2022-11-26 09:11:05

by Yang Yingliang

Subject: [PATCH] genirq/irqdesc: fix WARNING in irq_sysfs_del()

I got the lots of WARNING report when doing fault injection test:

kernfs: can not remove 'chip_name', no directory
WARNING: CPU: 0 PID: 253 at fs/kernfs/dir.c:1616 kernfs_remove_by_name_ns+0xce/0xe0
RIP: 0010:kernfs_remove_by_name_ns+0xce/0xe0
Call Trace:
<TASK>
remove_files.isra.1+0x3f/0xb0
sysfs_remove_group+0x68/0xe0
sysfs_remove_groups+0x41/0x70
__kobject_del+0x45/0xc0
kobject_del+0x29/0x40
free_desc+0x42/0x70
irq_free_descs+0x5e/0x90

kernfs: can not remove 'hwirq', no directory
WARNING: CPU: 0 PID: 253 at fs/kernfs/dir.c:1616 kernfs_remove_by_name_ns+0xce/0xe0
RIP: 0010:kernfs_remove_by_name_ns+0xce/0xe0
Call Trace:
<TASK>
remove_files.isra.1+0x3f/0xb0
sysfs_remove_group+0x68/0xe0
sysfs_remove_groups+0x41/0x70
__kobject_del+0x45/0xc0
kobject_del+0x29/0x40
free_desc+0x42/0x70
irq_free_descs+0x5e/0x90

If irq_sysfs_add() fails in alloc_descs(), the directory of interrupt
informations is not added to sysfs, it causes the WARNINGs when removing
the information files. Fix this by adding check kobj.state_in_sysfs in
irq_sysfs_del().

Fixes: ecb3f394c5db ("genirq: Expose interrupt information through sysfs")
Signed-off-by: Yang Yingliang <[email protected]>
---
kernel/irq/irqdesc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index a91f9001103c..e391f4195b87 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -303,7 +303,7 @@ static void irq_sysfs_del(struct irq_desc *desc)
* kobject_del() complains about a object with no parent, so make
* it conditional.
*/
- if (irq_kobj_base)
+ if (irq_kobj_base && desc->kobj.state_in_sysfs)
kobject_del(&desc->kobj);
}

--
2.25.1

2022-11-28 12:47:03

by Greg Kroah-Hartman

Subject: Re: [PATCH] genirq/irqdesc: fix WARNING in irq_sysfs_del()

On Sat, Nov 26, 2022 at 04:27:16PM +0800, Yang Yingliang wrote:
> I got the lots of WARNING report when doing fault injection test:
>
> kernfs: can not remove 'chip_name', no directory
> WARNING: CPU: 0 PID: 253 at fs/kernfs/dir.c:1616 kernfs_remove_by_name_ns+0xce/0xe0
> RIP: 0010:kernfs_remove_by_name_ns+0xce/0xe0
> Call Trace:
> <TASK>
> remove_files.isra.1+0x3f/0xb0
> sysfs_remove_group+0x68/0xe0
> sysfs_remove_groups+0x41/0x70
> __kobject_del+0x45/0xc0
> kobject_del+0x29/0x40
> free_desc+0x42/0x70
> irq_free_descs+0x5e/0x90
>
> kernfs: can not remove 'hwirq', no directory
> WARNING: CPU: 0 PID: 253 at fs/kernfs/dir.c:1616 kernfs_remove_by_name_ns+0xce/0xe0
> RIP: 0010:kernfs_remove_by_name_ns+0xce/0xe0
> Call Trace:
> <TASK>
> remove_files.isra.1+0x3f/0xb0
> sysfs_remove_group+0x68/0xe0
> sysfs_remove_groups+0x41/0x70
> __kobject_del+0x45/0xc0
> kobject_del+0x29/0x40
> free_desc+0x42/0x70
> irq_free_descs+0x5e/0x90
>
> If irq_sysfs_add() fails in alloc_descs(), the directory of interrupt
> informations is not added to sysfs, it causes the WARNINGs when removing
> the information files. Fix this by adding check kobj.state_in_sysfs in
> irq_sysfs_del().
>
> Fixes: ecb3f394c5db ("genirq: Expose interrupt information through sysfs")
> Signed-off-by: Yang Yingliang <[email protected]>
> ---
> kernel/irq/irqdesc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
> index a91f9001103c..e391f4195b87 100644
> --- a/kernel/irq/irqdesc.c
> +++ b/kernel/irq/irqdesc.c
> @@ -303,7 +303,7 @@ static void irq_sysfs_del(struct irq_desc *desc)
> * kobject_del() complains about a object with no parent, so make
> * it conditional.
> */
> - if (irq_kobj_base)
> + if (irq_kobj_base && desc->kobj.state_in_sysfs)

No, this is not ok, you are poking around in the core of sysfs in a
field that should be private and not be able to be seen by anyone else.
Fix this properly and do not try to remove a kobject that you know was
not registered properly.

thanks,

greg k-h