2.6.24-rc1: NULL pointer dereference using netconsole

PATCH Applied Andrew Nelless 3 participants 4 messages Oct 24, 2007 – Oct 25, 2007 Network drivers

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Andrew Nelless

author

2007-10-24 11:09 UTC #0 lore raw

Hi,

I booted up 2.6.24-rc1 this morning [Real early over a brew ;-)] and was having a problems with multiple ~5 second hangs on SATA/drive init (Something to do with "EH" something-or-other and resets but I'll email in separately about it later unless its fixed by the time I get the chance).

Anyway, I went to fire up netconsole to get a decent log dump and hit across the following nasty. Netconsole works fine in 2.6.23.1 with a similar config and the same kernel parameters.

A shot of the screen is the only method I could come up with to capture the log, I hope that is OK, it is pretty readable.

The nasty:
http://andotnet.nfshost.com/linux/2.6.24-rc1-netconsole-nullderef.jpg

The config:
http://andotnet.nfshost.com/linux/config-2.6.24-rc1.txt

The 'old' 2.6.23.1 config:
http://andotnet.nfshost.com/linux/config-2.6.23.1.txt

Netconsole log from successfully booting 2.6.23.1:
http://andotnet.nfshost.com/linux/successful-nclog-2.6.23.1.txt

The hardware, etc:
eth0 : Netgear FA311 10/100Mbps ethernet adapter (netsemi driver)
connected directly to another PC using a crossover cable.
cpu : athlon64 3500+
compiler : gcc 4.2.2
kernel params : root=/dev/sda3 vga=0x31B nmi_watchdog=0

                [email protected]/eth0,[email protected]/00:11:d8:c0:5e:96

I hope this report is helpful and it's not too early in the release cycle, I'm still pretty new and not subscribed, so please CC :-)

Btw, is it preferable for non-subscribers to use the kernel bugzilla? Or post to the list?

Andrew (On his 3rd brew of the day)

Ingo Molnar

2007-10-24 11:59 UTC #1 lore raw

PATCH 1/1 natsemi: fix oops, link back netdevice from private-struct

Quoted 12 lines · Andrew Nelless

Hi,
I booted up 2.6.24-rc1 this morning [Real early over a brew ;-)] and was having a problems with multiple ~5 second hangs on SATA/drive init (Something to do with "EH" something-or-other and resets but I'll email in separately about it later unless its fixed by the time I get the chance).
Anyway, I went to fire up netconsole to get a decent log dump and hit across the following nasty. Netconsole works fine in 2.6.23.1 with a similar config and the same kernel parameters.

Quoted 6 lines

A shot of the screen is the only method I could come up with to capture the log, I hope that is OK, it is pretty readable.
The nasty:
http://andotnet.nfshost.com/linux/2.6.24-rc1-netconsole-nullderef.jpg

the NULL dereference is here:

(gdb) list *0xffffffff804a9504
0xffffffff804a9504 is in natsemi_poll (drivers/net/natsemi.c:717).
712 return count;
713 }
714
715 static inline void __iomem *ns_ioaddr(struct net_device *dev)
716 {
717 return (void __iomem *) dev->base_addr;
718 }
719

which is this code from natsemi.c:

 2227            struct net_device *dev = np->dev;
 2228            void __iomem * ioaddr = ns_ioaddr(dev);
 2229            int work_done = 0;

seems like the NAPI changes in -rc1 added an np->dev field but forgot to initialize it ...

does the patch below fix the oops for you?

Ingo

-------------------->
Subject: natsemi: fix oops, link back netdevice from private-struct
From: Ingo Molnar <[email protected]>

this commit:

commit bea3348eef27e6044b6161fd04c3152215f96411
Author: Stephen Hemminger <[email protected]>
Date: Wed Oct 3 16:41:36 2007 -0700

[NET]: Make NAPI polling independent of struct net_device objects.

added np->dev to drivers/net/natsemi.c's struct netdev_private, but forgot to initialize that new field upon driver init. The result was a predictable NULL dereference oops the first time the hardware generated an interrupt.

