From 462e5d506573e61adce70f53176d5ae85d1ba92a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= <f4bug@amsat.org>
Date: Mon, 15 May 2017 21:11:49 -0300
Subject: [PATCH 1/5] oslib: strip trailing '\n' from error_setg() string
argument
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
spotted by Coccinelle script scripts/coccinelle/err-bad-newline.cocci
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
util/oslib-posix.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index 7e28c161b2..9ab2eb221b 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -400,7 +400,7 @@ void os_mem_prealloc(int fd, char *area, size_t memory, int smp_cpus,
/* touch pages simultaneously */
if (touch_all_pages(area, hpagesize, numpages, smp_cpus)) {
error_setg(errp, "os_mem_prealloc: Insufficient free host memory "
- "pages available to allocate guest RAM\n");
+ "pages available to allocate guest RAM");
}
ret = sigaction(SIGBUS, &oldact, NULL);
From f652402487be592402a5edc000a652344e842369 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= <f4bug@amsat.org>
Date: Mon, 15 May 2017 21:11:50 -0300
Subject: [PATCH 2/5] coccinelle: fix typo in comment
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
scripts/coccinelle/return_directly.cocci | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/scripts/coccinelle/return_directly.cocci b/scripts/coccinelle/return_directly.cocci
index 48680f2c2a..4cf50e75ea 100644
--- a/scripts/coccinelle/return_directly.cocci
+++ b/scripts/coccinelle/return_directly.cocci
@@ -1,4 +1,4 @@
-// replace 'R = X; return R;' with 'return R;'
+// replace 'R = X; return R;' with 'return X;'
@@
identifier VAR;
expression E;
From 3a586d2f0bb0cf9c1c7a53f7a183de199c93d0ea Mon Sep 17 00:00:00 2001
From: Stefan Hajnoczi <stefanha@redhat.com>
Date: Wed, 17 May 2017 13:40:42 +0100
Subject: [PATCH 3/5] .gdbinit: load QEMU sub-commands when gdb starts
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
The scripts/qemu-gdb.py file is not easily discoverable. Add a .gdbinit
file so GDB either loads qemu-gdb.py automatically or prints a message
informing the user how to enable them (some systems disable ./.gdbinit
loading for security reasons).
Symlink .gdbinit and the scripts directory in order to make out-of-tree
builds work. The scripts directory is used to find the qemu-gdb.py file
specified by a relative path in .gdbinit.
Suggested-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Eric Blake <eblake@redhat.com>
Message-id: 20170517124042.1430-1-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
.gdbinit | 8 ++++++++
configure | 1 +
2 files changed, 9 insertions(+)
create mode 100644 .gdbinit
diff --git a/.gdbinit b/.gdbinit
new file mode 100644
index 0000000000..9d322fca93
--- /dev/null
+++ b/.gdbinit
@@ -0,0 +1,8 @@
+# GDB may have ./.gdbinit loading disabled by default. In that case you can
+# follow the instructions it prints. They boil down to adding the following to
+# your home directory's ~/.gdbinit file:
+#
+# add-auto-load-safe-path /path/to/qemu/.gdbinit
+
+# Load QEMU-specific sub-commands and settings
+source scripts/qemu-gdb.py
diff --git a/configure b/configure
index 13e040d28c..2203b9818b 100755
--- a/configure
+++ b/configure
@@ -6376,6 +6376,7 @@ FILES="$FILES pc-bios/spapr-rtas/Makefile"
FILES="$FILES pc-bios/s390-ccw/Makefile"
FILES="$FILES roms/seabios/Makefile roms/vgabios/Makefile"
FILES="$FILES pc-bios/qemu-icon.bmp"
+FILES="$FILES .gdbinit scripts" # scripts needed by relative path in .gdbinit
for bios_file in \
$source_path/pc-bios/*.bin \
$source_path/pc-bios/*.lid \
From 528f449f590829b53ea01ed91817a695b540421d Mon Sep 17 00:00:00 2001
From: Roman Pen <roman.penyaev@profitbricks.com>
Date: Thu, 1 Jun 2017 18:08:47 +0200
Subject: [PATCH 4/5] coroutine-lock: do not touch coroutine after another one
has been entered
Submission of requests on linux aio is a bit tricky and can lead to
requests completions on submission path:
44713c9e8547 ("linux-aio: Handle io_submit() failure gracefully")
0ed93d84edab ("linux-aio: process completions from ioq_submit()")
That means that any coroutine which has been yielded in order to wait
for completion can be resumed from submission path and be eventually
terminated (freed).
