Messages in this thread | | | Date | Thu, 14 Oct 2021 16:27:55 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v3 3/6] ptrace: Order and comment PT_flags |
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On Thu, Oct 14, 2021 at 10:31:22AM +0100, Will Deacon wrote: > On Sat, Oct 09, 2021 at 12:07:57PM +0200, Peter Zijlstra wrote: > > Add a comment to the PT_flags to indicate their actual value, this > > makes it easier to see what bits are used and where there might be a > > possible hole to use. > > > > Notable PT_SEIZED was placed wrong, also PT_EVENT_FLAG() space seems > > ill defined, as written is seems to be meant to cover the entire > > PTRACE_O_ range offset by 3 bits, which would then be 3+[0..21], > > however PT_SEIZED is in the middle of that. > > Why do you think PT_EVENT_FLAG() should cover all the PTRACE_O_* options? > Just going by the name and current callers, I'd only expect it to cover > the PTRACE_EVENT_* flags, no?
Because PT_EXITKILL and PT_SUSPEND_SECCOMP are also exposed in that same mapping.
Ideally we'd change PT_OPT_FLAG_SHIFT to 8 or something and have the high 24 bits for OPT and then use the low 8 bits for SEIZED and the new flags.
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