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Alan Jenkins 1dc3039bc8 block: do not use interruptible wait anywhere
When blk_queue_enter() waits for a queue to unfreeze, or unset the
PREEMPT_ONLY flag, do not allow it to be interrupted by a signal.

The PREEMPT_ONLY flag was introduced later in commit 3a0a529971
("block, scsi: Make SCSI quiesce and resume work reliably").  Note the SCSI
device is resumed asynchronously, i.e. after un-freezing userspace tasks.

So that commit exposed the bug as a regression in v4.15.  A mysterious
SIGBUS (or -EIO) sometimes happened during the time the device was being
resumed.  Most frequently, there was no kernel log message, and we saw Xorg
or Xwayland killed by SIGBUS.[1]

[1] E.g. https://bugzilla.redhat.com/show_bug.cgi?id=1553979

Without this fix, I get an IO error in this test:

# dd if=/dev/sda of=/dev/null iflag=direct & \
  while killall -SIGUSR1 dd; do sleep 0.1; done & \
  echo mem > /sys/power/state ; \
  sleep 5; killall dd  # stop after 5 seconds

The interruptible wait was added to blk_queue_enter in
commit 3ef28e83ab ("block: generic request_queue reference counting").
Before then, the interruptible wait was only in blk-mq, but I don't think
it could ever have been correct.

Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: stable@vger.kernel.org
Signed-off-by: Alan Jenkins <alan.christopher.jenkins@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-04-14 13:54:33 -06:00
Documentation Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs 2018-04-13 16:55:41 -07:00
LICENSES LICENSES: Add MPL-1.1 license 2018-01-06 10:59:44 -07:00
arch Fixes for bugs in futex, device tree, and userspace breakpoint traps, 2018-04-13 12:27:11 -07:00
block block: do not use interruptible wait anywhere 2018-04-14 13:54:33 -06:00
certs certs/blacklist_nohashes.c: fix const confusion in certs blacklist 2018-02-21 15:35:43 -08:00
crypto MIPS changes for 4.17 2018-04-10 11:39:22 -07:00
drivers Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux 2018-04-13 16:52:26 -07:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs 2018-04-13 16:55:41 -07:00
include Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux 2018-04-13 16:52:26 -07:00
init seq_file: allocate seq_file from kmem_cache 2018-04-11 10:28:36 -07:00
ipc ipc/shm.c: shm_split(): remove unneeded test for NULL shm_file_data.vm_ops 2018-04-11 10:28:38 -07:00
kernel A few clean ups and bug fixes 2018-04-12 20:54:01 -07:00
lib We decided to request the latest three patches to be merged into this 2018-04-12 13:00:44 -07:00
mm page cache: use xa_lock 2018-04-11 10:28:39 -07:00
net NFS client updates for Linux 4.17 2018-04-12 12:55:50 -07:00
samples remoteproc updates for v4.17 2018-04-10 12:09:27 -07:00
scripts asm-generic fixes for v4.17-rc1 2018-04-12 09:15:48 -07:00
security + Features 2018-04-13 15:38:53 -07:00
sound amdgpu, omap and snd regression fix 2018-04-12 20:56:10 -07:00
tools proc: fixup copyright sign 2018-04-12 20:52:25 -07:00
usr kbuild: rename built-in.o to built-in.a 2018-03-26 02:01:19 +09:00
virt KVM/ARM updates for v4.17 2018-03-28 16:09:09 +02:00
.clang-format clang-format: add configuration file 2018-04-11 10:28:35 -07:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore clang-format: add configuration file 2018-04-11 10:28:35 -07:00
.mailmap Merge candidates for 4.17 merge window 2018-04-06 17:35:43 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS/CREDITS: Drop METAG ARCHITECTURE 2018-03-05 16:34:24 +00:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS Changes to chrome-platform for v4.17 2018-04-13 16:20:36 -07:00
Makefile Kconfig updates for v4.17 2018-04-03 16:28:01 -07:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -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.
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.