* [PATCH] net: add checks if dev->netdev_ops is NULL in register_netdevice()
@ 2013-04-08 9:43 dingtianhong
2013-04-08 15:16 ` Eric Dumazet
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: dingtianhong @ 2013-04-08 9:43 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet, Alexander Duyck, Netdev, Li Zefan,
Xinwei Hu
In some cases netdev->netdev_ops could be NULL in the register_netdevice(),
thus a NULL point deference happens and lead to oops:
[ 8260.836400] BUG: unable to handle kernel NULL pointer dereference at (null)
[ 8260.955306] IP: [<ffffffff81388333>] register_netdevice+0x73/0x2d0
[ 8261.054888] PGD 2f4dcd067 PUD 2f4de0067 PMD 0
[ 8261.134244] Oops: 0000 [#1] SMP
[ 8261.198938] CPU 0
[ 8262.605182] RIP: 0010:[<ffffffff81388333>] [<ffffffff81388333>] register_netdevice+0x73/0x2d0
[ 8262.741859] RSP: 0018:ffff8802f489f9f8 EFLAGS: 00010246
[ 8262.839463] RAX: 0000000000000000 RBX: ffff8802f4e73000 RCX: ffff8802f4e73006
[ 8262.959484] RDX: 0000000000000000 RSI: 00000000daa92527 RDI: ffff8802f4e73006
[ 8263.079352] RBP: 0000000000000000 R08: 0000000000000000 R09: ffff880327d898c0
[ 8263.198987] R10: 00000000000000c1 R11: 0000000000000000 R12: ffffffff81fed080
[ 8263.318401] R13: ffffffff81fed080 R14: ffff8802f4e73000 R15: 0000000000000000
[ 8263.438014] FS: 00007f01dfa81700(0000) GS:ffff88033f200000(0000) knlGS:0000000000000000
[ 8263.569778] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 8263.673859] CR2: 0000000000000000 CR3: 000000032893f000 CR4: 00000000000006f0
[ 8263.794922] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 8263.915734] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[ 8264.036251] Process rmcli (pid: 14089, threadinfo ffff8802f489e000, task ffff880324708080)
[ 8264.170961] Stack:
[ 8264.231328] ffff88032a3c0000 0000000000000003 0000000000000003 ffff88032a3c0000
[ 8264.356967] 0000000000000003 ffffffffa039dbcb 000000003ec216c0 0000000000000246
[ 8264.483081] 382e30363238205b 00205d3900000006 ff00305f63696e76 0000000000000003
We should check the point to avoid the oops.
Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
---
net/core/dev.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/core/dev.c b/net/core/dev.c
index e7d68ed..596a11e 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5159,7 +5159,7 @@ int register_netdevice(struct net_device *dev)
goto out;
/* Init, if this function is available */
- if (dev->netdev_ops->ndo_init) {
+ if (dev->netdev_ops && dev->netdev_ops->ndo_init) {
ret = dev->netdev_ops->ndo_init(dev);
if (ret) {
if (ret > 0)
-- 1.8.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] net: add checks if dev->netdev_ops is NULL in register_netdevice()
2013-04-08 9:43 [PATCH] net: add checks if dev->netdev_ops is NULL in register_netdevice() dingtianhong
@ 2013-04-08 15:16 ` Eric Dumazet
2013-04-08 15:34 ` David Miller
2013-04-08 15:49 ` Alexander Duyck
2013-04-10 20:45 ` Stephen Hemminger
2 siblings, 1 reply; 5+ messages in thread
From: Eric Dumazet @ 2013-04-08 15:16 UTC (permalink / raw)
To: dingtianhong
Cc: David S. Miller, Eric Dumazet, Alexander Duyck, Netdev, Li Zefan,
Xinwei Hu
On Mon, 2013-04-08 at 17:43 +0800, dingtianhong wrote:
> In some cases netdev->netdev_ops could be NULL in the register_netdevice(),
> thus a NULL point deference happens and lead to oops:
> /* Init, if this function is available */
> - if (dev->netdev_ops->ndo_init) {
> + if (dev->netdev_ops && dev->netdev_ops->ndo_init) {
> ret = dev->netdev_ops->ndo_init(dev);
> if (ret) {
> if (ret > 0)
> -- 1.8.0
>
Seriously ?
This patch is not needed, and not complete anyway.
Fix the driver instead, we don't want this to happen.
