Messages in this thread Patch in this message | | | Date | Tue, 15 Mar 2022 18:55:50 +0800 | From | Gao Xiang <> | Subject | Re: [PATCH] fs: erofs: remember if kobject_init_and_add was done |
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On Tue, Mar 15, 2022 at 06:43:01PM +0800, Huang Jianan wrote: > 在 2022/3/15 15:51, Dongliang Mu 写道: > > From: Dongliang Mu <mudongliangabcd@gmail.com> > > > > Syzkaller hit 'WARNING: kobject bug in erofs_unregister_sysfs'. This bug > > is triggered by injecting fault in kobject_init_and_add of > > erofs_unregister_sysfs. > > > > Fix this by remembering if kobject_init_and_add is successful. > > > > Note that I've tested the patch and the crash does not occur any more. > > > > Reported-by: syzkaller <syzkaller@googlegroups.com> > > Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com> > > --- > > fs/erofs/internal.h | 1 + > > fs/erofs/sysfs.c | 9 ++++++--- > > 2 files changed, 7 insertions(+), 3 deletions(-) > > > > diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h > > index 5aa2cf2c2f80..9e20665e3f68 100644 > > --- a/fs/erofs/internal.h > > +++ b/fs/erofs/internal.h > > @@ -144,6 +144,7 @@ struct erofs_sb_info { > > u32 feature_incompat; > > /* sysfs support */ > > + bool s_sysfs_inited; > > Hi Dongliang, > > How about using sbi->s_kobj.state_in_sysfs to avoid adding a extra member in > sbi ?
Ok, I have no tendency of these (I'm fine with either ways). I've seen some usage like:
static inline int device_is_registered(struct device *dev) { return dev->kobj.state_in_sysfs; }
But I'm still not sure if we need to rely on such internal interface.. More thoughts?
Thanks, Gao Xiang
> > Thanks, > Jianan > > > struct kobject s_kobj; /* /sys/fs/erofs/<devname> */ > > struct completion s_kobj_unregister; > > }; > > diff --git a/fs/erofs/sysfs.c b/fs/erofs/sysfs.c > > index dac252bc9228..2b48a4df19b4 100644 > > --- a/fs/erofs/sysfs.c > > +++ b/fs/erofs/sysfs.c > > @@ -209,6 +209,7 @@ int erofs_register_sysfs(struct super_block *sb) > > "%s", sb->s_id); > > if (err) > > goto put_sb_kobj; > > + sbi->s_sysfs_inited = true; > > return 0; > > put_sb_kobj: > > @@ -221,9 +222,11 @@ void erofs_unregister_sysfs(struct super_block *sb) > > { > > struct erofs_sb_info *sbi = EROFS_SB(sb); > > - kobject_del(&sbi->s_kobj); > > - kobject_put(&sbi->s_kobj); > > - wait_for_completion(&sbi->s_kobj_unregister); > > + if (sbi->s_sysfs_inited) { > > + kobject_del(&sbi->s_kobj); > > + kobject_put(&sbi->s_kobj); > > + wait_for_completion(&sbi->s_kobj_unregister); > > + } > > } > > int __init erofs_init_sysfs(void)
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