| Message ID | 20220221201931.296500-1-alvin@pqrs.dk (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] net: dsa: fix panic when removing unoffloaded port from bridge | expand |
On Mon, Feb 21, 2022 at 09:19:31PM +0100, Alvin Šipraga wrote: > From: Alvin Šipraga <alsi@bang-olufsen.dk> > > If a bridged port is not offloaded to the hardware - either because the > underlying driver does not implement the port_bridge_{join,leave} ops, > or because the operation failed - then its dp->bridge pointer will be > NULL when dsa_port_bridge_leave() is called. Avoid dereferncing NULL. > > This fixes the following splat when removing a port from a bridge: > > Unable to handle kernel access to user memory outside uaccess routines at virtual address 0000000000000000 > Internal error: Oops: 96000004 [#1] PREEMPT_RT SMP > CPU: 3 PID: 1119 Comm: brctl Tainted: G O 5.17.0-rc4-rt4 #1 > Call trace: > dsa_port_bridge_leave+0x8c/0x1e4 > dsa_slave_changeupper+0x40/0x170 > dsa_slave_netdevice_event+0x494/0x4d4 > notifier_call_chain+0x80/0xe0 > raw_notifier_call_chain+0x1c/0x24 > call_netdevice_notifiers_info+0x5c/0xac > __netdev_upper_dev_unlink+0xa4/0x200 > netdev_upper_dev_unlink+0x38/0x60 > del_nbp+0x1b0/0x300 > br_del_if+0x38/0x114 > add_del_if+0x60/0xa0 > br_ioctl_stub+0x128/0x2dc > br_ioctl_call+0x68/0xb0 > dev_ifsioc+0x390/0x554 > dev_ioctl+0x128/0x400 > sock_do_ioctl+0xb4/0xf4 > sock_ioctl+0x12c/0x4e0 > __arm64_sys_ioctl+0xa8/0xf0 > invoke_syscall+0x4c/0x110 > el0_svc_common.constprop.0+0x48/0xf0 > do_el0_svc+0x28/0x84 > el0_svc+0x1c/0x50 > el0t_64_sync_handler+0xa8/0xb0 > el0t_64_sync+0x17c/0x180 > Code: f9402f00 f0002261 f9401302 913cc021 (a9401404) > ---[ end trace 0000000000000000 ]--- > > Fixes: d3eed0e57d5d ("net: dsa: keep the bridge_dev and bridge_num as part of the same structure") > Signed-off-by: Alvin Šipraga <alsi@bang-olufsen.dk> > --- Sorry, I thought that the caller of dsa_port_bridge_leave() would check this, but clearly that is not the case. I see that there's a similar NULL pointer dereference in some patches I sent today, so I'd better fix that too before they get accepted. > net/dsa/port.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/net/dsa/port.c b/net/dsa/port.c > index eef4a98f2628..fc7a233653a0 100644 > --- a/net/dsa/port.c > +++ b/net/dsa/port.c > @@ -395,10 +395,17 @@ void dsa_port_bridge_leave(struct dsa_port *dp, struct net_device *br) > .tree_index = dp->ds->dst->index, > .sw_index = dp->ds->index, > .port = dp->index, > - .bridge = *dp->bridge, > }; > int err; > > + /* If the port could not be offloaded to begin with, then > + * there is nothing to do. > + */ > + if (!dp->bridge) > + return; > + > + info.bridge = *dp->bridge, By the way, does this patch compile, with the comma and not the semicolon, like that? > + > /* Here the port is already unbridged. Reflect the current configuration > * so that drivers can program their chips accordingly. > */ > -- > 2.35.1 >
