From: Richard Henderson <richard.henderson@linaro.org>
Date: Tue, 13 Aug 2024 06:33:58 +0000 (+1000)
Subject: linux-user: Preserve NULL hit in target_mmap subroutines
X-Git-Tag: v9.0.3~23
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=1f1cbbd0d707d532477c9c58360306ccd920ddf1;p=thirdparty%2Fqemu.git

linux-user: Preserve NULL hit in target_mmap subroutines

Do not pass guest_base to the host mmap instead of zero hint.

Cc: qemu-stable@nongnu.org
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2353
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
(cherry picked from commit 3aefee3ec01e607529a9918e2978f365c5c3b5e9)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
---

diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index be3b9a68ebc..2a11d921ab7 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -559,9 +559,13 @@ static abi_long mmap_h_eq_g(abi_ulong start, abi_ulong len,
                             int host_prot, int flags, int page_flags,
                             int fd, off_t offset)
 {
-    void *p, *want_p = g2h_untagged(start);
+    void *p, *want_p = NULL;
     abi_ulong last;
 
+    if (start || (flags & (MAP_FIXED | MAP_FIXED_NOREPLACE))) {
+        want_p = g2h_untagged(start);
+    }
+
     p = mmap(want_p, len, host_prot, flags, fd, offset);
     if (p == MAP_FAILED) {
         return -1;
@@ -609,11 +613,15 @@ static abi_long mmap_h_lt_g(abi_ulong start, abi_ulong len, int host_prot,
                             int mmap_flags, int page_flags, int fd,
                             off_t offset, int host_page_size)
 {
-    void *p, *want_p = g2h_untagged(start);
+    void *p, *want_p = NULL;
     off_t fileend_adj = 0;
     int flags = mmap_flags;
     abi_ulong last, pass_last;
 
+    if (start || (flags & (MAP_FIXED | MAP_FIXED_NOREPLACE))) {
+        want_p = g2h_untagged(start);
+    }
+
     if (!(flags & MAP_ANONYMOUS)) {
         struct stat sb;
 
@@ -739,12 +747,16 @@ static abi_long mmap_h_gt_g(abi_ulong start, abi_ulong len,
                             int flags, int page_flags, int fd,
                             off_t offset, int host_page_size)
 {
-    void *p, *want_p = g2h_untagged(start);
+    void *p, *want_p = NULL;
     off_t host_offset = offset & -host_page_size;
     abi_ulong last, real_start, real_last;
     bool misaligned_offset = false;
     size_t host_len;
 
+    if (start || (flags & (MAP_FIXED | MAP_FIXED_NOREPLACE))) {
+        want_p = g2h_untagged(start);
+    }
+
     if (!(flags & (MAP_FIXED | MAP_FIXED_NOREPLACE))) {
         /*
          * Adjust the offset to something representable on the host.