diff mbox series

[2/2] rtc: class: return error code when cdev_device_add() failed

Message ID 20211011080302.1982894-2-yangyingliang@huawei.com
State Superseded
Headers show
Series [1/2] rtc: class: check return value when calling dev_set_name() | expand

Commit Message

Yang Yingliang Oct. 11, 2021, 8:03 a.m. UTC 
I got a null-ptr-deref report when doing fault injection test:

general protection fault, probably for non-canonical address 0xdffffc0000000022: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000110-0x0000000000000117]
CPU: 1 PID: 1028 Comm: 33 Not tainted 5.15.0-rc3-00111-gf5dad42ed4fe-dirty #481 2a70b3e6ca240b8638beac7ef491cce6183bbec7
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:device_del+0x132/0xdc0
Code: 48 c1 ea 03 80 3c 02 00 0f 85 4f 0c 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 7b 48 4d 8d a7 10 01 00 00 4c 89 e2 48 c1 ea 03 <0f> b6 04 02 84 c0 74 06 0f 8e 7f 0a 00 00 45 0f b6 b7 10 01 00 00
RSP: 0018:ffffc90002e876b8 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: ffff88801eb84000 RCX: ffffffff97227644
RDX: 0000000000000022 RSI: ffff8880146a0000 RDI: 0000000000000002
RBP: ffff88801eb84120 R08: fffffbfff349a60d R09: fffffbfff349a60d
R10: ffffc90002e876b8 R11: fffffbfff349a60c R12: 0000000000000110
R13: 0000000000000001 R14: ffffc90002e87848 R15: 0000000000000000
FS:  00007fa514973500(0000) GS:ffff888104600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa51474ccb0 CR3: 000000002bcb0001 CR4: 0000000000770ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
 ? write_comp_data+0x2a/0x90
 ? cleanup_glue_dir+0x260/0x260
 ? is_rtc_hctosys.isra.0+0xb9/0xf0
 ? rtc_proc_show+0x440/0x440
 ? rcu_read_lock_held_common+0xe/0xa0
 ? rcu_read_lock_sched_held+0x62/0xe0
 cdev_device_del+0x1a/0x80
 devm_rtc_unregister_device+0x37/0x80
 release_nodes+0xc3/0x3b0

If cdev_device_add() fails, 'dev->p' is not set, it causes
null-ptr-deref when calling cdev_device_del(), return error
code when cdev_device_add() failed to fix this.

Reported-by: Hulk Robot <hulkci@huawei.com>
Fixes: 3068a254d5519 ("rtc: introduce new registration method")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
 drivers/rtc/class.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Comments

