From c692aced232da210469b2c04270edc5a980b72d7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alex=20R=C3=B8nne=20Petersen?= <alex@alexrp.com>
Date: Sun, 11 Oct 2026 09:21:54 +0200
Subject: [PATCH] compiler_rt.elf.tls: fix potential underflow if PT_TLS
 p_align is zero

Very unlikely with any sane linker, but technically allowed.
---
 lib/compiler_rt/elf/tls.zig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/compiler_rt/elf/tls.zig b/lib/compiler_rt/elf/tls.zig
index fd1bdb381d7eca0a038c967bdb48c0fff10cbec5..dccd2018ce02a2b32050b239a30f9d30dc9d06bd 100644
--- a/lib/compiler_rt/elf/tls.zig
+++ b/lib/compiler_rt/elf/tls.zig
@@ -499,7 +499,7 @@ fn computeAreaDesc(phdrs: []elf.ElfN.Phdr) void {
     var block_size: usize = undefined;
 
     if (tls_phdr) |phdr| {
-        align_factor = phdr.@"align";
+        align_factor = @max(phdr.@"align", 1);
 
         // The effective size in memory is represented by `memsz`; the length of the data stored
         // in the `PT.TLS` segment is `filesz` and may be less than the former.
-- 
2.54.0