CVS commit: src/sys/kern

["Juergen Hannken-Illjes" <hannken%netbsd.org@localhost>]

Module Name:    src
Committed By:   hannken
Date:           Thu Feb 10 10:59:12 UTC 2022

Modified Files:
        src/sys/kern: vfs_lookup.c

Log Message:
Remove the assertion "searchdir != foundobj" from lookup_crossmount().

It will trigger whenever we lookup "." on a directory that becomes
mounted

    fd = open("/mnt")
    mount(..., "/mnt", ...)
    fd2 = openat(fd, ".")

or

    Unlocked searchdir gets mounted mounted on between
    lookup_fastforward()/lookup_once() and the test for
    foundobj->v_mountedhere.

May address syzkaller:

Reported-by: syzbot+9197ac681ce50f707d9a%syzkaller.appspotmail.com@localhost
Reported-by: syzbot+eb4854df8ee3c9bc278d%syzkaller.appspotmail.com@localhost
Reported-by: syzbot+3cc5b4126ab554f145d3%syzkaller.appspotmail.com@localhost
Reported-by: syzbot+7eae48a3ea952efee8c8%syzkaller.appspotmail.com@localhost
Reported-by: syzbot+b7f662083ccf8be3e669%syzkaller.appspotmail.com@localhost


To generate a diff of this commit:
cvs rdiff -u -r1.230 -r1.231 src/sys/kern/vfs_lookup.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.