[PATCH AUTOSEL 5.8 20/24] riscv: Fixup bootup failure with HARDENED_USERCOPY

From: Sasha Levin
Date: Mon Oct 12 2020 - 15:08:58 EST


From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>

[ Upstream commit 84814460eef9af0fb56a4698341c9cb7996a6312 ]

6184358da000 ("riscv: Fixup static_obj() fail") attempted to elide a lockdep
failure by rearranging our kernel image to place all initdata within [_stext,
_end], thus triggering lockdep to treat these as static objects. These objects
are released and eventually reallocated, causing check_kernel_text_object() to
trigger a BUG().

This backs out the change to make [_stext, _end] all-encompassing, instead just
moving initdata. This results in initdata being outside of [__init_begin,
__init_end], which means initdata can't be freed.

Link: https://lore.kernel.org/linux-riscv/1593266228-61125-1-git-send-email-guoren@xxxxxxxxxx/T/#t
Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
Reported-by: Aurelien Jarno <aurelien@xxxxxxxxxxx>
Tested-by: Aurelien Jarno <aurelien@xxxxxxxxxxx>
[Palmer: Clean up commit text]
Signed-off-by: Palmer Dabbelt <palmerdabbelt@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
arch/riscv/kernel/vmlinux.lds.S | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S
index f3586e31ed1ec..34d00d9e6eac0 100644
--- a/arch/riscv/kernel/vmlinux.lds.S
+++ b/arch/riscv/kernel/vmlinux.lds.S
@@ -22,13 +22,11 @@ SECTIONS
/* Beginning of code and text segment */
. = LOAD_OFFSET;
_start = .;
- _stext = .;
HEAD_TEXT_SECTION
. = ALIGN(PAGE_SIZE);

__init_begin = .;
INIT_TEXT_SECTION(PAGE_SIZE)
- INIT_DATA_SECTION(16)
. = ALIGN(8);
__soc_early_init_table : {
__soc_early_init_table_start = .;
@@ -55,6 +53,7 @@ SECTIONS
. = ALIGN(SECTION_ALIGN);
.text : {
_text = .;
+ _stext = .;
TEXT_TEXT
SCHED_TEXT
CPUIDLE_TEXT
@@ -67,6 +66,8 @@ SECTIONS
_etext = .;
}

+ INIT_DATA_SECTION(16)
+
/* Start of data section */
_sdata = .;
RO_DATA(SECTION_ALIGN)
--
2.25.1