netlink: 20 bytes leftover after parsing attributes in process `syz.3.654'. 9pnet: Found fid 0 not clunked 9pnet: Tag 0 still in use ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 0 PID: 8129 at lib/refcount.c:28 refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28 Modules linked in: CPU: 0 UID: 0 PID: 8129 Comm: syz.3.654 Not tainted 6.15.0-rc6-syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28 Code: ff 89 de e8 e8 3e ea fc 84 db 0f 85 66 ff ff ff e8 fb 43 ea fc c6 05 e8 79 9c 0b 01 90 48 c7 c7 a0 2f f4 8b e8 77 d1 a9 fc 90 <0f> 0b 90 90 e9 43 ff ff ff e8 d8 43 ea fc 0f b6 1d c3 79 9c 0b 31 RSP: 0018:ffffc90007fb79e0 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc90006d41000 RDX: 0000000000080000 RSI: ffffffff817ac005 RDI: 0000000000000001 RBP: ffff88802a0f0778 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffff88802a0f0778 R13: ffff88804e7e9400 R14: dffffc0000000000 R15: 1ffff92000ff6f47 FS: 00007fc5946e06c0(0000) GS:ffff8880d69e1000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2958572720 CR3: 000000002f6e7000 CR4: 0000000000352ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __refcount_sub_and_test include/linux/refcount.h:400 [inline] __refcount_dec_and_test include/linux/refcount.h:432 [inline] refcount_dec_and_test include/linux/refcount.h:450 [inline] p9_req_put+0x1ec/0x250 net/9p/client.c:404 p9_tag_cleanup net/9p/client.c:431 [inline] p9_client_destroy+0x22b/0x480 net/9p/client.c:1086 v9fs_session_init+0xbab/0x1a80 fs/9p/v9fs.c:490 v9fs_mount+0xc5/0xa30 fs/9p/vfs_super.c:122 legacy_get_tree+0x109/0x220 fs/fs_context.c:662 vfs_get_tree+0x8b/0x340 fs/super.c:1759 do_new_mount fs/namespace.c:3881 [inline] path_mount+0x14d4/0x1f20 fs/namespace.c:4208 do_mount fs/namespace.c:4221 [inline] __do_sys_mount fs/namespace.c:4432 [inline] __se_sys_mount fs/namespace.c:4409 [inline] __x64_sys_mount+0x28d/0x310 fs/namespace.c:4409 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc59378e969 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fc5946e0038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007fc5939b5fa0 RCX: 00007fc59378e969 RDX: 0000200000000140 RSI: 0000200000000100 RDI: 0000200000000040 RBP: 00007fc593810ab1 R08: 0000200000000940 R09: 0000000000000000 R10: 0000000000800488 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fc5939b5fa0 R15: 00007ffe7a1068c8