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    x86/mm/pat, /dev/mem: Remove superfluous error message · 39380b80
    Jiri Kosina 提交于
    Currently it's possible for broken (or malicious) userspace to flood a
    kernel log indefinitely with messages a-la
    
    	Program dmidecode tried to access /dev/mem between f0000->100000
    
    because range_is_allowed() is case of CONFIG_STRICT_DEVMEM being turned on
    dumps this information each and every time devmem_is_allowed() fails.
    
    Reportedly userspace that is able to trigger contignuous flow of these
    messages exists.
    
    It would be possible to rate limit this message, but that'd have a
    questionable value; the administrator wouldn't get information about all
    the failing accessess, so then the information would be both superfluous
    and incomplete at the same time :)
    
    Returning EPERM (which is what is actually happening) is enough indication
    for userspace what has happened; no need to log this particular error as
    some sort of special condition.
    Signed-off-by: NJiri Kosina <jkosina@suse.cz>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Andy Lutomirski <luto@kernel.org>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Brian Gerst <brgerst@gmail.com>
    Cc: Denys Vlasenko <dvlasenk@redhat.com>
    Cc: H. Peter Anvin <hpa@zytor.com>
    Cc: Josh Poimboeuf <jpoimboe@redhat.com>
    Cc: Kees Cook <keescook@chromium.org>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Luis R. Rodriguez <mcgrof@suse.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Toshi Kani <toshi.kani@hp.com>
    Link: http://lkml.kernel.org/r/alpine.LNX.2.00.1607081137020.24757@cbobk.fhfr.pmSigned-off-by: NIngo Molnar <mingo@kernel.org>
    39380b80
mem.c 18.2 KB