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Vasilis Liaskovitis f92898e7f3 xen/blkfront: avoid NULL blkfront_info dereference on device removal
If a block device is hot-added when we are out of grants,
gnttab_grant_foreign_access fails with -ENOSPC (log message "28
granting access to ring page") in this code path:

  talk_to_blkback ->
	setup_blkring ->
		xenbus_grant_ring ->
			gnttab_grant_foreign_access

and the failing path in talk_to_blkback sets the driver_data to NULL:

 destroy_blkring:
        blkif_free(info, 0);

        mutex_lock(&blkfront_mutex);
        free_info(info);
        mutex_unlock(&blkfront_mutex);

        dev_set_drvdata(&dev->dev, NULL);

This results in a NULL pointer BUG when blkfront_remove and blkif_free
try to access the failing device's NULL struct blkfront_info.

Cc: stable@vger.kernel.org # 4.5 and later
Signed-off-by: Vasilis Liaskovitis <vliaskovitis@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-25 11:17:39 -06:00
arch pci-v4.20-changes 2018-10-25 06:50:48 -07:00
block for-4.20/block-20181021 2018-10-22 17:46:08 +01:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto Revert "net: simplify sock_poll_wait" 2018-10-23 10:57:06 -07:00
Documentation sound updates for 4.20 2018-10-25 09:00:15 -07:00
drivers xen/blkfront: avoid NULL blkfront_info dereference on device removal 2018-10-25 11:17:39 -06:00
firmware
fs Further restructure ext4 documentation; fix up ext4's delayed 2018-10-24 17:42:24 +01:00
include sound updates for 4.20 2018-10-25 09:00:15 -07:00
init Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-10-23 15:00:03 +01:00
ipc Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2018-10-24 11:22:39 +01:00
kernel Merge branch 'next-general' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2018-10-24 11:49:35 +01:00
lib This is a fairly typical cycle for documentation. There's some welcome 2018-10-24 18:01:11 +01:00
LICENSES This is a fairly typical cycle for documentation. There's some welcome 2018-10-24 18:01:11 +01:00
mm Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2018-10-24 11:22:39 +01:00
net This is a fairly typical cycle for documentation. There's some welcome 2018-10-24 18:01:11 +01:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-10-12 21:38:46 -07:00
scripts This is a fairly typical cycle for documentation. There's some welcome 2018-10-24 18:01:11 +01:00
security Merge branch 'next-general' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2018-10-24 11:49:35 +01:00
sound sound updates for 4.20 2018-10-25 09:00:15 -07:00
tools pci-v4.20-changes 2018-10-25 06:50:48 -07:00
usr initramfs: move gen_initramfs_list.sh from scripts/ to usr/ 2018-08-22 23:21:44 +09:00
virt Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2018-10-24 11:22:39 +01:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS 9p: remove Ron Minnich from MAINTAINERS 2018-08-17 16:20:26 -07:00
Kbuild
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS sound updates for 4.20 2018-10-25 09:00:15 -07:00
Makefile Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-10-23 13:08:53 +01:00
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.