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Mikulas Patocka b437275e89 add barriers to buffer_uptodate and set_buffer_uptodate
commit d4252071b9 upstream.

Let's have a look at this piece of code in __bread_slow:

	get_bh(bh);
	bh->b_end_io = end_buffer_read_sync;
	submit_bh(REQ_OP_READ, 0, bh);
	wait_on_buffer(bh);
	if (buffer_uptodate(bh))
		return bh;

Neither wait_on_buffer nor buffer_uptodate contain any memory barrier.
Consequently, if someone calls sb_bread and then reads the buffer data,
the read of buffer data may be executed before wait_on_buffer(bh) on
architectures with weak memory ordering and it may return invalid data.

Fix this bug by adding a memory barrier to set_buffer_uptodate and an
acquire barrier to buffer_uptodate (in a similar way as
folio_test_uptodate and folio_mark_uptodate).

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-08-17 14:22:46 +02:00
arch x86: link vdso and boot with -z noexecstack --no-warn-rwx-segments 2022-08-17 14:22:45 +02:00
block block: fix default IO priority handling again 2022-08-11 13:07:50 +02:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:22:01 +02:00
crypto crypto: memneq - move into lib/ 2022-06-22 14:22:03 +02:00
Documentation x86/speculation: Add RSB VM Exit protections 2022-08-11 13:07:54 +02:00
drivers wifi: mac80211_hwsim: use 32-bit skb cookie 2022-08-17 14:22:46 +02:00
fs nfsd: eliminate the NFSD_FILE_BREAK_* flags 2022-08-17 14:22:45 +02:00
include add barriers to buffer_uptodate and set_buffer_uptodate 2022-08-17 14:22:46 +02:00
init Kconfig: Add option for asm goto w/ tied outputs to workaround clang-13 bug 2022-06-09 10:23:26 +02:00
ipc ipc/mqueue: use get_tree_nodev() in mqueue_get_tree() 2022-06-09 10:23:10 +02:00
kernel locking/rwsem: Allow slowpath writer to ignore handoff bit if not set by first waiter 2022-08-03 12:03:56 +02:00
lib ida: don't use BUG_ON() for debugging 2022-07-12 16:35:18 +02:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm page_alloc: fix invalid watermark check on a negative value 2022-08-03 12:03:55 +02:00
net sctp: leave the err path free in sctp_stream_init to sctp_stream_free 2022-08-03 12:03:54 +02:00
samples samples/landlock: Format with clang-format 2022-06-09 10:23:23 +02:00
scripts x86/extable: Rework the exception table mechanics 2022-07-29 17:25:25 +02:00
security lockdown: Fix kexec lockdown bypass with ima policy 2022-07-29 17:25:05 +02:00
sound ALSA: hda/realtek: Add quirk for HP Spectre x360 15-eb0xxx 2022-08-17 14:22:46 +02:00
tools x86/speculation: Add RSB VM Exit protections 2022-08-11 13:07:54 +02:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:27:15 +01:00
virt KVM: Don't null dereference ops->destroy 2022-07-29 17:25:24 +02:00
.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: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
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 Input: goodix - add a goodix.h header file 2022-07-12 16:34:51 +02:00
Makefile Makefile: link with -z noexecstack --no-warn-rwx-segments 2022-08-17 14:22:44 +02:00
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.