WSL2-Linux-Kernel

The source for the Linux kernel used in Windows Subsystem for Linux 2 (WSL2)

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Niklas Cassel 50662d21e4 ata: libata-eh: do not clear ATA_PFLAG_EH_PENDING in ata_eh_reset() [ Upstream commit `80cc944eca` ] ata_scsi_port_error_handler() starts off by clearing ATA_PFLAG_EH_PENDING, before calling ap->ops->error_handler() (without holding the ap->lock). If an error IRQ is received while ap->ops->error_handler() is running, the irq handler will set ATA_PFLAG_EH_PENDING. Once ap->ops->error_handler() returns, ata_scsi_port_error_handler() checks if ATA_PFLAG_EH_PENDING is set, and if it is, another iteration of ATA EH is performed. The problem is that ATA_PFLAG_EH_PENDING is not only cleared by ata_scsi_port_error_handler(), it is also cleared by ata_eh_reset(). ata_eh_reset() is called by ap->ops->error_handler(). This additional clearing done by ata_eh_reset() breaks the whole retry logic in ata_scsi_port_error_handler(). Thus, if an error IRQ is received while ap->ops->error_handler() is running, the port will currently remain frozen and will never get re-enabled. The additional clearing in ata_eh_reset() was introduced in commit `1e641060c4` ("libata: clear eh_info on reset completion"). Looking at the original error report: https://marc.info/?l=linux-ide&m=124765325828495&w=2 We can see the following happening: [ 1.074659] ata3: XXX port freeze [ 1.074700] ata3: XXX hardresetting link, stopping engine [ 1.074746] ata3: XXX flipping SControl [ 1.411471] ata3: XXX irq_stat=400040 CONN\|PHY [ 1.411475] ata3: XXX port freeze [ 1.420049] ata3: XXX starting engine [ 1.420096] ata3: XXX rc=0, class=1 [ 1.420142] ata3: XXX clearing IRQs for thawing [ 1.420188] ata3: XXX port thawed [ 1.420234] ata3: SATA link up 3.0 Gbps (SStatus 123 SControl 300) We are not supposed to be able to receive an error IRQ while the port is frozen (PxIE is set to 0, i.e. all IRQs for the port are disabled). AHCI 1.3.1 section 10.7.1.1 First Tier (IS Register) states: "Each bit location can be thought of as reporting a '1' if the virtual "interrupt line" for that port is indicating it wishes to generate an interrupt. That is, if a port has one or more interrupt status bit set, and the enables for those status bits are set, then this bit shall be set." Additionally, AHCI state P:ComInit clearly shows that the state machine will only jump to P:ComInitSetIS (which sets IS.IPS(x) to '1'), if PxIE.PCE is set to '1'. In our case, PxIE is set to 0, so IS.IPS(x) won't get set. So IS.IPS(x) only gets set if PxIS and PxIE is set. AHCI 1.3.1 section 10.7.1.1 First Tier (IS Register) also states: "The bits in this register are read/write clear. It is set by the level of the virtual interrupt line being a set, and cleared by a write of '1' from the software." So if IS.IPS(x) is set, you need to explicitly clear it by writing a 1 to IS.IPS(x) for that port. Since PxIE is cleared, the only way to get an interrupt while the port is frozen, is if IS.IPS(x) is set, and the only way IS.IPS(x) can be set when the port is frozen, is if it was set before the port was frozen. However, since commit `737dd811a3` ("ata: libahci: clear pending interrupt status"), we clear both PxIS and IS.IPS(x) after freezing the port, but before the COMRESET, so the problem that commit `1e641060c4` ("libata: clear eh_info on reset completion") fixed can no longer happen. Thus, revert commit `1e641060c4` ("libata: clear eh_info on reset completion"), so that the retry logic in ata_scsi_port_error_handler() works once again. (The retry logic is still needed, since we can still get an error IRQ _after_ the port has been thawed, but before ata_scsi_port_error_handler() takes the ap->lock in order to check if ATA_PFLAG_EH_PENDING is set.) Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com> Signed-off-by: Damien Le Moal <dlemoal@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>		2023-10-06 13:18:17 +02:00
