffff88807d2f3fa8 R14: 0000000000000000 R15: ffff88807d2f3aa8 FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000021000000 CR3: 000000007673f000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __refcount_add include/linux/refcount.h:199 [inline] __refcount_inc include/linux/refcount.h:250 [inline] refcount_inc include/linux/refcount.h:267 [inline] get_task_struct include/linux/sched/task.h:110 [inline] mm_update_next_owner+0x585/0x7b0 kernel/exit.c:504 exit_mm kernel/exit.c:562 [inline] do_exit+0x9a4/0x2a90 kernel/exit.c:854 do_group_exit+0xd4/0x2a0 kernel/exit.c:1012 get_signal+0x225f/0x24f0 kernel/signal.c:2859 arch_do_signal_or_restart+0x79/0x5c0 arch/x86/kernel/signal.c:306 exit_to_user_mode_loop kernel/entry/common.c:168 [inline] exit_to_user_mode_prepare+0x11f/0x240 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:297 do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f9d6f48c0c9 Code: Unable to access opcode bytes at 0x7f9d6f48c09f. RSP: 002b:00007f9d70279218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f9d6f5abf88 RCX: 00007f9d6f48c0c9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f9d6f5abf88 RBP: 00007f9d6f5abf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f9d6f5abf8c R13: 00007ffd0405f78f R14: 00007f9d70279300 R15: 0000000000022000