Messages in this thread | | | From | David Laight <> | Subject | RE: [PATCH RFC 2/8] arm64: stacktrace: Add arch_within_stack_frames | Date | Wed, 20 Apr 2022 07:32:01 +0000 |
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> > Thanks for doing this implementation! One reason usercopy hardening > > didn't persue doing a "full" stacktrace was because it seemed relatively > > expensive. Did you do any usercopy-heavily workload testing to see if > > there was a noticeable performance impact?
Look at anything that uses sendmsg(). It is noticeably more expensive than sendto(). All the extra copy_from_user() cause measurable slow slowdowns. Using __copy_from_user()(to avoid 'hardending') in the socket code and when reading the iov[] gives a measurable improvement.
David
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