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[PATCH v2 1/9] bsd-user/mmap.c: Always zero MAP_ANONYMOUS memory in mmap
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From: |
Warner Losh |
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Subject: |
[PATCH v2 1/9] bsd-user/mmap.c: Always zero MAP_ANONYMOUS memory in mmap_frag() |
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Date: |
Tue, 21 Sep 2021 22:56:28 -0600 |
From: Mikaël Urankar <mikael.urankar@gmail.com>
Similar to the equivalent linux-user commit e6deac9cf99
When mapping MAP_ANONYMOUS memory fragments, still need notice about to
set it zero, or it will cause issues.
Signed-off-by: Mikaël Urankar <mikael.urankar@gmail.com>
Signed-off-by: Warner Losh <imp@bsdimp.com>
---
bsd-user/mmap.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/bsd-user/mmap.c b/bsd-user/mmap.c
index b40ab9045f..fc3c1480f5 100644
--- a/bsd-user/mmap.c
+++ b/bsd-user/mmap.c
@@ -180,10 +180,12 @@ static int mmap_frag(abi_ulong real_start,
if (prot_new != (prot1 | PROT_WRITE))
mprotect(host_start, qemu_host_page_size, prot_new);
} else {
- /* just update the protection */
if (prot_new != prot1) {
mprotect(host_start, qemu_host_page_size, prot_new);
}
+ if (prot_new & PROT_WRITE) {
+ memset(g2h_untagged(start), 0, end - start);
+ }
}
return 0;
}
--
2.32.0
- [PATCH v2 0/9] bsd-user mmap fixes, Warner Losh, 2021/09/22
- [PATCH v2 3/9] bsd-user/mmap.c: MAP_ symbols are defined, so no need for ifdefs, Warner Losh, 2021/09/22
- [PATCH v2 1/9] bsd-user/mmap.c: Always zero MAP_ANONYMOUS memory in mmap_frag(),
Warner Losh <=
- [PATCH v2 2/9] bsd-user/mmap.c: check pread's return value to fix warnings with _FORTIFY_SOURCE, Warner Losh, 2021/09/22
- [PATCH v2 4/9] bsd-user/mmap.c: mmap return ENOMEM on overflow, Warner Losh, 2021/09/22
- [PATCH v2 6/9] bsd-user/mmap.c: line wrap change, Warner Losh, 2021/09/22