From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Subject: Re: [PATCH v2] i2c: omap: Prevent NULL pointer dereference in remove Date: Thu, 6 Sep 2012 14:21:35 +0200 Message-ID: <20120906142135.2cdebf93@endymion.delvare> References: <1346932916-12365-1-git-send-email-shubhrajyoti@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1346932916-12365-1-git-send-email-shubhrajyoti-l0cyMroinI0@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Shubhrajyoti D Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org, w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org List-Id: linux-i2c@vger.kernel.org On Thu, 6 Sep 2012 17:31:56 +0530, Shubhrajyoti D wrote: > Prevent the NULL pointer access by moving the platform_set_drvdata function > after the access of the pdev. > > [ 654.961761] Unable to handle kernel NULL pointer dereference at virtual address 00000070 > [ 654.970611] pgd = df254000 > [ 654.973480] [00000070] *pgd=9f1da831, *pte=00000000, *ppte=00000000 > [ 654.980163] Internal error: Oops: 17 [#1] SMP ARM > [ 654.985076] Modules linked in: > [ 654.988281] CPU: 1 Not tainted (3.6.0-rc1-00031-ge547de1-dirty #339) > [ 654.995330] PC is at omap_i2c_runtime_resume+0x8/0x148 > [ 655.000732] LR is at omap_i2c_runtime_resume+0x8/0x148 > > Signed-off-by: Shubhrajyoti D Acked-by: Jean Delvare (This will rather go in Ben's or Wolfram's i2c tree.) > --- > v2: Implement Jean's suggestion of not deleting instead make it NULL at a safer time. > > drivers/i2c/busses/i2c-omap.c | 3 +-- > 1 files changed, 1 insertions(+), 2 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c > index 5d19a49..c4ddb08 100644 > --- a/drivers/i2c/busses/i2c-omap.c > +++ b/drivers/i2c/busses/i2c-omap.c > @@ -1112,8 +1112,6 @@ static int __devexit omap_i2c_remove(struct platform_device *pdev) > struct resource *mem; > int ret; > > - platform_set_drvdata(pdev, NULL); > - > free_irq(dev->irq, dev); > i2c_del_adapter(&dev->adapter); > ret = pm_runtime_get_sync(&pdev->dev); > @@ -1127,6 +1125,7 @@ static int __devexit omap_i2c_remove(struct platform_device *pdev) > kfree(dev); > mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); > release_mem_region(mem->start, resource_size(mem)); > + platform_set_drvdata(pdev, NULL); > return 0; > } > -- Jean Delvare