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Filename Latest commit message Latest commit date
Pete Zaitcev 9e28d2e932 usb: mon: Fix a deadlock in usbmon between mmap and read
commit 19e6317d24c25ee737c65d1ffb7483bdda4bb54a upstream.

The problem arises because our read() function grabs a lock of the
circular buffer, finds something of interest, then invokes copy_to_user()
straight from the buffer, which in turn takes mm->mmap_sem. In the same
time, the callback mon_bin_vma_fault() is invoked under mm->mmap_sem.
It attempts to take the fetch lock and deadlocks.

This patch does away with protecting of our page list with any
semaphores, and instead relies on the kernel not close the device
while mmap is active in a process.

In addition, we prohibit re-sizing of a buffer while mmap is active.
This way, when (now unlocked) fault is processed, it works with the
page that is intended to be mapped-in, and not some other random page.
Note that this may have an ABI impact, but hopefully no legitimate
program is this wrong.

Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Reported-by: syzbot+56f9673bb4cdcbeb0e92@syzkaller.appspotmail.com
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Fixes: 46eb14a6e1 ("USB: fix usbmon BUG trigger")
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191204203941.3503452b@suzdal.zaitcev.lan
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-17 19:55:49 +01:00
arch ARM: dts: pandora-common: define wl1251 as child node of mmc3 2019-12-17 19:55:39 +01:00
block iocost: check active_list of all the ancestors in iocg_activate() 2019-11-14 13:56:54 -07:00
certs
crypto crypto: user - fix memory leak in crypto_reportstat 2019-12-13 08:43:11 +01:00
Documentation USB: documentation: flags on usb-storage versus UAS 2019-12-17 19:55:32 +01:00
drivers usb: mon: Fix a deadlock in usbmon between mmap and read 2019-12-17 19:55:49 +01:00
fs ceph: fix compat_ioctl for ceph_dir_operations 2019-12-17 19:55:31 +01:00
include compat_ioctl: add compat_ptr_ioctl() 2019-12-17 19:55:30 +01:00
init
ipc
kernel time: Zero the upper 32-bits in __kernel_timespec on 32-bit 2019-12-13 08:42:18 +01:00
lib lib/xz: fix XZ_DYNALLOC to avoid useless memory reallocations 2019-11-15 18:34:00 -08:00
LICENSES
mm mm/ksm.c: don't WARN if page is still mapped in remove_stable_node() 2019-11-22 09:11:18 -08:00
net rfkill: allocate static minor 2019-12-13 08:43:18 +01:00
samples
scripts arm64 fix for -rc8 / final 2019-11-15 09:14:23 -08:00
security
sound ALSA: hda - Fix pending unsol events at shutdown 2019-12-13 08:43:27 +01:00
tools kselftest: Fix NULL INSTALL_PATH for TARGETS runlist 2019-12-13 08:43:31 +01:00
usr
virt KVM: arm/arm64: vgic: Don't rely on the wrong pending table 2019-12-13 08:43:00 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-11-22 14:28:14 -08:00
Makefile Linux 5.4.3 2019-12-13 08:43:32 +01:00
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.