| Message ID | 1497078250-19505-1-git-send-email-lizhengui@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sat, Jun 10, 2017 at 03:04:10PM +0800, Zhengui Li wrote: >Avoid empty pointer access if the bs is NULL. Looks like most (if not all) of the places these are called dereference bs anyway. Can it ever be NULL? Perhaps a check for each of those case (if any) would be a better idea. >Signed-off-by: Zhengui Li <lizhengui@huawei.com> >--- > block/io.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > >diff --git a/block/io.c b/block/io.c >index ed31810..b12d7cf 100644 >--- a/block/io.c >+++ b/block/io.c >@@ -492,7 +492,9 @@ static bool tracked_request_overlaps(BdrvTrackedRequest *req, > > void bdrv_inc_in_flight(BlockDriverState *bs) > { >- atomic_inc(&bs->in_flight); >+ if (bs) { >+ atomic_inc(&bs->in_flight); >+ } > } > > static void dummy_bh_cb(void *opaque) >@@ -508,8 +510,10 @@ void bdrv_wakeup(BlockDriverState *bs) > > void bdrv_dec_in_flight(BlockDriverState *bs) > { >- atomic_dec(&bs->in_flight); >- bdrv_wakeup(bs); >+ if (bs) { >+ atomic_dec(&bs->in_flight); >+ bdrv_wakeup(bs); >+ } > } > > static bool coroutine_fn wait_serialising_requests(BdrvTrackedRequest *self) >-- >1.8.3.1 > > >
On 06/10/2017 02:04 AM, Zhengui Li wrote: > Avoid empty pointer access if the bs is NULL. > > Signed-off-by: Zhengui Li <lizhengui@huawei.com> > --- > block/io.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) NACK; this is fixing a symptom, not the problem. If you have a coredump due to a bad caller passing in NULL, then post the backtrace and let's fix the broken caller instead.
diff --git a/block/io.c b/block/io.c index ed31810..b12d7cf 100644 --- a/block/io.c +++ b/block/io.c @@ -492,7 +492,9 @@ static bool tracked_request_overlaps(BdrvTrackedRequest *req, void bdrv_inc_in_flight(BlockDriverState *bs) { - atomic_inc(&bs->in_flight); + if (bs) { + atomic_inc(&bs->in_flight); + } } static void dummy_bh_cb(void *opaque) @@ -508,8 +510,10 @@ void bdrv_wakeup(BlockDriverState *bs) void bdrv_dec_in_flight(BlockDriverState *bs) { - atomic_dec(&bs->in_flight); - bdrv_wakeup(bs); + if (bs) { + atomic_dec(&bs->in_flight); + bdrv_wakeup(bs); + } } static bool coroutine_fn wait_serialising_requests(BdrvTrackedRequest *self)
Avoid empty pointer access if the bs is NULL. Signed-off-by: Zhengui Li <lizhengui@huawei.com> --- block/io.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)