Messages in this thread | | | Date | Fri, 29 May 2020 15:57:51 +0200 | From | Christoph Hellwig <> | Subject | Re: mmotm 2020-05-13-20-30 uploaded (objtool warnings) |
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On Thu, May 28, 2020 at 07:20:05PM +0200, Peter Zijlstra wrote: > > on x86_64: > > > > arch/x86/lib/csum-wrappers_64.o: warning: objtool: csum_and_copy_from_user()+0x2a4: call to memset() with UACCESS enabled > > arch/x86/lib/csum-wrappers_64.o: warning: objtool: csum_and_copy_to_user()+0x243: return with UACCESS enabled > > Urgh, that's horrible code. That's got plain stac()/clac() calls on > instead of the regular uaccess APIs.
Does it? If this is from the code in linux-next, then the code does a user_access_begin/end in csum_and_copy_{from,to}_user, then uses unsafe_{get,put}_user inside those function itself. But then they call csum_partial_copy_generic with the __user casted away, but without any comment on why this is safe.
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