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Filename Latest commit message Latest commit date
Dave Chinner f8f9ee4794 xfs: add kmem_alloc_io()
Memory we use to submit for IO needs strict alignment to the
underlying driver contraints. Worst case, this is 512 bytes. Given
that all allocations for IO are always a power of 2 multiple of 512
bytes, the kernel heap provides natural alignment for objects of
these sizes and that suffices.

Until, of course, memory debugging of some kind is turned on (e.g.
red zones, poisoning, KASAN) and then the alignment of the heap
objects is thrown out the window. Then we get weird IO errors and
data corruption problems because drivers don't validate alignment
and do the wrong thing when passed unaligned memory buffers in bios.

TO fix this, introduce kmem_alloc_io(), which will guaranteeat least
512 byte alignment of buffers for IO, even if memory debugging
options are turned on. It is assumed that the minimum allocation
size will be 512 bytes, and that sizes will be power of 2 mulitples
of 512 bytes.

Use this everywhere we allocate buffers for IO.

This no longer fails with log recovery errors when KASAN is enabled
due to the brd driver not handling unaligned memory buffers:

# mkfs.xfs -f /dev/ram0 ; mount /dev/ram0 /mnt/test

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-08-26 17:43:15 -07:00
arch This pull request contains a single bug fix for UML: 2019-08-25 11:40:24 -07:00
block block: remove REQ_NOWAIT_INLINE 2019-08-15 11:09:16 -06:00
certs
crypto
Documentation Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-08-25 10:10:15 -07:00
drivers A minor auxdisplay improvement: 2019-08-25 11:43:17 -07:00
fs xfs: add kmem_alloc_io() 2019-08-26 17:43:15 -07:00
include This pull request contains the following fixes for UBIFS and JFFS2: 2019-08-25 11:29:27 -07:00
init
ipc
kernel Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-08-25 10:08:01 -07:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-08-06 17:11:59 -07:00
LICENSES
mm mm/kasan: fix false positive invalid-free reports with CONFIG_KASAN_SW_TAGS=y 2019-08-24 19:48:42 -07:00
net Three important fixes tagged for stable (an indefinite hang, a crash on 2019-08-23 09:19:38 -07:00
samples auxdisplay: Fix a typo in cfag12864b-example.c 2019-08-08 20:00:18 +02:00
scripts SPDX fixes for 5.3-rc5 2019-08-18 09:26:16 -07:00
security KEYS: trusted: allow module init if TPM is inactive or deactivated 2019-08-13 19:59:23 +03:00
sound sound fixes for 5.3-rc5 2019-08-16 08:49:45 -07:00
tools - Fix for panics and network failures on PAE guests by Dexuan Cui. 2019-08-24 11:42:06 -07:00
usr
virt KVM/arm fixes for 5.3, take #3 2019-08-24 12:46:30 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS for-linus-20190823 2019-08-23 14:45:45 -07:00
Makefile Linux 5.3-rc6 2019-08-25 12:01:23 -07:00
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.