| Message ID | 1418661511-22348-27-git-send-email-pbonzini@redhat.com |
|---|---|
| State | New |
| Headers | show |
On Mon, Dec 15, 2014 at 05:38:10PM +0100, Paolo Bonzini wrote: > From: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru> > > Exception index is reset at every entry at every entry into cpu_exec() > function. This may cause missing the exceptions while replaying them. > This patch moves exception_index reset to the locations where they are > processed. > > Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> x86_64-linux-user is broken after applying this patch: [qemu/(e511b4d...)|BISECTING]$ ./install/bin/qemu-x86_64 /bin/true qemu: uncaught target signal 8 (Floating point exception) - core dumped Floating point exception (core dumped) > --- > cpu-exec.c | 3 ++- > cpus.c | 3 +++ > 2 files changed, 5 insertions(+), 1 deletion(-) > > diff --git a/cpu-exec.c b/cpu-exec.c > index 8830255..4df9856 100644 > --- a/cpu-exec.c > +++ b/cpu-exec.c > @@ -358,7 +358,6 @@ int cpu_exec(CPUArchState *env) > } > > cc->cpu_exec_enter(cpu); > - cpu->exception_index = -1; > > /* Calculate difference between guest clock and host clock. > * This delay includes the delay of the last cycle, so > @@ -378,6 +377,7 @@ int cpu_exec(CPUArchState *env) > if (ret == EXCP_DEBUG) { > cpu_handle_debug_exception(env); > } > + cpu->exception_index = -1; > break; > } else { > #if defined(CONFIG_USER_ONLY) > @@ -388,6 +388,7 @@ int cpu_exec(CPUArchState *env) > cc->do_interrupt(cpu); > #endif > ret = cpu->exception_index; > + cpu->exception_index = -1; > break; > #else > cc->do_interrupt(cpu); > diff --git a/cpus.c b/cpus.c > index 0c33458..91119bb 100644 > --- a/cpus.c > +++ b/cpus.c > @@ -934,6 +934,7 @@ static void *qemu_kvm_cpu_thread_fn(void *arg) > qemu_mutex_lock(&qemu_global_mutex); > qemu_thread_get_self(cpu->thread); > cpu->thread_id = qemu_get_thread_id(); > + cpu->exception_index = -1; > current_cpu = cpu; > > r = kvm_init_vcpu(cpu); > @@ -974,6 +975,7 @@ static void *qemu_dummy_cpu_thread_fn(void *arg) > qemu_mutex_lock_iothread(); > qemu_thread_get_self(cpu->thread); > cpu->thread_id = qemu_get_thread_id(); > + cpu->exception_index = -1; > > sigemptyset(&waitset); > sigaddset(&waitset, SIG_IPI); > @@ -1016,6 +1018,7 @@ static void *qemu_tcg_cpu_thread_fn(void *arg) > CPU_FOREACH(cpu) { > cpu->thread_id = qemu_get_thread_id(); > cpu->created = true; > + cpu->exception_index = -1; > } > qemu_cond_signal(&qemu_cpu_cond); > > -- > 1.8.3.1 > > >
> From: Eduardo Habkost [mailto:ehabkost@redhat.com] > On Mon, Dec 15, 2014 at 05:38:10PM +0100, Paolo Bonzini wrote: > > From: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru> > > > > Exception index is reset at every entry at every entry into cpu_exec() > > function. This may cause missing the exceptions while replaying them. > > This patch moves exception_index reset to the locations where they are > > processed. > > > > Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru> > > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > > x86_64-linux-user is broken after applying this patch: > > [qemu/(e511b4d...)|BISECTING]$ ./install/bin/qemu-x86_64 /bin/true > qemu: uncaught target signal 8 (Floating point exception) - core dumped > Floating point exception (core dumped) I cannot reproduce this bug. QEMU runs and terminates correctly. Can you show me call stack for the exception? Pavel Dovgalyuk
On 23/12/2014 07:55, Pavel Dovgaluk wrote: >> From: Eduardo Habkost [mailto:ehabkost@redhat.com] >> On Mon, Dec 15, 2014 at 05:38:10PM +0100, Paolo Bonzini wrote: >>> From: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru> >>> >>> Exception index is reset at every entry at every entry into cpu_exec() >>> function. This may cause missing the exceptions while replaying them. >>> This patch moves exception_index reset to the locations where they are >>> processed. >>> >>> Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru> >>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> >> >> x86_64-linux-user is broken after applying this patch: >> >> [qemu/(e511b4d...)|BISECTING]$ ./install/bin/qemu-x86_64 /bin/true >> qemu: uncaught target signal 8 (Floating point exception) - core dumped >> Floating point exception (core dumped) > > I cannot reproduce this bug. > QEMU runs and terminates correctly. > Can you show me call stack for the exception? It's already fixed in qemu.git. Paolo
diff --git a/cpu-exec.c b/cpu-exec.c index 8830255..4df9856 100644 --- a/cpu-exec.c +++ b/cpu-exec.c @@ -358,7 +358,6 @@ int cpu_exec(CPUArchState *env) } cc->cpu_exec_enter(cpu); - cpu->exception_index = -1; /* Calculate difference between guest clock and host clock. * This delay includes the delay of the last cycle, so @@ -378,6 +377,7 @@ int cpu_exec(CPUArchState *env) if (ret == EXCP_DEBUG) { cpu_handle_debug_exception(env); } + cpu->exception_index = -1; break; } else { #if defined(CONFIG_USER_ONLY) @@ -388,6 +388,7 @@ int cpu_exec(CPUArchState *env) cc->do_interrupt(cpu); #endif ret = cpu->exception_index; + cpu->exception_index = -1; break; #else cc->do_interrupt(cpu); diff --git a/cpus.c b/cpus.c index 0c33458..91119bb 100644 --- a/cpus.c +++ b/cpus.c @@ -934,6 +934,7 @@ static void *qemu_kvm_cpu_thread_fn(void *arg) qemu_mutex_lock(&qemu_global_mutex); qemu_thread_get_self(cpu->thread); cpu->thread_id = qemu_get_thread_id(); + cpu->exception_index = -1; current_cpu = cpu; r = kvm_init_vcpu(cpu); @@ -974,6 +975,7 @@ static void *qemu_dummy_cpu_thread_fn(void *arg) qemu_mutex_lock_iothread(); qemu_thread_get_self(cpu->thread); cpu->thread_id = qemu_get_thread_id(); + cpu->exception_index = -1; sigemptyset(&waitset); sigaddset(&waitset, SIG_IPI); @@ -1016,6 +1018,7 @@ static void *qemu_tcg_cpu_thread_fn(void *arg) CPU_FOREACH(cpu) { cpu->thread_id = qemu_get_thread_id(); cpu->created = true; + cpu->exception_index = -1; } qemu_cond_signal(&qemu_cpu_cond);