Alexandre Belloni Oct. 11, 2021, 8:36 a.m. UTC | #1 
On 11/10/2021 16:03:02+0800, Yang Yingliang wrote:
> I got a null-ptr-deref report when doing fault injection test:
> 
> general protection fault, probably for non-canonical address 0xdffffc0000000022: 0000 [#1] SMP KASAN PTI
> KASAN: null-ptr-deref in range [0x0000000000000110-0x0000000000000117]
> CPU: 1 PID: 1028 Comm: 33 Not tainted 5.15.0-rc3-00111-gf5dad42ed4fe-dirty #481 2a70b3e6ca240b8638beac7ef491cce6183bbec7
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
> RIP: 0010:device_del+0x132/0xdc0
> Code: 48 c1 ea 03 80 3c 02 00 0f 85 4f 0c 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 7b 48 4d 8d a7 10 01 00 00 4c 89 e2 48 c1 ea 03 <0f> b6 04 02 84 c0 74 06 0f 8e 7f 0a 00 00 45 0f b6 b7 10 01 00 00
> RSP: 0018:ffffc90002e876b8 EFLAGS: 00010206
> RAX: dffffc0000000000 RBX: ffff88801eb84000 RCX: ffffffff97227644
> RDX: 0000000000000022 RSI: ffff8880146a0000 RDI: 0000000000000002
> RBP: ffff88801eb84120 R08: fffffbfff349a60d R09: fffffbfff349a60d
> R10: ffffc90002e876b8 R11: fffffbfff349a60c R12: 0000000000000110
> R13: 0000000000000001 R14: ffffc90002e87848 R15: 0000000000000000
> FS:  00007fa514973500(0000) GS:ffff888104600000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007fa51474ccb0 CR3: 000000002bcb0001 CR4: 0000000000770ee0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> PKRU: 55555554
> Call Trace:
>  ? write_comp_data+0x2a/0x90
>  ? cleanup_glue_dir+0x260/0x260
>  ? is_rtc_hctosys.isra.0+0xb9/0xf0
>  ? rtc_proc_show+0x440/0x440
>  ? rcu_read_lock_held_common+0xe/0xa0
>  ? rcu_read_lock_sched_held+0x62/0xe0
>  cdev_device_del+0x1a/0x80
>  devm_rtc_unregister_device+0x37/0x80
>  release_nodes+0xc3/0x3b0
> 
> If cdev_device_add() fails, 'dev->p' is not set, it causes
> null-ptr-deref when calling cdev_device_del(), return error
> code when cdev_device_add() failed to fix this.
> 
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Fixes: 3068a254d5519 ("rtc: introduce new registration method")
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> ---
>  drivers/rtc/class.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
> index 1f18c39a4b82..76422faee05b 100644
> --- a/drivers/rtc/class.c
> +++ b/drivers/rtc/class.c
> @@ -399,12 +399,14 @@ int __devm_rtc_register_device(struct module *owner, struct rtc_device *rtc)
>  	rtc_dev_prepare(rtc);
>  
>  	err = cdev_device_add(&rtc->char_dev, &rtc->dev);
> -	if (err)
> +	if (err) {
>  		dev_warn(rtc->dev.parent, "failed to add char device %d:%d\n",
>  			 MAJOR(rtc->dev.devt), rtc->id);
> -	else
> +		return err;

As the checkpatch warning indicates, registering the character device as
always been optional. d5ed9177f64fe95d9de79e6504d41612d9127e8a is the
commit you want to fix.

> +	} else {
>  		dev_dbg(rtc->dev.parent, "char device (%d:%d)\n",
>  			MAJOR(rtc->dev.devt), rtc->id);
> +	}
>  
>  	rtc_proc_add_device(rtc);
>  
> -- 
> 2.25.1
>
Yang Yingliang Oct. 11, 2021, 9:40 a.m. UTC | #2 
Hi,

