* [PATCH] i2c: tegra: fix a possible NULL dereference @ 2015-11-12 7:26 LABBE Corentin 2015-11-12 12:29 ` Thierry Reding 0 siblings, 1 reply; 18+ messages in thread From: LABBE Corentin @ 2015-11-12 7:26 UTC (permalink / raw) To: gnurou, ldewangan, swarren, thierry.reding, wsa Cc: LABBE Corentin, linux-i2c, linux-kernel, linux-tegra of_match_device could return NULL, and so cause a NULL pointer dereference later at line 809: i2c_dev->hw = match->data; Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com> --- drivers/i2c/busses/i2c-tegra.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c index a0522fc..c803551 100644 --- a/drivers/i2c/busses/i2c-tegra.c +++ b/drivers/i2c/busses/i2c-tegra.c @@ -806,7 +806,10 @@ static int tegra_i2c_probe(struct platform_device *pdev) if (pdev->dev.of_node) { const struct of_device_id *match; + match = of_match_device(tegra_i2c_of_match, &pdev->dev); + if (!match) + return -ENODEV; i2c_dev->hw = match->data; i2c_dev->is_dvc = of_device_is_compatible(pdev->dev.of_node, "nvidia,tegra20-i2c-dvc"); -- 2.4.10 ^ permalink raw reply related [flat|nested] 18+ messages in thread
* Re: [PATCH] i2c: tegra: fix a possible NULL dereference 2015-11-12 7:26 [PATCH] i2c: tegra: fix a possible NULL dereference LABBE Corentin @ 2015-11-12 12:29 ` Thierry Reding 2015-11-12 12:54 ` LABBE Corentin 2015-11-12 13:40 ` Jon Hunter 0 siblings, 2 replies; 18+ messages in thread From: Thierry Reding @ 2015-11-12 12:29 UTC (permalink / raw) To: LABBE Corentin Cc: gnurou, ldewangan, swarren, wsa, linux-i2c, linux-kernel, linux-tegra [-- Attachment #1: Type: text/plain, Size: 1297 bytes --] On Thu, Nov 12, 2015 at 08:26:03AM +0100, LABBE Corentin wrote: > of_match_device could return NULL, and so cause a NULL pointer No. There is no way that of_match_device() can ever fail. The driver core uses the same table to match the OF device to the driver, so the only case where of_match_device() would return NULL is if no match was found, in which case the tegra_i2c_probe() function would never have been called in the first place. Thierry > dereference later at line 809: > i2c_dev->hw = match->data; > > Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com> > --- > drivers/i2c/busses/i2c-tegra.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c > index a0522fc..c803551 100644 > --- a/drivers/i2c/busses/i2c-tegra.c > +++ b/drivers/i2c/busses/i2c-tegra.c > @@ -806,7 +806,10 @@ static int tegra_i2c_probe(struct platform_device *pdev) > > if (pdev->dev.of_node) { > const struct of_device_id *match; > + > match = of_match_device(tegra_i2c_of_match, &pdev->dev); > + if (!match) > + return -ENODEV; > i2c_dev->hw = match->data; > i2c_dev->is_dvc = of_device_is_compatible(pdev->dev.of_node, > "nvidia,tegra20-i2c-dvc"); > -- > 2.4.10 > [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 819 bytes --] ^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] i2c: tegra: fix a possible NULL dereference 2015-11-12 12:29 ` Thierry Reding @ 2015-11-12 12:54 ` LABBE Corentin 2015-11-12 13:28 ` Thierry Reding 2015-11-12 13:40 ` Jon Hunter 1 sibling, 1 reply; 18+ messages in thread From: LABBE Corentin @ 2015-11-12 12:54 UTC (permalink / raw) To: Thierry Reding Cc: LABBE Corentin, gnurou, ldewangan, swarren, wsa, linux-i2c, linux-kernel, linux-tegra On Thu, Nov 12, 2015 at 01:29:23PM +0100, Thierry Reding wrote: > On Thu, Nov 12, 2015 at 08:26:03AM +0100, LABBE Corentin wrote: > > of_match_device could return NULL, and so cause a NULL pointer > > No. There is no way that of_match_device() can ever fail. The driver > core uses the same table to match the OF device to the driver, so the > only case where of_match_device() would return NULL is if no match was > found, in which case the tegra_i2c_probe() function would never have > been called in the first place. > > Thierry > In a parallel thread for i2c-rcar, the conclusion was different. https://lkml.org/lkml/2015/11/12/83 Regards ^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] i2c: tegra: fix a possible NULL dereference 2015-11-12 12:54 ` LABBE Corentin @ 2015-11-12 13:28 ` Thierry Reding 0 siblings, 0 replies; 18+ messages in thread From: Thierry Reding @ 2015-11-12 13:28 UTC (permalink / raw) To: LABBE Corentin Cc: LABBE Corentin, gnurou-Re5JQEeQqe8AvxtiuMwx3w, ldewangan-DDmLM1+adcrQT0dZR+AlfA, swarren-3lzwWm7+Weoh9ZMKESR00Q, wsa-z923LK4zBo2bacvFa/9K2g, linux-i2c-u79uwXL29TY76Z2rM5mHXA, linux-kernel-u79uwXL29TY76Z2rM5mHXA, linux-tegra-u79uwXL29TY76Z2rM5mHXA [-- Attachment #1: Type: text/plain, Size: 1218 bytes --] On Thu, Nov 12, 2015 at 01:54:22PM +0100, LABBE Corentin wrote: > On Thu, Nov 12, 2015 at 01:29:23PM +0100, Thierry Reding wrote: > > On Thu, Nov 12, 2015 at 08:26:03AM +0100, LABBE Corentin wrote: > > > of_match_device could return NULL, and so cause a NULL pointer > > > > No. There is no way that of_match_device() can ever fail. The driver > > core uses the same table to match the OF device to the driver, so the > > only case where of_match_device() would return NULL is if no match was > > found, in which case the tegra_i2c_probe() function would never have > > been called in the first place. > > > > Thierry > > > > In a parallel thread for i2c-rcar, the conclusion was different. > https://lkml.org/lkml/2015/11/12/83 The conclusion was the same: there should be no case where this happens. The example that Uwe gave is hypothetical and not valid DT in the first place. So instead of chickening out I think it'd be better to just crash to make sure people fix the DT. On a side-note I think that platform_match() should be stricter and do something like this instead: if (dev->of_node) { if (of_driver_match_device(dev, drv)) return 1; return 0; } Thierry [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 819 bytes --] ^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] i2c: tegra: fix a possible NULL dereference @ 2015-11-12 13:28 ` Thierry Reding 0 siblings, 0 replies; 18+ messages in thread From: Thierry Reding @ 2015-11-12 13:28 UTC (permalink / raw) To: LABBE Corentin Cc: LABBE Corentin, gnurou, ldewangan, swarren, wsa, linux-i2c, linux-kernel, linux-tegra [-- Attachment #1: Type: text/plain, Size: 1218 bytes --] On Thu, Nov 12, 2015 at 01:54:22PM +0100, LABBE Corentin wrote: > On Thu, Nov 12, 2015 at 01:29:23PM +0100, Thierry Reding wrote: > > On Thu, Nov 12, 2015 at 08:26:03AM +0100, LABBE Corentin wrote: > > > of_match_device could return NULL, and so cause a NULL pointer > > > > No. There is no way that of_match_device() can ever fail. The driver > > core uses the same table to match the OF device to the driver, so the > > only case where of_match_device() would return NULL is if no match was > > found, in which case the tegra_i2c_probe() function would never have > > been called in the first place. > > > > Thierry > > > > In a parallel thread for i2c-rcar, the conclusion was different. > https://lkml.org/lkml/2015/11/12/83 The conclusion was the same: there should be no case where this happens. The example that Uwe gave is hypothetical and not valid DT in the first place. So instead of chickening out I think it'd be better to just crash to make sure people fix the DT. On a side-note I think that platform_match() should be stricter and do something like this instead: if (dev->of_node) { if (of_driver_match_device(dev, drv)) return 1; return 0; } Thierry [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 819 bytes --] ^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] i2c: tegra: fix a possible NULL dereference 2015-11-12 13:28 ` Thierry Reding (?) @ 2015-11-12 13:45 ` Uwe Kleine-König [not found] ` <20151112134519.GJ24008-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> -1 siblings, 1 reply; 18+ messages in thread From: Uwe Kleine-König @ 2015-11-12 13:45 UTC (permalink / raw) To: Thierry Reding Cc: LABBE Corentin, LABBE Corentin, gnurou, ldewangan, swarren, wsa, linux-i2c, linux-kernel, linux-tegra On Thu, Nov 12, 2015 at 02:28:37PM +0100, Thierry Reding wrote: > On Thu, Nov 12, 2015 at 01:54:22PM +0100, LABBE Corentin wrote: > > On Thu, Nov 12, 2015 at 01:29:23PM +0100, Thierry Reding wrote: > > > On Thu, Nov 12, 2015 at 08:26:03AM +0100, LABBE Corentin wrote: > > > > of_match_device could return NULL, and so cause a NULL pointer > > > > > > No. There is no way that of_match_device() can ever fail. The driver > > > core uses the same table to match the OF device to the driver, so the > > > only case where of_match_device() would return NULL is if no match was > > > found, in which case the tegra_i2c_probe() function would never have > > > been called in the first place. > > > > > > Thierry > > > > > > > In a parallel thread for i2c-rcar, the conclusion was different. > > https://lkml.org/lkml/2015/11/12/83 > > The conclusion was the same: there should be no case where this happens. > The example that Uwe gave is hypothetical and not valid DT in the first > place. So instead of chickening out I think it'd be better to just crash > to make sure people fix the DT. It depends in your trust in the DT. Just because it's not