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riscv: kprobes/ftrace: Add recursion protection to the ftrace callback

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Currently, the riscv's kprobes(powerred by ftrace) handler is
preemptible. Futher check indicates we miss something similar as the
commit c536aa1c5b ("kprobes/ftrace: Add recursion protection to the
ftrace callback"), so do similar modifications as the commit does.

Fixes: 829adda597 ("riscv: Add KPROBES_ON_FTRACE supported")
Cc: stable@vger.kernel.org
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
This commit is contained in:
Jisheng Zhang 2021-03-30 02:14:40 +08:00 committed by Palmer Dabbelt
parent 2349a3b26e
commit e31be8d343
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GPG Key ID: 2E1319F35FBB1889
1 changed files with 10 additions and 1 deletions
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11
arch/riscv/kernel/probes/ftrace.c
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@ -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);