| Message ID | 1543741258-17433-1-git-send-email-hofrat@osadl.org (mailing list archive) |
|---|---|
| State | RFC |
| Headers | show |
| Series | [RFC] soc: fsl: guts: handle devm_kstrdup() failure | expand |
On Sun, Dec 2, 2018 at 3:07 AM Nicholas Mc Guire <hofrat@osadl.org> wrote: > > devm_kstrdup() may return NULL if internal allocation failed. > soc_dev_attr.machine should be checked (although its only use > in pr_info() would be safe even with a NULL). Therefor > in the unlikely case of allocation failure, fsl_guts_probe() returns > -ENOMEM as this allocating failing is an indication of something > more serious going wrong at system level. > > As machine is from the device tree which I assume to be RO - if > that assumption is always correct - a better alternative would be > to use devm_kstrdup_const() here. That would then simply copy the > reference to the RO data and not perform any allocation at all. I think your assumption is correct. Do you want to send a new and better version? :) > > Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org> > Fixes: a6fc3b698130 ("soc: fsl: add GUTS driver for QorIQ platforms") > --- > > Problem located by experimental coccinelle script > > Patch was compile tested with: multi_v7_defconfig (implies FSL_GUTS=y) > > Patch is against 4.20-rc4 (localversion-next is next-20181130) > > drivers/soc/fsl/guts.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/soc/fsl/guts.c b/drivers/soc/fsl/guts.c > index 302e0c8..a0c751b 100644 > --- a/drivers/soc/fsl/guts.c > +++ b/drivers/soc/fsl/guts.c > @@ -156,8 +156,11 @@ static int fsl_guts_probe(struct platform_device *pdev) > if (of_property_read_string(root, "model", &machine)) > of_property_read_string_index(root, "compatible", 0, &machine); > of_node_put(root); > - if (machine) > + if (machine) { > soc_dev_attr.machine = devm_kstrdup(dev, machine, GFP_KERNEL); > + if (!soc_dev_attr.machine) > + return -ENOMEM; > + } > > svr = fsl_guts_get_svr(); > soc_die = fsl_soc_die_match(svr, fsl_soc_die); > -- > 2.1.4 >
On Wed, Dec 05, 2018 at 02:42:55PM -0600, Li Yang wrote: > On Sun, Dec 2, 2018 at 3:07 AM Nicholas Mc Guire <hofrat@osadl.org> wrote: > > > > devm_kstrdup() may return NULL if internal allocation failed. > > soc_dev_attr.machine should be checked (although its only use > > in pr_info() would be safe even with a NULL). Therefor > > in the unlikely case of allocation failure, fsl_guts_probe() returns > > -ENOMEM as this allocating failing is an indication of something > > more serious going wrong at system level. > > > > As machine is from the device tree which I assume to be RO - if > > that assumption is always correct - a better alternative would be > > to use devm_kstrdup_const() here. That would then simply copy the > > reference to the RO data and not perform any allocation at all. > > I think your assumption is correct. Do you want to send a new and > better version? :) The issue was actually more general that I did not find a reliable method to assure that some object is *always* RO. Even for device tree data it was not clear to me if there could be systems where it is not RO. Anyway - will send the version using devm_kstrdup_const() then. thx! hofrat > > > > > Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org> > > Fixes: a6fc3b698130 ("soc: fsl: add GUTS driver for QorIQ platforms") > > --- > > > > Problem located by experimental coccinelle script > > > > Patch was compile tested with: multi_v7_defconfig (implies FSL_GUTS=y) > > > > Patch is against 4.20-rc4 (localversion-next is next-20181130) > > > > drivers/soc/fsl/guts.c | 5 ++++- > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/soc/fsl/guts.c b/drivers/soc/fsl/guts.c > > index 302e0c8..a0c751b 100644 > > --- a/drivers/soc/fsl/guts.c > > +++ b/drivers/soc/fsl/guts.c > > @@ -156,8 +156,11 @@ static int fsl_guts_probe(struct platform_device *pdev) > > if (of_property_read_string(root, "model", &machine)) > > of_property_read_string_index(root, "compatible", 0, &machine); > > of_node_put(root); > > - if (machine) > > + if (machine) { > > soc_dev_attr.machine = devm_kstrdup(dev, machine, GFP_KERNEL); > > + if (!soc_dev_attr.machine) > > + return -ENOMEM; > > + } > > > > svr = fsl_guts_get_svr(); > > soc_die = fsl_soc_die_match(svr, fsl_soc_die); > > -- > > 2.1.4 > >
diff --git a/drivers/soc/fsl/guts.c b/drivers/soc/fsl/guts.c index 302e0c8..a0c751b 100644 --- a/drivers/soc/fsl/guts.c +++ b/drivers/soc/fsl/guts.c @@ -156,8 +156,11 @@ static int fsl_guts_probe(struct platform_device *pdev) if (of_property_read_string(root, "model", &machine)) of_property_read_string_index(root, "compatible", 0, &machine); of_node_put(root); - if (machine) + if (machine) { soc_dev_attr.machine = devm_kstrdup(dev, machine, GFP_KERNEL); + if (!soc_dev_attr.machine) + return -ENOMEM; + } svr = fsl_guts_get_svr(); soc_die = fsl_soc_die_match(svr, fsl_soc_die);
devm_kstrdup() may return NULL if internal allocation failed. soc_dev_attr.machine should be checked (although its only use in pr_info() would be safe even with a NULL). Therefor in the unlikely case of allocation failure, fsl_guts_probe() returns -ENOMEM as this allocating failing is an indication of something more serious going wrong at system level. As machine is from the device tree which I assume to be RO - if that assumption is always correct - a better alternative would be to use devm_kstrdup_const() here. That would then simply copy the reference to the RO data and not perform any allocation at all. Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org> Fixes: a6fc3b698130 ("soc: fsl: add GUTS driver for QorIQ platforms") --- Problem located by experimental coccinelle script Patch was compile tested with: multi_v7_defconfig (implies FSL_GUTS=y) Patch is against 4.20-rc4 (localversion-next is next-20181130) drivers/soc/fsl/guts.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)