Hello,
syzbot found the following crash on:
HEAD commit: cddc52641fd2 kmsan: use __memmove() in fixup_bad_iret()
git tree: kmsan
console output: https://syzkaller.appspot.com/x/log.txt?x=15d27ad5400000
kernel config: https://syzkaller.appspot.com/x/.config?x=e2808e34f8becb71
dashboard link: https://syzkaller.appspot.com/bug?extid=d78b8a29241a195aefb8
compiler: clang version 8.0.0 (trunk 343298)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17682b0b400000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+d78b8a29241a195ae...@syzkaller.appspotmail.com
8021q: adding VLAN 0 to HW filter on device team0
8021q: adding VLAN 0 to HW filter on device team0
8021q: adding VLAN 0 to HW filter on device team0
8021q: adding VLAN 0 to HW filter on device team0
==================================================================
BUG: KMSAN: uninit-value in strlen+0x3b/0xa0 lib/string.c:485
CPU: 0 PID: 8222 Comm: syz-executor5 Not tainted 4.20.0-rc2+ #88
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+0x32d/0x480 lib/dump_stack.c:113
kmsan_report+0x19f/0x300 mm/kmsan/kmsan.c:911
__msan_warning+0x76/0xc0 mm/kmsan/kmsan_instr.c:415
strlen+0x3b/0xa0 lib/string.c:485
nla_put_string include/net/netlink.h:1154 [inline]
__tipc_nl_compat_link_set net/tipc/netlink_compat.c:708 [inline]
tipc_nl_compat_link_set+0xa37/0x18b0 net/tipc/netlink_compat.c:744
__tipc_nl_compat_doit net/tipc/netlink_compat.c:311 [inline]
tipc_nl_compat_doit+0x39f/0xae0 net/tipc/netlink_compat.c:344
tipc_nl_compat_handle net/tipc/netlink_compat.c:1107 [inline]
tipc_nl_compat_recv+0x148a/0x2770 net/tipc/netlink_compat.c:1210
genl_family_rcv_msg net/netlink/genetlink.c:601 [inline]
genl_rcv_msg+0x189e/0x1aa0 net/netlink/genetlink.c:626
netlink_rcv_skb+0x394/0x640 net/netlink/af_netlink.c:2477
genl_rcv+0x63/0x80 net/netlink/genetlink.c:637
netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
netlink_unicast+0x1699/0x1740 net/netlink/af_netlink.c:1336
netlink_sendmsg+0x13c7/0x1440 net/netlink/af_netlink.c:1917
sock_sendmsg_nosec net/socket.c:621 [inline]
sock_sendmsg net/socket.c:631 [inline]
___sys_sendmsg+0xe3b/0x1240 net/socket.c:2116
__sys_sendmsg net/socket.c:2154 [inline]
__do_sys_sendmsg net/socket.c:2163 [inline]
__se_sys_sendmsg+0x305/0x460 net/socket.c:2161
__x64_sys_sendmsg+0x4a/0x70 net/socket.c:2161
do_syscall_64+0xcf/0x110 arch/x86/entry/common.c:291
entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x457569
Code: fd b3 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 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f933fe2bc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457569
RDX: 0000000000000000 RSI: 0000000020000100 RDI: 0000000000000003
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f933fe2c6d4
R13: 00000000004c3b79 R14: 00000000004d5d90 R15: 00000000ffffffff
Uninit was created at:
kmsan_save_stack_with_flags mm/kmsan/kmsan.c:252 [inline]
kmsan_internal_poison_shadow+0xc8/0x1c0 mm/kmsan/kmsan.c:177
kmsan_kmalloc+0x98/0xf0 mm/kmsan/kmsan_hooks.c:104
kmsan_slab_alloc+0xe/0x10 mm/kmsan/kmsan_hooks.c:113
slab_post_alloc_hook mm/slab.h:446 [inline]
slab_alloc_node mm/slub.c:2765 [inline]
__kmalloc_node_track_caller+0xf62/0x14e0 mm/slub.c:4396
__kmalloc_reserve net/core/skbuff.c:138 [inline]
__alloc_skb+0x42b/0xeb0 net/core/skbuff.c:206
alloc_skb include/linux/skbuff.h:998 [inline]
netlink_alloc_large_skb net/netlink/af_netlink.c:1182 [inline]
netlink_sendmsg+0xc9e/0x1440 net/netlink/af_netlink.c:1892
sock_sendmsg_nosec net/socket.c:621 [inline]
sock_sendmsg net/socket.c:631 [inline]
___sys_sendmsg+0xe3b/0x1240 net/socket.c:2116
__sys_sendmsg net/socket.c:2154 [inline]
__do_sys_sendmsg net/socket.c:2163 [inline]
__se_sys_sendmsg+0x305/0x460 net/socket.c:2161
__x64_sys_sendmsg+0x4a/0x70 net/socket.c:2161
do_syscall_64+0xcf/0x110 arch/x86/entry/common.c:291
entry_SYSCALL_64_after_hwframe+0x63/0xe7
==================================================================
---
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