Messages in this thread | | | Date | Wed, 7 Oct 2020 11:20:53 -0700 | From | Kees Cook <> | Subject | Re: [PATCH v2 08/11] drivers/base/test/test_async_driver_probe: convert to use counter_atomic32 |
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On Tue, Oct 06, 2020 at 02:44:39PM -0600, Shuah Khan wrote: > counter_atomic* is introduced to be used when a variable is used as > a simple counter and doesn't guard object lifetimes. This clearly > differentiates atomic_t usages that guard object lifetimes. > > counter_atomic* variables will wrap around to 0 when it overflows and > should not be used to guard resource lifetimes, device usage and > open counts that control state changes, and pm states. > > atomic_t variables used to count errors, warns, keep track of timeout, > and async completion are counters. > > Unsure overflow is a concern for timeout and async completion, and there > are no checks for overflow to hold them to upper bounds. Overflow and > wrap around doesn't impact errors, and warns. > > Convert them to use counter_atomic32. > > This conversion doesn't change the overflow wrap around behavior. > > Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Signed-off-by: Shuah Khan <skhan@linuxfoundation.org> > --- > drivers/base/test/test_async_driver_probe.c | 23 ++++++++++++--------- > 1 file changed, 13 insertions(+), 10 deletions(-) > > diff --git a/drivers/base/test/test_async_driver_probe.c b/drivers/base/test/test_async_driver_probe.c > index 3bb7beb127a9..e969c1b09426 100644 > --- a/drivers/base/test/test_async_driver_probe.c > +++ b/drivers/base/test/test_async_driver_probe.c > @@ -14,11 +14,12 @@ > #include <linux/numa.h> > #include <linux/nodemask.h> > #include <linux/topology.h> > +#include <linux/counters.h> > > #define TEST_PROBE_DELAY (5 * 1000) /* 5 sec */ > #define TEST_PROBE_THRESHOLD (TEST_PROBE_DELAY / 2) > > -static atomic_t warnings, errors, timeout, async_completed; > +static struct counter_atomic32 warnings, errors, timeout, async_completed;
While it's currently harmless, this should likely be using COUNTER_ATOMIC_INIT(0)s...
> > static int test_probe(struct platform_device *pdev) > { > @@ -29,9 +30,9 @@ static int test_probe(struct platform_device *pdev) > * have then report it as an error, otherwise we wil sleep for the > * required amount of time and then report completion. > */ > - if (atomic_read(&timeout)) { > + if (counter_atomic32_read(&timeout)) { > dev_err(dev, "async probe took too long\n"); > - atomic_inc(&errors); > + counter_atomic32_inc(&errors); > } else { > dev_dbg(&pdev->dev, "sleeping for %d msecs in probe\n", > TEST_PROBE_DELAY); > @@ -48,10 +49,10 @@ static int test_probe(struct platform_device *pdev) > dev_to_node(dev) != numa_node_id()) { > dev_warn(dev, "NUMA node mismatch %d != %d\n", > dev_to_node(dev), numa_node_id()); > - atomic_inc(&warnings); > + counter_atomic32_inc(&warnings); > } > > - atomic_inc(&async_completed); > + counter_atomic32_inc(&async_completed); > } > > return 0; > @@ -244,11 +245,12 @@ static int __init test_async_probe_init(void) > * Otherwise if they completed without errors or warnings then > * report successful completion. > */ > - if (atomic_read(&async_completed) != async_id) { > + if (counter_atomic32_read(&async_completed) != async_id) { > pr_err("async events still pending, forcing timeout\n"); > - atomic_inc(&timeout); > + counter_atomic32_inc(&timeout); > err = -ETIMEDOUT; > - } else if (!atomic_read(&errors) && !atomic_read(&warnings)) { > + } else if (!counter_atomic32_read(&errors) && > + !counter_atomic32_read(&warnings)) { > pr_info("completed successfully\n"); > return 0; > } > @@ -271,12 +273,13 @@ static int __init test_async_probe_init(void) > * errors or warnings being reported by the probe routine. > */ > if (err) > - atomic_inc(&errors); > + counter_atomic32_inc(&errors); > else > err = -EINVAL; > > pr_err("Test failed with %d errors and %d warnings\n", > - atomic_read(&errors), atomic_read(&warnings)); > + counter_atomic32_read(&errors), > + counter_atomic32_read(&warnings)); > > return err; > } > -- > 2.25.1 >
But yeah, this is otherwise just reporting and simple one-time synchronization.
Reviewed-by: Kees Cook <keescook@chromium.org>
-- Kees Cook
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