Message ID | 1450665214-4467-1-git-send-email-chengang@emindsoft.com.cn |
---|---|
State | New |
Headers | show |
Le 21/12/2015 03:33, chengang@emindsoft.com.cn a écrit : > From: Chen Gang <chengang@emindsoft.com.cn> > > When mapping MAP_ANONYMOUS memory fragments, still need notice about to > set it zero, or it will cause issues. Perhaps you can explain in the commit message why this page is not already filled by zeros ? > Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com> > --- > linux-user/mmap.c | 4 +++- > 1 files changed, 3 insertions(+), 1 deletions(-) > > diff --git a/linux-user/mmap.c b/linux-user/mmap.c > index 7b459d5..29fe646 100644 > --- a/linux-user/mmap.c > +++ b/linux-user/mmap.c > @@ -186,10 +186,12 @@ 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) && ((flags & MAP_PRIVATE) || (fd == -1))) { According to manpage, for MAP_ANONYMOUS, fd can be ignored. Why do you check if the page is MAP_PRIVATE or not ? > + memset(g2h(start), 0, end - start); > + } > } > return 0; > } >
diff --git a/linux-user/mmap.c b/linux-user/mmap.c index 7b459d5..29fe646 100644 --- a/linux-user/mmap.c +++ b/linux-user/mmap.c @@ -186,10 +186,12 @@ 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) && ((flags & MAP_PRIVATE) || (fd == -1))) { + memset(g2h(start), 0, end - start); + } } return 0; }