From 8f77c286d5e0573dcd4bdbf22c3018d625a0c473 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Thu, 27 Mar 2025 22:04:21 -0700 Subject: [PATCH] objtool: Fix segfault in ignore_unreachable_insn() [ Upstream commit 69d41d6dafff0967565b971d950bd10443e4076c ] Check 'prev_insn' before dereferencing it. Fixes: bd841d6154f5 ("objtool: Fix CONFIG_UBSAN_TRAP unreachable warnings") Reported-by: Arnd Bergmann Reported-by: Ingo Molnar Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/5df4ff89c9e4b9e788b77b0531234ffa7ba03e9e.1743136205.git.jpoimboe@kernel.org Closes: https://lore.kernel.org/d86b4cc6-0b97-4095-8793-a7384410b8ab@app.fastmail.com Closes: https://lore.kernel.org/Z-V_rruKY0-36pqA@gmail.com Signed-off-by: Sasha Levin --- tools/objtool/check.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 5824aa68ff96..36412f1881e6 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -4089,7 +4089,7 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio * It may also insert a UD2 after calling a __noreturn function. */ prev_insn = prev_insn_same_sec(file, insn); - if (prev_insn->dead_end && + if (prev_insn && prev_insn->dead_end && (insn->type == INSN_BUG || (insn->type == INSN_JUMP_UNCONDITIONAL && insn->jump_dest && insn->jump_dest->type == INSN_BUG)))