advisable to do something that is not documented usually isn't a good excuse to not handle broken input. That't the case for webserver requests, arguments to system calls and several more. I admit DT is a bit special because you have to assume it's trusted, but still handling errors in a sane way is IMHO nice. > On a side-note I think that platform_match() should be stricter and do > something like this instead: > > if (dev->of_node) { > if (of_driver_match_device(dev, drv)) > return 1; > > return 0; > } That's equivalent to if (dev->of_node) return of_driver_match_device(dev, drv); and was already suggested in the thread referenced from my reply to http://article.gmane.org/gmane.linux.kernel/2083641 :-) Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | ^ permalink raw reply [flat|nested] 18+ messages in thread
[parent not found: <20151112134519.GJ24008-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>]
* Re: [PATCH] i2c: tegra: fix a possible NULL dereference 2015-11-12 13:45 ` Uwe Kleine-König @ 2015-11-12 13:55 ` Thierry Reding 0 siblings, 0 replies; 18+ messages in thread From: Thierry Reding @ 2015-11-12 13:55 UTC (permalink / raw) To: Uwe Kleine-König Cc: LABBE Corentin, LABBE Corentin, gnurou-Re5JQEeQqe8AvxtiuMwx3w, ldewangan-DDmLM1+adcrQT0dZR+AlfA, swarren-3lzwWm7+Weoh9ZMKESR00Q, wsa-z923LK4zBo2bacvFa/9K2g, linux-i2c-u79uwXL29TY76Z2rM5mHXA, linux-kernel-u79uwXL29TY76Z2rM5mHXA, linux-tegra-u79uwXL29TY76Z2rM5mHXA [-- Attachment #1: Type: text/plain, Size: 2632 bytes --] On Thu, Nov 12, 2015 at 02:45:20PM +0100, Uwe Kleine-König wrote: > On Thu, Nov 12, 2015 at 02:28:37PM +0100, Thierry Reding wrote: > > On Thu, Nov 12, 2015 at 01:54:22PM +0100, LABBE Corentin wrote: > > > On Thu, Nov 12, 2015 at 01:29:23PM +0100, Thierry Reding wrote: > > > > On Thu, Nov 12, 2015 at 08:26:03AM +0100, LABBE Corentin wrote: > > > > > of_match_device could return NULL, and so cause a NULL pointer > > > > > > > > No. There is no way that of_match_device() can ever fail. The driver > > > > core uses the same table to match the OF device to the driver, so the > > > > only case where of_match_device() would return NULL is if no match was > > > > found, in which case the tegra_i2c_probe() function would never have > > > > been called in the first place. > > > > > > > > Thierry > > > > > > > > > > In a parallel thread for i2c-rcar, the conclusion was different. > > > https://lkml.org/lkml/2015/11/12/83 > > > > The conclusion was the same: there should be no case where this happens. > > The example that Uwe gave is hypothetical and not valid DT in the first > > place. So instead of chickening out I think it'd be better to just crash > > to make sure people fix the DT. > > It depends in your trust in the DT. Just because it's not advisable to > do something that is not documented usually isn't a good excuse to not > handle broken input. That't the case for webserver requests, arguments > to system calls and several more. I admit DT is a bit special because > you have to assume it's trusted, but still handling errors in a sane way > is IMHO nice. Given that it's supposed to be provided by firmware and possibly from a ROM, crashing might be a better motivation for fixing it than erroring out, which people might just ignore or not notice until it's too late. > > On a side-note I think that platform_match() should be stricter and do > > something like this instead: > > > > if (dev->of_node) { > > if (of_driver_match_device(dev, drv)) > > return 1; > > > > return 0; > > } > That's equivalent to > > if (dev->of_node) > return of_driver_match_device(dev, drv); > > and was already suggested in the thread referenced from my reply to > http://article.gmane.org/gmane.linux.kernel/2083641 :-) Ah, too many cross-reference =) FWIW: Acked-by: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> If we want to gracefully handle this, then let's do it in the core by making sure that drivers where it would return NULL are never probed, rather than coding this check in every single driver. Thierry [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 819 bytes --] ^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] i2c: tegra: fix a possible NULL dereference @ 2015-11-12 13:55 ` Thierry Reding 0 siblings, 0 replies; 18+ messages in thread From: Thierry Reding @ 2015-11-12 13:55 UTC (permalink / raw) To: Uwe Kleine-König Cc: LABBE Corentin, LABBE Corentin, gnurou, ldewangan, swarren, wsa, linux-i2c, linux-kernel, linux-tegra [-- Attachment #1: Type: text/plain, Size: 2603 bytes --] On Thu, Nov 12, 2015 at 02:45:20PM +0100, Uwe Kleine-König wrote: > On Thu, Nov 12, 2015 at 02:28:37PM +0100, Thierry Reding wrote: > > On Thu, Nov 12, 2015 at 01:54:22PM +0100, LABBE Corentin wrote: > > > On Thu, Nov 12, 2015 at 01:29:23PM +0100, Thierry Reding wrote: > > > > On Thu, Nov 12, 2015 at 08:26:03AM +0100, LABBE Corentin wrote: > > > > > of_match_device could return NULL, and so cause a NULL pointer > > > > > > > > No. There is no way that of_match_device() can ever fail. The driver > > > > core uses the same table to match the OF device to the driver, so the > > > > only case where of_match_device() would return NULL is if no match was > > > > found, in which case the tegra_i2c_probe() function would never have > > > > been called in the first place. > > > > > > > > Thierry > > > > > > > > > > In a parallel thread for i2c-rcar, the conclusion was different. > > > https://lkml.org/lkml/2015/11/12/83 > > > > The conclusion was the same: there should be no case where this happens. > > The example that Uwe gave is hypothetical and not valid DT in the first > > place. So instead of chickening out I think it'd be better to just crash > > to make sure people fix the DT. > > It depends in your trust in the DT. Just because it's not advisable to > do something that is not documented usually isn't a good excuse to not > handle broken input. That't the case for webserver requests, arguments > to system calls and several more. I admit DT is a bit special because > you have to assume it's trusted, but still handling errors in a sane way > is IMHO nice. Given that it's supposed to be provided by firmware and possibly from a ROM, crashing might be a better motivation for fixing it than erroring out, which people might just ignore or not notice until it's too late. > > On a side-note I think that platform_match() should be stricter and do > > something like this instead: > > > > if (dev->of_node) { > > if (of_driver_match_device(dev, drv)) > > return 1; > > > > return 0; > > } > That's equivalent to > > if (dev->of_node) > return of_driver_match_device(dev, drv); > > and was already suggested in the thread referenced from my reply to > http://article.gmane.org/gmane.linux.kernel/2083641 :-) Ah, too many cross-reference =) FWIW: Acked-by: Thierry Reding <treding@nvidia.com> If we want to gracefully handle this, then let's do it in the core by making sure that drivers where it would return NULL are never probed, rather than coding this check in every single driver. Thierry [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 819 bytes --] ^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] i2c: tegra: fix a possible NULL dereference 2015-11-12 13:55 ` Thierry Reding (?) @ 2015-11-12 14:54 ` LABBE Corentin 2015-11-12 16:14 ` Thierry Reding 2016-01-23 11:07 ` Wolfram Sang -1 siblings, 2 replies; 18+ messages in thread From: LABBE Corentin @ 2015-11-12 14:54 UTC (permalink / raw) To: Thierry Reding Cc: Uwe Kleine-König, LABBE Corentin, gnurou, ldewangan, swarren, wsa, linux-i2c, linux-kernel, linux-tegra On Thu, Nov 12, 2015 at 02:55:00PM +0100, Thierry Reding wrote: > On Thu, Nov 12, 2015 at 02:45:20PM +0100, Uwe Kleine-König wrote: > > On Thu, Nov 12, 2015 at 02:28:37PM +0100, Thierry Reding wrote: > > > On Thu, Nov 12, 2015 at 01:54:22PM +0100, LABBE Corentin wrote: > > > > On Thu, Nov 12, 2015 at 01:29:23PM +0100, Thierry Reding wrote: > > > > > On Thu, Nov 12, 2015 at 08:26:03AM +0100, LABBE Corentin wrote: > > > > > > of_match_device could return NULL, and so cause a NULL pointer > > > > > > > > > > No. There is no way that of_match_device() can ever fail. The driver > > > > > core uses the same table to match the OF device to the driver, so the > > > > > only case where of_match_device() would return NULL is if no match was > > > > > found, in which case the tegra_i2c_probe() function would never have > > > > > been called in the first place. > > > > > > > > > > Thierry > > > > > > > > > > > > > In a parallel thread for i2c-rcar, the conclusion was different. > > > > https://lkml.org/lkml/2015/11/12/83 > > > > > > The conclusion was the same: there should be no case where this happens. > > > The example that Uwe gave is hypothetical and not valid DT in the first > > > place. So instead of chickening out I think it'd be better to just crash > > > to make sure people fix the DT. > > > > It depends in your trust in the DT. Just because it's not advisable to > > do something that is not documented usually isn't a good excuse to not > > handle broken