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qemu/0012-linux-user-fix-segfault-deadlock.patch
Andreas Färber 8c721a87ae Accepting request 408549 from home:algraf:branches:Virtualization
- Remove deprecated patch "work-around-SA_RESTART-race" (boo#982208)
- Patch queue updated from git://github.com/openSUSE/qemu.git opensuse-2.6
* Patches dropped:
  0002-XXX-work-around-SA_RESTART-race-wit.patch
  0003-qemu-0.9.0.cvs-binfmt.patch
  0004-qemu-cvs-alsa_bitfield.patch
  0005-qemu-cvs-alsa_ioctl.patch
  0006-qemu-cvs-alsa_mmap.patch
  0007-qemu-cvs-gettimeofday.patch
  0008-qemu-cvs-ioctl_debug.patch
  0009-qemu-cvs-ioctl_nodirection.patch
  0010-block-vmdk-Support-creation-of-SCSI.patch
  0011-linux-user-add-binfmt-wrapper-for-a.patch
  0012-PPC-KVM-Disable-mmu-notifier-check.patch
  0013-linux-user-fix-segfault-deadlock.patch
  0014-linux-user-binfmt-support-host-bina.patch
  0015-linux-user-Ignore-broken-loop-ioctl.patch
  0016-linux-user-lock-tcg.patch
  0017-linux-user-Run-multi-threaded-code-.patch
  0018-linux-user-lock-tb-flushing-too.patch
  0019-linux-user-Fake-proc-cpuinfo.patch
  0020-linux-user-implement-FS_IOC_GETFLAG.patch
  0021-linux-user-implement-FS_IOC_SETFLAG.patch
  0022-linux-user-XXX-disable-fiemap.patch
  0023-slirp-nooutgoing.patch
  0024-vnc-password-file-and-incoming-conn.patch
  0025-linux-user-add-more-blk-ioctls.patch
  0026-linux-user-use-target_ulong.patch
  0027-block-Add-support-for-DictZip-enabl.patch
  0028-block-Add-tar-container-format.patch

OBS-URL: https://build.opensuse.org/request/show/408549
OBS-URL: https://build.opensuse.org/package/show/Virtualization/qemu?expand=0&rev=305
2016-07-14 15:50:35 +00:00

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Diff

From 6b4338150763e8241cec19846a48a132d60fe75f Mon Sep 17 00:00:00 2001
From: Alexander Graf <agraf@suse.de>
Date: Fri, 13 Jan 2012 17:05:41 +0100
Subject: [PATCH] linux-user: fix segfault deadlock
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
When entering the guest we take a lock to ensure that nobody else messes
with our TB chaining while we're doing it. If we get a segfault inside that
code, we manage to work on, but will not unlock the lock.
This patch forces unlocking of that lock in the segv handler. I'm not sure
this is the right approach though. Maybe we should rather make sure we don't
segfault in the code? I would greatly appreciate someone more intelligible
than me to look at this :).
Example code to trigger this is at: http://csgraf.de/tmp/conftest.c
Reported-by: Fabio Erculiani <lxnay@sabayon.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
[AF: Drop spinlock_safe_unlock() and switch to tb_lock_reset() (bonzini)]
Signed-off-by: Andreas Färber <afaerber@suse.de>
---
user-exec.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/user-exec.c b/user-exec.c
index d8d597b..f8b7752 100644
--- a/user-exec.c
+++ b/user-exec.c
@@ -94,6 +94,10 @@ static inline int handle_cpu_signal(uintptr_t pc, unsigned long address,
printf("qemu: SIGSEGV pc=0x%08lx address=%08lx w=%d oldset=0x%08lx\n",
pc, address, is_write, *(unsigned long *)old_set);
#endif
+
+ /* Maybe we're still holding the TB fiddling lock? */
+ tb_lock_reset();
+
/* XXX: locking issue */
if (is_write && h2g_valid(address)
&& page_unprotect(h2g(address), pc, puc)) {