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] net: add checks if dev->netdev_ops is NULL in register_netdevice()
2013-04-08 15:16 ` Eric Dumazet
@ 2013-04-08 15:34 ` David Miller
0 siblings, 0 replies; 5+ messages in thread
From: David Miller @ 2013-04-08 15:34 UTC (permalink / raw)
To: eric.dumazet
Cc: dingtianhong, edumazet, alexander.h.duyck, netdev, lizefan,
huxinwei
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Mon, 08 Apr 2013 08:16:34 -0700
> On Mon, 2013-04-08 at 17:43 +0800, dingtianhong wrote:
>> In some cases netdev->netdev_ops could be NULL in the register_netdevice(),
>> thus a NULL point deference happens and lead to oops:
>
>> /* Init, if this function is available */
>> - if (dev->netdev_ops->ndo_init) {
>> + if (dev->netdev_ops && dev->netdev_ops->ndo_init) {
>> ret = dev->netdev_ops->ndo_init(dev);
>> if (ret) {
>> if (ret > 0)
>> -- 1.8.0
>>
>
> Seriously ?
>
> This patch is not needed, and not complete anyway.
>
> Fix the driver instead, we don't want this to happen.
Agreed, I'm not seriously considering patches like this at all.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] net: add checks if dev->netdev_ops is NULL in register_netdevice()
2013-04-08 9:43 [PATCH] net: add checks if dev->netdev_ops is NULL in register_netdevice() dingtianhong
2013-04-08 15:16 ` Eric Dumazet
@ 2013-04-08 15:49 ` Alexander Duyck
2013-04-10 20:45 ` Stephen Hemminger
2 siblings, 0 replies; 5+ messages in thread
From: Alexander Duyck @ 2013-04-08 15:49 UTC (permalink / raw)
To: dingtianhong; +Cc: David S. Miller, Eric Dumazet, Netdev, Li Zefan, Xinwei Hu
On 04/08/2013 02:43 AM, dingtianhong wrote:
> In some cases netdev->netdev_ops could be NULL in the register_netdevice(),
> thus a NULL point deference happens and lead to oops:
>
> [ 8260.836400] BUG: unable to handle kernel NULL pointer dereference at (null)
> [ 8260.955306] IP: [<ffffffff81388333>] register_netdevice+0x73/0x2d0
> [ 8261.054888] PGD 2f4dcd067 PUD 2f4de0067 PMD 0
> [ 8261.134244] Oops: 0000 [#1] SMP
> [ 8261.198938] CPU 0
> [ 8262.605182] RIP: 0010:[<ffffffff81388333>] [<ffffffff81388333>] register_netdevice+0x73/0x2d0
> [ 8262.741859] RSP: 0018:ffff8802f489f9f8 EFLAGS: 00010246
> [ 8262.839463] RAX: 0000000000000000 RBX: ffff8802f4e73000 RCX: ffff8802f4e73006
> [ 8262.959484] RDX: 0000000000000000 RSI: 00000000daa92527 RDI: ffff8802f4e73006
> [ 8263.079352] RBP: 0000000000000000 R08: 0000000000000000 R09: ffff880327d898c0
> [ 8263.198987] R10: 00000000000000c1 R11: 0000000000000000 R12: ffffffff81fed080
> [ 8263.318401] R13: ffffffff81fed080 R14: ffff8802f4e73000 R15: 0000000000000000
> [ 8263.438014] FS: 00007f01dfa81700(0000) GS:ffff88033f200000(0000) knlGS:0000000000000000
> [ 8263.569778] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 8263.673859] CR2: 0000000000000000 CR3: 000000032893f000 CR4: 00000000000006f0
> [ 8263.794922] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 8263.915734] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> [ 8264.036251] Process rmcli (pid: 14089, threadinfo ffff8802f489e000, task ffff880324708080)
> [ 8264.170961] Stack:
> [ 8264.231328] ffff88032a3c0000 0000000000000003 0000000000000003 ffff88032a3c0000
> [ 8264.356967] 0000000000000003 ffffffffa039dbcb 000000003ec216c0 0000000000000246
> [ 8264.483081] 382e30363238205b 00205d3900000006 ff00305f63696e76 0000000000000003
>
> We should check the point to avoid the oops.
