Messages in this thread | | | Subject | Re: [PATCH v1 2/2] perf/core: Fake regs for leaked kernel samples | From | "Jin, Yao" <> | Date | Tue, 11 Aug 2020 16:31:10 +0800 |
| |
Hi Peter,
On 8/11/2020 3:59 PM, Peter Zijlstra wrote: > On Tue, Aug 11, 2020 at 03:50:43PM +0800, Jin, Yao wrote: >> Could I post v2 which basically refers to your patch but removes some >> conditions since I see some issues in test if we use these conditions. >> >> 1. Remove '!event->attr.exclude_hv || !event->attr.exclude_host || >> !event->attr.exclude_guest' at the entry of sanitize_sample_regs(). >> >> 2. Remove '!attr.exclude_hv || !attr.exclude_host || !attr.exclude_guest' >> at the perf_event_open syscall entry. > > exclude_host, maybe -- due to the dodgy semantics of it, but the others > should definitely be there. >
exclude_guest and exclude_hv are tricky too.
If we do 'perf record -e cycles:u' in both host and guest, we can see:
event->attr.exclude_guest = 0
thus sanitize_sample_regs() returns regs directly even if exclude_kernel = 1.
And in guest, exclude_hv = 0, it's out of my expectation too.
Thanks Jin Yao
| |