input. That't the case for webserver requests, arguments > > to system calls and several more. I admit DT is a bit special because > > you have to assume it's trusted, but still handling errors in a sane way > > is IMHO nice. > > Given that it's supposed to be provided by firmware and possibly from a > ROM, crashing might be a better motivation for fixing it than erroring > out, which people might just ignore or not notice until it's too late. > > > > On a side-note I think that platform_match() should be stricter and do > > > something like this instead: > > > > > > if (dev->of_node) { > > > if (of_driver_match_device(dev, drv)) > > > return 1; > > > > > > return 0; > > > } > > That's equivalent to > > > > if (dev->of_node) > > return of_driver_match_device(dev, drv); > > > > and was already suggested in the thread referenced from my reply to > > http://article.gmane.org/gmane.linux.kernel/2083641 :-) > > Ah, too many cross-reference =) FWIW: > > Acked-by: Thierry Reding <treding@nvidia.com> > Just for be sure, since the thread goes in lot of direction, you ack my patch ? Perhaps is it better that I resent a version which use of_device_get_match_data() ? Regards ^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] i2c: tegra: fix a possible NULL dereference 2015-11-12 14:54 ` LABBE Corentin @ 2015-11-12 16:14 ` Thierry Reding 2016-01-23 11:07 ` Wolfram Sang 1 sibling, 0 replies; 18+ messages in thread From: Thierry Reding @ 2015-11-12 16:14 UTC (permalink / raw) To: LABBE Corentin Cc: Uwe Kleine-König, LABBE Corentin, gnurou-Re5JQEeQqe8AvxtiuMwx3w, ldewangan-DDmLM1+adcrQT0dZR+AlfA, swarren-3lzwWm7+Weoh9ZMKESR00Q, wsa-z923LK4zBo2bacvFa/9K2g, linux-i2c-u79uwXL29TY76Z2rM5mHXA, linux-kernel-u79uwXL29TY76Z2rM5mHXA, linux-tegra-u79uwXL29TY76Z2rM5mHXA [-- Attachment #1: Type: text/plain, Size: 3249 bytes --] On Thu, Nov 12, 2015 at 03:54:58PM +0100, LABBE Corentin wrote: > On Thu, Nov 12, 2015 at 02:55:00PM +0100, Thierry Reding wrote: > > On Thu, Nov 12, 2015 at 02:45:20PM +0100, Uwe Kleine-König wrote: > > > On Thu, Nov 12, 2015 at 02:28:37PM +0100, Thierry Reding wrote: > > > > On Thu, Nov 12, 2015 at 01:54:22PM +0100, LABBE Corentin wrote: > > > > > On Thu, Nov 12, 2015 at 01:29:23PM +0100, Thierry Reding wrote: > > > > > > On Thu, Nov 12, 2015 at 08:26:03AM +0100, LABBE Corentin wrote: > > > > > > > of_match_device could return NULL, and so cause a NULL pointer > > > > > > > > > > > > No. There is no way that of_match_device() can ever fail. The driver > > > > > > core uses the same table to match the OF device to the driver, so the > > > > > > only case where of_match_device() would return NULL is if no match was > > > > > > found, in which case the tegra_i2c_probe() function would never have > > > > > > been called in the first place. > > > > > > > > > > > > Thierry > > > > > > > > > > > > > > > > In a parallel thread for i2c-rcar, the conclusion was different. > > > > > https://lkml.org/lkml/2015/11/12/83 > > > > > > > > The conclusion was the same: there should be no case where this happens. > > > > The example that Uwe gave is hypothetical and not valid DT in the first > > > > place. So instead of chickening out I think it'd be better to just crash > > > > to make sure people fix the DT. > > > > > > It depends in your trust in the DT. Just because it's not advisable to > > > do something that is not documented usually isn't a good excuse to not > > > handle broken input. That't the case for webserver requests, arguments > > > to system calls and several more. I admit DT is a bit special because > > > you have to assume it's trusted, but still handling errors in a sane way > > > is IMHO nice. > > > > Given that it's supposed to be provided by firmware and possibly from a > > ROM, crashing might be a better motivation for fixing it than erroring > > out, which people might just ignore or not notice until it's too late. > > > > > > On a side-note I think that platform_match() should be stricter and do > > > > something like this instead: > > > > > > > > if (dev->of_node) { > > > > if (of_driver_match_device(dev, drv)) > > > > return 1; > > > > > > > > return 0; > > > > } > > > That's equivalent to > > > > > > if (dev->of_node) > > > return of_driver_match_device(dev, drv); > > > > > > and was already suggested in the thread referenced from my reply to > > > http://article.gmane.org/gmane.linux.kernel/2083641 :-) > > > > Ah, too many cross-reference =) FWIW: > > > > Acked-by: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> > > > > Just for be sure, since