• Peter Oberparleiter's avatar
    s390/debug: Remove pointer obfuscation · d2beeb3b
    Peter Oberparleiter authored
    When read via debugfs, s390dbf debug-views print the kernel address of
    the call-site that created a trace entry. The kernel's %p pointer
    hashing feature obfuscates this address, and commit 860ec7c6
    ("s390/debug: use pK for kernel pointers") made this obfuscation
    configurable via the kptr_restrict sysctl.
    
    Obfuscation of kernel address data printed via s390dbf debug-views does
    not add any additional protection since the associated debugfs files are
    only accessible to the root user that typically has enough other means
    to obtain kernel address data.
    
    Also trace payload data may contain binary representations of kernel
    addresses as part of logged data structues. Requiring such payload data
    to be obfuscated as well would be impractical and greatly diminish the
    use of s390dbf.
    
    Therefore completely remove pointer obfuscation from s390dbf
    debug-views.
    Reviewed-by: default avatarSteffen Maier <maier@linux.ibm.com>
    Acked-by: default avatarHeiko Carstens <hca@linux.ibm.com>
    Signed-off-by: default avatarPeter Oberparleiter <oberpar@linux.ibm.com>
    Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
    d2beeb3b
debug.c 35.6 KB