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Matthew Wilcox (Oracle) 23c84eb783 dax: Fix missed wakeup with PMD faults
RocksDB can hang indefinitely when using a DAX file.  This is due to
a bug in the XArray conversion when handling a PMD fault and finding a
PTE entry.  We use the wrong index in the hash and end up waiting on
the wrong waitqueue.

There's actually no need to wait; if we find a PTE entry while looking
for a PMD entry, we can return immediately as we know we should fall
back to a PTE fault (which may not conflict with the lock held).

We reuse the XA_RETRY_ENTRY to signal a conflicting entry was found.
This value can never be found in an XArray while holding its lock, so
it does not create an ambiguity.

Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/CAPcyv4hwHpX-MkUEqxwdTj7wCCZCN4RV-L4jsnuwLGyL_UEG4A@mail.gmail.com
Fixes: b15cd80068 ("dax: Convert page fault handlers to XArray")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Robert Barror <robert.barror@intel.com>
Reported-by: Seema Pandit <seema.pandit@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2019-07-16 19:30:59 -07:00
arch Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-06-16 07:28:14 -10:00
block blk-mq: remove WARN_ON(!q->elevator) from blk_mq_sched_free_requests 2019-06-13 03:05:58 -06:00
certs treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
crypto SPDX update for 5.2-rc4 2019-06-08 12:52:42 -07:00
Documentation Merge branch 'for-5.2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2019-06-14 17:46:14 -10:00
drivers device-dax: Add a 'resource' attribute 2019-06-20 17:40:00 -07:00
fs dax: Fix missed wakeup with PMD faults 2019-07-16 19:30:59 -07:00
include Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-06-16 07:28:14 -10:00
init Char/Misc driver fixes for 5.2-rc4 2019-06-08 12:50:36 -07:00
ipc treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
kernel Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-06-16 07:22:56 -10:00
lib lib/genalloc: introduce chunk owners 2019-06-13 17:34:56 -10:00
LICENSES
mm Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-06-16 07:28:14 -10:00
net SPDX update for 5.2-rc4 2019-06-08 12:52:42 -07:00
samples SPDX update for 5.2-rc4 2019-06-08 12:52:42 -07:00
scripts scripts/decode_stacktrace.sh: prefix addr2line with $CROSS_COMPILE 2019-06-13 17:34:56 -10:00
security Smack: Restore the smackfsdef mount option and add missing prefixes 2019-06-14 14:25:04 -10:00
sound sound fixes for 5.2-rc5 2019-06-14 05:37:06 -10:00
tools mm/devm_memremap_pages: fix final page put race 2019-06-13 17:34:56 -10:00
usr
virt treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes
.gitignore .gitignore: exclude .get_maintainer.ignore and .gitattributes 2019-05-18 11:49:54 +09:00
.mailmap A reasonably busy cycle for docs, including: 2019-05-08 12:42:50 -07:00
COPYING
CREDITS MAINTAINERS: Farewell Martin Schwidefsky 2019-05-31 10:14:11 +02:00
Kbuild
Kconfig
MAINTAINERS Merge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2019-06-08 12:48:49 -07:00
Makefile Linux 5.2-rc5 2019-06-16 08:49:45 -10:00
README

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.