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From: Stefan Hajnoczi <stefanha@redhat.com>
To: qemu-devel@nongnu.org
Cc: kwolf@redhat.com, Stefan Weil <sw@weilnetz.de>,
	Stefan Hajnoczi <stefanha@redhat.com>
Subject: [PATCH 0/3] coroutine: use QEMU_DEFINE_STATIC_CO_TLS()
Date: Mon,  7 Mar 2022 15:38:50 +0000	[thread overview]
Message-ID: <20220307153853.602859-1-stefanha@redhat.com> (raw)

The coroutine implementation uses __thread variables internally. Compiler
optimizations may cache Thread-Local Storage values across
qemu_coroutine_yield(), leading to stale values being used after the coroutine
is re-entered from another thread.

Kevin pointed out that the coroutine implementation itself is vulnerable to
this problem. As a follow-up to my coroutine TLS patch series I'm sending these
patches to convert __thread variables to the new "qemu/coroutine-tls.h" macros
so they are safe.

Stefan Hajnoczi (3):
  coroutine-ucontext: use QEMU_DEFINE_STATIC_CO_TLS()
  coroutine: use QEMU_DEFINE_STATIC_CO_TLS()
  coroutine-win32: use QEMU_DEFINE_STATIC_CO_TLS()

 util/coroutine-ucontext.c | 38 +++++++++++++++++++++++-------------
 util/coroutine-win32.c    | 18 ++++++++++++-----
 util/qemu-coroutine.c     | 41 +++++++++++++++++++++++----------------
 3 files changed, 61 insertions(+), 36 deletions(-)

-- 
2.35.1




             reply	other threads:[~2022-03-07 15:50 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-07 15:38 Stefan Hajnoczi [this message]
2022-03-07 15:38 ` [PATCH 1/3] coroutine-ucontext: use QEMU_DEFINE_STATIC_CO_TLS() Stefan Hajnoczi
2022-03-07 15:38 ` [PATCH 2/3] coroutine: " Stefan Hajnoczi
2022-03-07 15:38 ` [PATCH 3/3] coroutine-win32: " Stefan Hajnoczi
2022-03-07 16:03 ` [PATCH 0/3] coroutine: " Philippe Mathieu-Daudé
2022-03-16 13:28 ` Stefan Hajnoczi
2022-05-03 10:48 ` Kevin Wolf

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