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Stephen Boyd 10252bae86 mmc: core: Don't allocate IDA for OF aliases
There's a chance that the IDA allocated in mmc_alloc_host() is not freed
for some time because it's freed as part of a class' release function
(see mmc_host_classdev_release() where the IDA is freed). If another
thread is holding a reference to the class, then only once all balancing
device_put() calls (in turn calling kobject_put()) have been made will
the IDA be released and usable again.

Normally this isn't a problem because the kobject is released before
anything else that may want to use the same number tries to again, but
with CONFIG_DEBUG_KOBJECT_RELEASE=y and OF aliases it becomes pretty
easy to try to allocate an alias from the IDA twice while the first time
it was allocated is still pending a call to ida_simple_remove(). It's
also possible to trigger it by using CONFIG_DEBUG_KOBJECT_RELEASE and
probe defering a driver at boot that calls mmc_alloc_host() before
trying to get resources that may defer likes clks or regulators.

Instead of allocating from the IDA in this scenario, let's just skip it
if we know this is an OF alias. The number is already "claimed" and
devices that aren't using OF aliases won't try to use the claimed
numbers anyway (see mmc_first_nonreserved_index()). This should avoid
any issues with mmc_alloc_host() returning failures from the
ida_simple_get() in the case that we're using an OF alias.

Cc: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Cc: Sujit Kautkar <sujitka@chromium.org>
Reported-by: Zubin Mithra <zsm@chromium.org>
Fixes: fa2d0aa969 ("mmc: core: Allow setting slot index via device tree alias")
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20210623075002.1746924-3-swboyd@chromium.org
Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
History 2021-07-14 18:55:28 +02:00
arch Two fixes: 2021-07-11 11:17:57 -07:00
block block-5.14-2021-07-08 2021-07-09 12:05:33 -07:00
certs Kbuild updates for v5.13 (2nd) 2021-05-08 10:00:11 -07:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2021-07-09 11:00:44 -07:00
Documentation RTC for 5.14 2021-07-10 16:19:10 -07:00
drivers mmc: core: Don't allocate IDA for OF aliases 2021-07-14 18:55:28 +02:00
fs 13 cifs/smb3 fixes. Most are to address minor issues pointed out by Coverity. Also includes a packet signing enhancement and mount improvement 2021-07-10 12:04:58 -07:00
include Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
init Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
ipc Merge branch 'akpm' (patches from Andrew) 2021-07-02 12:08:10 -07:00
kernel Two fixes: 2021-07-11 11:17:57 -07:00
lib mm/page_alloc: Revert pahole zero-sized workaround 2021-07-10 16:09:39 -07:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
mm mm/rmap: try_to_migrate() skip zone_device !device_private 2021-07-11 15:05:15 -07:00
net We have new filesystem client metrics for reporting I/O sizes from 2021-07-09 09:52:13 -07:00
samples VFIO update for v5.14-rc1 2021-07-03 11:49:33 -07:00
scripts Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
security asm-generic/unaligned: Unify asm/unaligned.h around struct helper 2021-07-02 12:43:40 -07:00
sound sound fixes for 5.14-rc1 2021-07-09 11:40:26 -07:00
tools perf tools changes for v5.14: 2nd batch 2021-07-11 10:54:24 -07:00
usr .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
virt Merge branch 'akpm' (patches from Andrew) 2021-06-29 17:29:11 -07:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.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 m68k updates for v5.14 2021-06-28 14:01:03 -07:00
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 SCSI misc on 20210711 2021-07-11 10:59:53 -07:00
Makefile Linux 5.14-rc1 2021-07-11 15:07:40 -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.