!292 Automatically generate code patches with openeuler !118

From: @kuhnchen18
Reviewed-by: @imxcc,@imxcc
Signed-off-by: @imxcc,@imxcc

blockjob-Fix-crash-with-IOthread-when-block-commit-a.patch

@@ -0,0 +1,114 @@
+From e37cda3452309d147f1f7aec3c74249001e3db0c Mon Sep 17 00:00:00 2001
+From: Michael Qiu <qiudayu@huayun.com>
+Date: Wed, 12 May 2021 21:54:37 +0800
+Subject: [PATCH] blockjob: Fix crash with IOthread when block commit after
+ snapshot
+
+Currently, if guest has workloads, IO thread will acquire aio_context
+lock before do io_submit, it leads to segmentfault when do block commit
+after snapshot. Just like below:
+
+Program received signal SIGSEGV, Segmentation fault.
+
+[Switching to Thread 0x7f7c7d91f700 (LWP 99907)]
+0x00005576d0f65aab in bdrv_mirror_top_pwritev at ../block/mirror.c:1437
+1437    ../block/mirror.c: No such file or directory.
+(gdb) p s->job
+$17 = (MirrorBlockJob *) 0x0
+(gdb) p s->stop
+$18 = false
+
+Call trace of IO thread:
+0  0x00005576d0f65aab in bdrv_mirror_top_pwritev at ../block/mirror.c:1437
+1  0x00005576d0f7f3ab in bdrv_driver_pwritev at ../block/io.c:1174
+2  0x00005576d0f8139d in bdrv_aligned_pwritev at ../block/io.c:1988
+3  0x00005576d0f81b65 in bdrv_co_pwritev_part at ../block/io.c:2156
+4  0x00005576d0f8e6b7 in blk_do_pwritev_part at ../block/block-backend.c:1260
+5  0x00005576d0f8e84d in blk_aio_write_entry at ../block/block-backend.c:1476
+...
+
+Switch to qemu main thread:
+0  0x00007f903be704ed in __lll_lock_wait at
+/lib/../lib64/libpthread.so.0
+1  0x00007f903be6bde6 in _L_lock_941 at /lib/../lib64/libpthread.so.0
+2  0x00007f903be6bcdf in pthread_mutex_lock at
+/lib/../lib64/libpthread.so.0
+3  0x0000564b21456889 in qemu_mutex_lock_impl at
+../util/qemu-thread-posix.c:79
+4  0x0000564b213af8a5 in block_job_add_bdrv at ../blockjob.c:224
+5  0x0000564b213b00ad in block_job_create at ../blockjob.c:440
+6  0x0000564b21357c0a in mirror_start_job at ../block/mirror.c:1622
+7  0x0000564b2135a9af in commit_active_start at ../block/mirror.c:1867
+8  0x0000564b2133d132 in qmp_block_commit at ../blockdev.c:2768
+9  0x0000564b2141fef3 in qmp_marshal_block_commit at
+qapi/qapi-commands-block-core.c:346
+10 0x0000564b214503c9 in do_qmp_dispatch_bh at
+../qapi/qmp-dispatch.c:110
+11 0x0000564b21451996 in aio_bh_poll at ../util/async.c:164
+12 0x0000564b2146018e in aio_dispatch at ../util/aio-posix.c:381
+13 0x0000564b2145187e in aio_ctx_dispatch at ../util/async.c:306
+14 0x00007f9040239049 in g_main_context_dispatch at
+/lib/../lib64/libglib-2.0.so.0
+15 0x0000564b21447368 in main_loop_wait at ../util/main-loop.c:232
+16 0x0000564b21447368 in main_loop_wait at ../util/main-loop.c:255
+17 0x0000564b21447368 in main_loop_wait at ../util/main-loop.c:531
+18 0x0000564b212304e1 in qemu_main_loop at ../softmmu/runstate.c:721
+19 0x0000564b20f7975e in main at ../softmmu/main.c:50
+
+In IO thread when do bdrv_mirror_top_pwritev, the job is NULL, and stop field
+is false, this means the MirrorBDSOpaque "s" object has not been initialized
