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qemu/9pfs-fix-crash-in-v9fs_walk.patch
José Ricardo Ziviani 00b6d2ec43 Accepting request 919019 from home:jziviani:branches:Virtualization
- Replace patch to fix hardcoded binfmt handler
  (bsc#1186256)
* Patches dropped:
  qemu-binfmt-conf.sh-allow-overriding-SUS.patch
* Patches added:
  qemu-binfmt-conf.sh-should-use-F-as-shor.patch
- Stable fixes from upstream
* Patches added:
  9pfs-fix-crash-in-v9fs_walk.patch
  i386-cpu-Remove-AVX_VNNI-feature-from-Co.patch
  plugins-do-not-limit-exported-symbols-if.patch
  plugins-execlog-removed-unintended-s-at-.patch
  qemu-sockets-fix-unix-socket-path-copy-a.patch
  target-i386-add-missing-bits-to-CR4_RESE.patch
  virtio-balloon-don-t-start-free-page-hin.patch

OBS-URL: https://build.opensuse.org/request/show/919019
OBS-URL: https://build.opensuse.org/package/show/Virtualization/qemu?expand=0&rev=672
2021-09-14 22:18:25 +00:00

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2.8 KiB
Diff

From: Christian Schoenebeck <qemu_oss@crudebyte.com>
Date: Wed, 1 Sep 2021 18:15:10 +0200
Subject: 9pfs: fix crash in v9fs_walk()
Git-commit: f83df00900816476cca41bb536e4d532b297d76e
v9fs_walk() utilizes the v9fs_co_run_in_worker({...}) macro to run the
supplied fs driver code block on a background worker thread.
When either the 'Twalk' client request was interrupted or if the client
requested fid for that 'Twalk' request caused a stat error then that
fs driver code block was left by 'break' keyword, with the intention to
return from worker thread back to main thread as well:
v9fs_co_run_in_worker({
if (v9fs_request_cancelled(pdu)) {
err = -EINTR;
break;
}
err = s->ops->lstat(&s->ctx, &dpath, &fidst);
if (err < 0) {
err = -errno;
break;
}
...
});
However that 'break;' statement also skipped the v9fs_co_run_in_worker()
macro's final and mandatory
/* re-enter back to qemu thread */
qemu_coroutine_yield();
call and thus caused the rest of v9fs_walk() to be continued being
executed on the worker thread instead of main thread, eventually
leading to a crash in the transport virtio transport driver.
To fix this issue and to prevent the same error from happening again by
other users of v9fs_co_run_in_worker() in future, auto wrap the supplied
code block into its own
do { } while (0);
loop inside the 'v9fs_co_run_in_worker' macro definition.
Full discussion and backtrace:
https://lists.gnu.org/archive/html/qemu-devel/2021-08/msg05209.html
https://lists.gnu.org/archive/html/qemu-devel/2021-09/msg00174.html
Fixes: 8d6cb100731c4d28535adbf2a3c2d1f29be3fef4
Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Cc: qemu-stable@nongnu.org
Reviewed-by: Greg Kurz <groug@kaod.org>
Message-Id: <E1mLTBg-0002Bh-2D@lizzy.crudebyte.com>
Signed-off-by: Jose R. Ziviani <jziviani@suse.de>
---
hw/9pfs/coth.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/hw/9pfs/coth.h b/hw/9pfs/coth.h
index c51289903d0df0ff65f9d3f2649b..f83c7dda7bb8df8295c6a6db59c5 100644
--- a/hw/9pfs/coth.h
+++ b/hw/9pfs/coth.h
@@ -51,7 +51,9 @@
*/ \
qemu_coroutine_yield(); \
qemu_bh_delete(co_bh); \
- code_block; \
+ do { \
+ code_block; \
+ } while (0); \
/* re-enter back to qemu thread */ \
qemu_coroutine_yield(); \
} while (0)