Re: [PATCH v2 1/2] KVM: selftests: Make rseq compatible with glibc-2.35

From: Gavin Shan
Date: Wed Aug 10 2022 - 19:57:56 EST


On 8/10/22 10:29 PM, Paolo Bonzini wrote:
On 8/10/22 14:22, Mathieu Desnoyers wrote:

    /*
     * Create and run a dummy VM that immediately exits to userspace via
@@ -256,7 +244,7 @@ int main(int argc, char *argv[])
             */
            smp_rmb();
            cpu = sched_getcpu();
-            rseq_cpu = READ_ONCE(__rseq.cpu_id);
+            rseq_cpu = READ_ONCE(__rseq->cpu_id);
#include <rseq.h>

and use

rseq_current_cpu_raw().

Thanks, I squashed it and queued it for -rc1 (tested on both
glibc 2.34 and 2.35).


Paolo, Thanks for the makeup, which looks good to me :)

diff --git a/tools/testing/selftests/kvm/rseq_test.c b/tools/testing/selftests/kvm/rseq_test.c
index 84e8425edc2c..987a76674f4f 100644
--- a/tools/testing/selftests/kvm/rseq_test.c
+++ b/tools/testing/selftests/kvm/rseq_test.c
@@ -29,7 +29,6 @@
 #define NR_TASK_MIGRATIONS 100000

 static pthread_t migration_thread;
-static struct rseq_abi *__rseq;
 static cpu_set_t possible_mask;
 static int min_cpu, max_cpu;
 static bool done;
@@ -218,7 +217,6 @@ int main(int argc, char *argv[])
     r = rseq_register_current_thread();
     TEST_ASSERT(!r, "rseq_register_current_thread failed, errno = %d (%s)",
             errno, strerror(errno));
-    __rseq = rseq_get_abi();

     /*
      * Create and run a dummy VM that immediately exits to userspace via
@@ -256,7 +254,7 @@ int main(int argc, char *argv[])
              */
             smp_rmb();
             cpu = sched_getcpu();
-            rseq_cpu = READ_ONCE(__rseq->cpu_id);
+            rseq_cpu = rseq_current_cpu_raw();
             smp_rmb();
         } while (snapshot != atomic_read(&seq_cnt));