| Message ID | 3b5c9b693749a956b525c54bed0eeac9f958b8e8.1641734402.git.christophe.jaillet@wanadoo.fr (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] fsi: Aspeed: Fix a potential double free | expand |
On 1/9/22 5:20 AM, Christophe JAILLET wrote: > A struct device can never be devm_alloc()'ed. > Here, it is embedded in "struct fsi_master", and "struct fsi_master" is > embedded in "struct fsi_master_aspeed". > > Since "struct device" is embedded, the data structure embedding it must be > released with the release function, as is already done here. > > So use kzalloc() instead of devm_kzalloc() when allocating "aspeed". > This prevent a potential double free(). > > Fixes: 606397d67f41 ("fsi: Add ast2600 master driver") > Suggested-by: Greg KH <gregkh@linuxfoundation.org> > Suggested-by: Guenter Roeck <linux@roeck-us.net> > Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> > --- > v2: Keep the release function which is correct > s/devm_kzalloc()/kzalloc()/ instead > --- > drivers/fsi/fsi-master-aspeed.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/fsi/fsi-master-aspeed.c b/drivers/fsi/fsi-master-aspeed.c > index 8606e55c1721..ae6319818b14 100644 > --- a/drivers/fsi/fsi-master-aspeed.c > +++ b/drivers/fsi/fsi-master-aspeed.c > @@ -542,7 +542,7 @@ static int fsi_master_aspeed_probe(struct platform_device *pdev) > return rc; > } > > - aspeed = devm_kzalloc(&pdev->dev, sizeof(*aspeed), GFP_KERNEL); > + aspeed = kzalloc(sizeof(*aspeed), GFP_KERNEL); Unfortunately it isn't that easy. error handling in the probe function must take this into account and free the memory. Looking at that exposes another bug: The failure in opb_readl() should not result in a direct return but disable and unprepare the clock. Guenter
diff --git a/drivers/fsi/fsi-master-aspeed.c b/drivers/fsi/fsi-master-aspeed.c index 8606e55c1721..ae6319818b14 100644 --- a/drivers/fsi/fsi-master-aspeed.c +++ b/drivers/fsi/fsi-master-aspeed.c @@ -542,7 +542,7 @@ static int fsi_master_aspeed_probe(struct platform_device *pdev) return rc; } - aspeed = devm_kzalloc(&pdev->dev, sizeof(*aspeed), GFP_KERNEL); + aspeed = kzalloc(sizeof(*aspeed), GFP_KERNEL); if (!aspeed) return -ENOMEM;
A struct device can never be devm_alloc()'ed. Here, it is embedded in "struct fsi_master", and "struct fsi_master" is embedded in "struct fsi_master_aspeed". Since "struct device" is embedded, the data structure embedding it must be released with the release function, as is already done here. So use kzalloc() instead of devm_kzalloc() when allocating "aspeed". This prevent a potential double free(). Fixes: 606397d67f41 ("fsi: Add ast2600 master driver") Suggested-by: Greg KH <gregkh@linuxfoundation.org> Suggested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> --- v2: Keep the release function which is correct s/devm_kzalloc()/kzalloc()/ instead --- drivers/fsi/fsi-master-aspeed.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)