the thread goes in lot of direction, you ack my patch ? > Perhaps is it better that I resent a version which use of_device_get_match_data() ? No, the Acked-by was for Uwe's proposal to modify platform_match(). I think if we want to gracefully handle these cases, then the right way to do so is by having the driver core not fallback to name matches for devices instantiated from device tree. Sorry for being unclear. Thierry [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 819 bytes --] ^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] i2c: tegra: fix a possible NULL dereference @ 2015-11-12 16:14 ` Thierry Reding 0 siblings, 0 replies; 18+ messages in thread From: Thierry Reding @ 2015-11-12 16:14 UTC (permalink / raw) To: LABBE Corentin Cc: Uwe Kleine-König, LABBE Corentin, gnurou, ldewangan, swarren, wsa, linux-i2c, linux-kernel, linux-tegra [-- Attachment #1: Type: text/plain, Size: 3220 bytes --] On Thu, Nov 12, 2015 at 03:54:58PM +0100, LABBE Corentin wrote: > On Thu, Nov 12, 2015 at 02:55:00PM +0100, Thierry Reding wrote: > > On Thu, Nov 12, 2015 at 02:45:20PM +0100, Uwe Kleine-König wrote: > > > On Thu, Nov 12, 2015 at 02:28:37PM +0100, Thierry Reding wrote: > > > > On Thu, Nov 12, 2015 at 01:54:22PM +0100, LABBE Corentin wrote: > > > > > On Thu, Nov 12, 2015 at 01:29:23PM +0100, Thierry Reding wrote: > > > > > > On Thu, Nov 12, 2015 at 08:26:03AM +0100, LABBE Corentin wrote: > > > > > > > of_match_device could return NULL, and so cause a NULL pointer > > > > > > > > > > > > No. There is no way that of_match_device() can ever fail. The driver > > > > > > core uses the same table to match the OF device to the driver, so the > > > > > > only case where of_match_device() would return NULL is if no match was > > > > > > found, in which case the tegra_i2c_probe() function would never have > > > > > > been called in the first place. > > > > > > > > > > > > Thierry > > > > > > > > > > > > > > > > In a parallel thread for i2c-rcar, the conclusion was different. > > > > > https://lkml.org/lkml/2015/11/12/83 > > > > > > > > The conclusion was the same: there should be no case where this happens. > > > > The example that Uwe gave is hypothetical and not valid DT in the first > > > > place. So instead of chickening out I think it'd be better to just crash > > > > to make sure people fix the DT. > > > > > > It depends in your trust in the DT. Just because it's not advisable to > > > do something that is not documented usually isn't a good excuse to not > > > handle broken input. That't the case for webserver requests, arguments > > > to system calls and several more. I admit DT is a bit special because > > > you have to assume it's trusted, but still handling errors in a sane way > > > is IMHO nice. > > > > Given that it's supposed to be provided by firmware and possibly from a > > ROM, crashing might be a better motivation for fixing it than erroring > > out, which people might just ignore or not notice until it's too late. > > > > > > On a side-note I think that platform_match() should be stricter and do > > > > something like this instead: > > > > > > > > if (dev->of_node) { > > > > if (of_driver_match_device(dev, drv)) > > > > return 1; > > > > > > > > return 0; > > > > } > > > That's equivalent to > > > > > > if (dev->of_node) > > > return of_driver_match_device(dev, drv); > > > > > > and was already suggested in the thread referenced from my reply to > > > http://article.gmane.org/gmane.linux.kernel/2083641 :-) > > > > Ah, too many cross-reference =) FWIW: > > > > Acked-by: Thierry Reding <treding@nvidia.com> > > > > Just for be sure, since the thread goes in lot of direction, you ack my patch ? > Perhaps is it better that I resent a version which use of_device_get_match_data() ? No, the Acked-by was for Uwe's proposal to modify platform_match(). I think if we want to gracefully handle these cases, then the right way to do so is by having the driver core not fallback to name matches for devices instantiated from device tree. Sorry for being unclear. Thierry [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 819 bytes --] ^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] i2c: tegra: fix a possible NULL dereference 2015-11-12 14:54 ` LABBE Corentin @ 2016-01-23 11:07 ` Wolfram Sang 2016-01-23 11:07 ` Wolfram Sang 1 sibling, 0 replies; 18+ messages in thread From: Wolfram Sang @ 2016-01-23 11:07 UTC (permalink / raw) To: LABBE Corentin Cc: Thierry Reding, Uwe Kleine-König, LABBE