Vladimir Oltean <olteanv@gmail.com> writes: > On Mon, Feb 21, 2022 at 09:19:31PM +0100, Alvin Šipraga wrote: >> From: Alvin Šipraga <alsi@bang-olufsen.dk> >> >> If a bridged port is not offloaded to the hardware - either because the >> underlying driver does not implement the port_bridge_{join,leave} ops, >> or because the operation failed - then its dp->bridge pointer will be >> NULL when dsa_port_bridge_leave() is called. Avoid dereferncing NULL. >> >> This fixes the following splat when removing a port from a bridge: >> >> Unable to handle kernel access to user memory outside uaccess routines at virtual address 0000000000000000 >> Internal error: Oops: 96000004 [#1] PREEMPT_RT SMP >> CPU: 3 PID: 1119 Comm: brctl Tainted: G O 5.17.0-rc4-rt4 #1 >> Call trace: >> dsa_port_bridge_leave+0x8c/0x1e4 >> dsa_slave_changeupper+0x40/0x170 >> dsa_slave_netdevice_event+0x494/0x4d4 >> notifier_call_chain+0x80/0xe0 >> raw_notifier_call_chain+0x1c/0x24 >> call_netdevice_notifiers_info+0x5c/0xac >> __netdev_upper_dev_unlink+0xa4/0x200 >> netdev_upper_dev_unlink+0x38/0x60 >> del_nbp+0x1b0/0x300 >> br_del_if+0x38/0x114 >> add_del_if+0x60/0xa0 >> br_ioctl_stub+0x128/0x2dc >> br_ioctl_call+0x68/0xb0 >> dev_ifsioc+0x390/0x554 >> dev_ioctl+0x128/0x400 >> sock_do_ioctl+0xb4/0xf4 >> sock_ioctl+0x12c/0x4e0 >> __arm64_sys_ioctl+0xa8/0xf0 >> invoke_syscall+0x4c/0x110 >> el0_svc_common.constprop.0+0x48/0xf0 >> do_el0_svc+0x28/0x84 >> el0_svc+0x1c/0x50 >> el0t_64_sync_handler+0xa8/0xb0 >> el0t_64_sync+0x17c/0x180 >> Code: f9402f00 f0002261 f9401302 913cc021 (a9401404) >> ---[ end trace 0000000000000000 ]--- >> >> Fixes: d3eed0e57d5d ("net: dsa: keep the bridge_dev and bridge_num as part of the same structure") >> Signed-off-by: Alvin Šipraga <alsi@bang-olufsen.dk> >> --- > > Sorry, I thought that the caller of dsa_port_bridge_leave() would check > this, but clearly that is not the case. > > I see that there's a similar NULL pointer dereference in some patches I > sent today, so I'd better fix that too before they get accepted. > >> net/dsa/port.c | 9 ++++++++- >> 1 file changed, 8 insertions(+), 1 deletion(-) >> >> diff --git a/net/dsa/port.c b/net/dsa/port.c >> index eef4a98f2628..fc7a233653a0 100644 >> --- a/net/dsa/port.c >> +++ b/net/dsa/port.c >> @@ -395,10 +395,17 @@ void dsa_port_bridge_leave(struct dsa_port *dp, struct net_device *br) >> .tree_index = dp->ds->dst->index, >> .sw_index = dp->ds->index, >> .port = dp->index, >> - .bridge = *dp->bridge, >> }; >> int err; >> >> + /* If the port could not be offloaded to begin with, then >> + * there is nothing to do. >> + */ >> + if (!dp->bridge) >> + return; >> + >> + info.bridge = *dp->bridge, > > By the way, does this patch compile, with the comma and not the > semicolon, like that? Yikes, sorry about that. Sent a corrected v2 now. It does actually compile though. Kind regards, Alvin
On Mon, Feb 21, 2022 at 08:38:21PM +0000, Alvin Šipraga wrote: > >> + info.bridge = *dp->bridge, > > > > By the way, does this patch compile, with the comma and not the > > semicolon, like that? > > Yikes, sorry about that. Sent a corrected v2 now. > > It does actually compile though. Yes, I see, I think it probably works too: info.bridge = *dp->bridge, dsa_port_bridge_destroy(dp, br); although I would never write code like that.
diff --git a/net/dsa/port.c b/net/dsa/port.c index eef4a98f2628..fc7a233653a0 100644 --- a/net/dsa/port.c +++ b/net/dsa/port.c @@ -395,10 +395,17 @@ void dsa_port_bridge_leave(struct dsa_port *dp, struct net_device *br) .tree_index = dp->ds->dst->index, .sw_index = dp->ds->index, .port = dp->index, - .bridge = *dp->bridge, }; int err; + /* If the port could not be offloaded to begin with, then + * there is nothing to do. + */ + if (!dp->bridge) + return; + + info.bridge = *dp->bridge, + /* Here the port is already unbridged. Reflect the current configuration * so that drivers can program their chips accordingly. */