On Wed, 26 Aug 2020 07:07:09 +0000 "eddy...@trendmicro.com" <eddy...@trendmicro.com> wrote:
> > > -----Original Message----- > > From: pet...@infradead.org <pet...@infradead.org> > > Sent: Tuesday, August 25, 2020 8:09 PM > > To: Masami Hiramatsu <mhira...@kernel.org> > > Cc: Eddy Wu (RD-TW) <eddy...@trendmicro.com>; linux-kernel@vger.kernel.org; > > x...@kernel.org; David S. Miller > > <da...@davemloft.net> > > Subject: Re: x86/kprobes: kretprobe fails to triggered if kprobe at > > function entry is not optimized (trigger by int3 breakpoint) > > > > Surely we can do a lockless list for this. We have llist_add() and > > llist_del_first() to make a lockless LIFO/stack. > > > > llist operations require atomic cmpxchg, for some arch doesn't have > CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG, in_nmi() check might still needed. > (HAVE_KRETPROBES && !CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG): arc, arm, csky, mips Good catch. In those cases, we can add in_nmi() check at arch dependent code. Thank you, -- Masami Hiramatsu <mhira...@kernel.org>
