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authorJisheng Zhang <jszhang@kernel.org>2021-03-29 21:14:40 +0300
committerPalmer Dabbelt <palmerdabbelt@google.com>2021-04-16 07:32:34 +0300
commite31be8d343e64e7ab17aef55c1d1b36dc504da67 (patch)
treeddaad7d4e24b5d2ff2f63069e0be6482a5d0af14 /arch/riscv
parent2349a3b26e29b8d860466bafda2e02b4b87a9e40 (diff)
downloadlinux-e31be8d343e64e7ab17aef55c1d1b36dc504da67.tar.xz
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 <jszhang@kernel.org> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Diffstat (limited to 'arch/riscv')
-rw-r--r--arch/riscv/kernel/probes/ftrace.c11
1 files changed, 10 insertions, 1 deletions
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);