linux-kernel - KMSAN: uninit-value in __request

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Date:   Mon, 16 Sep 2019 03:19:07 -0700
From:   syzbot <syzbot+618aacd49e8c8b8486bd@...kaller.appspotmail.com>
To:     glider@...gle.com, linux-kernel@...r.kernel.org, mcgrof@...nel.org,
        syzkaller-bugs@...glegroups.com
Subject: KMSAN: uninit-value in __request_module

Hello,

syzbot found the following crash on:

HEAD commit:    014077b5 DO-NOT-SUBMIT: usb-fuzzer: main usb gadget fuzzer..
git tree:       https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=10820859600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f03c659d0830ab8d
dashboard link: https://syzkaller.appspot.com/bug?extid=618aacd49e8c8b8486bd
compiler:       clang version 9.0.0 (/home/glider/llvm/clang  
80fee25776c2fb61e74c1ecb1a523375c2500b69)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=171a72f1600000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=162ff949600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+618aacd49e8c8b8486bd@...kaller.appspotmail.com

netlink: 76 bytes leftover after parsing attributes in process  
`syz-executor501'.
==================================================================
BUG: KMSAN: uninit-value in string_nocheck lib/vsprintf.c:606 [inline]
BUG: KMSAN: uninit-value in string+0x4be/0x600 lib/vsprintf.c:668
CPU: 1 PID: 12341 Comm: syz-executor501 Not tainted 5.3.0-rc7+ #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+0x191/0x1f0 lib/dump_stack.c:113
  kmsan_report+0x162/0x2d0 mm/kmsan/kmsan_report.c:109
  __msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:294
  string_nocheck lib/vsprintf.c:606 [inline]
  string+0x4be/0x600 lib/vsprintf.c:668
  vsnprintf+0x218f/0x3210 lib/vsprintf.c:2503
  __request_module+0x2b1/0x11c0 kernel/kmod.c:143
  tcf_proto_lookup_ops+0x3e7/0x700 net/sched/cls_api.c:80
  tcf_proto_is_unlocked net/sched/cls_api.c:168 [inline]
  tc_new_tfilter+0xfe0/0x4ce0 net/sched/cls_api.c:2041
  rtnetlink_rcv_msg+0xcb6/0x1580 net/core/rtnetlink.c:5214
  netlink_rcv_skb+0x431/0x620 net/netlink/af_netlink.c:2477
  rtnetlink_rcv+0x50/0x60 net/core/rtnetlink.c:5241
  netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
  netlink_unicast+0xf6c/0x1050 net/netlink/af_netlink.c:1328
  netlink_sendmsg+0x110f/0x1330 net/netlink/af_netlink.c:1917
  sock_sendmsg_nosec net/socket.c:637 [inline]
  sock_sendmsg net/socket.c:657 [inline]
  ___sys_sendmsg+0x14ff/0x1590 net/socket.c:2311
  __sys_sendmsg net/socket.c:2356 [inline]
  __do_sys_sendmsg net/socket.c:2365 [inline]
  __se_sys_sendmsg+0x305/0x460 net/socket.c:2363
  __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2363
  do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:297
  entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x4401e9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc3690c568 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004401e9
RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401a70
R13: 0000000000401b00 R14: 0000000000000000 R15: 0000000000000000

Uninit was created at:
  kmsan_save_stack_with_flags mm/kmsan/kmsan.c:189 [inline]
  kmsan_internal_poison_shadow+0x58/0xb0 mm/kmsan/kmsan.c:148
  kmsan_slab_alloc+0xaa/0x120 mm/kmsan/kmsan_hooks.c:175
  slab_alloc_node mm/slub.c:2790 [inline]
  __kmalloc_node_track_caller+0xb55/0x1320 mm/slub.c:4388
  __kmalloc_reserve net/core/skbuff.c:141 [inline]
  __alloc_skb+0x306/0xa10 net/core/skbuff.c:209
  alloc_skb include/linux/skbuff.h:1056 [inline]
  netlink_alloc_large_skb net/netlink/af_netlink.c:1174 [inline]
  netlink_sendmsg+0x783/0x1330 net/netlink/af_netlink.c:1892
  sock_sendmsg_nosec net/socket.c:637 [inline]
  sock_sendmsg net/socket.c:657 [inline]
  ___sys_sendmsg+0x14ff/0x1590 net/socket.c:2311
  __sys_sendmsg net/socket.c:2356 [inline]
  __do_sys_sendmsg net/socket.c:2365 [inline]
  __se_sys_sendmsg+0x305/0x460 net/socket.c:2363
  __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2363
  do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:297
  entry_SYSCALL_64_after_hwframe+0x63/0xe7
==================================================================


---
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