From 822e42509997cfc8582ab1108eef1a280524b26a Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 16 May 2023 06:18:32 -0700 Subject: [PATCH 1/4] torture: Scale scftorture memory based on number of CPUs As the number of CPUs increases, the number of outstanding no-wait smp_call_function() handlers also increases, so that the default of 2G of memory is not always sufficient on 80-CPU systems. This commit therefore scales the amount of memory specified to qemu based on the number of CPUs specified to the scftorture test instance. Signed-off-by: Paul E. McKenney --- tools/testing/selftests/rcutorture/bin/torture.sh | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/rcutorture/bin/torture.sh b/tools/testing/selftests/rcutorture/bin/torture.sh index 5a2ae2264403..9fa6526067f0 100755 --- a/tools/testing/selftests/rcutorture/bin/torture.sh +++ b/tools/testing/selftests/rcutorture/bin/torture.sh @@ -376,8 +376,10 @@ fi if test "$do_scftorture" = "yes" then + # Scale memory based on the number of CPUs. + scfmem=$((2+HALF_ALLOTED_CPUS/16)) torture_bootargs="scftorture.nthreads=$HALF_ALLOTED_CPUS torture.disable_onoff_at_boot csdlock_debug=1" - torture_set "scftorture" tools/testing/selftests/rcutorture/bin/kvm.sh --torture scf --allcpus --duration "$duration_scftorture" --configs "$configs_scftorture" --kconfig "CONFIG_NR_CPUS=$HALF_ALLOTED_CPUS" --memory 2G --trust-make + torture_set "scftorture" tools/testing/selftests/rcutorture/bin/kvm.sh --torture scf --allcpus --duration "$duration_scftorture" --configs "$configs_scftorture" --kconfig "CONFIG_NR_CPUS=$HALF_ALLOTED_CPUS" --memory ${scfmem}G --trust-make fi if test "$do_rt" = "yes" From 013608cd0812bdb21fc26d39ed8fdd2fc76e8b9b Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 15 May 2023 19:00:10 -0700 Subject: [PATCH 2/4] scftorture: Forgive memory-allocation failure if KASAN Kernels built with CONFIG_KASAN=y quarantine newly freed memory in order to better detect use-after-free errors. However, this can exhaust memory more quickly in allocator-heavy tests, which can result in spurious scftorture failure. This commit therefore forgives memory-allocation failure in kernels built with CONFIG_KASAN=y, but continues counting the errors for use in detailed test-result analyses. Signed-off-by: Paul E. McKenney --- kernel/scftorture.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/scftorture.c b/kernel/scftorture.c index 5d113aa59e77..83c33ba0ca7e 100644 --- a/kernel/scftorture.c +++ b/kernel/scftorture.c @@ -171,7 +171,8 @@ static void scf_torture_stats_print(void) scfs.n_all_wait += scf_stats_p[i].n_all_wait; } if (atomic_read(&n_errs) || atomic_read(&n_mb_in_errs) || - atomic_read(&n_mb_out_errs) || atomic_read(&n_alloc_errs)) + atomic_read(&n_mb_out_errs) || + (!IS_ENABLED(CONFIG_KASAN) && atomic_read(&n_alloc_errs))) bangstr = "!!! "; pr_alert("%s %sscf_invoked_count %s: %lld resched: %lld single: %lld/%lld single_ofl: %lld/%lld single_rpc: %lld single_rpc_ofl: %lld many: %lld/%lld all: %lld/%lld ", SCFTORT_FLAG, bangstr, isdone ? "VER" : "ver", invoked_count, scfs.n_resched, @@ -323,7 +324,8 @@ static void scftorture_invoke_one(struct scf_statistics *scfp, struct torture_ra preempt_disable(); if (scfsp->scfs_prim == SCF_PRIM_SINGLE || scfsp->scfs_wait) { scfcp = kmalloc(sizeof(*scfcp), GFP_ATOMIC); - if (WARN_ON_ONCE(!scfcp)) { + if (!scfcp) { + WARN_ON_ONCE(!IS_ENABLED(CONFIG_KASAN)); atomic_inc(&n_alloc_errs); } else { scfcp->scfc_cpu = -1; From 4a71be93876171e2d30e413abd33126d8c526791 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 16 May 2023 06:21:02 -0700 Subject: [PATCH 3/4] scftorture: Pause testing after memory-allocation failure The scftorture test can quickly execute a large number of calls to no-wait smp_call_function(), each of which holds a block of memory until the corresponding handler is invoked. Especially when the longwait module parameter is specified, this can chew up an arbitrarily large amount of memory. This commit therefore blocks after each memory-allocation failure, with the duration a function of longwait. Signed-off-by: Paul E. McKenney --- kernel/scftorture.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/kernel/scftorture.c b/kernel/scftorture.c index 83c33ba0ca7e..59032aaccd18 100644 --- a/kernel/scftorture.c +++ b/kernel/scftorture.c @@ -313,6 +313,7 @@ static void scf_handler_1(void *scfc_in) // Randomly do an smp_call_function*() invocation. static void scftorture_invoke_one(struct scf_statistics *scfp, struct torture_random_state *trsp) { + bool allocfail = false; uintptr_t cpu; int ret = 0; struct scf_check *scfcp = NULL; @@ -327,6 +328,7 @@ static void scftorture_invoke_one(struct scf_statistics *scfp, struct torture_ra if (!scfcp) { WARN_ON_ONCE(!IS_ENABLED(CONFIG_KASAN)); atomic_inc(&n_alloc_errs); + allocfail = true; } else { scfcp->scfc_cpu = -1; scfcp->scfc_wait = scfsp->scfs_wait; @@ -433,7 +435,9 @@ static void scftorture_invoke_one(struct scf_statistics *scfp, struct torture_ra cpus_read_unlock(); else preempt_enable(); - if (!(torture_random(trsp) & 0xfff)) + if (allocfail) + schedule_timeout_idle((1 + longwait) * HZ); // Let no-wait handlers complete. + else if (!(torture_random(trsp) & 0xfff)) schedule_timeout_uninterruptible(1); } From 3f68f9c822ebe208f961ab0402e49a10465278ca Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 6 Jul 2023 17:44:15 -0700 Subject: [PATCH 4/4] scftorture: Add CONFIG_PREEMPT_DYNAMIC=n to NOPREEMPT scenario It is no longer possible to build a kernel with a preemption-disabled RCU without use of CONFIG_PREEMPT_DYNAMIC=n. This commit therefore adds CONFIG_PREEMPT_DYNAMIC=n to the scf torture type's NOPREEMPT scenario file. Signed-off-by: Paul E. McKenney --- tools/testing/selftests/rcutorture/configs/scf/NOPREEMPT | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tools/testing/selftests/rcutorture/configs/scf/NOPREEMPT b/tools/testing/selftests/rcutorture/configs/scf/NOPREEMPT index 3a59346b3de7..6133f54ce2a7 100644 --- a/tools/testing/selftests/rcutorture/configs/scf/NOPREEMPT +++ b/tools/testing/selftests/rcutorture/configs/scf/NOPREEMPT @@ -2,6 +2,8 @@ CONFIG_SMP=y CONFIG_PREEMPT_NONE=y CONFIG_PREEMPT_VOLUNTARY=n CONFIG_PREEMPT=n +CONFIG_PREEMPT_DYNAMIC=n +#CHECK#CONFIG_PREEMPT_RCU=n CONFIG_HZ_PERIODIC=n CONFIG_NO_HZ_IDLE=n CONFIG_NO_HZ_FULL=y