On Tue, 4 Aug 2026 01:08:40 +0200 Peter Zijlstra <[email protected]> wrote:
> On Tue, Aug 04, 2026 at 08:00:35AM +0900, Masami Hiramatsu wrote: > > On Mon, 3 Aug 2026 09:03:56 +0200 > > Peter Zijlstra <[email protected]> wrote: > > > > > On Sun, Aug 02, 2026 at 05:19:10PM +0900, Masami Hiramatsu (Google) wrote: > > > > From: Masami Hiramatsu (Google) <[email protected]> > > > > > > > > Add a new probe event for the hardware breakpoint called wprobe-event. > > > > This wprobe allows user to trace (watch) the memory access at the > > > > specified memory address. > > > > > > s/the memory/the kernel memory/ > > > > Indeed. > > > > > > > > > The new syntax is; > > > > > > > > w[:[GROUP/]EVENT] [r|w|rw]@[ADDR|SYM][:SIZE] [FETCH_ARGs] > > > > > > > > User also can use $addr to fetch the accessed address and $value to > > > > fetch > > > > the accessed memory value (shorthand for '+0($addr)'). No other > > > > variables > > > > are supported. > > > > > > This seems limited to kernel addresses only? Should not also userspace > > > addresses be supported? > > > > Hmm, for x86, yes, since it causes a trap after executing (all page fault > > are handled). But other architecture like arm64 may not be able to support > > it because it needs to enable watchpoint after major page fault. > > At this step, I would like to limit it just for kernel memory. > > Sure, but suppose you were to add userspace, what would the ABI be? Ahh, sorry. It was misreading, I mean it should be only for the kernel address, not for user space. So I don't want to add userspace. (I answered the first one) Thank you, > > That is, don't paint yourself in a corner etc. -- Masami Hiramatsu (Google) <[email protected]>
