fprobe: Fix to ensure the number of active retprobes is not zero

The number of active retprobes can be zero but it is not acceptable,
so return EINVAL error if detected.

Link: https://lore.kernel.org/all/169750018550.186853.11198884812017796410.stgit@devnote2/
Reported-by: wuqiang.matt <wuqiang.matt@bytedance.com>
Closes: https://lore.kernel.org/all/20231016222103.cb9f426edc60220eabd8aa6a@kernel.org/
Fixes: 5b0ab78998e3 ("fprobe: Add exit_handler support")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index 3b21f406325829ceedfb3911ce76ed0f219005b8..881f90f0cbcfac92831e97bca869347d52b15e3e 100644 (file)
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@ -189,7 +189,7 @@ static int fprobe_init_rethook(struct fprobe *fp, int num)
 {
        int i, size;
 
-       if (num < 0)
+       if (num <= 0)
                return -EINVAL;
 
        if (!fp->exit_handler) {
@@ -202,8 +202,8 @@ static int fprobe_init_rethook(struct fprobe *fp, int num)
                size = fp->nr_maxactive;
        else
                size = num * num_possible_cpus() * 2;
-       if (size < 0)
-               return -E2BIG;
+       if (size <= 0)
+               return -EINVAL;
 
        fp->rethook = rethook_alloc((void *)fp, fprobe_exit_handler);
        if (!fp->rethook)