+yet, and this object is initialized by block_job_create(), but the initialize
+process is stuck in acquiring the lock.
+
+In this situation, IO thread come to bdrv_mirror_top_pwritev(),which means that
+mirror-top node is already inserted into block graph, but its bs->opaque->job
+is not initialized.
+
+The root cause is that qemu main thread do release/acquire when hold the lock,
+at the same time, IO thread get the lock after release stage, and the crash
+occured.
+
+Actually, in this situation, job->job.aio_context will not equal to
+qemu_get_aio_context(), and will be the same as bs->aio_context,
+thus, no need to release the lock, becasue bdrv_root_attach_child()
+will not change the context.
+
+This patch fix this issue.
+
+Fixes: 132ada80 "block: Adjust AioContexts when attaching nodes"
+
+Signed-off-by: Michael Qiu <qiudayu@huayun.com>
+Message-Id: <20210203024059.52683-1-08005325@163.com>
+Signed-off-by: Kevin Wolf <kwolf@redhat.com>
+---
+ blockjob.c | 8 ++++++--
+ 1 file changed, 6 insertions(+), 2 deletions(-)
+
+diff --git a/blockjob.c b/blockjob.c
+index 74abb97bfd..72865a4a6e 100644
+--- a/blockjob.c
++++ b/blockjob.c
+@@ -223,14 +223,18 @@ int block_job_add_bdrv(BlockJob *job, const char *name, BlockDriverState *bs,
+                        uint64_t perm, uint64_t shared_perm, Error **errp)
+ {
+     BdrvChild *c;
++    bool need_context_ops;
+ 
+     bdrv_ref(bs);
+-    if (job->job.aio_context != qemu_get_aio_context()) {
++
++    need_context_ops = bdrv_get_aio_context(bs) != job->job.aio_context;
++
++    if (need_context_ops && job->job.aio_context != qemu_get_aio_context()) {
+         aio_context_release(job->job.aio_context);
+     }
+     c = bdrv_root_attach_child(bs, name, &child_job, job->job.aio_context,
+                                perm, shared_perm, job, errp);
+-    if (job->job.aio_context != qemu_get_aio_context()) {
++    if (need_context_ops && job->job.aio_context != qemu_get_aio_context()) {
+         aio_context_acquire(job->job.aio_context);
+     }
+     if (c == NULL) {
+-- 
+2.27.0
+

qemu.spec

@@ -1,6 +1,6 @@
 Name: qemu
 Version: 4.1.0
-Release: 57
+Release: 58
 Epoch: 2
 Summary: QEMU is a generic and open source machine emulator and virtualizer
 License: GPLv2 and BSD and MIT and CC-BY-SA-4.0
@@ -326,6 +326,7 @@ Patch0313: tz-ppc-add-dummy-read-write-methods.patch
 Patch0314: imx7-ccm-add-digprog-mmio-write-method.patch
 Patch0315: util-cacheinfo-fix-crash-when-compiling-with-uClibc.patch
 Patch0316: arm-cpu-Fixed-function-undefined-error-at-compile-ti.patch
+Patch0317: blockjob-Fix-crash-with-IOthread-when-block-commit-a.patch
 
 BuildRequires: flex
 BuildRequires: bison
@@ -719,6 +720,9 @@ getent passwd qemu >/dev/null || \
 %endif
 
 %changelog
+* Fri May 28 2021 Chen Qun <kuhn.chenqun@huawei.com>
+- blockjob: Fix crash with IOthread when block commit after snapshot
+
 * Thu 20 May 2021 zhouli57 <zhouli57@huawei.com>
 - arm/cpu: Fixed function undefined error at compile time under arm