From 3502440397bbb840e2f7223734aa5cc2cc0e29b6 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Wed, 20 Dec 2023 16:31:43 -0800 Subject: [PATCH] x86-64: Fix the dtv field load for x32 [BZ #31184] On x32, I got FAIL: elf/tst-tlsgap $ gdb elf/tst-tlsgap ... open tst-tlsgap-mod1.so Thread 2 "tst-tlsgap" received signal SIGSEGV, Segmentation fault. [Switching to LWP 2268754] _dl_tlsdesc_dynamic () at ../sysdeps/x86_64/dl-tlsdesc.S:108 108 movq (%rsi), %rax (gdb) p/x $rsi $4 = 0xf7dbf9005655fb18 (gdb) This is caused by _dl_tlsdesc_dynamic: _CET_ENDBR /* Preserve call-clobbered registers that we modify. We need two scratch regs anyway. */ movq %rsi, -16(%rsp) movq %fs:DTV_OFFSET, %rsi Since the dtv field in TCB is a pointer, %fs:DTV_OFFSET is a 32-bit location, not 64-bit. Load the dtv field to RSI_LP instead of rsi. This fixes BZ #31184. --- sysdeps/x86_64/dl-tlsdesc.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sysdeps/x86_64/dl-tlsdesc.S b/sysdeps/x86_64/dl-tlsdesc.S index 5593897e29..c4823547d7 100644 --- a/sysdeps/x86_64/dl-tlsdesc.S +++ b/sysdeps/x86_64/dl-tlsdesc.S @@ -102,7 +102,7 @@ _dl_tlsdesc_dynamic: /* Preserve call-clobbered registers that we modify. We need two scratch regs anyway. */ movq %rsi, -16(%rsp) - movq %fs:DTV_OFFSET, %rsi + mov %fs:DTV_OFFSET, %RSI_LP movq %rdi, -8(%rsp) movq TLSDESC_ARG(%rax), %rdi movq (%rsi), %rax -- 2.11.4.GIT