From: Alvin Šipraga <[email protected]>
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 <[email protected]>
---
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,
+
/* Here the port is already unbridged. Reflect the current configuration
* so that drivers can program their chips accordingly.
*/
--
2.35.1
On Mon, Feb 21, 2022 at 09:19:31PM +0100, Alvin Šipraga wrote:
> From: Alvin Šipraga <[email protected]>
>
> 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 <[email protected]>
> ---
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 <[email protected]> writes:
> On Mon, Feb 21, 2022 at 09:19:31PM +0100, Alvin Šipraga wrote:
>> From: Alvin Šipraga <[email protected]>
>>
>> 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 <[email protected]>
>> ---
>
> 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.