Precisely, these that are called within kprobe_busy_{begin, end}, which the previous patch does not resolve. I will refine the commit message to make it clear. FYI, details can checked out here: Link: https://lore.kernel.org/linux-trace-kernel/20230516132516.c902edcf21028874a74fb868@xxxxxxxxxx/ Regards, Ze On Tue, May 16, 2023 at 5:18 PM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > > On Tue, May 16, 2023 at 03:18:28PM +0800, Ze Gao wrote: > > Current implementation calls kprobe related functions before doing > > ftrace recursion check in fprobe_kprobe_handler, which opens door > > to kernel crash due to stack recursion if preempt_count_{add, sub} > > is traceable. > > Which preempt_count*() are you referring to? The ones you just made > _notrace in the previous patch?