The following use-after-free crash was observed when IO throttling
was enabled:
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7f5813dff700 (LWP 56417)]
virtqueue_unmap_sg (elem=0x7f5804009a30, len=1, vq=<optimized out>) at virtio.c:252
(gdb) bt
#0 virtqueue_unmap_sg (elem=0x7f5804009a30, len=1, vq=<optimized out>) at virtio.c:252
^^^^^^^^^^^^^^
remember the address
#1 virtqueue_fill (vq=0x5598b20d21b0, elem=0x7f5804009a30, len=1, idx=0) at virtio.c:282
#2 virtqueue_push (vq=0x5598b20d21b0, elem=elem@entry=0x7f5804009a30, len=<optimized out>) at virtio.c:308
#3 virtio_blk_req_complete (req=req@entry=0x7f5804009a30, status=status@entry=0 '\000') at virtio-blk.c:61
#4 virtio_blk_rw_complete (opaque=<optimized out>, ret=0) at virtio-blk.c:126
#5 blk_aio_complete (acb=0x7f58040068d0) at block-backend.c:923
#6 coroutine_trampoline (i0=<optimized out>, i1=<optimized out>) at coroutine-ucontext.c:78
(gdb) p * elem
$8 = {index = 77, out_num = 2, in_num = 1,
in_addr = 0x7f5804009ad8, out_addr = 0x7f5804009ae0,
in_sg = 0x0, out_sg = 0x7f5804009a50}
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
'in_sg' and 'out_sg' are invalid.
e.g. it is impossible that 'in_sg' is zero,
instead its value must be equal to:
(gdb) p/x 0x7f5804009ad8 + sizeof(elem->in_addr[0]) + 2 * sizeof(elem->out_addr[0])
$26 = 0x7f5804009af0
Seems 'elem' was corrupted. Meanwhile another thread raised an abort:
Thread 12 (Thread 0x7f57f2ffd700 (LWP 56426)):
#0 raise () from /lib/x86_64-linux-gnu/libc.so.6
#1 abort () from /lib/x86_64-linux-gnu/libc.so.6
#2 qemu_coroutine_enter (co=0x7f5804009af0) at qemu-coroutine.c:113
#3 qemu_co_queue_run_restart (co=0x7f5804009a30) at qemu-coroutine-lock.c:60
#4 qemu_coroutine_enter (co=0x7f5804009a30) at qemu-coroutine.c:119
^^^^^^^^^^^^^^^^^^
WTF?? this is equal to elem from crashed thread
#5 qemu_co_queue_run_restart (co=0x7f57e7f16ae0) at qemu-coroutine-lock.c:60
#6 qemu_coroutine_enter (co=0x7f57e7f16ae0) at qemu-coroutine.c:119
#7 qemu_co_queue_run_restart (co=0x7f5807e112a0) at qemu-coroutine-lock.c:60
#8 qemu_coroutine_enter (co=0x7f5807e112a0) at qemu-coroutine.c:119
#9 qemu_co_queue_run_restart (co=0x7f5807f17820) at qemu-coroutine-lock.c:60
#10 qemu_coroutine_enter (co=0x7f5807f17820) at qemu-coroutine.c:119
#11 qemu_co_queue_run_restart (co=0x7f57e7f18e10) at qemu-coroutine-lock.c:60
#12 qemu_coroutine_enter (co=0x7f57e7f18e10) at qemu-coroutine.c:119
#13 qemu_co_enter_next (queue=queue@entry=0x5598b1e742d0) at qemu-coroutine-lock.c:106
#14 timer_cb (blk=0x5598b1e74280, is_write=<optimized out>) at throttle-groups.c:419
Crash can be explained by access of 'co' object from the loop inside
qemu_co_queue_run_restart():
while ((next = QSIMPLEQ_FIRST(&co->co_queue_wakeup))) {
QSIMPLEQ_REMOVE_HEAD(&co->co_queue_wakeup, co_queue_next);
^^^^^^^^^^^^^^^^^^^^
on each iteration 'co' is accessed,
but 'co' can be already freed
qemu_coroutine_enter(next);
}
When 'next' coroutine is resumed (entered) it can in its turn resume
'co', and eventually free it. That's why we see 'co' (which was freed)
has the same address as 'elem' from the first backtrace.