On 2021/10/11 16:36, Alexandre Belloni wrote:
> On 11/10/2021 16:03:02+0800, Yang Yingliang wrote:
>> I got a null-ptr-deref report when doing fault injection test:
>>
>> general protection fault, probably for non-canonical address 0xdffffc0000000022: 0000 [#1] SMP KASAN PTI
>> KASAN: null-ptr-deref in range [0x0000000000000110-0x0000000000000117]
>> CPU: 1 PID: 1028 Comm: 33 Not tainted 5.15.0-rc3-00111-gf5dad42ed4fe-dirty #481 2a70b3e6ca240b8638beac7ef491cce6183bbec7
>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
>> RIP: 0010:device_del+0x132/0xdc0
>> Code: 48 c1 ea 03 80 3c 02 00 0f 85 4f 0c 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 7b 48 4d 8d a7 10 01 00 00 4c 89 e2 48 c1 ea 03 <0f> b6 04 02 84 c0 74 06 0f 8e 7f 0a 00 00 45 0f b6 b7 10 01 00 00
>> RSP: 0018:ffffc90002e876b8 EFLAGS: 00010206
>> RAX: dffffc0000000000 RBX: ffff88801eb84000 RCX: ffffffff97227644
>> RDX: 0000000000000022 RSI: ffff8880146a0000 RDI: 0000000000000002
>> RBP: ffff88801eb84120 R08: fffffbfff349a60d R09: fffffbfff349a60d
>> R10: ffffc90002e876b8 R11: fffffbfff349a60c R12: 0000000000000110
>> R13: 0000000000000001 R14: ffffc90002e87848 R15: 0000000000000000
>> FS:  00007fa514973500(0000) GS:ffff888104600000(0000) knlGS:0000000000000000
>> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 00007fa51474ccb0 CR3: 000000002bcb0001 CR4: 0000000000770ee0
>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>> PKRU: 55555554
>> Call Trace:
>>   ? write_comp_data+0x2a/0x90
>>   ? cleanup_glue_dir+0x260/0x260
>>   ? is_rtc_hctosys.isra.0+0xb9/0xf0
>>   ? rtc_proc_show+0x440/0x440
>>   ? rcu_read_lock_held_common+0xe/0xa0
>>   ? rcu_read_lock_sched_held+0x62/0xe0
>>   cdev_device_del+0x1a/0x80
>>   devm_rtc_unregister_device+0x37/0x80
>>   release_nodes+0xc3/0x3b0
>>
>> If cdev_device_add() fails, 'dev->p' is not set, it causes
>> null-ptr-deref when calling cdev_device_del(), return error
>> code when cdev_device_add() failed to fix this.
>>
>> Reported-by: Hulk Robot <hulkci@huawei.com>
>> Fixes: 3068a254d5519 ("rtc: introduce new registration method")
>> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
>> ---
>>   drivers/rtc/class.c | 6 ++++--
>>   1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
>> index 1f18c39a4b82..76422faee05b 100644
>> --- a/drivers/rtc/class.c
>> +++ b/drivers/rtc/class.c
>> @@ -399,12 +399,14 @@ int __devm_rtc_register_device(struct module *owner, struct rtc_device *rtc)
>>   	rtc_dev_prepare(rtc);
>>   
>>   	err = cdev_device_add(&rtc->char_dev, &rtc->dev);
>> -	if (err)
>> +	if (err) {
>>   		dev_warn(rtc->dev.parent, "failed to add char device %d:%d\n",
>>   			 MAJOR(rtc->dev.devt), rtc->id);
>> -	else
>> +		return err;
> As the checkpatch warning indicates, registering the character device as
> always been optional. d5ed9177f64fe95d9de79e6504d41612d9127e8a is the
> commit you want to fix.
So we can keep doing rtc register, even if cdev_device_add() failed ?

