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Linux kernel source tree for SHARP Brain series (PW-SH1 or later)
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Jan Kara a87a201989 dax: fix ENOMEM handling in grab_mapping_entry() 
[ Upstream commit 1a14e3779dd58c16b30e56558146e5cc850ba8b0 ]

grab_mapping_entry() has a bug in handling of ENOMEM condition.  Suppose
we have a PMD entry at index i which we are downgrading to a PTE entry.
grab_mapping_entry() will set pmd_downgrade to true, lock the entry, clear
the entry in xarray, and decrement mapping->nrpages.  The it will call:

	entry = dax_make_entry(pfn_to_pfn_t(0), flags);
	dax_lock_entry(xas, entry);

which inserts new PTE entry into xarray.  However this may fail allocating
the new node.  We handle this by:

	if (xas_nomem(xas, mapping_gfp_mask(mapping) & ~__GFP_HIGHMEM))
		goto retry;

however pmd_downgrade stays set to true even though 'entry' returned from
get_unlocked_entry() will be NULL now.  And we will go again through the
downgrade branch.  This is mostly harmless except that mapping->nrpages is
decremented again and we temporarily have an invalid entry stored in
xarray.  Fix the problem by setting pmd_downgrade to false each time we
lookup the entry we work with so that it matches the entry we found.

Link: https://lkml.kernel.org/r/20210622160015.18004-1-jack@suse.cz
Fixes: b15cd80068 ("dax: Convert page fault handlers to XArray")
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
 		2021-07-14 16:53:25 +02:00
Documentation clocksource: Retry clock read if long delays detected 2021-07-14 16:53:18 +02:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch KVM: nVMX: Ensure 64-bit shift when checking VMFUNC bitmap 2021-07-14 16:53:23 +02:00
block blk-wbt: make sure throttle is enabled properly 2021-07-14 16:53:25 +02:00
certs certs: Move load_system_certificate_list to a common function 2021-06-30 08:47:55 -04:00
crypto crypto: shash - avoid comparing pointers to exported functions under CFI 2021-07-14 16:53:13 +02:00
drivers cpufreq: Make cpufreq_online() call driver->offline() on errors 2021-07-14 16:53:25 +02:00
fs dax: fix ENOMEM handling in grab_mapping_entry() 2021-07-14 16:53:25 +02:00
include random32: Fix implicit truncation warning in prandom_seed_state() 2021-07-14 16:53:17 +02:00
init kbuild: add CONFIG_LD_IS_LLD 2021-06-30 08:47:44 -04:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:20:16 +02:00
kernel sched/uclamp: Fix uclamp_tg_restrict() 2021-07-14 16:53:24 +02:00
lib lib: vsprintf: Fix handling of number field widths in vsscanf 2021-07-14 16:53:16 +02:00
mm mm, futex: fix shared futex pgoff on shmem huge page 2021-06-30 08:47:55 -04:00
net SUNRPC: Should wake up the privileged task firstly. 2021-07-14 16:53:05 +02:00
samples samples: vfio-mdev: fix error handing in mdpy_fb_probe() 2021-06-10 13:37:03 +02:00
scripts kbuild: Fix objtool dependency for 'OBJECT_FILES_NON_STANDARD_<obj> := n' 2021-07-14 16:53:20 +02:00
security evm: fix writing <securityfs>/evm overflow 2021-07-14 16:53:21 +02:00
sound ALSA: hda/realtek: Apply LED fixup for HP Dragonfly G1, too 2021-07-14 16:52:59 +02:00
tools KVM: selftests: Fix kvm_check_cap() assertion 2021-06-30 08:47:49 -04:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: do not allow mapping valid but non-reference-counted pages 2021-06-30 08:47:50 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +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: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-08-26 10:40:46 +02:00
Makefile Makefile: fix GDB warning with CONFIG_RELR 2021-07-14 16:53:12 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.