Corentin, gnurou-Re5JQEeQqe8AvxtiuMwx3w, ldewangan-DDmLM1+adcrQT0dZR+AlfA, swarren-3lzwWm7+Weoh9ZMKESR00Q, linux-i2c-u79uwXL29TY76Z2rM5mHXA, linux-kernel-u79uwXL29TY76Z2rM5mHXA, linux-tegra-u79uwXL29TY76Z2rM5mHXA [-- Attachment #1: Type: text/plain, Size: 178 bytes --] > Perhaps is it better that I resent a version which use of_device_get_match_data() ? I'd like that for both of your patches anyhow. It is more concise and better to read IMO. [-- Attachment #2: Digital signature --] [-- Type: application/pgp-signature, Size: 819 bytes --] ^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] i2c: tegra: fix a possible NULL dereference @ 2016-01-23 11:07 ` Wolfram Sang 0 siblings, 0 replies; 18+ messages in thread From: Wolfram Sang @ 2016-01-23 11:07 UTC (permalink / raw) To: LABBE Corentin Cc: Thierry Reding, Uwe Kleine-König, LABBE Corentin, gnurou, ldewangan, swarren, linux-i2c, linux-kernel, linux-tegra [-- Attachment #1: Type: text/plain, Size: 178 bytes --] > Perhaps is it better that I resent a version which use of_device_get_match_data() ? I'd like that for both of your patches anyhow. It is more concise and better to read IMO. [-- Attachment #2: Digital signature --] [-- Type: application/pgp-signature, Size: 819 bytes --] ^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] i2c: tegra: fix a possible NULL dereference 2015-11-12 13:45 ` Uwe Kleine-König @ 2016-01-23 10:56 ` Wolfram Sang 0 siblings, 0 replies; 18+ messages in thread From: Wolfram Sang @ 2016-01-23 10:56 UTC (permalink / raw) To: Uwe Kleine-König Cc: Thierry Reding, LABBE Corentin, LABBE Corentin, gnurou-Re5JQEeQqe8AvxtiuMwx3w, ldewangan-DDmLM1+adcrQT0dZR+AlfA, swarren-3lzwWm7+Weoh9ZMKESR00Q, linux-i2c-u79uwXL29TY76Z2rM5mHXA, linux-kernel-u79uwXL29TY76Z2rM5mHXA, linux-tegra-u79uwXL29TY76Z2rM5mHXA [-- Attachment #1: Type: text/plain, Size: 444 bytes --] Hi Uwe, > That's equivalent to > > if (dev->of_node) > return of_driver_match_device(dev, drv); > > and was already suggested in the thread referenced from my reply to > http://article.gmane.org/gmane.linux.kernel/2083641 :-) Did you make a proper patch out of it? Can't find it, though I also think this would be useful. Acked-by: Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org> All the best, Wolfram [-- Attachment #2: Digital signature --] [-- Type: application/pgp-signature, Size: 819 bytes --] ^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] i2c: tegra: fix a possible NULL dereference @ 2016-01-23 10:56 ` Wolfram Sang 0 siblings, 0 replies; 18+ messages in thread From: Wolfram Sang @ 2016-01-23 10:56 UTC (permalink / raw) To: Uwe Kleine-König Cc: Thierry Reding, LABBE Corentin, LABBE Corentin, gnurou, ldewangan, swarren, linux-i2c, linux-kernel, linux-tegra [-- Attachment #1: Type: text/plain, Size: 418 bytes --] Hi Uwe, > That's equivalent to > > if (dev->of_node) > return of_driver_match_device(dev, drv); > > and was already suggested in the thread referenced from my reply to > http://article.gmane.org/gmane.linux.kernel/2083641 :-) Did you make a proper patch out of it? Can't find it, though I also think this would be useful. Acked-by: Wolfram Sang <wsa@the-dreams.de> All the best, Wolfram [-- Attachment #2: Digital signature --] [-- Type: application/pgp-signature, Size: 819 bytes --] ^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] i2c: tegra: fix a possible NULL dereference 2015-11-12 12:29 ` Thierry Reding @ 2015-11-12 13:40 ` Jon Hunter 2015-11-12 13:40 ` Jon Hunter 1 sibling, 0 replies; 18+ messages in thread From: Jon Hunter @ 2015-11-12 13:40 UTC (permalink / raw) To: Thierry Reding, LABBE Corentin Cc: gnurou-Re5JQEeQqe8AvxtiuMwx3w, ldewangan-DDmLM1+adcrQT0dZR+AlfA, swarren-3lzwWm7+Weoh9ZMKESR00Q, wsa-z923LK4zBo2bacvFa/9K2g, linux-i2c-u79uwXL29TY76Z2rM5mHXA, linux-kernel-u79uwXL29TY76Z2rM5mHXA, linux-tegra-u79uwXL29TY76Z2rM5mHXA On 12/11/15 12:29, Thierry Reding wrote: > * PGP Signed by an unknown key > > On Thu, Nov 12, 2015 at 08:26:03AM +0100, LABBE Corentin wrote: >> of_match_device could return NULL, and so cause a NULL pointer > > No. There is no way that of_match_device() can ever fail. The driver > core uses the same table to match the OF device to the driver, so the > only case where of_match_device() would return NULL is if no match was > found, in which case the tegra_i2c_probe() function would never have > been called in the first place. Right and so ... >> dereference later at line 809: >> i2c_dev->hw = match->data; >> >> Signed-off-by: LABBE Corentin <clabbe.montjoie-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> >> --- >> drivers/i2c/busses/i2c-tegra.