WARNING in sysfs_warn_dup

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 1ec8f1f0 Linux 4.14.111
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1538aabf200000
kernel config: https://syzkaller.appspot.com/x/.config?x=fdadf290ea9fc6f9
dashboard link: https://syzkaller.appspot.com/bug?extid=96b6fd94ec6131a7405a
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+96b6fd...@syzkaller.appspotmail.com

sysfs: cannot create duplicate filename '/class/ieee80211/⫴�vE V�!v'
------------[ cut here ]------------
WARNING: CPU: 0 PID: 21737 at fs/sysfs/dir.c:30
sysfs_warn_dup.cold+0x17/0x31 fs/sysfs/dir.c:30
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 21737 Comm: syz-executor.0 Not tainted 4.14.111 #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x138/0x19c lib/dump_stack.c:53
panic+0x1f2/0x438 kernel/panic.c:182
__warn.cold+0x2f/0x34 kernel/panic.c:546
report_bug+0x216/0x254 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:177 [inline]
fixup_bug arch/x86/kernel/traps.c:172 [inline]
do_error_trap+0x1bb/0x310 arch/x86/kernel/traps.c:295
do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:314
invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:944
RIP: 0010:sysfs_warn_dup.cold+0x17/0x31 fs/sysfs/dir.c:30
RSP: 0018:ffff888071287220 EFLAGS: 00010286
RAX: 0000000000000047 RBX: ffffffffffffffef RCX: 0000000000000000
RDX: 0000000000013e24 RSI: ffffffff814b2a55 RDI: ffffed100e250e3a
RBP: ffff888071287238 R08: 0000000000000047 R09: ffff8880a97e29f0
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88806ab0c740
R13: ffff8880a83f07e0 R14: ffff8880a0ba65c0 R15: 0000000000000001
sysfs_do_create_link_sd.isra.0+0xff/0x120 fs/sysfs/symlink.c:51
sysfs_do_create_link fs/sysfs/symlink.c:80 [inline]
sysfs_create_link+0x65/0xc0 fs/sysfs/symlink.c:92
device_add_class_symlinks drivers/base/core.c:1621 [inline]
device_add+0x737/0x1490 drivers/base/core.c:1823
wiphy_register+0x133c/0x1d20 net/wireless/core.c:809
ieee80211_register_hw+0x1152/0x2f30 net/mac80211/main.c:1055
mac80211_hwsim_new_radio+0x19a1/0x2980
drivers/net/wireless/mac80211_hwsim.c:2705
hwsim_new_radio_nl+0x3f2/0x62e drivers/net/wireless/mac80211_hwsim.c:3164
genl_family_rcv_msg+0x61c/0xc40 net/netlink/genetlink.c:600
genl_rcv_msg+0xb4/0x150 net/netlink/genetlink.c:625
netlink_rcv_skb+0x152/0x3c0 net/netlink/af_netlink.c:2432
genl_rcv+0x29/0x40 net/netlink/genetlink.c:636
netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline]
netlink_unicast+0x466/0x780 net/netlink/af_netlink.c:1312
netlink_sendmsg+0x7c4/0xc60 net/netlink/af_netlink.c:1877
sock_sendmsg_nosec net/socket.c:646 [inline]
sock_sendmsg+0xd0/0x110 net/socket.c:656
___sys_sendmsg+0x70c/0x850 net/socket.c:2062
__sys_sendmsg+0xb9/0x140 net/socket.c:2096
SYSC_sendmsg net/socket.c:2107 [inline]
SyS_sendmsg+0x2d/0x50 net/socket.c:2103
do_syscall_64+0x1eb/0x630 arch/x86/entry/common.c:289
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4582f9
RSP: 002b:00007f5e64e3ac78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004582f9
RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000003
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5e64e3b6d4
R13: 00000000004c5945 R14: 00000000004d9c30 R15: 00000000ffffffff
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
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[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit: 1ec8f1f0 Linux 4.14.111
git tree: linux-4.14.y

console output: https://syzkaller.appspot.com/x/log.txt?x=1404c1af200000

kernel config: https://syzkaller.appspot.com/x/.config?x=fdadf290ea9fc6f9
dashboard link: https://syzkaller.appspot.com/bug?extid=96b6fd94ec6131a7405a
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10fe0dbb200000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1230acd3200000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+96b6fd...@syzkaller.appspotmail.com

audit: type=1400 audit(1555000603.156:38): avc: denied { write } for
pid=6995 comm="syz-executor043"
scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
tclass=netlink_generic_socket permissive=1

sysfs: cannot create duplicate filename '/class/ieee80211/⫴�vE

V�!v�� �(�ju�� oi��{ڿO���W�RS� ��˖��i!K�Q3�bf��+�͝'
------------[ cut here ]------------
WARNING: CPU: 0 PID: 6997 at fs/sysfs/dir.c:30

sysfs_warn_dup.cold+0x17/0x31 fs/sysfs/dir.c:30
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 6997 Comm: syz-executor043 Not tainted 4.14.111 #1

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x138/0x19c lib/dump_stack.c:53
panic+0x1f2/0x438 kernel/panic.c:182
__warn.cold+0x2f/0x34 kernel/panic.c:546
report_bug+0x216/0x254 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:177 [inline]
fixup_bug arch/x86/kernel/traps.c:172 [inline]
do_error_trap+0x1bb/0x310 arch/x86/kernel/traps.c:295
do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:314
invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:944
RIP: 0010:sysfs_warn_dup.cold+0x17/0x31 fs/sysfs/dir.c:30

RSP: 0018:ffff888096c37220 EFLAGS: 00010286
RAX: 000000000000007a RBX: ffffffffffffffef RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff8880a5e64b50 RDI: ffffed1012d86e3a
RBP: ffff888096c37238 R08: 000000000000007a R09: ffff8880a5e64b70
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88808f038e00
R13: ffff8880a7cadc40 R14: ffff8880a8e7c000 R15: 0000000000000001

RIP: 0033:0x441219
RSP: 002b:00007fffc6caf468 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441219

RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000003

RBP: 000000000000d6e0 R08: 00000000004002c8 R09: 00000000004002c8
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000402040
R13: 00000000004020d0 R14: 0000000000000000 R15: 0000000000000000