>
> Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
> ---
> net/core/dev.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/core/dev.c b/net/core/dev.c
> index e7d68ed..596a11e 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -5159,7 +5159,7 @@ int register_netdevice(struct net_device *dev)
> goto out;
>
> /* Init, if this function is available */
> - if (dev->netdev_ops->ndo_init) {
> + if (dev->netdev_ops && dev->netdev_ops->ndo_init) {
> ret = dev->netdev_ops->ndo_init(dev);
> if (ret) {
> if (ret > 0)
> -- 1.8.0
>
The correct fix for this is to not allow the registration of devices
with a null netdev_ops pointer. The subtle approach to resolving this
is adding a check for the null pointer near the start of the function
and returning -EVINAL since the dev structure passed was configured
incorrectly. The blunt approach is to just add a BUG_ON with a comment
on the line before it explaining that you should always set the
netdev_ops pointer before trying to register a netdev. That way if
someone else makes the mistake then they will hit the BUG_ON and realize
what they are doing wrong.
Thanks,
Alex
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] net: add checks if dev->netdev_ops is NULL in register_netdevice()
2013-04-08 9:43 [PATCH] net: add checks if dev->netdev_ops is NULL in register_netdevice() dingtianhong
2013-04-08 15:16 ` Eric Dumazet
2013-04-08 15:49 ` Alexander Duyck
@ 2013-04-10 20:45 ` Stephen Hemminger
2 siblings, 0 replies; 5+ messages in thread
From: Stephen Hemminger @ 2013-04-10 20:45 UTC (permalink / raw)
To: dingtianhong
Cc: David S. Miller, Eric Dumazet, Alexander Duyck, Netdev, Li Zefan,
Xinwei Hu
On Mon, 8 Apr 2013 17:43:53 +0800
dingtianhong <dingtianhong@huawei.com> wrote:
> In some cases netdev->netdev_ops could be NULL in the register_netdevice(),
> thus a NULL point deference happens and lead to oops:
>
> [ 8260.836400] BUG: unable to handle kernel NULL pointer dereference at (null)
> [ 8260.955306] IP: [<ffffffff81388333>] register_netdevice+0x73/0x2d0
> [ 8261.054888] PGD 2f4dcd067 PUD 2f4de0067 PMD 0
> [ 8261.134244] Oops: 0000 [#1] SMP
> [ 8261.198938] CPU 0
> [ 8262.605182] RIP: 0010:[<ffffffff81388333>] [<ffffffff81388333>] register_netdevice+0x73/0x2d0
> [ 8262.741859] RSP: 0018:ffff8802f489f9f8 EFLAGS: 00010246
> [ 8262.839463] RAX: 0000000000000000 RBX: ffff8802f4e73000 RCX: ffff8802f4e73006
> [ 8262.959484] RDX: 0000000000000000 RSI: 00000000daa92527 RDI: ffff8802f4e73006
> [ 8263.079352] RBP: 0000000000000000 R08: 0000000000000000 R09: ffff880327d898c0
> [ 8263.198987] R10: 00000000000000c1 R11: 0000000000000000 R12: ffffffff81fed080
> [ 8263.318401] R13: ffffffff81fed080 R14: ffff8802f4e73000 R15: 0000000000000000
> [ 8263.438014] FS: 00007f01dfa81700(0000) GS:ffff88033f200000(0000) knlGS:0000000000000000
> [ 8263.569778] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 8263.673859] CR2: 0000000000000000 CR3: 000000032893f000 CR4: 00000000000006f0
> [ 8263.794922] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 8263.915734] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> [ 8264.036251] Process rmcli (pid: 14089, threadinfo ffff8802f489e000, task ffff880324708080)
> [ 8264.170961] Stack:
> [ 8264.231328] ffff88032a3c0000 0000000000000003 0000000000000003 ffff88032a3c0000
> [ 8264.356967] 0000000000000003 ffffffffa039dbcb 000000003ec216c0 0000000000000246
> [ 8264.483081] 382e30363238205b 00205d3900000006 ff00305f63696e76 0000000000000003
>
> We should check the point to avoid the oops.
>
> Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
I notice you truncated the back trace. You should include the whole thing
so the buggy driver can be found and shot. If it is your own code fix it.
Adding a BUG_ON() is a waste, the NULL trap is the same effect.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2013-04-10 20:45 UTC | newest]
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2013-04-08 9:43 [PATCH] net: add checks if dev->netdev_ops is NULL in register_netdevice() dingtianhong
2013-04-08 15:16 ` Eric Dumazet
2013-04-08 15:34 ` David Miller
2013-04-08 15:49 ` Alexander Duyck
2013-04-10 20:45 ` Stephen Hemminger
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