Subject: KMSAN: uninit-value in hwsim_cloned_frame_received_nl

From: syzbot <[email-masked]>
Date: Thu, 24 Sep 2020 02:26:25 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    c5a13b33 kmsan: clang-format core
git tree:       https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=12a19c03900000
kernel config:  https://syzkaller.appspot.com/x/.config?x=20f149ad694ba4be
dashboard link: https://syzkaller.appspot.com/bug?extid=b2645b5bf1512b81fa22
compiler:       clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=118689ab900000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=104fc409900000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

=====================================================
BUG: KMSAN: uninit-value in hwsim_cloned_frame_received_nl+0x104e/0x13e0 drivers/net/wireless/mac80211_hwsim.c:3553
CPU: 1 PID: 8531 Comm: syz-executor177 Not tainted 5.9.0-rc4-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+0x21c/0x280 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:122
 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:219
 hwsim_cloned_frame_received_nl+0x104e/0x13e0 drivers/net/wireless/mac80211_hwsim.c:3553
 genl_family_rcv_msg_doit net/netlink/genetlink.c:669 [inline]
 genl_family_rcv_msg net/netlink/genetlink.c:714 [inline]
 genl_rcv_msg+0x1703/0x18a0 net/netlink/genetlink.c:731
 netlink_rcv_skb+0x6d7/0x7e0 net/netlink/af_netlink.c:2470
 genl_rcv+0x63/0x80 net/netlink/genetlink.c:742
 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
 netlink_unicast+0x11c8/0x1490 net/netlink/af_netlink.c:1330
 netlink_sendmsg+0x173a/0x1840 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg net/socket.c:671 [inline]
 __sys_sendto+0x9dc/0xc80 net/socket.c:1992
 __do_sys_sendto net/socket.c:2004 [inline]
 __se_sys_sendto+0x107/0x130 net/socket.c:2000
 __x64_sys_sendto+0x6e/0x90 net/socket.c:2000
 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x401a73
Code: ff ff ff f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb cd 66 0f 1f 44 00 00 83 3d bd 8c 2d 00 00 75 17 49 89 ca b8 2c 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 f1 0b 00 00 c3 48 83 ec 08 e8 57 01 00 00
RSP: 002b:00007ffc0c9fdd58 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007ffc0c9fddd0 RCX: 0000000000401a73
RDX: 0000000000000034 RSI: 00007ffc0c9fde20 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffc0c9fdd60 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007ffc0c9fde20 R15: 0000000000000003

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:143 [inline]
 kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:126
 kmsan_slab_alloc+0x8a/0xe0 mm/kmsan/kmsan_hooks.c:80
 slab_alloc_node mm/slub.c:2907 [inline]
 __kmalloc_node_track_caller+0x9aa/0x12f0 mm/slub.c:4511
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 __alloc_skb+0x35f/0xb30 net/core/skbuff.c:210
 alloc_skb include/linux/skbuff.h:1094 [inline]
 hwsim_cloned_frame_received_nl+0x20e/0x13e0 drivers/net/wireless/mac80211_hwsim.c:3498
 genl_family_rcv_msg_doit net/netlink/genetlink.c:669 [inline]
 genl_family_rcv_msg net/netlink/genetlink.c:714 [inline]
 genl_rcv_msg+0x1703/0x18a0 net/netlink/genetlink.c:731
 netlink_rcv_skb+0x6d7/0x7e0 net/netlink/af_netlink.c:2470
 genl_rcv+0x63/0x80 net/netlink/genetlink.c:742
 netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
 netlink_unicast+0x11c8/0x1490 net/netlink/af_netlink.c:1330
 netlink_sendmsg+0x173a/0x1840 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg net/socket.c:671 [inline]
 __sys_sendto+0x9dc/0xc80 net/socket.c:1992
 __do_sys_sendto net/socket.c:2004 [inline]
 __se_sys_sendto+0x107/0x130 net/socket.c:2000
 __x64_sys_sendto+0x6e/0x90 net/socket.c:2000
 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
=====================================================

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