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c >> index a0522fc..c803551 100644 >> --- a/drivers/i2c/busses/i2c-tegra.c >> +++ b/drivers/i2c/busses/i2c-tegra.c >> @@ -806,7 +806,10 @@ static int tegra_i2c_probe(struct platform_device *pdev) >> >> if (pdev->dev.of_node) { Can we get rid of this if-statement? Jon ^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] i2c: tegra: fix a possible NULL dereference @ 2015-11-12 13:40 ` Jon Hunter 0 siblings, 0 replies; 18+ messages in thread From: Jon Hunter @ 2015-11-12 13:40 UTC (permalink / raw) To: Thierry Reding, LABBE Corentin Cc: gnurou, ldewangan, swarren, wsa, linux-i2c, linux-kernel, linux-tegra On 12/11/15 12:29, Thierry Reding wrote: > * PGP Signed by an unknown key > > On Thu, Nov 12, 2015 at 08:26:03AM +0100, LABBE Corentin wrote: >> of_match_device could return NULL, and so cause a NULL pointer > > No. There is no way that of_match_device() can ever fail. The driver > core uses the same table to match the OF device to the driver, so the > only case where of_match_device() would return NULL is if no match was > found, in which case the tegra_i2c_probe() function would never have > been called in the first place. Right and so ... >> dereference later at line 809: >> i2c_dev->hw = match->data; >> >> Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com> >> --- >> drivers/i2c/busses/i2c-tegra.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c >> index a0522fc..c803551 100644 >> --- a/drivers/i2c/busses/i2c-tegra.c >> +++ b/drivers/i2c/busses/i2c-tegra.c >> @@ -806,7 +806,10 @@ static int tegra_i2c_probe(struct platform_device *pdev) >> >> if (pdev->dev.of_node) { Can we get rid of this if-statement? Jon ^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: [PATCH] i2c: tegra: fix a possible NULL dereference 2015-11-12 13:40 ` Jon Hunter (?) @ 2015-11-12 13:55 ` Thierry Reding -1 siblings, 0 replies; 18+ messages in thread From: Thierry Reding @ 2015-11-12 13:55 UTC (permalink / raw) To: Jon Hunter Cc: LABBE Corentin, gnurou, ldewangan, swarren, wsa, linux-i2c, linux-kernel, linux-tegra [-- Attachment #1: Type: text/plain, Size: 1386 bytes --] On Thu, Nov 12, 2015 at 01:40:56PM +0000, Jon Hunter wrote: > > On 12/11/15 12:29, Thierry Reding wrote: > > * PGP Signed by an unknown key > > > > On Thu, Nov 12, 2015 at 08:26:03AM +0100, LABBE Corentin wrote: > >> of_match_device could return NULL, and so cause a NULL pointer > > > > No. There is no way that of_match_device() can ever fail. The driver > > core uses the same table to match the OF device to the driver, so the > > only case where of_match_device() would return NULL is if no match was > > found, in which case the tegra_i2c_probe() function would never have > > been called in the first place. > > Right and so ... > > >> dereference later at line 809: > >> i2c_dev->hw = match->data; > >> > >> Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com> > >> --- > >> drivers/i2c/busses/i2c-tegra.c | 3 +++ > >> 1 file changed, 3 insertions(+) > >> > >> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c > >> index a0522fc..c803551 100644 > >> --- a/drivers/i2c/busses/i2c-tegra.c > >> +++ b/drivers/i2c/busses/i2c-tegra.c > >> @@ -806,7 +806,10 @@ static int tegra_i2c_probe(struct platform_device *pdev) > >> > >> if (pdev->dev.of_node) { > > Can we get rid of this if-statement? Yeah, I guess we can drop that, too. It's been a long time since Tegra was converted to OF only. Thierry [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 819 bytes --] ^ permalink raw reply [flat|nested] 18+ messages in thread
end of thread, other threads:[~2016-01-23 11:07 UTC | newest] Thread overview: 18+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2015-11-12 7:26 [PATCH] i2c: tegra: fix a possible NULL dereference LABBE Corentin 2015-11-12 12:29 ` Thierry Reding 2015-11-12 12:54 ` LABBE Corentin 2015-11-12 13:28 ` Thierry Reding 2015-11-12 13:28 ` Thierry Reding 2015-11-12 13:45 ` Uwe Kleine-König [not found] ` <20151112134519.GJ24008-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> 2015-11-12 13:55 ` Thierry Reding 2015-11-12 13:55 ` Thierry Reding 2015-11-12 14:54 ` LABBE Corentin 2015-11-12 16:14 ` Thierry Reding 2015-11-12 16:14 ` Thierry Reding 2016-01-23 11:07 ` Wolfram Sang 2016-01-23 11:07 ` Wolfram Sang 2016-01-23 10:56 ` Wolfram Sang 2016-01-23 10:56 ` Wolfram Sang 2015-11-12 13:40 ` Jon Hunter 2015-11-12 13:40 ` Jon Hunter 2015-11-12 13:55 ` Thierry Reding
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