The fix is obvious: use temporary queue and do not touch coroutine after
first qemu_coroutine_enter() is invoked.
The issue is quite rare and happens every ~12 hours on very high IO
and CPU load (building linux kernel with -j512 inside guest) when IO
throttling is enabled. With the fix applied guest is running ~35 hours
and is still alive so far.
Signed-off-by: Roman Pen <roman.penyaev@profitbricks.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170601160847.23720-1-roman.penyaev@profitbricks.com
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Fam Zheng <famz@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: qemu-devel@nongnu.org
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
util/qemu-coroutine-lock.c | 19 +++++++++++++++++--
util/qemu-coroutine.c | 5 +++++
2 files changed, 22 insertions(+), 2 deletions(-)
diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c
index 6328eed26b..b44b5d55eb 100644
--- a/util/qemu-coroutine-lock.c
+++ b/util/qemu-coroutine-lock.c
@@ -77,10 +77,25 @@ void coroutine_fn qemu_co_queue_wait(CoQueue *queue, CoMutex *mutex)
void qemu_co_queue_run_restart(Coroutine *co)
{
Coroutine *next;
+ QSIMPLEQ_HEAD(, Coroutine) tmp_queue_wakeup =
+ QSIMPLEQ_HEAD_INITIALIZER(tmp_queue_wakeup);
trace_qemu_co_queue_run_restart(co);
- while ((next = QSIMPLEQ_FIRST(&co->co_queue_wakeup))) {
- QSIMPLEQ_REMOVE_HEAD(&co->co_queue_wakeup, co_queue_next);
+
+ /* Because "co" has yielded, any coroutine that we wakeup can resume it.
+ * If this happens and "co" terminates, co->co_queue_wakeup becomes
+ * invalid memory. Therefore, use a temporary queue and do not touch
+ * the "co" coroutine as soon as you enter another one.
+ *
+ * In its turn resumed "co" can pupulate "co_queue_wakeup" queue with
+ * new coroutines to be woken up. The caller, who has resumed "co",
+ * will be responsible for traversing the same queue, which may cause
+ * a different wakeup order but not any missing wakeups.
+ */
+ QSIMPLEQ_CONCAT(&tmp_queue_wakeup, &co->co_queue_wakeup);
+
+ while ((next = QSIMPLEQ_FIRST(&tmp_queue_wakeup))) {
+ QSIMPLEQ_REMOVE_HEAD(&tmp_queue_wakeup, co_queue_next);
qemu_coroutine_enter(next);
}
}
diff --git a/util/qemu-coroutine.c b/util/qemu-coroutine.c
index 486af9a622..d6095c1d5a 100644
--- a/util/qemu-coroutine.c
+++ b/util/qemu-coroutine.c
@@ -126,6 +126,11 @@ void qemu_aio_coroutine_enter(AioContext *ctx, Coroutine *co)
qemu_co_queue_run_restart(co);
+ /* Beware, if ret == COROUTINE_YIELD and qemu_co_queue_run_restart()
+ * has started any other coroutine, "co" might have been reentered
+ * and even freed by now! So be careful and do not touch it.
+ */
+
switch (ret) {
case COROUTINE_YIELD:
return;
From 11cde1c81093a33c46c7a4039bf750bb61551087 Mon Sep 17 00:00:00 2001
From: Bruno Dominguez <bru.dominguez@gmail.com>
Date: Tue, 6 Jun 2017 14:07:47 +0100
Subject: [PATCH 5/5] configure: split c and cxx extra flags
There was no possibility to add specific cxx flags using the configure
file. So A new entrance has been created to support it.
Duplication of information in configure and rules.mak. Taking
QEMU_CFLAGS and add them to QEMU_CXXFLAGS, now the value of
QEMU_CXXFLAGS is stored in config-host.mak, so there is no need for
it.