Thanks,
Yang
>
>> +	} else {
>>   		dev_dbg(rtc->dev.parent, "char device (%d:%d)\n",
>>   			MAJOR(rtc->dev.devt), rtc->id);
>> +	}
>>   
>>   	rtc_proc_add_device(rtc);
>>   
>> -- 
>> 2.25.1
>>
Alexandre Belloni Oct. 11, 2021, 9:47 a.m. UTC | #3 
On 11/10/2021 17:40:34+0800, Yang Yingliang wrote:
> 
> Hi,
> 
> On 2021/10/11 16:36, Alexandre Belloni wrote:
> > On 11/10/2021 16:03:02+0800, Yang Yingliang wrote:
> > > I got a null-ptr-deref report when doing fault injection test:
> > > 
> > > general protection fault, probably for non-canonical address 0xdffffc0000000022: 0000 [#1] SMP KASAN PTI
> > > KASAN: null-ptr-deref in range [0x0000000000000110-0x0000000000000117]
> > > CPU: 1 PID: 1028 Comm: 33 Not tainted 5.15.0-rc3-00111-gf5dad42ed4fe-dirty #481 2a70b3e6ca240b8638beac7ef491cce6183bbec7
> > > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
> > > RIP: 0010:device_del+0x132/0xdc0
> > > Code: 48 c1 ea 03 80 3c 02 00 0f 85 4f 0c 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 7b 48 4d 8d a7 10 01 00 00 4c 89 e2 48 c1 ea 03 <0f> b6 04 02 84 c0 74 06 0f 8e 7f 0a 00 00 45 0f b6 b7 10 01 00 00
> > > RSP: 0018:ffffc90002e876b8 EFLAGS: 00010206
> > > RAX: dffffc0000000000 RBX: ffff88801eb84000 RCX: ffffffff97227644
> > > RDX: 0000000000000022 RSI: ffff8880146a0000 RDI: 0000000000000002
> > > RBP: ffff88801eb84120 R08: fffffbfff349a60d R09: fffffbfff349a60d
> > > R10: ffffc90002e876b8 R11: fffffbfff349a60c R12: 0000000000000110
> > > R13: 0000000000000001 R14: ffffc90002e87848 R15: 0000000000000000
> > > FS:  00007fa514973500(0000) GS:ffff888104600000(0000) knlGS:0000000000000000
> > > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > > CR2: 00007fa51474ccb0 CR3: 000000002bcb0001 CR4: 0000000000770ee0
> > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> > > PKRU: 55555554
> > > Call Trace:
> > >   ? write_comp_data+0x2a/0x90
> > >   ? cleanup_glue_dir+0x260/0x260
> > >   ? is_rtc_hctosys.isra.0+0xb9/0xf0
> > >   ? rtc_proc_show+0x440/0x440
> > >   ? rcu_read_lock_held_common+0xe/0xa0
> > >   ? rcu_read_lock_sched_held+0x62/0xe0
> > >   cdev_device_del+0x1a/0x80
> > >   devm_rtc_unregister_device+0x37/0x80
> > >   release_nodes+0xc3/0x3b0
> > > 
> > > If cdev_device_add() fails, 'dev->p' is not set, it causes
> > > null-ptr-deref when calling cdev_device_del(), return error
> > > code when cdev_device_add() failed to fix this.
> > > 
> > > Reported-by: Hulk Robot <hulkci@huawei.com>
> > > Fixes: 3068a254d5519 ("rtc: introduce new registration method")
> > > Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> > > ---
> > >   drivers/rtc/class.c | 6 ++++--
> > >   1 file changed, 4 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
> > > index 1f18c39a4b82..76422faee05b 100644
> > > --- a/drivers/rtc/class.c
> > > +++ b/drivers/rtc/class.c
> > > @@ -399,12 +399,14 @@ int __devm_rtc_register_device(struct module *owner, struct rtc_device *rtc)
> > >   	rtc_dev_prepare(rtc);
> > >   	err = cdev_device_add(&rtc->char_dev, &rtc->dev);
> > > -	if (err)
> > > +	if (err) {
> > >   		dev_warn(rtc->dev.parent, "failed to add char device %d:%d\n",
> > >   			 MAJOR(rtc->dev.devt), rtc->id);
> > > -	else
> > > +		return err;
> > As the checkpatch warning indicates, registering the character device as
> > always been optional. d5ed9177f64fe95d9de79e6504d41612d9127e8a is the
> > commit you want to fix.
> So we can keep doing rtc register, even if cdev_device_add() failed ?
> 

Yes, this has always been the case.
diff mbox series

Patch

diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c
index 1f18c39a4b82..76422faee05b 100644
--- a/drivers/rtc/class.c
+++ b/drivers/rtc/class.c
@@ -399,12 +399,14 @@  int __devm_rtc_register_device(struct module *owner, struct rtc_device *rtc)
 	rtc_dev_prepare(rtc);
 
 	err = cdev_device_add(&rtc->char_dev, &rtc->dev);
-	if (err)
+	if (err) {
 		dev_warn(rtc->dev.parent, "failed to add char device %d:%d\n",
 			 MAJOR(rtc->dev.devt), rtc->id);
-	else
+		return err;
+	} else {
 		dev_dbg(rtc->dev.parent, "char device (%d:%d)\n",
 			MAJOR(rtc->dev.devt), rtc->id);
+	}
 
 	rtc_proc_add_device(rtc);