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Damien Le Moal 8f882a6b0b dm zoned: fix various dmz_get_mblock() issues
commit 3d4e738311 upstream.

dmz_fetch_mblock() called from dmz_get_mblock() has a race since the
allocation of the new metadata block descriptor and its insertion in
the cache rbtree with the READING state is not atomic. Two different
contexts requesting the same block may end up each adding two different
descriptors of the same block to the cache.

Another problem for this function is that the BIO for processing the
block read is allocated after the metadata block descriptor is inserted
in the cache rbtree. If the BIO allocation fails, the metadata block
descriptor is freed without first being removed from the rbtree.

Fix the first problem by checking again if the requested block is not in
the cache right before inserting the newly allocated descriptor,
atomically under the mblk_lock spinlock. The second problem is fixed by
simply allocating the BIO before inserting the new block in the cache.

Finally, since dmz_fetch_mblock() also increments a block reference
counter, rename the function to dmz_get_mblock_slow(). To be symmetric
and clear, also rename dmz_lookup_mblock() to dmz_get_mblock_fast() and
increment the block reference counter directly in that function rather
than in dmz_get_mblock().

Fixes: 3b1a94c88b ("dm zoned: drive-managed zoned block device target")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-11-13 11:08:49 -08:00
arch crypto: speck - remove Speck 2018-11-13 11:08:46 -08:00
block block, bfq: correctly charge and reset entity service in all cases 2018-11-13 11:08:28 -08:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto crypto: speck - remove Speck 2018-11-13 11:08:46 -08:00
Documentation crypto: speck - remove Speck 2018-11-13 11:08:46 -08:00
drivers dm zoned: fix various dmz_get_mblock() issues 2018-11-13 11:08:49 -08:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs lockd: fix access beyond unterminated strings in prints 2018-11-13 11:08:49 -08:00
include crypto: speck - remove Speck 2018-11-13 11:08:46 -08:00
init Kbuild updates for v4.19 (2nd) 2018-08-25 13:40:38 -07:00
ipc ipc/shm.c: use ERR_CAST() for shm_lock() error return 2018-10-05 16:32:04 -07:00
kernel genirq: Fix race on spurious interrupt detection 2018-11-13 11:08:48 -08:00
lib locking/lockdep: Fix debug_locks off performance problem 2018-11-13 11:08:20 -08:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm mm/hmm: fix race between hmm_mirror_unregister() and mmu_notifier callback 2018-11-13 11:08:47 -08:00
net nfsd: Fix an Oops in free_session() 2018-11-13 11:08:49 -08:00
samples samples: disable CONFIG_SAMPLES for UML 2018-10-11 02:15:46 +09:00
scripts Kbuild fixes for v4.19 (2nd) 2018-10-11 19:23:07 +02:00
security ima: open a new file instance if no read permissions 2018-11-13 11:08:46 -08:00
sound ASoC: sta32x: set ->component pointer in private struct 2018-11-13 11:08:42 -08:00
tools cpupower: Fix AMD Family 0x17 msr_pstate size 2018-11-13 11:08:38 -08:00
usr initramfs: move gen_initramfs_list.sh from scripts/ to usr/ 2018-08-22 23:21:44 +09:00
virt KVM: arm64: Fix caching of host MDCR_EL2 value 2018-11-13 11:08:47 -08:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.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 Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS MAINTAINERS: Add an entry for the code of conduct 2018-10-22 07:33:36 +01:00
Makefile Linux 4.19.1 2018-11-04 14:50:54 +01:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.