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https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git
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| Filename | Latest commit message | Latest commit date |
|---|---|---|
ea748ebb90
[ Upstream commit 8d63c83d8eb922f6c316320f50c82fa88d099bea ]
Yunseong Kim and the syzbot fuzzer both reported a problem in
RT-enabled kernels caused by the way dummy-hcd mixes interrupt
management and spin-locking. The pattern was:
local_irq_save(flags);
spin_lock(&dum->lock);
...
spin_unlock(&dum->lock);
... // calls usb_gadget_giveback_request()
local_irq_restore(flags);
The code was written this way because usb_gadget_giveback_request()
needs to be called with interrupts disabled and the private lock not
held.
While this pattern works fine in non-RT kernels, it's not good when RT
is enabled. RT kernels handle spinlocks much like mutexes; in particular,
spin_lock() may sleep. But sleeping is not allowed while local
interrupts are disabled.
To fix the problem, rewrite the code to conform to the pattern used
elsewhere in dummy-hcd and other UDC drivers:
spin_lock_irqsave(&dum->lock, flags);
...
spin_unlock(&dum->lock);
usb_gadget_giveback_request(...);
spin_lock(&dum->lock);
...
spin_unlock_irqrestore(&dum->lock, flags);
This approach satisfies the RT requirements.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Fixes:
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| .. | ||
| atm | ||
| c67x00 | ||
| cdns3 | ||
| chipidea | ||
| class | ||
| common | ||
| core | ||
| dwc2 | ||
| dwc3 | ||
| early | ||
| gadget | ||
| host | ||
| image | ||
| isp1760 | ||
| misc | ||
| mon | ||
| mtu3 | ||
| musb | ||
| phy | ||
| renesas_usbhs | ||
| roles | ||
| serial | ||
| storage | ||
| typec | ||
| usbip | ||
| Kconfig | ||
| Makefile | ||
| usb-skeleton.c | ||