Messages in this thread | | | Date | Tue, 15 Mar 2022 19:05:34 +0800 | Subject | Re: [PATCH] fs: erofs: remember if kobject_init_and_add was done | From | Huang Jianan <> |
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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.
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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