KMSAN: uninit-value in gc

KMSAN: uninit-value in gc_worker (3)
Status: upstream: reported on 2020/09/21 17:42
Reported-by: syzbot+b3dbc715a0b6201346f4@syzkaller.appspotmail.com
First crash: 39d, last: 39d

similar bugs (2):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KMSAN: uninit-value in gc_worker				10	825d	837d	9/17	fixed on 2018/08/08 18:10
upstream	KMSAN: uninit-value in gc_worker (2)				1	245d	245d	0/17	auto-closed as invalid on 2020/05/24 00:33

Sample crash report:

=====================================================
BUG: KMSAN: uninit-value in gc_worker+0x953/0x1740 net/netfilter/nf_conntrack_core.c:1389
CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.8.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_power_efficient gc_worker
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x21c/0x280 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121
 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215
 gc_worker+0x953/0x1740 net/netfilter/nf_conntrack_core.c:1389
 process_one_work+0x1688/0x2140 kernel/workqueue.c:2269
 worker_thread+0x10bc/0x2730 kernel/workqueue.c:2415
 kthread+0x551/0x590 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Uninit was created at:
 kmsan_save_stack_with_flags+0x3c/0x90 mm/kmsan/kmsan.c:144
 kmsan_internal_alloc_meta_for_pages mm/kmsan/kmsan_shadow.c:269 [inline]
 kmsan_alloc_page+0xc5/0x1a0 mm/kmsan/kmsan_shadow.c:293
 __alloc_pages_nodemask+0xdf0/0x1030 mm/page_alloc.c:4889
 alloc_pages_current+0x685/0xb50 mm/mempolicy.c:2292
 alloc_pages include/linux/gfp.h:545 [inline]
 alloc_slab_page+0x11c/0x1240 mm/slub.c:1560
 allocate_slab mm/slub.c:1705 [inline]
 new_slab+0x2bf/0x10c0 mm/slub.c:1771
 new_slab_objects mm/slub.c:2528 [inline]
 ___slab_alloc+0xcd3/0x18a0 mm/slub.c:2689
 __slab_alloc mm/slub.c:2729 [inline]
 slab_alloc_node mm/slub.c:2803 [inline]
 slab_alloc mm/slub.c:2848 [inline]
 kmem_cache_alloc+0xb70/0xc50 mm/slub.c:2853
 __nf_conntrack_alloc+0x1a9/0x790 net/netfilter/nf_conntrack_core.c:1509
 init_conntrack+0x3c2/0x2180 net/netfilter/nf_conntrack_core.c:1588
 resolve_normal_ct net/netfilter/nf_conntrack_core.c:1686 [inline]
 nf_conntrack_in+0x158a/0x2b10 net/netfilter/nf_conntrack_core.c:1846
 ipv6_conntrack_local+0x68/0x80 net/netfilter/nf_conntrack_proto.c:398
 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline]
 nf_hook_slow+0x17b/0x460 net/netfilter/core.c:512
 nf_hook include/linux/netfilter.h:262 [inline]
 NF_HOOK include/linux/netfilter.h:305 [inline]
 ip6_xmit+0x2301/0x2b40 net/ipv6/ip6_output.c:280
 inet6_csk_xmit+0x47f/0x5a0 net/ipv6/inet6_connection_sock.c:135
 __tcp_transmit_skb+0x4b9e/0x5d70 net/ipv4/tcp_output.c:1240
 tcp_transmit_skb net/ipv4/tcp_output.c:1256 [inline]
 tcp_connect+0x153f/0x3bb0 net/ipv4/tcp_output.c:3673
 tcp_v6_connect+0x2be8/0x2d40 net/ipv6/tcp_ipv6.c:334
 __inet_stream_connect+0x14fe/0x16f0 net/ipv4/af_inet.c:658
 inet_stream_connect+0x101/0x180 net/ipv4/af_inet.c:722
 rds_tcp_conn_path_connect+0x93d/0xcc0 net/rds/tcp_connect.c:172
 rds_connect_worker+0x36b/0x550 net/rds/threads.c:176
 process_one_work+0x1688/0x2140 kernel/workqueue.c:2269
 worker_thread+0x10bc/0x2730 kernel/workqueue.c:2415
 kthread+0x551/0x590 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293
=====================================================

Crashes (1):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Maintainers
ci-upstream-kmsan-gce	2020/09/16 20:44	https://github.com/google/kmsan.git master	6c24608b	18d7d030	.config	log	report			info	coreteam@netfilter.org, davem@davemloft.net, fw@strlen.de, kadlec@netfilter.org, kuba@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, pablo@netfilter.org