KCSAN: data-race in netlink_recvmsg / netlink_recvmsg (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3d5e28bf Merge branch 'stable/for-linus-5.10-rc2' of git:/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13d4f7dc500000
kernel config: https://syzkaller.appspot.com/x/.config?x=671e27f23e60a67b
dashboard link: https://syzkaller.appspot.com/bug?extid=00c83f021f4d7299ab64
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [0x7f4...@gmail.com and...@kernel.org a...@kernel.org b...@vger.kernel.org dan...@iogearbox.net da...@davemloft.net john.fa...@gmail.com ka...@fb.com kps...@chromium.org ku...@kernel.org linux-...@vger.kernel.org mkub...@suse.cz net...@vger.kernel.org songliu...@fb.com y...@fb.com]

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+00c83f...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in netlink_recvmsg / netlink_recvmsg

write to 0xffff88811d24a320 of 8 bytes by task 872 on cpu 1:
netlink_recvmsg+0x129/0x790 net/netlink/af_netlink.c:1967
sock_recvmsg_nosec net/socket.c:885 [inline]
sock_recvmsg net/socket.c:903 [inline]
__sys_recvfrom+0x1cb/0x290 net/socket.c:2049
__do_sys_recvfrom net/socket.c:2067 [inline]
__se_sys_recvfrom net/socket.c:2063 [inline]
__x64_sys_recvfrom+0x74/0x90 net/socket.c:2063
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88811d24a320 of 8 bytes by task 859 on cpu 0:
netlink_recvmsg+0xea/0x790 net/netlink/af_netlink.c:1966
sock_recvmsg_nosec net/socket.c:885 [inline]
sock_recvmsg net/socket.c:903 [inline]
__sys_recvfrom+0x1cb/0x290 net/socket.c:2049
__do_sys_recvfrom net/socket.c:2067 [inline]
__se_sys_recvfrom net/socket.c:2063 [inline]
__x64_sys_recvfrom+0x74/0x90 net/socket.c:2063
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 859 Comm: syz-executor.5 Not tainted 5.10.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 859 Comm: syz-executor.5 Not tainted 5.10.0-rc3-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+0x116/0x15d lib/dump_stack.c:118
panic+0x1e7/0x5fa kernel/panic.c:231
kcsan_report+0x67b/0x680 kernel/kcsan/report.c:634
kcsan_setup_watchpoint+0x46a/0x4d0 kernel/kcsan/core.c:568
netlink_recvmsg+0xea/0x790 net/netlink/af_netlink.c:1966
sock_recvmsg_nosec net/socket.c:885 [inline]
sock_recvmsg net/socket.c:903 [inline]
__sys_recvfrom+0x1cb/0x290 net/socket.c:2049
__do_sys_recvfrom net/socket.c:2067 [inline]
__se_sys_recvfrom net/socket.c:2063 [inline]
__x64_sys_recvfrom+0x74/0x90 net/socket.c:2063
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4178bf
Code: 53 49 89 f4 89 fb 48 83 ec 10 e8 6c fb ff ff 45 31 c9 89 c5 45 31 c0 4d 63 d5 4c 89 f2 4c 89 e6 48 63 fb b8 2d 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 1e 89 ef 48 89 44 24 08 e8 9d fb ff ff 48 8b
RSP: 002b:00007f60d763ab10 EFLAGS: 00000246 ORIG_RAX: 000000000000002d
RAX: ffffffffffffffda RBX: 0000000000000007 RCX: 00000000004178bf
RDX: 0000000000001000 RSI: 00007f60d763ac40 RDI: 0000000000000007
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f60d763ac40
R13: 0000000000000000 R14: 0000000000001000 R15: 0000000000000007
Kernel Offset: disabled
Rebooting in 86400 seconds..


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.