On Wed, 10 Jun 2026 11:20:24 +0200 "Markus Schneider-Pargmann" <[email protected]> wrote:
> Hi Masami, > > On Wed Jun 10, 2026 at 10:17 AM CEST, Masami Hiramatsu wrote: > > Hi Markus, > > > > Thanks for ping me. > > > > On Tue, 28 Apr 2026 10:30:29 +0200 > > "Markus Schneider-Pargmann (The Capable Hub)" <[email protected]> wrote: > > > >> fp pointer and unsigned long have the same size on all relevant > >> architectures that build Linux. Furthermore this struct is only used in > >> architectures that do not set ARCH_DEFINE_ENCODE_FPROBE_HEADER which is > >> set only for 64bit architectures (apart from LoongArch). > >> > >> Both fields are aligned on these architectures so the struct with > >> __packed and without it are the same. > >> > >> Remove the __packed as it is unnecessary. > >> > >> Fixes: 4346ba160409 ("fprobe: Rewrite fprobe on function-graph tracer") > > > > NOTE: This is not a Fix, but just cleanup or minor update. Or, you have > > any problem with this __packed attribute? > > Thanks, yes it is not fixing a bug, I can remove this. > > > > > Unless there is no problem (or any concern), I would like to keep this > > as it is. > > There is currently no problem with __packed in the upstream kernel. I > just thought this would be a good cleanup to remove the unnecessary > attribute. I am working on CHERI architectures where pointers have > capabilities. __packed breaks these capability tags and therefore > doesn't work on CHERI. When looking into why this struct has a __packed > attribute I didn't see a reason, so I thought this would be a good patch > for upstream as well even though CHERI is not yet relevant for upstream > linux. Hi Markus, Ah, OK. CHERI makes pointers to non-long value. Are you sure removing __packed makes fprobe working with CHERI? If so, please describe it. Then I can pick it. Thanks! -- Masami Hiramatsu (Google) <[email protected]>
