From fa527b44c2d65d48cc3c5ac018dc935cc286f5a9 Mon Sep 17 00:00:00 2001
From: Ilya Leoshkevich <iii@linux.ibm.com>
Date: Mon, 25 Mar 2024 20:23:01 +0100
Subject: [PATCH] linux-user: Fix shmat(NULL) for h != g
In the h != g && shmaddr == NULL && !reserved_va case, target_shmat()
incorrectly mmap()s the initial anonymous range with
MAP_FIXED_NOREPLACE, even though the earlier mmap_find_vma() has
already reserved the respective address range.
Fix by using MAP_FIXED when "mapped", which is set after
mmap_find_vma(), is true.
Fixes: 78bc8ed9a8f0 ("linux-user: Rewrite target_shmat")
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Message-Id: <20240325192436.561154-4-iii@linux.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
linux-user/mmap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index 4505fd7376..be3b9a68eb 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -1354,7 +1354,7 @@ abi_ulong target_shmat(CPUArchState *cpu_env, int shmid,
if (h_len != t_len) {
int mmap_p = PROT_READ | (shmflg & SHM_RDONLY ? 0 : PROT_WRITE);
int mmap_f = MAP_PRIVATE | MAP_ANONYMOUS
- | (reserved_va || (shmflg & SHM_REMAP)
+ | (reserved_va || mapped || (shmflg & SHM_REMAP)
? MAP_FIXED : MAP_FIXED_NOREPLACE);
test = mmap(want, m_len, mmap_p, mmap_f, -1, 0);
--
2.30.2