The makefile for libvixl was adding flags for QEMU_CXXFLAGS in
QEMU_CFLAGS because of the addition in rules.mak. That was removed, so
adding them where it should be.
Signed-off-by: Bruno Dominguez <bru.dominguez@gmail.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1496754467-20893-1-git-send-email-bru.dominguez@gmail.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
configure | 74 +++++++++++++++++++++----------------
disas/libvixl/Makefile.objs | 4 +-
rules.mak | 3 --
3 files changed, 44 insertions(+), 37 deletions(-)
diff --git a/configure b/configure
index 2203b9818b..98012abc0f 100755
--- a/configure
+++ b/configure
@@ -91,7 +91,8 @@ update_cxxflags() {
# Set QEMU_CXXFLAGS from QEMU_CFLAGS by filtering out those
# options which some versions of GCC's C++ compiler complain about
# because they only make sense for C programs.
- QEMU_CXXFLAGS=
+ QEMU_CXXFLAGS="$QEMU_CXXFLAGS -D__STDC_LIMIT_MACROS"
+
for arg in $QEMU_CFLAGS; do
case $arg in
-Wstrict-prototypes|-Wmissing-prototypes|-Wnested-externs|\
@@ -345,6 +346,9 @@ for opt do
--extra-cflags=*) QEMU_CFLAGS="$QEMU_CFLAGS $optarg"
EXTRA_CFLAGS="$optarg"
;;
+ --extra-cxxflags=*) QEMU_CXXFLAGS="$QEMU_CXXFLAGS $optarg"
+ EXTRA_CXXFLAGS="$optarg"
+ ;;
--extra-ldflags=*) LDFLAGS="$LDFLAGS $optarg"
EXTRA_LDFLAGS="$optarg"
;;
@@ -788,6 +792,8 @@ for opt do
;;
--extra-cflags=*)
;;
+ --extra-cxxflags=*)
+ ;;
--extra-ldflags=*)
;;
--enable-debug-info)
@@ -1305,6 +1311,7 @@ Advanced options (experts only):
--cxx=CXX use C++ compiler CXX [$cxx]
--objcc=OBJCC use Objective-C compiler OBJCC [$objcc]
--extra-cflags=CFLAGS append extra C compiler flags QEMU_CFLAGS
+ --extra-cxxflags=CXXFLAGS append extra C++ compiler flags QEMU_CXXFLAGS
--extra-ldflags=LDFLAGS append extra linker flags LDFLAGS
--make=MAKE use specified make [$make]
--install=INSTALL use specified install [$install]
@@ -1490,37 +1497,6 @@ if test "$bogus_os" = "yes"; then
error_exit "Unrecognized host OS $targetos"
fi
-# Check that the C++ compiler exists and works with the C compiler
-if has $cxx; then
- cat > $TMPC <<EOF
-int c_function(void);
-int main(void) { return c_function(); }
-EOF
-
- compile_object
-
- cat > $TMPCXX <<EOF
-extern "C" {
- int c_function(void);
-}
-int c_function(void) { return 42; }
-EOF
-
- update_cxxflags
-
- if do_cxx $QEMU_CXXFLAGS -o $TMPE $TMPCXX $TMPO $LDFLAGS; then
- # C++ compiler $cxx works ok with C compiler $cc
- :
- else
- echo "C++ compiler $cxx does not work with C compiler $cc"
- echo "Disabling C++ specific optional code"
- cxx=
- fi
-else
- echo "No C++ compiler available; disabling C++ specific optional code"
- cxx=
-fi
-
gcc_flags="-Wold-style-declaration -Wold-style-definition -Wtype-limits"
gcc_flags="-Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers $gcc_flags"
gcc_flags="-Wno-missing-include-dirs -Wempty-body -Wnested-externs $gcc_flags"
@@ -5064,6 +5040,38 @@ EOF
fi
fi
+# Check that the C++ compiler exists and works with the C compiler.
+# All the QEMU_CXXFLAGS are based on QEMU_CFLAGS. Keep this at the end to don't miss any other that could be added.
