| Message ID | 20220307074516.6920-2-dtcccc@linux.alibaba.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | provide the flexibility to enable KFENCE | expand |
On Mon, 7 Mar 2022 at 08:45, Tianchen Ding <dtcccc@linux.alibaba.com> wrote: > > If once KFENCE is disabled by: > echo 0 > /sys/module/kfence/parameters/sample_interval > KFENCE could never be re-enabled until next rebooting. > > Allow re-enabling it by writing a positive num to sample_interval. > > Signed-off-by: Tianchen Ding <dtcccc@linux.alibaba.com> Reviewed-by: Marco Elver <elver@google.com> > --- > mm/kfence/core.c | 21 ++++++++++++++++++--- > 1 file changed, 18 insertions(+), 3 deletions(-) > > diff --git a/mm/kfence/core.c b/mm/kfence/core.c > index 13128fa13062..caa4e84c8b79 100644 > --- a/mm/kfence/core.c > +++ b/mm/kfence/core.c > @@ -38,14 +38,17 @@ > #define KFENCE_WARN_ON(cond) \ > ({ \ > const bool __cond = WARN_ON(cond); \ > - if (unlikely(__cond)) \ > + if (unlikely(__cond)) { \ > WRITE_ONCE(kfence_enabled, false); \ > + disabled_by_warn = true; \ > + } \ > __cond; \ > }) > > /* === Data ================================================================= */ > > static bool kfence_enabled __read_mostly; > +static bool disabled_by_warn __read_mostly; > > unsigned long kfence_sample_interval __read_mostly = CONFIG_KFENCE_SAMPLE_INTERVAL; > EXPORT_SYMBOL_GPL(kfence_sample_interval); /* Export for test modules. */ > @@ -55,6 +58,7 @@ EXPORT_SYMBOL_GPL(kfence_sample_interval); /* Export for test modules. */ > #endif > #define MODULE_PARAM_PREFIX "kfence." > > +static int kfence_enable_late(void); > static int param_set_sample_interval(const char *val, const struct kernel_param *kp) > { > unsigned long num; > @@ -65,10 +69,11 @@ static int param_set_sample_interval(const char *val, const struct kernel_param > > if (!num) /* Using 0 to indicate KFENCE is disabled. */ > WRITE_ONCE(kfence_enabled, false); > - else if (!READ_ONCE(kfence_enabled) && system_state != SYSTEM_BOOTING) > - return -EINVAL; /* Cannot (re-)enable KFENCE on-the-fly. */ > > *((unsigned long *)kp->arg) = num; > + > + if (num && !READ_ONCE(kfence_enabled) && system_state != SYSTEM_BOOTING) > + return disabled_by_warn ? -EINVAL : kfence_enable_late(); > return 0; > } > > @@ -787,6 +792,16 @@ void __init kfence_init(void) > (void *)(__kfence_pool + KFENCE_POOL_SIZE)); > } > > +static int kfence_enable_late(void) > +{ > + if (!__kfence_pool) > + return -EINVAL; > + > + WRITE_ONCE(kfence_enabled, true); > + queue_delayed_work(system_unbound_wq, &kfence_timer, 0); > + return 0; > +} > + > void kfence_shutdown_cache(struct kmem_cache *s) > { > unsigned long flags; > -- > 2.27.0 >
diff --git a/mm/kfence/core.c b/mm/kfence/core.c index 13128fa13062..caa4e84c8b79 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -38,14 +38,17 @@ #define KFENCE_WARN_ON(cond) \ ({ \ const bool __cond = WARN_ON(cond); \ - if (unlikely(__cond)) \ + if (unlikely(__cond)) { \ WRITE_ONCE(kfence_enabled, false); \ + disabled_by_warn = true; \ + } \ __cond; \ }) /* === Data ================================================================= */ static bool kfence_enabled __read_mostly; +static bool disabled_by_warn __read_mostly; unsigned long kfence_sample_interval __read_mostly = CONFIG_KFENCE_SAMPLE_INTERVAL; EXPORT_SYMBOL_GPL(kfence_sample_interval); /* Export for test modules. */ @@ -55,6 +58,7 @@ EXPORT_SYMBOL_GPL(kfence_sample_interval); /* Export for test modules. */ #endif #define MODULE_PARAM_PREFIX "kfence." +static int kfence_enable_late(void); static int param_set_sample_interval(const char *val, const struct kernel_param *kp) { unsigned long num; @@ -65,10 +69,11 @@ static int param_set_sample_interval(const char *val, const struct kernel_param if (!num) /* Using 0 to indicate KFENCE is disabled. */ WRITE_ONCE(kfence_enabled, false); - else if (!READ_ONCE(kfence_enabled) && system_state != SYSTEM_BOOTING) - return -EINVAL; /* Cannot (re-)enable KFENCE on-the-fly. */ *((unsigned long *)kp->arg) = num; + + if (num && !READ_ONCE(kfence_enabled) && system_state != SYSTEM_BOOTING) + return disabled_by_warn ? -EINVAL : kfence_enable_late(); return 0; } @@ -787,6 +792,16 @@ void __init kfence_init(void) (void *)(__kfence_pool + KFENCE_POOL_SIZE)); } +static int kfence_enable_late(void) +{ + if (!__kfence_pool) + return -EINVAL; + + WRITE_ONCE(kfence_enabled, true); + queue_delayed_work(system_unbound_wq, &kfence_timer, 0); + return 0; +} + void kfence_shutdown_cache(struct kmem_cache *s) { unsigned long flags;
If once KFENCE is disabled by: echo 0 > /sys/module/kfence/parameters/sample_interval KFENCE could never be re-enabled until next rebooting. Allow re-enabling it by writing a positive num to sample_interval. Signed-off-by: Tianchen Ding <dtcccc@linux.alibaba.com> --- mm/kfence/core.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-)