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Date: Thu, 14 Mar 2024 07:06:38 -0700
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Subject: [syzbot] [net?] KCSAN: data-race in dev_queue_xmit_nit / packet_setsockopt
From: syzbot <syzbot+c669c1136495a2e7c31f@syzkaller.appspotmail.com>
To: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, 
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, 
	syzkaller-bugs@googlegroups.com, willemdebruijn.kernel@gmail.com
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Hello,

syzbot found the following issue on:

HEAD commit:    480e035fc4c7 Merge tag 'drm-next-2024-03-13' of https://gi..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11e6a901180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=943916f31352dd09
dashboard link: https://syzkaller.appspot.com/bug?extid=c669c1136495a2e7c31f
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6e7a2dd336dc/disk-480e035f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8cb00a02987d/vmlinux-480e035f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f325a1992de8/bzImage-480e035f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c669c1136495a2e7c31f@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in dev_queue_xmit_nit / packet_setsockopt

write to 0xffff888107804542 of 1 bytes by task 22618 on cpu 0:
 packet_setsockopt+0xd83/0xfd0 net/packet/af_packet.c:4003
 do_sock_setsockopt net/socket.c:2311 [inline]
 __sys_setsockopt+0x1d8/0x250 net/socket.c:2334
 __do_sys_setsockopt net/socket.c:2343 [inline]
 __se_sys_setsockopt net/socket.c:2340 [inline]
 __x64_sys_setsockopt+0x66/0x80 net/socket.c:2340
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

read to 0xffff888107804542 of 1 bytes by task 27 on cpu 1:
 dev_queue_xmit_nit+0x82/0x620 net/core/dev.c:2248
 xmit_one net/core/dev.c:3527 [inline]
 dev_hard_start_xmit+0xcc/0x3f0 net/core/dev.c:3547
 __dev_queue_xmit+0xf24/0x1dd0 net/core/dev.c:4335
 dev_queue_xmit include/linux/netdevice.h:3091 [inline]
 batadv_send_skb_packet+0x264/0x300 net/batman-adv/send.c:108
 batadv_send_broadcast_skb+0x24/0x30 net/batman-adv/send.c:127
 batadv_iv_ogm_send_to_if net/batman-adv/bat_iv_ogm.c:392 [inline]
 batadv_iv_ogm_emit net/batman-adv/bat_iv_ogm.c:420 [inline]
 batadv_iv_send_outstanding_bat_ogm_packet+0x3f0/0x4b0 net/batman-adv/bat_iv_ogm.c:1700
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0x465/0x990 kernel/workqueue.c:3335
 worker_thread+0x526/0x730 kernel/workqueue.c:3416
 kthread+0x1d1/0x210 kernel/kthread.c:388
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 27 Comm: kworker/u8:1 Tainted: G        W          6.8.0-syzkaller-08073-g480e035fc4c7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
==================================================================


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