Messages in this thread | | | From | Eric Dumazet <> | Date | Fri, 12 Jan 2024 13:01:54 +0100 | Subject | Re: [syzbot] [net?] KCSAN: data-race in ipv6_mc_down / mld_ifc_work (2) |
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On Fri, Jan 12, 2024 at 11:10 AM syzbot <syzbot+a9400cabb1d784e49abf@syzkaller.appspotmail.com> wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: 8735c7c84d1b Merge tag '6.7rc7-smb3-srv-fix' of git://git.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=17948c9ae80000 > kernel config: https://syzkaller.appspot.com/x/.config?x=4da1e2da456c3a7d > dashboard link: https://syzkaller.appspot.com/bug?extid=a9400cabb1d784e49abf > 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/f263d974af01/disk-8735c7c8.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/9faf34fc0b3e/vmlinux-8735c7c8.xz > kernel image: https://storage.googleapis.com/syzbot-assets/0b52a58ecd0e/bzImage-8735c7c8.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+a9400cabb1d784e49abf@syzkaller.appspotmail.com > > ================================================================== > BUG: KCSAN: data-race in ipv6_mc_down / mld_ifc_work > > write to 0xffff88813a80c832 of 1 bytes by task 3771 on cpu 0: > mld_ifc_stop_work net/ipv6/mcast.c:1080 [inline] > ipv6_mc_down+0x10a/0x280 net/ipv6/mcast.c:2725 > addrconf_ifdown+0xe32/0xf10 net/ipv6/addrconf.c:3949 > addrconf_notify+0x310/0x980 > notifier_call_chain kernel/notifier.c:93 [inline] > raw_notifier_call_chain+0x6b/0x1c0 kernel/notifier.c:461 > __dev_notify_flags+0x205/0x3d0 > dev_change_flags+0xab/0xd0 net/core/dev.c:8685 > do_setlink+0x9f6/0x2430 net/core/rtnetlink.c:2916 > rtnl_group_changelink net/core/rtnetlink.c:3458 [inline] > __rtnl_newlink net/core/rtnetlink.c:3717 [inline] > rtnl_newlink+0xbb3/0x1670 net/core/rtnetlink.c:3754 > rtnetlink_rcv_msg+0x807/0x8c0 net/core/rtnetlink.c:6558 > netlink_rcv_skb+0x126/0x220 net/netlink/af_netlink.c:2545 > rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:6576 > netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline] > netlink_unicast+0x589/0x650 net/netlink/af_netlink.c:1368 > netlink_sendmsg+0x66e/0x770 net/netlink/af_netlink.c:1910 > sock_sendmsg_nosec net/socket.c:730 [inline] > __sock_sendmsg net/socket.c:745 [inline] > ____sys_sendmsg+0x37c/0x4d0 net/socket.c:2584 > ___sys_sendmsg net/socket.c:2638 [inline] > __sys_sendmsg+0x1e9/0x270 net/socket.c:2667 > __do_sys_sendmsg net/socket.c:2676 [inline] > __se_sys_sendmsg net/socket.c:2674 [inline] > __x64_sys_sendmsg+0x46/0x50 net/socket.c:2674 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x63/0x6b > > write to 0xffff88813a80c832 of 1 bytes by task 22 on cpu 1: > mld_ifc_work+0x54c/0x7b0 net/ipv6/mcast.c:2653 > process_one_work kernel/workqueue.c:2627 [inline] > process_scheduled_works+0x5b8/0xa30 kernel/workqueue.c:2700 > worker_thread+0x525/0x730 kernel/workqueue.c:2781 > kthread+0x1d7/0x210 kernel/kthread.c:388 > ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147 > ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 > > value changed: 0x02 -> 0x00 > > Reported by Kernel Concurrency Sanitizer on: > CPU: 1 PID: 22 Comm: kworker/1:0 Not tainted 6.7.0-rc7-syzkaller-00029-g8735c7c84d1b #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023 > Workqueue: mld mld_ifc_work > ================================================================== > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@googlegroups.com. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > If the report is already addressed, let syzbot know by replying with: > #syz fix: exact-commit-title > > If you want to overwrite report's subsystems, reply with: > #syz set subsystems: new-subsystem > (See the list of subsystem names on the web dashboard) > > If the report is a duplicate of another one, reply with: > #syz dup: exact-subject-of-another-report > > If you want to undo deduplication, reply with: > #syz undup
Bug added in
commit 63ed8de4be81b699ca727e9f8e3344bd487806d7 Author: Taehee Yoo <ap420073@gmail.com> Date: Thu Mar 25 16:16:57 2021 +0000
mld: add mc_lock for protecting per-interface mld data
ipv6_mc_down() calls mld_ifc_stop_work() while mc_lock is not held.
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