diff options
| -rw-r--r-- | drivers/usb/core/hcd.c | 12 | ||||
| -rw-r--r-- | include/linux/kcov.h | 47 |
2 files changed, 14 insertions, 45 deletions
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c index 0b2490347b9f..81e9700eeabc 100644 --- a/drivers/usb/core/hcd.c +++ b/drivers/usb/core/hcd.c @@ -1623,7 +1623,6 @@ static void __usb_hcd_giveback_urb(struct urb *urb) struct usb_hcd *hcd = bus_to_hcd(urb->dev->bus); struct usb_anchor *anchor = urb->anchor; int status = urb->unlinked; - unsigned long flags; urb->hcpriv = NULL; if (unlikely((urb->transfer_flags & URB_SHORT_NOT_OK) && @@ -1641,14 +1640,13 @@ static void __usb_hcd_giveback_urb(struct urb *urb) /* pass ownership to the completion handler */ urb->status = status; /* - * Only collect coverage in the softirq context and disable interrupts - * to avoid scenarios with nested remote coverage collection sections - * that KCOV does not support. - * See the comment next to kcov_remote_start_usb_softirq() for details. + * This function can be called in task context inside another remote + * coverage collection section, but kcov doesn't support that kind of + * recursion yet. Only collect coverage in softirq context for now. */ - flags = kcov_remote_start_usb_softirq((u64)urb->dev->bus->busnum); + kcov_remote_start_usb_softirq((u64)urb->dev->bus->busnum); urb->complete(urb); - kcov_remote_stop_softirq(flags); + kcov_remote_stop_softirq(); usb_anchor_resume_wakeups(anchor); atomic_dec(&urb->use_count); diff --git a/include/linux/kcov.h b/include/linux/kcov.h index 75a2fb8b16c3..0143358874b0 100644 --- a/include/linux/kcov.h +++ b/include/linux/kcov.h @@ -57,47 +57,21 @@ static inline void kcov_remote_start_usb(u64 id) /* * The softirq flavor of kcov_remote_*() functions is introduced as a temporary - * workaround for KCOV's lack of nested remote coverage sections support. - * - * Adding support is tracked in https://bugzilla.kernel.org/show_bug.cgi?id=210337. - * - * kcov_remote_start_usb_softirq(): - * - * 1. Only collects coverage when called in the softirq context. This allows - * avoiding nested remote coverage collection sections in the task context. - * For example, USB/IP calls usb_hcd_giveback_urb() in the task context - * within an existing remote coverage collection section. Thus, KCOV should - * not attempt to start collecting coverage within the coverage collection - * section in __usb_hcd_giveback_urb() in this case. - * - * 2. Disables interrupts for the duration of the coverage collection section. - * This allows avoiding nested remote coverage collection sections in the - * softirq context (a softirq might occur during the execution of a work in - * the BH workqueue, which runs with in_serving_softirq() > 0). - * For example, usb_giveback_urb_bh() runs in the BH workqueue with - * interrupts enabled, so __usb_hcd_giveback_urb() might be interrupted in - * the middle of its remote coverage collection section, and the interrupt - * handler might invoke __usb_hcd_giveback_urb() again. + * work around for kcov's lack of nested remote coverage sections support in + * task context. Adding support for nested sections is tracked in: + * https://bugzilla.kernel.org/show_bug.cgi?id=210337 */ -static inline unsigned long kcov_remote_start_usb_softirq(u64 id) +static inline void kcov_remote_start_usb_softirq(u64 id) { - unsigned long flags = 0; - - if (in_serving_softirq()) { - local_irq_save(flags); + if (in_serving_softirq() && !in_hardirq()) kcov_remote_start_usb(id); - } - - return flags; } -static inline void kcov_remote_stop_softirq(unsigned long flags) +static inline void kcov_remote_stop_softirq(void) { - if (in_serving_softirq()) { + if (in_serving_softirq() && !in_hardirq()) kcov_remote_stop(); - local_irq_restore(flags); - } } #ifdef CONFIG_64BIT @@ -131,11 +105,8 @@ static inline u64 kcov_common_handle(void) } static inline void kcov_remote_start_common(u64 id) {} static inline void kcov_remote_start_usb(u64 id) {} -static inline unsigned long kcov_remote_start_usb_softirq(u64 id) -{ - return 0; -} -static inline void kcov_remote_stop_softirq(unsigned long flags) {} +static inline void kcov_remote_start_usb_softirq(u64 id) {} +static inline void kcov_remote_stop_softirq(void) {} #endif /* CONFIG_KCOV */ #endif /* _LINUX_KCOV_H */ |