diff options
| author | Andrey Konovalov | 2024-05-27 19:35:38 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman | 2024-06-04 15:34:44 +0200 |
| commit | f85d39dd7ed89ffdd622bc1de247ffba8d961504 (patch) | |
| tree | 13964fb94a4c336f6ae0cbd24fcadfc16b798a85 /drivers/usb | |
| parent | e4228cfd092351c2d9b1a3048b2070287291ccbb (diff) | |
kcov, usb: disable interrupts in kcov_remote_start_usb_softirq
After commit 8fea0c8fda30 ("usb: core: hcd: Convert from tasklet to BH
workqueue"), usb_giveback_urb_bh() runs in the BH workqueue with
interrupts enabled.
Thus, the remote coverage collection section in usb_giveback_urb_bh()->
__usb_hcd_giveback_urb() might be interrupted, and the interrupt handler
might invoke __usb_hcd_giveback_urb() again.
This breaks KCOV, as it does not support nested remote coverage collection
sections within the same context (neither in task nor in softirq).
Update kcov_remote_start/stop_usb_softirq() to disable interrupts for the
duration of the coverage collection section to avoid nested sections in
the softirq context (in addition to such in the task context, which are
already handled).
Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Closes: https://lore.kernel.org/linux-usb/0f4d1964-7397-485b-bc48-11c01e2fcbca@I-love.SAKURA.ne.jp/
Closes: https://syzkaller.appspot.com/bug?extid=0438378d6f157baae1a2
Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Fixes: 8fea0c8fda30 ("usb: core: hcd: Convert from tasklet to BH workqueue")
Cc: stable@vger.kernel.org
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrey Konovalov <andreyknvl@gmail.com>
Link: https://lore.kernel.org/r/20240527173538.4989-1-andrey.konovalov@linux.dev
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb')
| -rw-r--r-- | drivers/usb/core/hcd.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c index e3366f4d82b9..1ff7d901fede 100644 --- a/drivers/usb/core/hcd.c +++ b/drivers/usb/core/hcd.c @@ -1623,6 +1623,7 @@ 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) && @@ -1640,13 +1641,14 @@ static void __usb_hcd_giveback_urb(struct urb *urb) /* pass ownership to the completion handler */ urb->status = status; /* - * 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. + * 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. */ - kcov_remote_start_usb_softirq((u64)urb->dev->bus->busnum); + flags = kcov_remote_start_usb_softirq((u64)urb->dev->bus->busnum); urb->complete(urb); - kcov_remote_stop_softirq(); + kcov_remote_stop_softirq(flags); usb_anchor_resume_wakeups(anchor); atomic_dec(&urb->use_count); |