Reported-by Andrew Nelless <[email protected]>

Signed-off-by Ingo Molnar <[email protected]>

---
 drivers/net/natsemi.c |    1 +
 1 file changed, 1 insertion(+)

drivers/net/natsemi.c +1 -0

Index: linux/drivers/net/natsemi.c
===================================================================
@@ -864,6 +864,7 @@ static int __devinit natsemi_probe1 (str
 
 	np = netdev_priv(dev);
 	netif_napi_add(dev, &np->napi, natsemi_poll, 64);
+	np->dev = dev;
 
 	np->pci_dev = pdev;
 	pci_set_drvdata(pdev, dev);

Andrew

author

2007-10-24 17:37 UTC #2 lore raw

Re: [patch] natsemi: fix oops, link back netdevice from private-struct

Quoted 22 lines · Ingo Molnar

the NULL dereference is here:
(gdb) list *0xffffffff804a9504
0xffffffff804a9504 is in natsemi_poll (drivers/net/natsemi.c:717).
712 return count;
713 }
714
715 static inline void __iomem *ns_ioaddr(struct net_device *dev)
716 {
717 return (void __iomem *) dev->base_addr;
718 }
719
which is this code from natsemi.c:
2227            struct net_device *dev = np->dev;
2228            void __iomem * ioaddr = ns_ioaddr(dev);
2229            int work_done = 0;

Quoted 7 lines

seems like the NAPI changes in -rc1 added an np->dev field but forgot to initialize it ...
does the patch below fix the oops for you?
Ingo

Yep, that got it, thanks.

Jeff Garzik

Applied

2007-10-25 07:33 UTC #3 lore raw

Re: [patch] natsemi: fix oops, link back netdevice from private-struct

In reply to Ingo Molnar

Quoted 67 lines · Ingo Molnar

Quoted 10 lines · Andrew Nelless
Hi,
I booted up 2.6.24-rc1 this morning [Real early over a brew ;-)] and was having a problems with multiple ~5 second hangs on SATA/drive init (Something to do with "EH" something-or-other and resets but I'll email in separately about it later unless its fixed by the time I get the chance).
Anyway, I went to fire up netconsole to get a decent log dump and hit across the following nasty. Netconsole works fine in 2.6.23.1 with a similar config and the same kernel parameters.
A shot of the screen is the only method I could come up with to capture the log, I hope that is OK, it is pretty readable.
The nasty: http://andotnet.nfshost.com/linux/2.6.24-rc1-netconsole-nullderef.jpg
the NULL dereference is here:
(gdb) list *0xffffffff804a9504
0xffffffff804a9504 is in natsemi_poll (drivers/net/natsemi.c:717).
712 return count;
713 }
714
715 static inline void __iomem *ns_ioaddr(struct net_device *dev)
716 {
717 return (void __iomem *) dev->base_addr;
718 }
719
which is this code from natsemi.c:
 2227            struct net_device *dev = np->dev;
 2228            void __iomem * ioaddr = ns_ioaddr(dev);
 2229            int work_done = 0;
seems like the NAPI changes in -rc1 added an np->dev field but forgot to initialize it ...
does the patch below fix the oops for you?
Ingo
-------------------->
Subject: natsemi: fix oops, link back netdevice from private-struct
From: Ingo Molnar <[email protected]>
this commit:
commit bea3348eef27e6044b6161fd04c3152215f96411
Author: Stephen Hemminger <[email protected]>
Date: Wed Oct 3 16:41:36 2007 -0700
[NET]: Make NAPI polling independent of struct net_device objects.
added np->dev to drivers/net/natsemi.c's struct netdev_private, but forgot to initialize that new field upon driver init. The result was a predictable NULL dereference oops the first time the hardware generated an interrupt.
Reported-by Andrew Nelless <[email protected]>
Signed-off-by Ingo Molnar <[email protected]>
---
 drivers/net/natsemi.c |    1 +
 1 file changed, 1 insertion(+)
Index: linux/drivers/net/natsemi.c
===================================================================

drivers/net/natsemi.c static int __devinit natsemi_probe1 (str · line 870

Quoted 7 lines

drivers/net/natsemi.c +1 -0

@@ -864,6 +864,7 @@ static int __devinit natsemi_probe1 (str
 
 	np = netdev_priv(dev);
 	netif_napi_add(dev, &np->napi, natsemi_poll, 64);
+	np->dev = dev;
 
 	np->pci_dev = pdev;
 	pci_set_drvdata(pdev, dev);

applied