Message ID | 20101017184340.GA12524@redhat.com |
---|---|
State | New |
Headers | show |
On Sun, 2010-10-17 at 20:43 +0200, Michael S. Tsirkin wrote: > host_from_stream_offset returns NULL on error, > return error instead of trying to use that address, > to avoid segfault on invalid stream. > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > --- > arch_init.c | 5 +++++ > 1 files changed, 5 insertions(+), 0 deletions(-) > > diff --git a/arch_init.c b/arch_init.c > index e468c0c..bc7528d 100644 > --- a/arch_init.c > +++ b/arch_init.c > @@ -116,6 +116,8 @@ static int ram_save_block(QEMUFile *f) > > if (!block) > block = QLIST_FIRST(&ram_list.blocks); > + if (!last_block) > + last_block = block; > > current_addr = block->offset + offset; NAK, last_block == block will cause us to set the continue flag on the first block. I assume you're trying to prevent the last_block->offset segv in the while test, but that should never happen. The only time last_block is NULL is at the beginning of stage 1, where all pages are dirty. At that point we should always enter the if {} block at the beginning of the do {} while, which breaks out rather than hitting the segv. We'll then set last_block for the next pass. > @@ -390,6 +392,9 @@ int ram_load(QEMUFile *f, void *opaque, int version_id) > host = qemu_get_ram_ptr(addr); > else > host = host_from_stream_offset(f, addr, flags); > + if (!host) { > + return -EINVAL; > + } > This should also never happen since we've synchronized ramblocks at the beginning of migration, but probably a good idea to return an error. Thanks, Alex
On Sun, Oct 17, 2010 at 03:01:45PM -0600, Alex Williamson wrote: > On Sun, 2010-10-17 at 20:43 +0200, Michael S. Tsirkin wrote: > > host_from_stream_offset returns NULL on error, > > return error instead of trying to use that address, > > to avoid segfault on invalid stream. > > > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > > --- > > arch_init.c | 5 +++++ > > 1 files changed, 5 insertions(+), 0 deletions(-) > > > > diff --git a/arch_init.c b/arch_init.c > > index e468c0c..bc7528d 100644 > > --- a/arch_init.c > > +++ b/arch_init.c > > @@ -116,6 +116,8 @@ static int ram_save_block(QEMUFile *f) > > > > if (!block) > > block = QLIST_FIRST(&ram_list.blocks); > > + if (!last_block) > > + last_block = block; > > > > current_addr = block->offset + offset; > > NAK, last_block == block will cause us to set the continue flag on the > first block. I assume you're trying to prevent the last_block->offset > segv in the while test, but that should never happen. The only time > last_block is NULL is at the beginning of stage 1, where all pages are > dirty. At that point we should always enter the if {} block at the > beginning of the do {} while, which breaks out rather than hitting the > segv. We'll then set last_block for the next pass. Sorry, sent this chunk in error. > > @@ -390,6 +392,9 @@ int ram_load(QEMUFile *f, void *opaque, int version_id) > > host = qemu_get_ram_ptr(addr); > > else > > host = host_from_stream_offset(f, addr, flags); > > + if (!host) { > > + return -EINVAL; > > + } > > > > This should also never happen since we've synchronized ramblocks at the > beginning of migration, but probably a good idea to return an error. > Thanks, > > Alex
diff --git a/arch_init.c b/arch_init.c index e468c0c..bc7528d 100644 --- a/arch_init.c +++ b/arch_init.c @@ -116,6 +116,8 @@ static int ram_save_block(QEMUFile *f) if (!block) block = QLIST_FIRST(&ram_list.blocks); + if (!last_block) + last_block = block; current_addr = block->offset + offset; @@ -390,6 +392,9 @@ int ram_load(QEMUFile *f, void *opaque, int version_id) host = qemu_get_ram_ptr(addr); else host = host_from_stream_offset(f, addr, flags); + if (!host) { + return -EINVAL; + } ch = qemu_get_byte(f); memset(host, ch, TARGET_PAGE_SIZE);
host_from_stream_offset returns NULL on error, return error instead of trying to use that address, to avoid segfault on invalid stream. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> --- arch_init.c | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-)