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author | Deepa Srinivasan <deepa.srinivasan@oracle.com> | 2017-12-15 16:59:13 -0800 |
---|---|---|
committer | Stefan Hajnoczi <stefanha@redhat.com> | 2018-03-08 15:43:11 +0000 |
commit | c060332c762acbe7899b01edda972da7f9ec9057 (patch) | |
tree | f8e61f407d4b17c039f93e8b7a4137ec65c29794 /block | |
parent | 0ab4537f08e09b13788db67efd760592fb7db769 (diff) | |
download | qemu-c060332c762acbe7899b01edda972da7f9ec9057.zip qemu-c060332c762acbe7899b01edda972da7f9ec9057.tar.gz qemu-c060332c762acbe7899b01edda972da7f9ec9057.tar.bz2 |
block: Fix qemu crash when using scsi-block
Starting qemu with the following arguments causes qemu to segfault:
... -device lsi,id=lsi0 -drive file=iscsi:<...>,format=raw,if=none,node-name=
iscsi1 -device scsi-block,bus=lsi0.0,id=<...>,drive=iscsi1
This patch fixes blk_aio_ioctl() so it does not pass stack addresses to
blk_aio_ioctl_entry() which may be invoked after blk_aio_ioctl() returns. More
details about the bug follow.
blk_aio_ioctl() invokes blk_aio_prwv() with blk_aio_ioctl_entry as the
coroutine parameter. blk_aio_prwv() ultimately calls aio_co_enter().
When blk_aio_ioctl() is executed from within a coroutine context (e.g.
iscsi_bh_cb()), aio_co_enter() adds the coroutine (blk_aio_ioctl_entry) to
the current coroutine's wakeup queue. blk_aio_ioctl() then returns.
When blk_aio_ioctl_entry() executes later, it accesses an invalid pointer:
....
BlkRwCo *rwco = &acb->rwco;
rwco->ret = blk_co_ioctl(rwco->blk, rwco->offset,
rwco->qiov->iov[0].iov_base); <--- qiov is
invalid here
...
In the case when blk_aio_ioctl() is called from a non-coroutine context,
blk_aio_ioctl_entry() executes immediately. But if bdrv_co_ioctl() calls
qemu_coroutine_yield(), blk_aio_ioctl() will return. When the coroutine
execution is complete, control returns to blk_aio_ioctl_entry() after the call
to blk_co_ioctl(). There is no invalid reference after this point, but the
function is still holding on to invalid pointers.
The fix is to change blk_aio_prwv() to accept a void pointer for the IO buffer
rather than a QEMUIOVector. blk_aio_prwv() passes this through in BlkRwCo and the
coroutine function casts it to QEMUIOVector or uses the void pointer directly.
Signed-off-by: Deepa Srinivasan <deepa.srinivasan@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Mark Kanda <mark.kanda@oracle.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'block')
-rw-r--r-- | block/block-backend.c | 51 |
1 files changed, 25 insertions, 26 deletions
diff --git a/block/block-backend.c b/block/block-backend.c index b3c790e..f2e0a85 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -1150,7 +1150,7 @@ int coroutine_fn blk_co_pwritev(BlockBackend *blk, int64_t offset, typedef struct BlkRwCo { BlockBackend *blk; int64_t offset; - QEMUIOVector *qiov; + void *iobuf; int ret; BdrvRequestFlags flags; } BlkRwCo; @@ -1158,17 +1158,19 @@ typedef struct BlkRwCo { static void blk_read_entry(void *opaque) { BlkRwCo *rwco = opaque; + QEMUIOVector *qiov = rwco->iobuf; - rwco->ret = blk_co_preadv(rwco->blk, rwco->offset, rwco->qiov->size, - rwco->qiov, rwco->flags); + rwco->ret = blk_co_preadv(rwco->blk, rwco->offset, qiov->size, + qiov, rwco->flags); } static void blk_write_entry(void *opaque) { BlkRwCo *rwco = opaque; + QEMUIOVector *qiov = rwco->iobuf; - rwco->ret = blk_co_pwritev(rwco->blk, rwco->offset, rwco->qiov->size, - rwco->qiov, rwco->flags); + rwco->ret = blk_co_pwritev(rwco->blk, rwco->offset, qiov->size, + qiov, rwco->flags); } static int blk_prw(BlockBackend *blk, int64_t offset, uint8_t *buf, @@ -1188,7 +1190,7 @@ static int blk_prw(BlockBackend *blk, int64_t offset, uint8_t *buf, rwco = (BlkRwCo) { .blk = blk, .offset = offset, - .qiov = &qiov, + .iobuf = &qiov, .flags = flags, .ret = NOT_DONE, }; @@ -1296,7 +1298,7 @@ static void blk_aio_complete_bh(void *opaque) } static BlockAIOCB *blk_aio_prwv(BlockBackend *blk, int64_t offset, int bytes, - QEMUIOVector *qiov, CoroutineEntry co_entry, + void *iobuf, CoroutineEntry co_entry, BdrvRequestFlags flags, BlockCompletionFunc *cb, void *opaque) { @@ -1308,7 +1310,7 @@ static BlockAIOCB *blk_aio_prwv(BlockBackend *blk, int64_t offset, int bytes, acb->rwco = (BlkRwCo) { .blk = blk, .offset = offset, - .qiov = qiov, + .iobuf = iobuf, .flags = flags, .ret = NOT_DONE, }; @@ -1331,10 +1333,11 @@ static void blk_aio_read_entry(void *opaque) { BlkAioEmAIOCB *acb = opaque; BlkRwCo *rwco = &acb->rwco; + QEMUIOVector *qiov = rwco->iobuf; - assert(rwco->qiov->size == acb->bytes); + assert(qiov->size == acb->bytes); rwco->ret = blk_co_preadv(rwco->blk, rwco->offset, acb->bytes, - rwco->qiov, rwco->flags); + qiov, rwco->flags); blk_aio_complete(acb); } @@ -1342,10 +1345,11 @@ static void blk_aio_write_entry(void *opaque) { BlkAioEmAIOCB *acb = opaque; BlkRwCo *rwco = &acb->rwco; + QEMUIOVector *qiov = rwco->iobuf; - assert(!rwco->qiov || rwco->qiov->size == acb->bytes); + assert(!qiov || qiov->size == acb->bytes); rwco->ret = blk_co_pwritev(rwco->blk, rwco->offset, acb->bytes, - rwco->qiov, rwco->flags); + qiov, rwco->flags); blk_aio_complete(acb); } @@ -1474,8 +1478,10 @@ int blk_co_ioctl(BlockBackend *blk, unsigned long int req, void *buf) static void blk_ioctl_entry(void *opaque) { BlkRwCo *rwco = opaque; + QEMUIOVector *qiov = rwco->iobuf; + rwco->ret = blk_co_ioctl(rwco->blk, rwco->offset, - rwco->qiov->iov[0].iov_base); + qiov->iov[0].iov_base); } int blk_ioctl(BlockBackend *blk, unsigned long int req, void *buf) @@ -1488,24 +1494,15 @@ static void blk_aio_ioctl_entry(void *opaque) BlkAioEmAIOCB *acb = opaque; BlkRwCo *rwco = &acb->rwco; - rwco->ret = blk_co_ioctl(rwco->blk, rwco->offset, - rwco->qiov->iov[0].iov_base); + rwco->ret = blk_co_ioctl(rwco->blk, rwco->offset, rwco->iobuf); + blk_aio_complete(acb); } BlockAIOCB *blk_aio_ioctl(BlockBackend *blk, unsigned long int req, void *buf, BlockCompletionFunc *cb, void *opaque) { - QEMUIOVector qiov; - struct iovec iov; - - iov = (struct iovec) { - .iov_base = buf, - .iov_len = 0, - }; - qemu_iovec_init_external(&qiov, &iov, 1); - - return blk_aio_prwv(blk, req, 0, &qiov, blk_aio_ioctl_entry, 0, cb, opaque); + return blk_aio_prwv(blk, req, 0, buf, blk_aio_ioctl_entry, 0, cb, opaque); } int blk_co_pdiscard(BlockBackend *blk, int64_t offset, int bytes) @@ -1949,7 +1946,9 @@ int blk_truncate(BlockBackend *blk, int64_t offset, PreallocMode prealloc, static void blk_pdiscard_entry(void *opaque) { BlkRwCo *rwco = opaque; - rwco->ret = blk_co_pdiscard(rwco->blk, rwco->offset, rwco->qiov->size); + QEMUIOVector *qiov = rwco->iobuf; + + rwco->ret = blk_co_pdiscard(rwco->blk, rwco->offset, qiov->size); } int blk_pdiscard(BlockBackend *blk, int64_t offset, int bytes) |