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scsi: protect req->aiocb with AioContext lock 

If requests are being processed in the IOThread when a SCSIDevice is
unplugged, scsi_device_purge_requests() -> scsi_req_cancel_async() races
with I/O completion callbacks. Both threads load and store req->aiocb.
This can lead to assert(r->req.aiocb == NULL) failures and undefined
behavior.

Protect r->req.aiocb with the AioContext lock to prevent the race.

Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230221212218.1378734-2-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2023-02-21 16:22:16 -05:00 committed by Kevin Wolf
parent 8ab8140a04
commit 7b7fc3d010
2 changed files with 22 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
hw/scsi/scsi-disk.c
View File

@ -273,9 +273,11 @@ static void scsi_aio_complete(void *opaque, int ret)
SCSIDiskReq *r = (SCSIDiskReq *)opaque;
SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, r->req.dev);
aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
assert(r->req.aiocb != NULL);
r->req.aiocb = NULL;
aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
if (scsi_disk_req_check_error(r, ret, true)) {
goto done;
}
@ -357,10 +359,11 @@ static void scsi_dma_complete(void *opaque, int ret)
SCSIDiskReq *r = (SCSIDiskReq *)opaque;
SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, r->req.dev);
aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
assert(r->req.aiocb != NULL);
r->req.aiocb = NULL;
aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
if (ret < 0) {
block_acct_failed(blk_get_stats(s->qdev.conf.blk), &r->acct);
} else {
@ -393,10 +396,11 @@ static void scsi_read_complete(void *opaque, int ret)
SCSIDiskReq *r = (SCSIDiskReq *)opaque;
SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, r->req.dev);
aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
assert(r->req.aiocb != NULL);
r->req.aiocb = NULL;
aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
if (ret < 0) {
block_acct_failed(blk_get_stats(s->qdev.conf.blk), &r->acct);
} else {
@ -446,10 +450,11 @@ static void scsi_do_read_cb(void *opaque, int ret)
SCSIDiskReq *r = (SCSIDiskReq *)opaque;
SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, r->req.dev);
aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
assert (r->req.aiocb != NULL);
r->req.aiocb = NULL;
aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
if (ret < 0) {
block_acct_failed(blk_get_stats(s->qdev.conf.blk), &r->acct);
} else {
@ -530,10 +535,11 @@ static void scsi_write_complete(void * opaque, int ret)
SCSIDiskReq *r = (SCSIDiskReq *)opaque;
SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, r->req.dev);
aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
assert (r->req.aiocb != NULL);
r->req.aiocb = NULL;
aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
if (ret < 0) {
block_acct_failed(blk_get_stats(s->qdev.conf.blk), &r->acct);
} else {
@ -1737,10 +1743,11 @@ static void scsi_unmap_complete(void *opaque, int ret)
SCSIDiskReq *r = data->r;
SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, r->req.dev);
aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
assert(r->req.aiocb != NULL);
r->req.aiocb = NULL;
aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
if (scsi_disk_req_check_error(r, ret, true)) {
scsi_req_unref(&r->req);
g_free(data);
@ -1816,9 +1823,11 @@ static void scsi_write_same_complete(void *opaque, int ret)
SCSIDiskReq *r = data->r;
SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, r->req.dev);
aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
assert(r->req.aiocb != NULL);
r->req.aiocb = NULL;
aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
if (scsi_disk_req_check_error(r, ret, true)) {
goto done;
}

11
hw/scsi/scsi-generic.c
View File

@ -111,10 +111,11 @@ static void scsi_command_complete(void *opaque, int ret)
SCSIGenericReq *r = (SCSIGenericReq *)opaque;
SCSIDevice *s = r->req.dev;
aio_context_acquire(blk_get_aio_context(s->conf.blk));
assert(r->req.aiocb != NULL);
r->req.aiocb = NULL;
aio_context_acquire(blk_get_aio_context(s->conf.blk));
scsi_command_complete_noio(r, ret);
aio_context_release(blk_get_aio_context(s->conf.blk));
}
@ -269,11 +270,11 @@ static void scsi_read_complete(void * opaque, int ret)
SCSIDevice *s = r->req.dev;
int len;
aio_context_acquire(blk_get_aio_context(s->conf.blk));
assert(r->req.aiocb != NULL);
r->req.aiocb = NULL;
aio_context_acquire(blk_get_aio_context(s->conf.blk));
if (ret || r->req.io_canceled) {
scsi_command_complete_noio(r, ret);
goto done;
@ -386,11 +387,11 @@ static void scsi_write_complete(void * opaque, int ret)
trace_scsi_generic_write_complete(ret);
aio_context_acquire(blk_get_aio_context(s->conf.blk));
assert(r->req.aiocb != NULL);
r->req.aiocb = NULL;
aio_context_acquire(blk_get_aio_context(s->conf.blk));
if (ret || r->req.io_canceled) {
scsi_command_complete_noio(r, ret);
goto done;