------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 2 PID: 22 at lib/refcount.c:28 refcount_warn_saturate+0x1d1/0x1e0 lib/refcount.c:28 Kernel panic - not syncing: panic_on_warn set ... CPU: 2 PID: 22 Comm: ksoftirqd/2 Not tainted 5.7.0-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x188/0x20d lib/dump_stack.c:118 panic+0x2e3/0x75c kernel/panic.c:221 __warn.cold+0x2f/0x35 kernel/panic.c:582 report_bug+0x27b/0x2f0 lib/bug.c:195 fixup_bug arch/x86/kernel/traps.c:105 [inline] fixup_bug arch/x86/kernel/traps.c:100 [inline] do_error_trap+0x12b/0x220 arch/x86/kernel/traps.c:197 do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:216 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027 RIP: 0010:refcount_warn_saturate+0x1d1/0x1e0 lib/refcount.c:28 Code: e9 db fe ff ff 48 89 df e8 fc a3 18 fe e9 8a fe ff ff e8 a2 8c d9 fd 48 c7 c7 40 e7 72 88 c6 05 b7 45 ec 06 01 e8 37 91 aa fd <0f> 0b e9 af fe ff ff 0f 1f 84 00 00 00 00 00 41 56 41 55 41 54 55 RSP: 0018:ffffc90000517c18 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff815d88a7 RDI: fffff520000a2f75 RBP: 0000000000000003 R08: ffff88802c3306c0 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000000 R12: ffff888026e20000 R13: ffff888026eec040 R14: ffff888026eec044 R15: ffff88802c3306c0 refcount_sub_and_test include/linux/refcount.h:274 [inline] refcount_dec_and_test include/linux/refcount.h:294 [inline] put_net include/net/net_namespace.h:266 [inline] __sk_destruct+0x696/0x7c0 net/core/sock.c:1813 sk_destruct+0xc6/0x100 net/core/sock.c:1829 __sk_free+0xef/0x3d0 net/core/sock.c:1840 sk_free+0x78/0xa0 net/core/sock.c:1851 deferred_put_nlk_sk+0x151/0x2e0 net/netlink/af_netlink.c:729 rcu_do_batch kernel/rcu/tree.c:2396 [inline] rcu_core+0x59f/0x1370 kernel/rcu/tree.c:2623 __do_softirq+0x26c/0x9f7 kernel/softirq.c:292 run_ksoftirqd kernel/softirq.c:604 [inline] run_ksoftirqd+0x89/0x100 kernel/softirq.c:596 smpboot_thread_fn+0x653/0x9e0 kernel/smpboot.c:165 kthread+0x388/0x470 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351 Kernel Offset: disabled Rebooting in 86400 seconds..