acct_on(): don't mess with freeze protection
What happens there is that we are replacing file->path.mnt of a file we'd just opened with a clone and we need the write count contribution to be transferred from original mount to new one. That's it. We do *NOT* want any kind of freeze protection for the duration of switchover. IOW, we should just use __mnt_{want,drop}_write() for that switchover; no need to bother with mnt_{want,drop}_write() there. Tested-by: Amir Goldstein <amir73il@gmail.com> Reported-by: syzbot+2a73a6ea9507b7112141@syzkaller.appspotmail.com Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>hifive-unleashed-5.2
parent
79a3aaa7b8
commit
9419a3191d
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@ -89,9 +89,7 @@ extern int sb_prepare_remount_readonly(struct super_block *);
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extern void __init mnt_init(void);
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extern void __init mnt_init(void);
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extern int __mnt_want_write(struct vfsmount *);
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extern int __mnt_want_write_file(struct file *);
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extern int __mnt_want_write_file(struct file *);
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extern void __mnt_drop_write(struct vfsmount *);
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extern void __mnt_drop_write_file(struct file *);
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extern void __mnt_drop_write_file(struct file *);
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/*
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/*
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@ -87,6 +87,8 @@ extern bool mnt_may_suid(struct vfsmount *mnt);
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struct path;
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struct path;
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extern struct vfsmount *clone_private_mount(const struct path *path);
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extern struct vfsmount *clone_private_mount(const struct path *path);
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extern int __mnt_want_write(struct vfsmount *);
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extern void __mnt_drop_write(struct vfsmount *);
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struct file_system_type;
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struct file_system_type;
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extern struct vfsmount *fc_mount(struct fs_context *fc);
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extern struct vfsmount *fc_mount(struct fs_context *fc);
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@ -227,7 +227,7 @@ static int acct_on(struct filename *pathname)
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filp_close(file, NULL);
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filp_close(file, NULL);
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return PTR_ERR(internal);
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return PTR_ERR(internal);
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}
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}
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err = mnt_want_write(internal);
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err = __mnt_want_write(internal);
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if (err) {
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if (err) {
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mntput(internal);
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mntput(internal);
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kfree(acct);
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kfree(acct);
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@ -252,7 +252,7 @@ static int acct_on(struct filename *pathname)
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old = xchg(&ns->bacct, &acct->pin);
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old = xchg(&ns->bacct, &acct->pin);
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mutex_unlock(&acct->lock);
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mutex_unlock(&acct->lock);
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pin_kill(old);
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pin_kill(old);
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mnt_drop_write(mnt);
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__mnt_drop_write(mnt);
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mntput(mnt);
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mntput(mnt);
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return 0;
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return 0;
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}
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}
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