On Thu, Sep 04, 2025 at 10:49:50AM +0200, Oleg Nesterov wrote: > On 09/03, Jiri Olsa wrote: > > > > On Wed, Sep 03, 2025 at 01:26:48PM +0200, Oleg Nesterov wrote: > > > On 09/02, Jiri Olsa wrote: > > > > > > > > If user decided to take execution elsewhere, it makes little sense > > > > to execute the original instruction, so let's skip it. > > > > > > Exactly. > > > > > > So why do we need all these "is_unique" complications? Only a single > > > is_unique/exclusive consumer can change regs->ip, so I guess handle_swbp() > > > can just do > > > > > > handler_chain(uprobe, regs); > > > if (instruction_pointer(regs) != bp_vaddr) > > > goto out; > > > > hum, that's what I did in rfc [1] but I thought you did not like that [2] > > > > [1] https://lore.kernel.org/bpf/20250801210238.2207429-2-jolsa@xxxxxxxxxx/ > > [2] https://lore.kernel.org/bpf/20250802103426.GC31711@xxxxxxxxxx/ > > > > I guess I misunderstood your reply [2], I'd be happy to drop the > > unique/exclusive flag > > Well, but that rfc didn't introduce the exclusive consumers, and I think > we agree that even with these changes the non-exclusive consumers must > never change regs->ip? ok, got excited too soon.. so you meant getting rid of is_unique check only for this patch and have just change below.. but keep the unique/exclusive flag from patch#1 IIUC Andrii would remove the unique flag completely? jirka -- diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index b9b088f7333a..1baf5d2792ff 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -2791,6 +2791,9 @@ static void handle_swbp(struct pt_regs *regs) handler_chain(uprobe, regs); + if (instruction_pointer(regs) != bp_vaddr) + goto out; + /* Try to optimize after first hit. */ arch_uprobe_optimize(&uprobe->arch, bp_vaddr);
