WARNING: refcount bug in sk

WARNING: refcount bug in sk_alloc (2)
Status: upstream: reported syz repro on 2020/03/10 22:25
Reported-by: syzbot+b1212b1215db82ff9211@syzkaller.appspotmail.com
First crash: 433d, last: 303d

Cause bisection: introduced by (bisect log) :
commit b78e9d63a3b6307b6b786e6ba189d3978b60ceb5
Author: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Date: Thu Jan 9 12:33:40 2020 +0000

MIPS: SGI-IP27: use asm/sn/agent.h for including HUB related stuff

Crash: WARNING: refcount bug in sk_alloc (log)
Repro: syz .config

Fix bisection: failed (bisect log)

similar bugs (1):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	WARNING: refcount bug in sk_alloc				46	1046d	1066d	0/21	auto-closed as invalid on 2019/02/22 10:22

Sample crash report:

------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 0 PID: 7273 at lib/refcount.c:25 refcount_warn_saturate+0x13d/0x1a0 lib/refcount.c:25
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 7273 Comm: syz-executor.0 Not tainted 5.6.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1e9/0x30e lib/dump_stack.c:118
 panic+0x264/0x7a0 kernel/panic.c:221
 __warn+0x209/0x210 kernel/panic.c:582
 report_bug+0x1ac/0x2d0 lib/bug.c:195
 fixup_bug arch/x86/kernel/traps.c:175 [inline]
 do_error_trap+0xca/0x1c0 arch/x86/kernel/traps.c:267
 do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:286
 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027
RIP: 0010:refcount_warn_saturate+0x13d/0x1a0 lib/refcount.c:25
Code: c7 33 ff f1 88 31 c0 e8 d1 f9 b1 fd 0f 0b eb a3 e8 28 97 df fd c6 05 e0 1c d2 05 01 48 c7 c7 6a ff f1 88 31 c0 e8 b3 f9 b1 fd <0f> 0b eb 85 e8 0a 97 df fd c6 05 c3 1c d2 05 01 48 c7 c7 96 ff f1
RSP: 0018:ffffc900020f7d40 EFLAGS: 00010246
RAX: ef5780d4f83b8300 RBX: 0000000000000002 RCX: ffff88809ed44540
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000000000002 R08: ffffffff815e4dd6 R09: ffffed1015d06660
R10: ffffed1015d06660 R11: 0000000000000000 R12: ffff8880a4cfe040
R13: dffffc0000000000 R14: ffff8880a4cfe044 R15: ffff88809e110000
 refcount_add include/linux/refcount.h:192 [inline]
 refcount_inc include/linux/refcount.h:228 [inline]
 get_net include/net/net_namespace.h:246 [inline]
 sk_alloc+0x8a6/0x990 net/core/sock.c:1670
 __netlink_create+0x6a/0x270 net/netlink/af_netlink.c:629
 netlink_create+0x370/0x4d0 net/netlink/af_netlink.c:692
 __sock_create+0x5c9/0x8d0 net/socket.c:1433
 sock_create net/socket.c:1484 [inline]
 __sys_socket+0xde/0x2d0 net/socket.c:1526
 __do_sys_socket net/socket.c:1535 [inline]
 __se_sys_socket net/socket.c:1533 [inline]
 __x64_sys_socket+0x76/0x80 net/socket.c:1533
 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45c849
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007efd85580c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000029
RAX: ffffffffffffffda RBX: 00007efd855816d4 RCX: 000000000045c849
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000010
RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000b8e R14: 00000000004cdbf4 R15: 000000000076bf0c
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (27):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro
ci-upstream-kasan-gce-smack-root	2020/04/02 18:56	upstream	919dce24	a34e2c33	.config	log	report	syz
ci-upstream-net-this-kasan-gce	2020/03/15 12:08	net	0d1c3530	749688d2	.config	log	report	syz
ci-upstream-net-this-kasan-gce	2020/02/27 06:42	net	6132c1d9	59b57593	.config	log	report	syz
ci-upstream-net-kasan-gce	2020/03/15 00:14	net-next	94229d45	749688d2	.config	log	report	syz
ci-upstream-net-kasan-gce	2020/02/27 05:44	net-next	c3e042f5	59b57593	.config	log	report	syz
ci-upstream-linux-next-kasan-gce-root	2020/03/15 16:53	linux-next	770fbb32	749688d2	.config	log	report	syz
ci-upstream-kasan-gce-smack-root	2020/03/08 04:43	upstream	61a09258	2e9971bb	.config	log	report
ci-upstream-kasan-gce	2020/03/07 22:19	upstream	63849c8f	2e9971bb	.config	log	report
ci-upstream-kasan-gce-smack-root	2020/03/07 21:38	upstream	63849c8f	2e9971bb	.config	log	report
ci-upstream-kasan-gce	2020/03/07 18:43	upstream	63849c8f	2e9971bb	.config	log	report
ci-upstream-kasan-gce-smack-root	2020/03/07 01:38	upstream	fb279f4e	fd2a5f28	.config	log	report
ci-upstream-kasan-gce-smack-root	2020/03/04 18:24	upstream	63623fd4	c88c7b75	.config	log	report
ci-upstream-kasan-gce-smack-root	2020/03/04 04:08	upstream	63623fd4	c88c7b75	.config	log	report
ci-upstream-kasan-gce-smack-root	2020/02/27 03:44	upstream	f8788d86	59b57593	.config	log	report
ci-upstream-kasan-gce-smack-root	2020/02/24 18:00	upstream	f8788d86	59b57593	.config	log	report
ci-upstream-kasan-gce	2020/02/21 12:37	upstream	ca7e1fd1	bd2a74a3	.config	log	report
ci-upstream-kasan-gce-root	2020/02/19 16:22	upstream	0a44cac8	b690a6e3	.config	log	report
ci-upstream-kasan-gce-root	2020/02/19 14:30	upstream	0a44cac8	135c18aa	.config	log	report
ci-upstream-kasan-gce-selinux-root	2020/02/19 14:25	upstream	0a44cac8	135c18aa	.config	log	report
ci-upstream-kasan-gce-386	2020/03/07 22:08	upstream	63849c8f	2e9971bb	.config	log	report
ci-upstream-kasan-gce-386	2020/02/19 14:15	upstream	0a44cac8	135c18aa	.config	log	report
ci-upstream-net-this-kasan-gce	2020/03/07 22:02	net	aeaa925b	2e9971bb	.config	log	report
ci-upstream-net-kasan-gce	2020/03/14 14:01	net-next	1d343579	749688d2	.config	log	report
ci-upstream-net-kasan-gce	2020/02/19 14:14	net-next	00796b92	135c18aa	.config	log	report
ci-upstream-net-kasan-gce	2020/01/23 16:29	net-next	fd786fb1	3334d684	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2020/01/11 17:40	linux-next	6c09d7db	4c04afaa	.config	log	report
ci-upstream-linux-next-kasan-gce-root	2019/12/24 12:36	linux-next	7ddd09fc	be5c2c81	.config	log	report