+if has $cxx; then
+ cat > $TMPC <<EOF
+int c_function(void);
+int main(void) { return c_function(); }
+EOF
+
+ compile_object
+
+ cat > $TMPCXX <<EOF
+extern "C" {
+ int c_function(void);
+}
+int c_function(void) { return 42; }
+EOF
+
+ update_cxxflags
+
+ if do_cxx $QEMU_CXXFLAGS -o $TMPE $TMPCXX $TMPO $LDFLAGS; then
+ # C++ compiler $cxx works ok with C compiler $cc
+ :
+ else
+ echo "C++ compiler $cxx does not work with C compiler $cc"
+ echo "Disabling C++ specific optional code"
+ cxx=
+ fi
+else
+ echo "No C++ compiler available; disabling C++ specific optional code"
+ cxx=
+fi
+
echo_version() {
if test "$1" = "yes" ; then
echo "($2)"
@@ -5269,6 +5277,7 @@ if test "$mingw32" = "no" ; then
fi
echo "qemu_helperdir=$libexecdir" >> $config_host_mak
echo "extra_cflags=$EXTRA_CFLAGS" >> $config_host_mak
+echo "extra_cxxflags=$EXTRA_CXXFLAGS" >> $config_host_mak
echo "extra_ldflags=$EXTRA_LDFLAGS" >> $config_host_mak
echo "qemu_localedir=$qemu_localedir" >> $config_host_mak
echo "libs_softmmu=$libs_softmmu" >> $config_host_mak
@@ -5911,6 +5920,7 @@ echo "WINDRES=$windres" >> $config_host_mak
echo "CFLAGS=$CFLAGS" >> $config_host_mak
echo "CFLAGS_NOPIE=$CFLAGS_NOPIE" >> $config_host_mak
echo "QEMU_CFLAGS=$QEMU_CFLAGS" >> $config_host_mak
+echo "QEMU_CXXFLAGS=$QEMU_CXXFLAGS" >> $config_host_mak
echo "QEMU_INCLUDES=$QEMU_INCLUDES" >> $config_host_mak
if test "$sparse" = "yes" ; then
echo "CC := REAL_CC=\"\$(CC)\" cgcc" >> $config_host_mak
diff --git a/disas/libvixl/Makefile.objs b/disas/libvixl/Makefile.objs
index 860fb7f384..27183b7c20 100644
--- a/disas/libvixl/Makefile.objs
+++ b/disas/libvixl/Makefile.objs
@@ -6,9 +6,9 @@ libvixl_OBJS = vixl/utils.o \
# The -Wno-sign-compare is needed only for gcc 4.6, which complains about
# some signed-unsigned equality comparisons which later gcc versions do not.
-$(addprefix $(obj)/,$(libvixl_OBJS)): QEMU_CFLAGS := -I$(SRC_PATH)/disas/libvixl $(QEMU_CFLAGS) -Wno-sign-compare
+$(addprefix $(obj)/,$(libvixl_OBJS)): QEMU_CXXFLAGS := -I$(SRC_PATH)/disas/libvixl $(QEMU_CXXFLAGS) -Wno-sign-compare
# Ensure that C99 macros are defined regardless of the inclusion order of
# headers in vixl. This is required at least on NetBSD.
-$(addprefix $(obj)/,$(libvixl_OBJS)): QEMU_CFLAGS += -D__STDC_CONSTANT_MACROS -D__STDC_LIMIT_MACROS -D__STDC_FORMAT_MACROS
+$(addprefix $(obj)/,$(libvixl_OBJS)): QEMU_CXXFLAGS += -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS
common-obj-$(CONFIG_ARM_A64_DIS) += $(libvixl_OBJS)
diff --git a/rules.mak b/rules.mak
index 1c0eabb367..2a2fb72e85 100644
--- a/rules.mak
+++ b/rules.mak
@@ -20,9 +20,6 @@ MAKEFLAGS += -rR
%.mak:
clean-target:
-# Flags for C++ compilation
-QEMU_CXXFLAGS = -D__STDC_LIMIT_MACROS $(filter-out -Wstrict-prototypes -Wmissing-prototypes -Wnested-externs -Wold-style-declaration -Wold-style-definition -Wredundant-decls, $(QEMU_CFLAGS))
-
# Flags for dependency generation
QEMU_DGFLAGS += -MMD -MP -MT $@ -MF $(@D)/$(*F).d