From e31be8d343e64e7ab17aef55c1d1b36dc504da67 Mon Sep 17 00:00:00 2001 From: Jisheng Zhang Date: Tue, 30 Mar 2021 02:14:40 +0800 Subject: riscv: kprobes/ftrace: Add recursion protection to the ftrace callback Currently, the riscv's kprobes(powerred by ftrace) handler is preemptible. Futher check indicates we miss something similar as the commit c536aa1c5b17 ("kprobes/ftrace: Add recursion protection to the ftrace callback"), so do similar modifications as the commit does. Fixes: 829adda597fe ("riscv: Add KPROBES_ON_FTRACE supported") Cc: stable@vger.kernel.org Signed-off-by: Jisheng Zhang Reviewed-by: Steven Rostedt (VMware) Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/probes/ftrace.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/riscv/kernel/probes/ftrace.c b/arch/riscv/kernel/probes/ftrace.c index 17ca5e923bb0..aab85a82f419 100644 --- a/arch/riscv/kernel/probes/ftrace.c +++ b/arch/riscv/kernel/probes/ftrace.c @@ -9,10 +9,16 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, struct kprobe *p; struct pt_regs *regs; struct kprobe_ctlblk *kcb; + int bit; + bit = ftrace_test_recursion_trylock(ip, parent_ip); + if (bit < 0) + return; + + preempt_disable_notrace(); p = get_kprobe((kprobe_opcode_t *)ip); if (unlikely(!p) || kprobe_disabled(p)) - return; + goto out; regs = ftrace_get_regs(fregs); kcb = get_kprobe_ctlblk(); @@ -45,6 +51,9 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, */ __this_cpu_write(current_kprobe, NULL); } +out: + preempt_enable_notrace(); + ftrace_test_recursion_unlock(bit); } NOKPROBE_SYMBOL(kprobe_ftrace_handler); -- cgit v1.2.3