| Message ID | 20231221003143.2289327-1-hjl.tools@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | x86-64: Fix the dtv field load for x32 [BZ #31184] | expand |
On Wed, Dec 20, 2023 at 4:31 PM H.J. Lu <hjl.tools@gmail.com> wrote: > > 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 > -- > 2.43.0 > I will check it in tomorrow and back it to release branches later. Thanks.
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
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(-)