* Tue Feb 21 2023 Miroslav Rezanina <mrezanin@redhat.com> - 7.2.0-10

- kvm-block-temporarily-hold-the-new-AioContext-of-bs_top-.patch [bz#2168209] - Resolves: bz#2168209 (Qemu coredump after do snapshot of mirrored top image and its converted base image(iothread enabled))
2023-02-21 10:14:28 -05:00 · 2023-02-21 10:14:28 -05:00 · c849977b02
commit c849977b02
parent 382f65f59d
2 changed files with 107 additions and 1 deletions
--- a/kvm-block-temporarily-hold-the-new-AioContext-of-bs_top-.patch
+++ b/kvm-block-temporarily-hold-the-new-AioContext-of-bs_top-.patch
@ -0,0 +1,99 @@
+From b952c8f1da6f8597736c0e040565830139369359 Mon Sep 17 00:00:00 2001
+From: Stefano Garzarella <sgarzare@redhat.com>
+Date: Tue, 14 Feb 2023 18:16:21 +0100
+Subject: [PATCH] block: temporarily hold the new AioContext of bs_top in
+ bdrv_append()
+
+RH-Author: Stefano Garzarella <sgarzare@redhat.com>
+RH-MergeRequest: 153: block: temporarily hold the new AioContext of bs_top in bdrv_append()
+RH-Bugzilla: 2168209
+RH-Acked-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
+RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
+RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
+RH-Commit: [1/1] 5b190426d996e8c9f7a781bd97aee8d25756dbd3 (sgarzarella/qemu-kvm-c-9-s)
+
+bdrv_append() is called with bs_top AioContext held, but
+bdrv_attach_child_noperm() could change the AioContext of bs_top.
+
+bdrv_replace_node_noperm() calls bdrv_drained_begin() starting from
+commit 2398747128 ("block: Don't poll in bdrv_replace_child_noperm()").
+bdrv_drained_begin() can call BDRV_POLL_WHILE that assumes the new lock
+is taken, so let's temporarily hold the new AioContext to prevent QEMU
+from failing in BDRV_POLL_WHILE when it tries to release the wrong
+AioContext.
+
+Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2168209
+Reported-by: Aihua Liang <aliang@redhat.com>
+Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
+Message-Id: <20230214171621.11574-1-sgarzare@redhat.com>
+Reviewed-by: Kevin Wolf <kwolf@redhat.com>
+Signed-off-by: Kevin Wolf <kwolf@redhat.com>
+(cherry picked from commit 60d90bf43c169b9d1dbcb17ed794b7b02c6862b1)
+Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
+---
+ block.c | 23 +++++++++++++++++++++++
+ 1 file changed, 23 insertions(+)
+
+diff --git a/block.c b/block.c
+index 0d78711416..9e1dcb9e47 100644
+--- a/block.c
+++ b/block.c
+@@ -5275,6 +5275,8 @@ int bdrv_drop_filter(BlockDriverState *bs, Error **errp)
+  * child.
+  *
+  * This function does not create any image files.
+ *
+ * The caller must hold the AioContext lock for @bs_top.
+  */
+ int bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
+                 Error **errp)
+@@ -5282,11 +5284,14 @@ int bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
+     int ret;
+     BdrvChild *child;
+     Transaction *tran = tran_new();
+    AioContext *old_context, *new_context = NULL;
+ 
+     GLOBAL_STATE_CODE();
+ 
+     assert(!bs_new->backing);
+ 
+    old_context = bdrv_get_aio_context(bs_top);
+
+     child = bdrv_attach_child_noperm(bs_new, bs_top, "backing",
+                                      &child_of_bds, bdrv_backing_role(bs_new),
+                                      tran, errp);
+@@ -5295,6 +5300,19 @@ int bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top,
+         goto out;
+     }
+ 
+    /*
+     * bdrv_attach_child_noperm could change the AioContext of bs_top.
+     * bdrv_replace_node_noperm calls bdrv_drained_begin, so let's temporarily
+     * hold the new AioContext, since bdrv_drained_begin calls BDRV_POLL_WHILE
+     * that assumes the new lock is taken.
+     */
+    new_context = bdrv_get_aio_context(bs_top);
+
+    if (old_context != new_context) {
+        aio_context_release(old_context);
+        aio_context_acquire(new_context);
+    }
+
+     ret = bdrv_replace_node_noperm(bs_top, bs_new, true, tran, errp);
+     if (ret < 0) {
+         goto out;
+@@ -5306,6 +5324,11 @@ out:
+ 
+     bdrv_refresh_limits(bs_top, NULL, NULL);
+ 
+    if (new_context && old_context != new_context) {
+        aio_context_release(new_context);
+        aio_context_acquire(old_context);
+    }
+
+     return ret;
+ }
+ 
+-- 
+2.31.1
+
--- a/qemu-kvm.spec
+++ b/qemu-kvm.spec
@ -148,7 +148,7 @@ Obsoletes: %{name}-block-ssh <= %{epoch}:%{version}                    \
 Summary: QEMU is a machine emulator and virtualizer
 Name: qemu-kvm
 Version: 7.2.0
-Release: 9%{?rcrel}%{?dist}%{?cc_suffix}
+Release: 10%{?rcrel}%{?dist}%{?cc_suffix}
 # Epoch because we pushed a qemu-1.0 package. AIUI this can't ever be dropped
 # Epoch 15 used for RHEL 8
 # Epoch 17 used for RHEL 9 (due to release versioning offset in RHEL 8.5)
@ -372,6 +372,8 @@ Patch111: kvm-io-Add-support-for-MSG_PEEK-for-socket-channel.patch
 Patch112: kvm-migration-check-magic-value-for-deciding-the-mapping.patch
 # For bz#2168172 - [s390x] qemu-kvm coredumps when SE crashes
 Patch113: kvm-target-s390x-arch_dump-Fix-memory-corruption-in-s390.patch
+# For bz#2168209 - Qemu coredump after do snapshot of mirrored top image and its converted base image(iothread enabled)
+Patch114: kvm-block-temporarily-hold-the-new-AioContext-of-bs_top-.patch

 %if %{have_clang}
 BuildRequires: clang
@ -1402,6 +1404,11 @@ useradd -r -u 107 -g qemu -G kvm -d / -s /sbin/nologin \
 %endif

 %changelog
+* Tue Feb 21 2023 Miroslav Rezanina <mrezanin@redhat.com> - 7.2.0-10
+- kvm-block-temporarily-hold-the-new-AioContext-of-bs_top-.patch [bz#2168209]
+- Resolves: bz#2168209
+  (Qemu coredump after do snapshot of mirrored top image and its converted base image(iothread enabled))
+
 * Fri Feb 17 2023 Miroslav Rezanina <mrezanin@redhat.com> - 7.2.0-9
 - kvm-tests-qtest-netdev-test-stream-and-dgram-backends.patch [bz#2169232]
 - kvm-net-stream-add-a-new-option-to-automatically-reconne.patch [bz#2169232]