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Filename Latest commit message Latest commit date
Anirudh Rayabharam efa99087ea usb: gadget: dummy_hcd: fix gpf in gadget_setup
commit 4a5d797a9f9c4f18585544237216d7812686a71f upstream.

Fix a general protection fault reported by syzbot due to a race between
gadget_setup() and gadget_unbind() in raw_gadget.

The gadget core is supposed to guarantee that there won't be any more
callbacks to the gadget driver once the driver's unbind routine is
called. That guarantee is enforced in usb_gadget_remove_driver as
follows:

        usb_gadget_disconnect(udc->gadget);
        if (udc->gadget->irq)
                synchronize_irq(udc->gadget->irq);
        udc->driver->unbind(udc->gadget);
        usb_gadget_udc_stop(udc);

usb_gadget_disconnect turns off the pullup resistor, telling the host
that the gadget is no longer connected and preventing the transmission
of any more USB packets. Any packets that have already been received
are sure to processed by the UDC driver's interrupt handler by the time
synchronize_irq returns.

But this doesn't work with dummy_hcd, because dummy_hcd doesn't use
interrupts; it uses a timer instead. It does have code to emulate the
effect of synchronize_irq, but that code doesn't get invoked at the
right time -- it currently runs in usb_gadget_udc_stop, after the unbind
callback instead of before. Indeed, there's no way for
usb_gadget_remove_driver to invoke this code before the unbind callback.

To fix this, move the synchronize_irq() emulation code to dummy_pullup
so that it runs before unbind. Also, add a comment explaining why it is
necessary to have it there.

Reported-by: syzbot+eb4674092e6cc8d9e0bd@syzkaller.appspotmail.com
Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Anirudh Rayabharam <mail@anirudhrb.com>
Link: https://lore.kernel.org/r/20210419033713.3021-1-mail@anirudhrb.com
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-11 14:04:17 +02:00
arch x86/cpu: Initialize MSR_TSC_AUX if RDTSCP *or* RDPID is supported 2021-05-11 14:04:16 +02:00
block block: only update parent bi_status when bio fail 2021-04-16 11:46:38 +02:00
certs certs: Fix blacklist flag type confusion 2021-03-04 10:26:29 +01:00
crypto crypto: rng - fix crypto_rng_reset() refcounting when !CRYPTO_STATS 2021-05-11 14:04:15 +02:00
Documentation dt-bindings: net: ethernet-controller: fix typo in NVMEM 2021-04-14 08:24:18 +02:00
drivers usb: gadget: dummy_hcd: fix gpf in gadget_setup 2021-05-11 14:04:17 +02:00
fs ext4: fix error code in ext4_commit_super 2021-05-11 14:04:16 +02:00
include Fix misc new gcc warnings 2021-05-11 14:04:16 +02:00
init init/Kconfig: make COMPILE_TEST depend on HAS_IOMEM 2021-04-10 13:34:32 +02:00
ipc
kernel kbuild: update config_data.gz only when the content of .config is changed 2021-05-11 14:04:16 +02:00
lib avoid __memcat_p link failure 2021-05-07 10:51:37 +02:00
LICENSES
mm mm: fix race by making init_zero_pfn() early_initcall 2021-04-07 14:47:42 +02:00
net Fix misc new gcc warnings 2021-05-11 14:04:16 +02:00
samples samples, bpf: Add missing munmap in xdpsock 2021-03-17 17:03:33 +01:00
scripts ftrace: Have recordmcount use w8 to read relp->r_info in arm64_is_fake_mcount 2021-03-09 11:09:39 +01:00
security security: commoncap: fix -Wstringop-overread warning 2021-05-11 14:04:16 +02:00
sound ALSA: hda/realtek: Add quirk for Intel Clevo PCx0Dx 2021-05-11 14:04:13 +02:00
tools perf ftrace: Fix access to pid in array when setting a pid filter 2021-05-07 10:51:37 +02:00
usr
virt KVM: arm64: Ensure I-cache isolation between vcpus of a same VM 2021-03-17 17:03:57 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Makefile: Move -Wno-unused-but-set-variable out of GCC only block 2021-05-11 14:04:14 +02:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.