[PATCH] net: appletalk: cops: Fix data race in cops_probe1

[PATCH] net: appletalk: cops: Fix data race in cops_probe1

[Saubhik Mukherjee]

In cops_probe1(), there is a write to dev->base_addr after requesting an
interrupt line and registering the interrupt handler cops_interrupt().
The handler might be called in parallel to handle an interrupt.
cops_interrupt() tries to read dev->base_addr leading to a potential
data race. So write to dev->base_addr before calling request_irq().

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Saubhik Mukherjee <saubhik.mukherjee@gmail.com>
---
 drivers/net/appletalk/cops.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/appletalk/cops.c b/drivers/net/appletalk/cops.c
index ba8e70a8e312..6b12ce822e51 100644
--- a/drivers/net/appletalk/cops.c
+++ b/drivers/net/appletalk/cops.c
@@ -327,6 +327,8 @@ static int __init cops_probe1(struct net_device *dev, int ioaddr)
 			break;
 	}
 
+	dev->base_addr = ioaddr;
+
 	/* Reserve any actual interrupt. */
 	if (dev->irq) {
 		retval = request_irq(dev->irq, cops_interrupt, 0, dev->name, dev);
@@ -334,8 +336,6 @@ static int __init cops_probe1(struct net_device *dev, int ioaddr)
 			goto err_out;
 	}
 
-	dev->base_addr = ioaddr;
-
         lp = netdev_priv(dev);
         spin_lock_init(&lp->lock);
 
-- 
2.30.2

Re: [PATCH] net: appletalk: cops: Fix data race in cops_probe1

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (refs/heads/master):

On Mon, 24 May 2021 19:07:12 +0530 you wrote:
> In cops_probe1(), there is a write to dev->base_addr after requesting an
> interrupt line and registering the interrupt handler cops_interrupt().
> The handler might be called in parallel to handle an interrupt.
> cops_interrupt() tries to read dev->base_addr leading to a potential
> data race. So write to dev->base_addr before calling request_irq().
> 
> Found by Linux Driver Verification project (linuxtesting.org).
> 
> [...]

Here is the summary with links:
  - net: appletalk: cops: Fix data race in cops_probe1
    https://git.kernel.org/netdev/net/c/a4dd4fc6105e

You are awesome, thank you!
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