Documentation	perf/smmuv3: Enable HiSilicon Erratum 162001900 quirk for HIP08/09	2023-09-23 11:09:55 +02:00
LICENSES	LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes"	2021-07-15 06:31:24 -06:00
arch	parisc: irq: Make irq_stack_union static to avoid sparse warning	2023-10-06 13:18:15 +02:00
block	block: don't add or resize partition on the disk with GENHD_FL_NO_PART	2023-09-19 12:23:03 +02:00
certs	certs/blacklist_hashes.c: fix const confusion in certs blacklist	2022-06-22 14:22:01 +02:00
crypto	crypto: lrw,xts - Replace strlcpy with strscpy	2023-09-23 11:09:55 +02:00
drivers	ata: libata-eh: do not clear ATA_PFLAG_EH_PENDING in ata_eh_reset()	2023-10-06 13:18:17 +02:00
fs	smb3: correct places where ENOTSUPP is used instead of preferred EOPNOTSUPP	2023-10-06 13:18:17 +02:00
include	ata: libata: Rename link flag ATA_LFLAG_NO_DB_DELAY	2023-10-06 13:18:11 +02:00
init	x86/mm: Initialize text poking earlier	2023-08-08 19:58:33 +02:00
io_uring	io_uring: break iopolling on signal	2023-09-19 12:22:54 +02:00
ipc	ipc/sem: Fix dangling sem_array access in semtimedop race	2022-12-08 11:28:45 +01:00
kernel	ring-buffer: Do not attempt to read past "commit"	2023-10-06 13:18:16 +02:00
lib	kobject: Add sanity check for kset->kobj.ktype in kset_register()	2023-09-23 11:09:59 +02:00
mm	mm/vmalloc: add a safer version of find_vm_area() for debug	2023-09-19 12:22:50 +02:00
net	netfilter: nft_exthdr: Fix non-linear header modification	2023-10-06 13:18:10 +02:00
samples	samples/hw_breakpoint: fix building without module unloading	2023-09-23 11:10:01 +02:00
scripts	kconfig: fix possible buffer overflow	2023-09-19 12:22:56 +02:00
security	smackfs: Prevent underflow in smk_set_cipso()	2023-09-19 12:22:39 +02:00
sound	ASoC: imx-audmix: Fix return error with devm_clk_get()	2023-10-06 13:18:05 +02:00
tools	selftests: fix dependency checker script	2023-10-06 13:18:16 +02:00
usr	usr/include/Makefile: add linux/nfc.h to the compile-test coverage	2022-02-01 17:27:15 +01:00
virt	KVM: Grab a reference to KVM for VM and vCPU stats file descriptors	2023-08-03 10:22:40 +02:00
.clang-format	clang-format: Update with the latest for_each macro list	2021-05-12 23:32:39 +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: use 'dts' diff driver for dts files	2019-12-04 19:44:11 -08:00
.gitignore	.gitignore: ignore only top-level modules.builtin	2021-05-02 00:43:35 +09:00
.mailmap	mailmap: add Andrej Shadura	2021-10-18 20:22:03 -10:00
COPYING	COPYING: state that all contributions really are covered by this file	2020-02-10 13:32:20 -08:00
CREDITS	MAINTAINERS: Move Daniel Drake to credits	2021-09-21 08:34:58 +03:00
Kbuild	kbuild: rename hostprogs-y/always to hostprogs/always-y	2020-02-04 01:53:07 +09:00
Kconfig	kbuild: ensure full rebuild when the compiler is updated	2020-05-12 13:28:33 +09:00
MAINTAINERS	iio: stx104: Move to addac subdirectory	2023-08-26 14:23:27 +02:00
Makefile	Linux 5.15.133	2023-09-23 11:10:03 +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.