From 7fcb1380d3fa751a1559a2632a23ebf23f404077 Mon Sep 17 00:00:00 2001 From: He Zhe Date: Fri, 21 Aug 2020 00:52:50 +0800 Subject: [PATCH] arm64/perf: Fix wrong cast that may cause wrong truncation tail is a pointer while buftail.fp is a u32. arch/arm64/kernel/perf_callchain.c:100:6: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast] 100 | if ((u32)tail + 4 >= buftail.fp) | ^ arch/arm64/kernel/perf_callchain.c:103:9: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]{noformat} 103 | return (struct compat_frame_tail __user *)(buftail.fp - 4); | ^ Fixes: 8818670c17d2 ("arm64/perf: fix backtrace for AAPCS with FP enabled") Signed-off-by: He Zhe Signed-off-by: Bruce Ashfield --- arch/arm64/kernel/perf_callchain.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/perf_callchain.c b/arch/arm64/kernel/perf_callchain.c index 1be96e3631ea..a4b0864c4e32 100644 --- a/arch/arm64/kernel/perf_callchain.c +++ b/arch/arm64/kernel/perf_callchain.c @@ -97,10 +97,10 @@ compat_user_backtrace(struct compat_frame_tail __user *tail, * Frame pointers should strictly progress back up the stack * (towards higher addresses). */ - if ((u32)tail + 4 >= buftail.fp) + if ((u64)tail + 4 >= (u64)buftail.fp) return NULL; - return (struct compat_frame_tail __user *)(buftail.fp - 4); + return (struct compat_frame_tail __user *)((u64)buftail.fp - 4); } #endif /* CONFIG_COMPAT */ -- 2.19.1