| Message ID | 20230311214447.7359-1-linux@zary.sk |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] pata_parport: fix possible memory leak | expand |
On 3/12/23 06:44, Ondrej Zary wrote: > When ida_alloc() fails, "pi" is not freed although the misleading > comment says otherwise. > Move the ida_alloc() call up so we really don't have to free it. Certainly you meant: "so we really do free it in case of error.", no ? > > Reported-by: kernel test robot <lkp@intel.com> > Reported-by: Dan Carpenter <error27@gmail.com> > Link: https://lore.kernel.org/r/202303111822.IHNchbkp-lkp@intel.com/ > Signed-off-by: Ondrej Zary <linux@zary.sk> > --- > drivers/ata/pata_parport/pata_parport.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/drivers/ata/pata_parport/pata_parport.c b/drivers/ata/pata_parport/pata_parport.c > index 6165ee9aa7da..a9eff6003098 100644 > --- a/drivers/ata/pata_parport/pata_parport.c > +++ b/drivers/ata/pata_parport/pata_parport.c > @@ -503,18 +503,19 @@ static struct pi_adapter *pi_init_one(struct parport *parport, > if (bus_for_each_dev(&pata_parport_bus_type, NULL, &match, pi_find_dev)) > return NULL; > > + id = ida_alloc(&pata_parport_bus_dev_ids, GFP_KERNEL); > + if (id < 0) > + return NULL; > + > pi = kzalloc(sizeof(struct pi_adapter), GFP_KERNEL); > if (!pi) > - return NULL; > + goto out_ida_free; > > /* set up pi->dev before pi_probe_unit() so it can use dev_printk() */ > pi->dev.parent = &pata_parport_bus; > pi->dev.bus = &pata_parport_bus_type; > pi->dev.driver = &pr->driver; > pi->dev.release = pata_parport_dev_release; > - id = ida_alloc(&pata_parport_bus_dev_ids, GFP_KERNEL); > - if (id < 0) > - return NULL; /* pata_parport_dev_release will do kfree(pi) */ > pi->dev.id = id; > dev_set_name(&pi->dev, "pata_parport.%u", pi->dev.id); > if (device_register(&pi->dev)) { > @@ -571,7 +572,7 @@ static struct pi_adapter *pi_init_one(struct parport *parport, > out_unreg_dev: > device_unregister(&pi->dev); Same comment as Sergey: isn't this going to do the ida free ? So shouldn't you return here ? > out_ida_free: > - ida_free(&pata_parport_bus_dev_ids, pi->dev.id); > + ida_free(&pata_parport_bus_dev_ids, id); > return NULL; > } >
On Sunday 12 March 2023 01:56:25 Damien Le Moal wrote: > On 3/12/23 06:44, Ondrej Zary wrote: > > When ida_alloc() fails, "pi" is not freed although the misleading > > comment says otherwise. > > Move the ida_alloc() call up so we really don't have to free it. > > Certainly you meant: "so we really do free it in case of error.", no ? I meant "so we don't have to free pi in case of ida_alloc failure". > > > > Reported-by: kernel test robot <lkp@intel.com> > > Reported-by: Dan Carpenter <error27@gmail.com> > > Link: https://lore.kernel.org/r/202303111822.IHNchbkp-lkp@intel.com/ > > Signed-off-by: Ondrej Zary <linux@zary.sk> > > --- > > drivers/ata/pata_parport/pata_parport.c | 11 ++++++----- > > 1 file changed, 6 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/ata/pata_parport/pata_parport.c b/drivers/ata/pata_parport/pata_parport.c > > index 6165ee9aa7da..a9eff6003098 100644 > > --- a/drivers/ata/pata_parport/pata_parport.c > > +++ b/drivers/ata/pata_parport/pata_parport.c > > @@ -503,18 +503,19 @@ static struct pi_adapter *pi_init_one(struct parport *parport, > > if (bus_for_each_dev(&pata_parport_bus_type, NULL, &match, pi_find_dev)) > > return NULL; > > > > + id = ida_alloc(&pata_parport_bus_dev_ids, GFP_KERNEL); > > + if (id < 0) > > + return NULL; > > + > > pi = kzalloc(sizeof(struct pi_adapter), GFP_KERNEL); > > if (!pi) > > - return NULL; > > + goto out_ida_free; > > > > /* set up pi->dev before pi_probe_unit() so it can use dev_printk() */ > > pi->dev.parent = &pata_parport_bus; > > pi->dev.bus = &pata_parport_bus_type; > > pi->dev.driver = &pr->driver; > > pi->dev.release = pata_parport_dev_release; > > - id = ida_alloc(&pata_parport_bus_dev_ids, GFP_KERNEL); > > - if (id < 0) > > - return NULL; /* pata_parport_dev_release will do kfree(pi) */ > > pi->dev.id = id; > > dev_set_name(&pi->dev, "pata_parport.%u", pi->dev.id); > > if (device_register(&pi->dev)) { > > @@ -571,7 +572,7 @@ static struct pi_adapter *pi_init_one(struct parport *parport, > > out_unreg_dev: > > device_unregister(&pi->dev); > > Same comment as Sergey: isn't this going to do the ida free ? So shouldn't you > return here ? No. device_unregister() calls pata_parport_dev_release() which does only kfree(pi), not ida_free(). But it probably should do ida_free() too. > > > out_ida_free: > > - ida_free(&pata_parport_bus_dev_ids, pi->dev.id); > > + ida_free(&pata_parport_bus_dev_ids, id); > > return NULL; > > } > > >
On 3/13/23 06:24, Ondrej Zary wrote: > On Sunday 12 March 2023 01:56:25 Damien Le Moal wrote: >> On 3/12/23 06:44, Ondrej Zary wrote: >>> When ida_alloc() fails, "pi" is not freed although the misleading >>> comment says otherwise. >>> Move the ida_alloc() call up so we really don't have to free it. >> >> Certainly you meant: "so we really do free it in case of error.", no ? > > I meant "so we don't have to free pi in case of ida_alloc failure". That is better. Please rephrase the commit message to this. >>> /* set up pi->dev before pi_probe_unit() so it can use dev_printk() */ >>> pi->dev.parent = &pata_parport_bus; >>> pi->dev.bus = &pata_parport_bus_type; >>> pi->dev.driver = &pr->driver; >>> pi->dev.release = pata_parport_dev_release; >>> - id = ida_alloc(&pata_parport_bus_dev_ids, GFP_KERNEL); >>> - if (id < 0) >>> - return NULL; /* pata_parport_dev_release will do kfree(pi) */ >>> pi->dev.id = id; >>> dev_set_name(&pi->dev, "pata_parport.%u", pi->dev.id); >>> if (device_register(&pi->dev)) { >>> @@ -571,7 +572,7 @@ static struct pi_adapter *pi_init_one(struct parport *parport, >>> out_unreg_dev: >>> device_unregister(&pi->dev); >> >> Same comment as Sergey: isn't this going to do the ida free ? So shouldn't you >> return here ? > > No. device_unregister() calls pata_parport_dev_release() which does only kfree(pi), not ida_free(). But it probably should do ida_free() too. Yes, it should, otherwise you are leaking the ida with the normal (no errors) case. Care to send a fix for that too ?
