Re: [Qemu-devel] [PATCH v2] net/colo-compare.c: Fix a crash in COLO Primary.
On 2019/5/6 下午6:32, Lukas Straub wrote: On Sat, 20 Apr 2019 19:14:25 +0200 Lukas Straub wrote: From: Lukas Straub Because event_unhandled_count may be accessed concurrently, it needs to be protected by taking the lock. However the assert is outside the lock, probably causing it to read garbage and aborting Qemu erroneously. The Bug only happens when running Qemu in COLO mode. This Patch fixes the following bug: https://bugs.launchpad.net/qemu/+bug/1824622 Signed-off-by: Lukas Straub --- net/colo-compare.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/colo-compare.c b/net/colo-compare.c index bf10526f05..fcb491121b 100644 --- a/net/colo-compare.c +++ b/net/colo-compare.c @@ -813,9 +813,8 @@ static void colo_compare_handle_event(void *opaque) break; } -assert(event_unhandled_count > 0); - qemu_mutex_lock(_mtx); +assert(event_unhandled_count > 0); event_unhandled_count--; qemu_cond_broadcast(_complete_cond); qemu_mutex_unlock(_mtx); Ping. Regards, Lukas Straub Applied. Thanks
Re: [Qemu-devel] [PATCH v2] net/colo-compare.c: Fix a crash in COLO Primary.
Cc'ing Paolo & Stefan On 4/20/19 7:14 PM, Lukas Straub wrote: > From: Lukas Straub > Because event_unhandled_count may be accessed concurrently, it needs > to be protected by taking the lock. However the assert is outside the > lock, probably causing it to read garbage and aborting Qemu erroneously. > > The Bug only happens when running Qemu in COLO mode. > > This Patch fixes the following bug: > https://bugs.launchpad.net/qemu/+bug/1824622 > > Signed-off-by: Lukas Straub > --- > net/colo-compare.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/net/colo-compare.c b/net/colo-compare.c > index bf10526f05..fcb491121b 100644 > --- a/net/colo-compare.c > +++ b/net/colo-compare.c > @@ -813,9 +813,8 @@ static void colo_compare_handle_event(void *opaque) > break; > } > > -assert(event_unhandled_count > 0); > - > qemu_mutex_lock(_mtx); > +assert(event_unhandled_count > 0); > event_unhandled_count--; > qemu_cond_broadcast(_complete_cond); > qemu_mutex_unlock(_mtx); > -- > 2.20.1 > >
Re: [Qemu-devel] [PATCH v2] net/colo-compare.c: Fix a crash in COLO Primary.
On Sat, 20 Apr 2019 19:14:25 +0200 Lukas Straub wrote: > From: Lukas Straub > Because event_unhandled_count may be accessed concurrently, it needs > to be protected by taking the lock. However the assert is outside the > lock, probably causing it to read garbage and aborting Qemu > erroneously. > > The Bug only happens when running Qemu in COLO mode. > > This Patch fixes the following bug: > https://bugs.launchpad.net/qemu/+bug/1824622 > > Signed-off-by: Lukas Straub > --- > net/colo-compare.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/net/colo-compare.c b/net/colo-compare.c > index bf10526f05..fcb491121b 100644 > --- a/net/colo-compare.c > +++ b/net/colo-compare.c > @@ -813,9 +813,8 @@ static void colo_compare_handle_event(void > *opaque) break; > } > > -assert(event_unhandled_count > 0); > - > qemu_mutex_lock(_mtx); > +assert(event_unhandled_count > 0); > event_unhandled_count--; > qemu_cond_broadcast(_complete_cond); > qemu_mutex_unlock(_mtx); Ping. Regards, Lukas Straub
Re: [Qemu-devel] [PATCH v2] net/colo-compare.c: Fix a crash in COLO Primary.
> -Original Message- > From: Lukas Straub [mailto:lukasstra...@web.de] > Sent: Sunday, April 21, 2019 1:14 AM > To: qemu-devel@nongnu.org > Cc: Zhang, Chen > Subject: [PATCH v2] net/colo-compare.c: Fix a crash in COLO Primary. > > From: Lukas Straub Because event_unhandled_count > may be accessed concurrently, it needs to be protected by taking the lock. > However the assert is outside the lock, probably causing it to read garbage > and > aborting Qemu erroneously. > > The Bug only happens when running Qemu in COLO mode. > > This Patch fixes the following bug: > https://bugs.launchpad.net/qemu/+bug/1824622 > > Signed-off-by: Lukas Straub Looks good for me. Reviewed-by: Zhang Chen Thanks Zhang Chen > --- > net/colo-compare.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/net/colo-compare.c b/net/colo-compare.c index > bf10526f05..fcb491121b 100644 > --- a/net/colo-compare.c > +++ b/net/colo-compare.c > @@ -813,9 +813,8 @@ static void colo_compare_handle_event(void *opaque) > break; > } > > -assert(event_unhandled_count > 0); > - > qemu_mutex_lock(_mtx); > +assert(event_unhandled_count > 0); > event_unhandled_count--; > qemu_cond_broadcast(_complete_cond); > qemu_mutex_unlock(_mtx); > -- > 2.20.1
Re: [Qemu-devel] [PATCH v2] net/colo-compare.c: Fix a crash in COLO Primary.
On 4/20/19 7:14 PM, Lukas Straub wrote: > From: Lukas Straub > Because event_unhandled_count may be accessed concurrently, it needs > to be protected by taking the lock. However the assert is outside the > lock, probably causing it to read garbage and aborting Qemu erroneously. > > The Bug only happens when running Qemu in COLO mode. > > This Patch fixes the following bug: > https://bugs.launchpad.net/qemu/+bug/1824622 > > Signed-off-by: Lukas Straub > --- > net/colo-compare.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/net/colo-compare.c b/net/colo-compare.c > index bf10526f05..fcb491121b 100644 > --- a/net/colo-compare.c > +++ b/net/colo-compare.c > @@ -813,9 +813,8 @@ static void colo_compare_handle_event(void *opaque) > break; > } > > -assert(event_unhandled_count > 0); > - > qemu_mutex_lock(_mtx); > +assert(event_unhandled_count > 0); > event_unhandled_count--; > qemu_cond_broadcast(_complete_cond); > qemu_mutex_unlock(_mtx); > -- > 2.20.1 > > Reviewed-by: Philippe Mathieu-Daudé
