If a large count is provided, it will triger a warning in bitmap_parse_user.
Also check zero for it.

Reported-by: [email protected]
Closes: https://syzkaller.appspot.com/bug?extid=0aecfd34fb878546f3fd
Tested-by: [email protected]
Signed-off-by: Lizhi Xu <[email protected]>
---
 kernel/trace/trace.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index be62f0ea1814..109f301549b8 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5225,6 +5225,9 @@ tracing_cpumask_write(struct file *filp, const char 
__user *ubuf,
        cpumask_var_t tracing_cpumask_new;
        int err;
 
+       if (count == 0 || count << PAGE_SHIFT > MAX_PAGE_ORDER)
+               return -EINVAL;
+
        if (!zalloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
                return -ENOMEM;
 
-- 
2.43.0


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