From 4023b7424ecd5d38cc75b650d6c1bf630ef8cb40 Mon Sep 17 00:00:00 2001 From: Wentao Guan Date: Mon, 13 Apr 2026 17:54:59 +0800 Subject: [PATCH] arm64/scs: Fix potential sign extension issue of advance_loc4 The expression (*opcode++ << 24) and exp * code_alignment_factor may overflow signed int and becomes negative. Fix this by casting each byte to u64 before shifting. Also fix the misaligned break statement while we are here. Example of the result can be seen here: Link: https://godbolt.org/z/zhY8d3595 It maybe not a real problem, but could be a issue in future. Fixes: d499e9627d70 ("arm64/scs: Fix handling of advance_loc4") Signed-off-by: Wentao Guan Signed-off-by: Catalin Marinas --- arch/arm64/kernel/pi/patch-scs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/pi/patch-scs.c b/arch/arm64/kernel/pi/patch-scs.c index dac568e4a54f..3944ad899021 100644 --- a/arch/arm64/kernel/pi/patch-scs.c +++ b/arch/arm64/kernel/pi/patch-scs.c @@ -196,9 +196,9 @@ static int scs_handle_fde_frame(const struct eh_frame *frame, loc += *opcode++ * code_alignment_factor; loc += (*opcode++ << 8) * code_alignment_factor; loc += (*opcode++ << 16) * code_alignment_factor; - loc += (*opcode++ << 24) * code_alignment_factor; + loc += ((u64)*opcode++ << 24) * code_alignment_factor; size -= 4; - break; + break; case DW_CFA_def_cfa: case DW_CFA_offset_extended: