KMSAN: uninit-value in __request

KMSAN: uninit-value in __request_module (2)
Status: fixed on 2020/01/08 01:07
Reported-by: syzbot+@syzkaller.appspotmail.com
Fix commit: 2dd5616e net-backports: net_sched: validate TCA_KIND attribute in tc_chain_tmplt_add()
First crash: 333d, last: 311d

similar bugs (3):
Kernel	Title	Repro	Count	Last	Reported	Patched	Status
upstream	KMSAN: uninit-value in __request_module (4)		3	101d	115d	0/17	upstream: reported on 2020/07/02 11:32
upstream	KMSAN: uninit-value in __request_module	C	13	386d	405d	14/17	fixed on 2019/10/15 23:40
upstream	KMSAN: uninit-value in __request_module (3)	C	58	251d	279d	16/17	fixed on 2020/02/18 14:31

Sample crash report:

netlink: 12 bytes leftover after parsing attributes in process `syz-executor.3'.
=====================================================
BUG: KMSAN: uninit-value in string_nocheck lib/vsprintf.c:608 [inline]
BUG: KMSAN: uninit-value in string+0x4be/0x600 lib/vsprintf.c:689
CPU: 1 PID: 31984 Comm: syz-executor.3 Not tainted 5.5.0-rc1-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+0x1c9/0x220 lib/dump_stack.c:118
 kmsan_report+0x128/0x220 mm/kmsan/kmsan_report.c:108
 __msan_warning+0x57/0xa0 mm/kmsan/kmsan_instr.c:245
 string_nocheck lib/vsprintf.c:608 [inline]
 string+0x4be/0x600 lib/vsprintf.c:689
 vsnprintf+0x218f/0x3210 lib/vsprintf.c:2574
 __request_module+0x2b1/0x11c0 kernel/kmod.c:143
 tcf_proto_lookup_ops+0x171/0x700 net/sched/cls_api.c:139
 tcf_proto_create net/sched/cls_api.c:262 [inline]
 tc_new_tfilter+0x2b45/0x5230 net/sched/cls_api.c:2079
 rtnetlink_rcv_msg+0xcb6/0x1580 net/core/rtnetlink.c:5415
 netlink_rcv_skb+0x431/0x620 net/netlink/af_netlink.c:2477
 rtnetlink_rcv+0x50/0x60 net/core/rtnetlink.c:5442
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0xfa0/0x1100 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x11f0/0x1480 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:639 [inline]
 sock_sendmsg net/socket.c:659 [inline]
 ____sys_sendmsg+0x1362/0x13f0 net/socket.c:2330
 ___sys_sendmsg net/socket.c:2384 [inline]
 __sys_sendmmsg+0x5ae/0xc90 net/socket.c:2474
 __do_sys_sendmmsg net/socket.c:2503 [inline]
 __se_sys_sendmmsg+0xbd/0xe0 net/socket.c:2500
 __x64_sys_sendmmsg+0x56/0x70 net/socket.c:2500
 do_syscall_64+0xb6/0x160 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45a919
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:00007f3a7ba89c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000045a919
RDX: 0000000000000332 RSI: 0000000020000140 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3a7ba8a6d4
R13: 00000000004c9265 R14: 00000000004e0f80 R15: 00000000ffffffff

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:145 [inline]
 kmsan_internal_poison_shadow+0x5c/0xf0 mm/kmsan/kmsan.c:128
 kmsan_slab_alloc+0x8a/0xe0 mm/kmsan/kmsan_hooks.c:85
 slab_alloc_node mm/slub.c:2774 [inline]
 __kmalloc_node_track_caller+0xe47/0x11f0 mm/slub.c:4382
 __kmalloc_reserve net/core/skbuff.c:141 [inline]
 __alloc_skb+0x309/0xa50 net/core/skbuff.c:209
 alloc_skb include/linux/skbuff.h:1049 [inline]
 netlink_alloc_large_skb net/netlink/af_netlink.c:1174 [inline]
 netlink_sendmsg+0x76f/0x1480 net/netlink/af_netlink.c:1892
 sock_sendmsg_nosec net/socket.c:639 [inline]
 sock_sendmsg net/socket.c:659 [inline]
 ____sys_sendmsg+0x1362/0x13f0 net/socket.c:2330
 ___sys_sendmsg net/socket.c:2384 [inline]
 __sys_sendmmsg+0x5ae/0xc90 net/socket.c:2474
 __do_sys_sendmmsg net/socket.c:2503 [inline]
 __se_sys_sendmmsg+0xbd/0xe0 net/socket.c:2500
 __x64_sys_sendmmsg+0x56/0x70 net/socket.c:2500
 do_syscall_64+0xb6/0x160 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
=====================================================

Crashes (3):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Maintainers
ci-upstream-kmsan-gce	2019/12/19 20:56	https://github.com/google/kmsan.git master	fafa67ae	36650b4b	.config	log	report	linux-kernel@vger.kernel.org, mcgrof@kernel.org
ci-upstream-kmsan-gce	2019/12/17 19:45	https://github.com/google/kmsan.git master	c2ff9f6c	a6bc9c88	.config	log	report	linux-kernel@vger.kernel.org, mcgrof@kernel.org
ci-upstream-kmsan-gce	2019/11/28 07:00	https://github.com/google/kmsan.git master	c543ab66	0d63f89c	.config	log	report	linux-kernel@vger.kernel.org, mcgrof@kernel.org