Go to file
Alan Stern 50896c4103 USB: dummy-hcd: Fix failure to give back unlinked URBs
The syzkaller USB fuzzer identified a failure mode in which dummy-hcd
would never give back an unlinked URB.  This causes usb_kill_urb() to
hang, leading to WARNINGs and unkillable threads.

In dummy-hcd, all URBs are given back by the dummy_timer() routine as
it scans through the list of pending URBS.  Failure to give back URBs
can be caused by failure to start or early exit from the scanning
loop.  The code currently has two such pathways: One is triggered when
an unsupported bus transfer speed is encountered, and the other by
exhausting the simulated bandwidth for USB transfers during a frame.

This patch removes those two paths, thereby allowing all unlinked URBs
to be given back in a timely manner.  It adds a check for the bus
speed when the gadget first starts running, so that dummy_timer() will
never thereafter encounter an unsupported speed.  And it prevents the
loop from exiting as soon as the total bandwidth has been used up (the
scanning loop continues, giving back unlinked URBs as they are found,
but not transferring any more data).

Thanks to Andrey Konovalov for manually running the syzkaller fuzzer
to help track down the source of the bug.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-and-tested-by: syzbot+d919b0f29d7b5a4994b9@syzkaller.appspotmail.com
CC: <stable@vger.kernel.org>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
2019-05-03 09:13:47 +03:00
arch Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-04-20 10:05:02 -07:00
block bfq: update internal depth state when queue depth changes 2019-04-13 19:08:22 -06:00
certs kexec, KEYS: Make use of platform keyring for signature verify 2019-02-04 17:34:07 -05:00
crypto crypto: x86/poly1305 - fix overflow during partial reduction 2019-04-08 14:43:06 +08:00
Documentation Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2019-04-19 10:28:27 -07:00
drivers USB: dummy-hcd: Fix failure to give back unlinked URBs 2019-05-03 09:13:47 +03:00
fs for-linus-20190420 2019-04-20 12:20:58 -07:00
include for-linus-20190420 2019-04-20 12:20:58 -07:00
init init: initialize jump labels before command line option parsing 2019-04-19 09:46:05 -07:00
ipc Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-03-12 14:08:19 -07:00
kernel Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-04-20 10:10:49 -07:00
lib kcov: improve CONFIG_ARCH_HAS_KCOV help text 2019-04-19 09:46:05 -07:00
LICENSES LICENSES: Add GCC runtime library exception text 2019-01-16 14:54:15 -07:00
mm Merge branch 'for-5.1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu 2019-04-19 15:37:22 -07:00
net NFS client bugfixes for Linux 5.1 2019-04-20 12:55:23 -07:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-03-11 08:54:01 -07:00
scripts locking/atomics: Don't assume that scripts are executable 2019-04-19 14:21:43 +02:00
security Merge branch 'for-5.1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2019-04-19 18:03:55 -07:00
sound ALSA: hda/realtek - add two more pin configuration sets to quirk table 2019-04-17 10:41:38 +02:00
tools Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-04-20 10:05:02 -07:00
usr user/Makefile: Fix typo and capitalization in comment section 2018-12-11 00:18:03 +09:00
virt KVM: fix spectrev1 gadgets 2019-04-16 15:38:07 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2019-04-12 12:49:54 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support for DT binding schema checks 2018-12-13 09:41:32 -06:00
.mailmap Update Nicolas Pitre's email address 2019-04-02 18:12:44 -10:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Char/Misc driver patches for 5.1-rc1 2019-03-06 14:18:59 -08:00
Kbuild Kbuild updates for v5.1 2019-03-10 17:48:21 -07:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS - Fix the random PID check 2019-04-20 10:43:37 -07:00
Makefile Linux 5.1-rc6 2019-04-21 10:45:57 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.