From f344ad3060c4cb9cb2b26e671405e04f28966d7a Mon Sep 17 00:00:00 2001
From: Tong Tiangen <tongtiangen@huawei.com>
Date: Wed, 1 Sep 2021 02:46:21 +0000
Subject: [PATCH] riscv/vdso: make arch_setup_additional_pages wait for mmap_sem for write killable
Git-commit: 8bb0ab3ae7a4dbe6cf32deb830cf2bdbf5736867
Patch-mainline: v5.15-rc5
References: stable-5.14.12

[ Upstream commit 8bb0ab3ae7a4dbe6cf32deb830cf2bdbf5736867 ]

riscv architectures relying on mmap_sem for write in their
arch_setup_additional_pages. If the waiting task gets killed by the oom
killer it would block oom_reaper from asynchronous address space reclaim
and reduce the chances of timely OOM resolving.  Wait for the lock in
the killable mode and return with EINTR if the task got killed while
waiting.

Signed-off-by: Tong Tiangen <tongtiangen@huawei.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Fixes: 76d2a0493a17 ("RISC-V: Init and Halt Code")
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 arch/riscv/kernel/vdso.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/vdso.c b/arch/riscv/kernel/vdso.c
index e7bd92d8749b..b70956d80408 100644
--- a/arch/riscv/kernel/vdso.c
+++ b/arch/riscv/kernel/vdso.c
@@ -77,7 +77,9 @@ int arch_setup_additional_pages(struct linux_binprm *bprm,
 
 	vdso_len = (vdso_pages + VVAR_NR_PAGES) << PAGE_SHIFT;
 
-	mmap_write_lock(mm);
+	if (mmap_write_lock_killable(mm))
+		return -EINTR;
+
 	vdso_base = get_unmapped_area(NULL, 0, vdso_len, 0, 0);
 	if (IS_ERR_VALUE(vdso_base)) {
 		ret = vdso_base;
-- 
2.26.2