Messages in this thread | | | Date | Fri, 7 Apr 2023 15:22:36 +0800 | Subject | Re: [syzbot] kernel panic: kernel stack overflow | From | wangyufen <> |
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在 2022/10/21 19:08, Taehee Yoo 写道: > Hi, > > 2022. 10. 14. 오전 12:00에 Taehee Yoo 이(가) 쓴 글: > > Hi, > > > > On 10/12/22 21:19, Eric Dumazet wrote: > > > On Wed, Oct 12, 2022 at 12:53 AM Dmitry Vyukov <dvyukov@google.com> > > wrote: > > >> > > >> On Wed, 12 Oct 2022 at 09:48, syzbot > > >> <syzbot+60748c96cf5c6df8e581@syzkaller.appspotmail.com> wrote: > > >>> > > >>> Hello, > > >>> > > >>> syzbot found the following issue on: > > >>> > > >>> HEAD commit: bbed346d5a96 Merge branch 'for-next/core' into > > for-kernelci > > >>> git tree: > > git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git > for-kernelci > > >>> console output: > > https://syzkaller.appspot.com/x/log.txt?x=14a03a2a880000 > > >>> kernel config: > > https://syzkaller.appspot.com/x/.config?x=aae2d21e7dd80684 > > >>> dashboard link: > > https://syzkaller.appspot.com/bug?extid=60748c96cf5c6df8e581 > > >>> compiler: Debian clang version > > 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld > > (GNU Binutils for Debian) 2.35.2 > > >>> userspace arch: arm64 > > >>> > > >>> Unfortunately, I don't have any reproducer for this issue yet. > > >>> > > >>> Downloadable assets: > > >>> disk image: > > > https://storage.googleapis.com/syzbot-assets/11078f50b80b/disk-bbed346d.raw.xz > > > > >>> vmlinux: > > > https://storage.googleapis.com/syzbot-assets/398e5f1e6c84/vmlinux-bbed346d.xz > > > > >>> > > >>> IMPORTANT: if you fix the issue, please add the following tag to > > the commit: > > >>> Reported-by: syzbot+60748c96cf5c6df8e581@syzkaller.appspotmail.com > > >> > > >> +Jiri > > >> > > >> It looks like the issue is with the team device. It seems to call > > >> itself infinitely. > > >> team_device_event was mentioned in stack overflow bugs in the past: > > >> > > > https://groups.google.com/g/syzkaller-bugs/search?q=%22team_device_event%22 > > >> > > > > > > > > > Taehee Yoo, can you take a look ? > > > > > > Patch series of yours was supposed to limit max nest level to 8 > > > > > > > > > https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=65921376425fc9c8b7ce647e1f7989f7cdf5dd70 > > > > > > > > > I found a reproducer. > > > > #test_team.sh > > ip link add dummy0 type dummy > > ip link set dummy0 up > > for a1 in {0..1} > > do > > ip link add team$a1 type team > > for a2 in {0..1} > > do > > ip link add team$a1$a2 master team$a1 type team > > for a3 in {0..1} > > do > > ip link add team$a1$a2$a3 master team$a1$a2 > > type team > > for a4 in {0..1} > > do > > ip link add team$a1$a2$a3$a4 master > > team$a1$a2$a3 type team > > for a5 in {0..1} > > do > > ip link add team$a1$a2$a3$a4$a5 > > master team$a1$a2$a3$a4 type team > > for a6 in {0..1} > > do > > ip link add > > team$a1$a2$a3$a4$a5$a6 master team$a1$a2$a3$a4$a5 type team > > ip link add > > macvlan$a1$a2$a3$a4$a5$a6 link dummy0 master team$a1$a2$a3$a4$a5$a6 type > > macvlan > > ip link set > > macvlan$a1$a2$a3$a4$a5$a6 up > > ip link set > > team$a1$a2$a3$a4$a5$a6 up > > done > > ip link set > team$a1$a2$a3$a4$a5 up > > done > > ip link set team$a1$a2$a3$a4 up > > done > > ip link set team$a1$a2$a3 up > > done > > ip link set team$a1$a2 up > > done > > ip link set team$a1 up > > done > > > > #test_ethtool.sh > > for a1 in {0..1} > > do > > ethtool -K team$a1 lro $1 > > for a2 in {0..1} > > do > > ethtool -K team$a1$a2 lro $1 > > for a3 in {0..1} > > do > > ethtool -K team$a1$a2$a3 lro $1 > > for a4 in {0..1} > > do > > ethtool -K team$a1$a2$a3$a4 lro $1 > > for a5 in {0..1} > > do > > ethtool -K team$a1$a2$a3$a4$a5 > > lro $1 > > for a6 in {0..1} > > do > > ethtool -K > > team$a1$a2$a3$a4$a5$a6 lro $1 > > ethtool -K > > macvlan$a1$a2$a3$a4$a5$a6 lro $1 > > done > > done > > done > > done > > done > > done > > > > shell#1 > > bash test_team.sh > > while : > > do > > bash test_ethtool.sh on > > done > > shell#2 > > while : > > do > > bash test_ethtool.sh off > > done > > > > We can see a very similar call trace with the above reproducer. > > I think it is the same issue. > > Could you please test it? > > > > And, I found the fixed same issue too. > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v6.0&id=dd912306ff008891c82cd9f63e8181e47a9cb2fb > > > > https://groups.google.com/g/syzkaller-bugs/c/-5OV1OW-dS4/m/o2Oq6AYSAwAJ > > > > I found the root cause of this issue. > > This is simpler reproducer. > > ip link add team0 type team > ethtool -K team0 lro on > for i in {1..100} > do > ip link add team$i master team0 type team > ethtool -K team$i lro on > done > > ethtool -K team0 lro off > > The above graph is like below: > team0 > | > +------+------+-----+-----+ > | | | | | > team1 team2 team3 ... team100 > > int __netdev_update_features(struct net_device *dev) > { > struct net_device *upper, *lower; > netdev_features_t features; > struct list_head *iter; > int err = -1; > ... > sync_lower: > /* some features must be disabled on lower devices when disabled > * on an upper device (think: bonding master or bridge) > */ > netdev_for_each_lower_dev(dev, lower, iter) > netdev_sync_lower_features(dev, lower, features); > ... > > > static void netdev_sync_lower_features(struct net_device *upper, > struct net_device *lower, netdev_features_t features) > { > netdev_features_t upper_disables = NETIF_F_UPPER_DISABLES; > netdev_features_t feature; > int feature_bit; > > for_each_netdev_feature(upper_disables, feature_bit) { > feature = __NETIF_F_BIT(feature_bit); > if (!(features & feature) && (lower->features & > feature)) { > netdev_dbg(upper, "Disabling feature %pNF on > lower dev %s.\n", > &feature, lower->name); > lower->wanted_features &= ~feature; > __netdev_update_features(lower); > > if (unlikely(lower->features & feature)) > netdev_WARN(upper, "failed to disable > %pNF on %s!\n", > &feature, lower->name); > else > netdev_features_change(lower);<-----HERE > } > } > } > > void netdev_features_change(struct net_device *dev) > { > call_netdevice_notifiers(NETDEV_FEAT_CHANGE, dev); > } > > The code looks like an iterator. > But it would work recursively because of notification. > > When team0's feature(LRO) is changed with <ethtool -K team0 lro off>", > __netdev_update_features(team0) is called. > __netdev_update_features(team0) internally sends NETDEV_FEAT_CHANGE > event to all lower interfaces(team1, team2, ... team100). > team1 will receive NETDEV_FEAT_CHANGE, and it sends NETDEV_FEAT_CHANGE > to the upper interface(team0). > team0 will receive NETDEV_FEAT_CHANGE again, and it sends > NETDEV_FEAT_CHANGE to the all lower interfaces(team1, team2, ... team100). > (At this point, team1 flag was already set, so it will be skipped.) > team2 will receive NETDEV_FEAT_CHANGE, and it sends NETDEV_FEAT_CHANGE > to the upper interface(team0). > team0 will receive NETDEV_FEAT_CHANGE again again, and it sends > NETDEV_FEAT_CHANGE to the all lower interfaces(team1, team2, ... team100). > (team1, team2 skipped.) > ... > So, if there are a few lower interfaces(roughly under 30 lower > interfaces), it anyway works even if internally works recursively. > But so many lower interfaces exist, stack overflow will occur. > This is the root cause of this issue. > > I think synchronization direction should be one way. > Up or Down. > It means that if the team0 interface can send the NETDEV_FEAT_CHANGE > notification event to the lower interface, > the lower interfaces should be disallowed to send NETDEV_FEAT_CHANGE > event to the upper interface. > > bonding has same issue.
Excuse me, is there a fix for this issue? I had the same issue with the 5.10 version of the bonding.
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