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scftorture: Add smp_call_function() memory-ordering checks

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This commit adds checks for memory misordering across calls to and
returns from smp_call_function() in the case where the caller waits.
Misordering results in a splat.

Note that in contrast to smp_call_function_single(), this code does not
test memory ordering into the handler in the no-wait case because none
of the handlers would be able to free the scf_check structure without
introducing heavy synchronization to work out which was last.

[ paulmck: s/GFP_KERNEL/GFP_ATOMIC/ per kernel test robot feedback. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Paul E. McKenney 2020-07-01 13:49:06 -07:00
parent 980205ee84
commit 34e8c4837a
1 changed files with 17 additions and 8 deletions
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25
kernel/scftorture.c
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@ -297,11 +297,13 @@ static void scftorture_invoke_one(struct scf_statistics *scfp, struct torture_ra
cpus_read_lock();
else
preempt_disable();
switch (scfsp->scfs_prim) {
case SCF_PRIM_SINGLE:
if (scfsp->scfs_prim == SCF_PRIM_SINGLE || scfsp->scfs_wait) {
scfcp = kmalloc(sizeof(*scfcp), GFP_ATOMIC);
if (WARN_ON_ONCE(!scfcp))
atomic_inc(&n_alloc_errs);
}
switch (scfsp->scfs_prim) {
case SCF_PRIM_SINGLE:
cpu = torture_random(trsp) % nr_cpu_ids;
if (scfsp->scfs_wait)
scfp->n_single_wait++;
@ -328,11 +330,6 @@ static void scftorture_invoke_one(struct scf_statistics *scfp, struct torture_ra
}
break;
case SCF_PRIM_MANY:
if (scfsp->scfs_wait) {
scfcp = kmalloc(sizeof(*scfcp), GFP_ATOMIC);
if (WARN_ON_ONCE(!scfcp))
atomic_inc(&n_alloc_errs);
}
if (scfsp->scfs_wait)
scfp->n_many_wait++;
else
@ -356,7 +353,19 @@ static void scftorture_invoke_one(struct scf_statistics *scfp, struct torture_ra
scfp->n_all_wait++;
else
scfp->n_all++;
smp_call_function(scf_handler, NULL, scfsp->scfs_wait);
if (scfcp) {
scfcp->scfc_cpu = -1;
scfcp->scfc_wait = true;
scfcp->scfc_out = false;
scfcp->scfc_in = true;
}
smp_call_function(scf_handler, scfcp, scfsp->scfs_wait);
if (scfcp) {
if (WARN_ON_ONCE(!scfcp->scfc_out))
atomic_inc(&n_mb_out_errs); // Leak rather than trash!
else
kfree(scfcp);
}
break;
}
if (use_cpus_read_lock)