Messages in this thread | | | From | Dongliang Mu <> | Date | Tue, 15 Mar 2022 19:59:26 +0800 | Subject | Re: [PATCH] fs: erofs: remember if kobject_init_and_add was done |
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On Tue, Mar 15, 2022 at 7:05 PM Huang Jianan <jnhuang95@gmail.com> wrote: > > 在 2022/3/15 18:55, Gao Xiang 写道: > > 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? > > Yeah... It seems that it is better to use some of the interfaces > provided by kobject, > otherwise we should still maintain this state in sbi. >
I am fine with either way. Let me know if you reach to an agreement.
> Thanks, > Jianan > > > 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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