On Monday 13 March 2023, Damien Le Moal wrote: > On 3/13/23 06:24, Ondrej Zary wrote: > > On Sunday 12 March 2023 01:56:25 Damien Le Moal wrote: > >> On 3/12/23 06:44, Ondrej Zary wrote: > >>> When ida_alloc() fails, "pi" is not freed although the misleading > >>> comment says otherwise. > >>> Move the ida_alloc() call up so we really don't have to free it. > >> > >> Certainly you meant: "so we really do free it in case of error.", no ? > > > > I meant "so we don't have to free pi in case of ida_alloc failure". > > That is better. Please rephrase the commit message to this. > > >>> /* set up pi->dev before pi_probe_unit() so it can use dev_printk() */ > >>> pi->dev.parent = &pata_parport_bus; > >>> pi->dev.bus = &pata_parport_bus_type; > >>> pi->dev.driver = &pr->driver; > >>> pi->dev.release = pata_parport_dev_release; > >>> - id = ida_alloc(&pata_parport_bus_dev_ids, GFP_KERNEL); > >>> - if (id < 0) > >>> - return NULL; /* pata_parport_dev_release will do kfree(pi) */ > >>> pi->dev.id = id; > >>> dev_set_name(&pi->dev, "pata_parport.%u", pi->dev.id); > >>> if (device_register(&pi->dev)) { > >>> @@ -571,7 +572,7 @@ static struct pi_adapter *pi_init_one(struct parport *parport, > >>> out_unreg_dev: > >>> device_unregister(&pi->dev); > >> > >> Same comment as Sergey: isn't this going to do the ida free ? So shouldn't you > >> return here ? > > > > No. device_unregister() calls pata_parport_dev_release() which does only kfree(pi), not ida_free(). But it probably should do ida_free() too. > > Yes, it should, otherwise you are leaking the ida with the normal (no errors) > case. Care to send a fix for that too ? Yes, I'll send it as soon as I fix a problem that I noticed during testing. The ida is never freed with this fix. And neither "pi" because pata_parport_dev_release is never called (confirmed by adding printk).
diff --git a/drivers/ata/pata_parport/pata_parport.c b/drivers/ata/pata_parport/pata_parport.c index 6165ee9aa7da..a9eff6003098 100644 --- a/drivers/ata/pata_parport/pata_parport.c +++ b/drivers/ata/pata_parport/pata_parport.c @@ -503,18 +503,19 @@ static struct pi_adapter *pi_init_one(struct parport *parport, if (bus_for_each_dev(&pata_parport_bus_type, NULL, &match, pi_find_dev)) return NULL; + id = ida_alloc(&pata_parport_bus_dev_ids, GFP_KERNEL); + if (id < 0) + return NULL; + pi = kzalloc(sizeof(struct pi_adapter), GFP_KERNEL); if (!pi) - return NULL; + goto out_ida_free; /* set up pi->dev before pi_probe_unit() so it can use dev_printk() */ pi->dev.parent = &pata_parport_bus; pi->dev.bus = &pata_parport_bus_type; pi->dev.driver = &pr->driver; pi->dev.release = pata_parport_dev_release; - id = ida_alloc(&pata_parport_bus_dev_ids, GFP_KERNEL); - if (id < 0) - return NULL; /* pata_parport_dev_release will do kfree(pi) */ pi->dev.id = id; dev_set_name(&pi->dev, "pata_parport.%u", pi->dev.id); if (device_register(&pi->dev)) { @@ -571,7 +572,7 @@ static struct pi_adapter *pi_init_one(struct parport *parport, out_unreg_dev: device_unregister(&pi->dev); out_ida_free: - ida_free(&pata_parport_bus_dev_ids, pi->dev.id); + ida_free(&pata_parport_bus_dev_ids, id); return NULL; }
When ida_alloc() fails, "pi" is not freed although the misleading comment says otherwise. Move the ida_alloc() call up so we really don't have to free it. Reported-by: kernel test robot <lkp@intel.com> Reported-by: Dan Carpenter <error27@gmail.com> Link: https://lore.kernel.org/r/202303111822.IHNchbkp-lkp@intel.com/ Signed-off-by: Ondrej Zary <linux@zary.sk> --- drivers/ata/pata_parport/pata_parport.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)