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Wen Xiong 5ecb28b156 scsi: ipr: Fix softlockup when rescanning devices in petitboot [ Upstream commit `394b61711f` ] When trying to rescan disks in petitboot shell, we hit the following softlockup stacktrace: Kernel panic - not syncing: System is deadlocked on memory [ 241.223394] CPU: 32 PID: 693 Comm: sh Not tainted 5.4.16-openpower1 #1 [ 241.223406] Call Trace: [ 241.223415] [c0000003f07c3180] [c000000000493fc4] dump_stack+0xa4/0xd8 (unreliable) [ 241.223432] [c0000003f07c31c0] [c00000000007d4ac] panic+0x148/0x3cc [ 241.223446] [c0000003f07c3260] [c000000000114b10] out_of_memory+0x468/0x4c4 [ 241.223461] [c0000003f07c3300] [c0000000001472b0] __alloc_pages_slowpath+0x594/0x6d8 [ 241.223476] [c0000003f07c3420] [c00000000014757c] __alloc_pages_nodemask+0x188/0x1a4 [ 241.223492] [c0000003f07c34a0] [c000000000153e10] alloc_pages_current+0xcc/0xd8 [ 241.223508] [c0000003f07c34e0] [c0000000001577ac] alloc_slab_page+0x30/0x98 [ 241.223524] [c0000003f07c3520] [c0000000001597fc] new_slab+0x138/0x40c [ 241.223538] [c0000003f07c35f0] [c00000000015b204] ___slab_alloc+0x1e4/0x404 [ 241.223552] [c0000003f07c36c0] [c00000000015b450] __slab_alloc+0x2c/0x48 [ 241.223566] [c0000003f07c36f0] [c00000000015b754] kmem_cache_alloc_node+0x9c/0x1b4 [ 241.223582] [c0000003f07c3760] [c000000000218c48] blk_alloc_queue_node+0x34/0x270 [ 241.223599] [c0000003f07c37b0] [c000000000226574] blk_mq_init_queue+0x2c/0x78 [ 241.223615] [c0000003f07c37e0] [c0000000002ff710] scsi_mq_alloc_queue+0x28/0x70 [ 241.223631] [c0000003f07c3810] [c0000000003005b8] scsi_alloc_sdev+0x184/0x264 [ 241.223647] [c0000003f07c38a0] [c000000000300ba0] scsi_probe_and_add_lun+0x288/0xa3c [ 241.223663] [c0000003f07c3a00] [c000000000301768] __scsi_scan_target+0xcc/0x478 [ 241.223679] [c0000003f07c3b20] [c000000000301c64] scsi_scan_channel.part.9+0x74/0x7c [ 241.223696] [c0000003f07c3b70] [c000000000301df4] scsi_scan_host_selected+0xe0/0x158 [ 241.223712] [c0000003f07c3bd0] [c000000000303f04] store_scan+0x104/0x114 [ 241.223727] [c0000003f07c3cb0] [c0000000002d5ac4] dev_attr_store+0x30/0x4c [ 241.223741] [c0000003f07c3cd0] [c0000000001dbc34] sysfs_kf_write+0x64/0x78 [ 241.223756] [c0000003f07c3cf0] [c0000000001da858] kernfs_fop_write+0x170/0x1b8 [ 241.223773] [c0000003f07c3d40] [c0000000001621fc] __vfs_write+0x34/0x60 [ 241.223787] [c0000003f07c3d60] [c000000000163c2c] vfs_write+0xa8/0xcc [ 241.223802] [c0000003f07c3db0] [c000000000163df4] ksys_write+0x70/0xbc [ 241.223816] [c0000003f07c3e20] [c00000000000b40c] system_call+0x5c/0x68 As a part of the scan process Linux will allocate and configure a scsi_device for each target to be scanned. If the device is not present, then the scsi_device is torn down. As a part of scsi_device teardown a workqueue item will be scheduled and the lockups we see are because there are 250k workqueue items to be processed. Accoding to the specification of SIS-64 sas controller, max_channel should be decreased on SIS-64 adapters to 4. The patch fixes softlockup issue. Thanks for Oliver Halloran's help with debugging and explanation! Link: https://lore.kernel.org/r/1583510248-23672-1-git-send-email-wenxiong@linux.vnet.ibm.com Signed-off-by: Wen Xiong <wenxiong@linux.vnet.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Sasha Levin <sashal@kernel.org>		2020-04-01 11:01:54 +02:00
Documentation	dt-bindings: net: FMan erratum A050385	2020-04-01 11:01:52 +02:00
LICENSES	LICENSES: Rename other to deprecated	2019-05-03 06:34:32 -06:00
arch	arm64: dts: ls1043a: FMan erratum A050385	2020-04-01 11:01:52 +02:00
block	block, bfq: fix overwrite of bfq_group pointer in bfq_find_set_group()	2020-03-25 08:25:49 +01:00
certs	PKCS#7: Refactor verify_pkcs7_signature()	2019-08-05 18:40:18 -04:00
crypto	crypto: rename sm3-256 to sm3 in hash_algo_name	2020-02-28 17:22:26 +01:00
drivers	scsi: ipr: Fix softlockup when rescanning devices in petitboot	2020-04-01 11:01:54 +02:00
fs	nfs: add minor version to nfs_server_key for fscache	2020-04-01 11:01:50 +02:00
include	iommu/vt-d: Silence RCU-list debugging warnings	2020-04-01 11:01:53 +02:00
init	kbuild: remove header compile test	2020-03-05 16:43:47 +01:00
ipc	Revert "ipc,sem: remove uneeded sem_undo_list lock usage in exit_sem()"	2020-02-28 17:22:20 +01:00
kernel	cgroup1: don't call release_agent when it is ""	2020-04-01 11:01:51 +02:00
lib	kbuild: move headers_check rule to usr/include/Makefile	2020-03-05 16:43:47 +01:00
mm	x86/mm: split vmalloc_sync_all()	2020-03-25 08:25:58 +01:00
net	hsr: set .netnsok flag	2020-04-01 11:01:49 +02:00
samples	samples/bpf: Set -fno-stack-protector when building BPF programs	2020-02-24 08:36:36 +01:00
scripts	modpost: move the namespace field in Module.symvers last	2020-03-25 08:25:55 +01:00
security	efi: Only print errors about failing to get certs if EFI vars are found	2020-03-12 13:00:14 +01:00
sound	ALSA: hda/realtek: Fix pop noise on ALC225	2020-03-25 08:25:59 +01:00
tools	cpupower: avoid multiple definition with gcc -fno-common	2020-04-01 11:01:51 +02:00
usr	kbuild: fix 'No such file or directory' warning when cleaning	2020-03-12 13:00:09 +01:00
virt	KVM: Check for a bad hva before dropping into the ghc slow path	2020-03-05 16:43:48 +01:00
.clang-format	clang-format: Update with the latest for_each macro list	2019-08-31 10:00:51 +02:00
.cocciconfig	…
.get_maintainer.ignore	Opt out of scripts/get_maintainer.pl	2019-05-16 10:53:40 -07:00
.gitattributes	…
.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	MAINTAINERS: Update drm/i915 bug filing URL	2020-02-28 17:22:19 +01:00
Makefile	Linux 5.4.28	2020-03-25 08:26:00 +01:00
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.