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Julian Wiedmann 248f064af2 s390/qeth: fix NULL deref in qeth_clear_working_pool_list()
When qeth_set_online() calls qeth_clear_working_pool_list() to roll
back after an error exit from qeth_hardsetup_card(), we are at risk of
accessing card->qdio.in_q before it was allocated by
qeth_alloc_qdio_queues() via qeth_mpc_initialize().

qeth_clear_working_pool_list() then dereferences NULL, and by writing to
queue->bufs[i].pool_entry scribbles all over the CPU's lowcore.
Resulting in a crash when those lowcore areas are used next (eg. on
the next machine-check interrupt).

Such a scenario would typically happen when the device is first set
online and its queues aren't allocated yet. An early IO error or certain
misconfigs (eg. mismatched transport mode, bad portno) then cause us to
error out from qeth_hardsetup_card() with card->qdio.in_q still being
NULL.

Fix it by checking the pointer for NULL before accessing it.

Note that we also have (rare) paths inside qeth_mpc_initialize() where
a configuration change can cause us to free the existing queues,
expecting that subsequent code will allocate them again. If we then
error out before that re-allocation happens, the same bug occurs.

Fixes: eff73e16ee ("s390/qeth: tolerate pre-filled RX buffer")
Reported-by: Stefan Raspl <raspl@linux.ibm.com>
Root-caused-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-09-21 20:02:23 -07:00
arch alpha: Declare virt_to_phys and virt_to_bus parameter as pointer to volatile 2021-09-16 11:27:32 -07:00
block block-5.15-2021-09-11 2021-09-11 10:19:51 -07:00
certs certs: Add support for using elliptic curve keys for signing modules 2021-08-23 19:55:42 +03:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2021-08-30 12:57:10 -07:00
Documentation Doc: networking: Fox a typo in ice.rst 2021-09-21 11:01:25 +01:00
drivers s390/qeth: fix NULL deref in qeth_clear_working_pool_list() 2021-09-21 20:02:23 -07:00
fs qnx4: avoid stringop-overread errors 2021-09-15 13:56:37 -07:00
include net: dsa: tear down devlink port regions when tearing down the devlink port on error 2021-09-19 13:05:44 +01:00
init memblock: introduce saner 'memblock_free_ptr()' interface 2021-09-14 13:23:22 -07:00
ipc ipc: remove memcg accounting for sops objects in do_semtimedop() 2021-09-14 10:22:11 -07:00
kernel Networking fixes for 5.15-rc2, including fixes from bpf. 2021-09-16 13:05:42 -07:00
lib net: update NXP copyright text 2021-09-17 13:52:17 +01:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm memblock: introduce saner 'memblock_free_ptr()' interface 2021-09-14 13:23:22 -07:00
net net: dsa: don't allocate the slave_mii_bus using devres 2021-09-21 13:52:16 +01:00
samples kgdb patches for 5.15 2021-09-07 12:08:04 -07:00
scripts Merge branch 'gcc-min-version-5.1' (make gcc-5.1 the minimum version) 2021-09-13 10:43:04 -07:00
security Kbuild updates for v5.15 2021-09-03 15:33:47 -07:00
sound sound fixes for 5.15-rc1 2021-09-09 16:05:10 -07:00
tools selftests: net: af_unix: Fix makefile to use TEST_GEN_PROGS 2021-09-19 13:22:18 +01:00
usr .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
virt KVM: Drop unused kvm_dirty_gfn_invalid() 2021-09-06 08:23:46 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: update email address of Matthias Fuchs and Thomas Körper 2021-08-19 09:39:44 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: move Murali Karicheri to credits 2021-04-29 15:47:30 -07:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Compiler Attributes improvements: 2021-09-12 16:09:26 -07:00
Makefile Merge branch 'gcc-min-version-5.1' (make gcc-5.1 the minimum version) 2021-09-13 10:43:04 -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.