> -----Original Message-----
> From: Jim Quinlan <jim2101...@gmail.com>
> Sent: Monday, January 4, 2021 11:56 PM
> To: Jim Quinlan <james.quin...@broadcom.com>; Li, Meng
> <meng...@windriver.com>; open list <linux-kernel@vger.kernel.org>
> Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>; raf...@kernel.org;
> Hao, Kexin <kexin....@windriver.com>; Jim Quinlan
> <jim2101...@gmail.com>; Christoph Hellwig <h...@lst.de>
> Subject: Re: [PATCH] drivers core: Free dma_range_map when driver probe
> failed
>
> > Subject: [PATCH] drivers core: Free dma_range_map when driver probe
> > failed
> >
> > There will be memory leak if driver probe failed. Trace as below:
> > backtrace:
> > [<000000002415258f>] kmemleak_alloc+0x3c/0x50
> > [<00000000f447ebe4>] __kmalloc+0x208/0x530
> > [<0000000048bc7b3a>] of_dma_get_range+0xe4/0x1b0
> > [<0000000041e39065>] of_dma_configure_id+0x58/0x27c
> > [<000000006356866a>] platform_dma_configure+0x2c/0x40
> > ......
> > [<000000000afcf9b5>] ret_from_fork+0x10/0x3c
> >
> > This issue is introduced by commit e0d072782c73("dma-mapping:
> > introduce DMA range map, supplanting dma_pfn_offset "). It doesn't
> > free dma_range_map when driver probe failed and cause above memory
> > leak. So, add code to free it in error path.
> >
> > Fixes: e0d072782c73("dma-mapping: introduce DMA range map,
> supplanting
> > dma_pfn_offset ")
> > Cc: sta...@vger.kernel.org
> > Signed-off-by: Meng Li <meng...@windriver.com>
> > ---
> > drivers/base/dd.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/base/dd.c b/drivers/base/dd.c index
> > 148e81969e04..8e4871aa34bc 100644
> > --- a/drivers/base/dd.c
> > +++ b/drivers/base/dd.c
> > @@ -612,6 +612,7 @@ static int really_probe(struct device *dev, struct
> > device_driver *drv)
> > else if (drv->remove)
> > drv->remove(dev);
> > probe_failed:
> > + kfree(dev->dma_range_map);
> > if (dev->bus)
> > blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
> >
> > BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
> > --
> > 2.17.1
> >
> > --
>
> Hi Meng,
>
> Sorry for the delay -- I was on vacation. I agree with you -- thanks.
> However, note that in function device_release() in drivers/base/core.c
> there is this line:
>
> kfree(dev->dma_range_map);
>
> Won't this also be called if all of the appropriate drivers' probes fail for
> this
> device, effecting a double kfree?
If there are more than one driver compatible with the device, all the drivers
will allocate memory for dma_range_map in function dev->bus->dma_configure().
If all the drivers probe failed, they all need to free memory. So, I think
there is no double kfree case.
Perhaps your patch could also set "dev-
> >dma_range_map" to NULL after calling kfree()?
I agree with you. Based on all drivers probe failed case, it is need to set
dma_range_map as NULL after calling kfree() to avoid the NULL pointer.
In additional, could you please help to check whether we also need to set
dma_range_map as NULL in device_release()?
Because I found out some other cases(for example, all drivers register failed)
may free dma_range_map multiple times.
Thanks,
Limeng
>
> Thanks much,
> Jim Quinlan
> Broadcom STB
