From 0a4f5bcc2a6f8ac31431e971c1dce9e6ab2191c2 Mon Sep 17 00:00:00 2001
From: Stefan Hajnoczi <stefanha@redhat.com>
Date: Tue, 21 Feb 2023 16:22:16 -0500
Subject: [PATCH 01/12] scsi: protect req->aiocb with AioContext lock
RH-Author: Stefan Hajnoczi <stefanha@redhat.com>
RH-MergeRequest: 155: virtio-scsi: reset SCSI devices from main loop thread
RH-Bugzilla: 2155748
RH-Acked-by: Eric Blake <eblake@redhat.com>
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
RH-Commit: [1/3] 61727297bd31dfe18220b61f1d265ced0649c60d (stefanha/centos-stream-qemu-kvm)
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>
(cherry picked from commit 7b7fc3d0102dafe8eb44802493036a526e921a71)
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
hw/scsi/scsi-disk.c | 23 ++++++++++++++++-------
hw/scsi/scsi-generic.c | 11 ++++++-----
2 files changed, 22 insertions(+), 12 deletions(-)
diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c
index e493c28814..5327f93f4c 100644
--- a/hw/scsi/scsi-disk.c
+++ b/hw/scsi/scsi-disk.c
@@ -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;
}
diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c
index 92cce20a4d..ac9fa662b4 100644
--- a/hw/scsi/scsi-generic.c
+++ b/hw/scsi/scsi-generic.c
@@ -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;
--
2.39.1