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Mike Marciniszyn 9a293d1e21 IB/hfi1: Ensure pq is not left on waitlist
The following warning can occur when a pq is left on the dmawait list and
the pq is then freed:

  WARNING: CPU: 47 PID: 3546 at lib/list_debug.c:29 __list_add+0x65/0xc0
  list_add corruption. next->prev should be prev (ffff939228da1880), but was ffff939cabb52230. (next=ffff939cabb52230).
  Modules linked in: mmfs26(OE) mmfslinux(OE) tracedev(OE) 8021q garp mrp ib_isert iscsi_target_mod target_core_mod crc_t10dif crct10dif_generic opa_vnic rpcrdma ib_iser libiscsi scsi_transport_iscsi ib_ipoib(OE) bridge stp llc iTCO_wdt iTCO_vendor_support intel_powerclamp coretemp intel_rapl iosf_mbi kvm_intel kvm irqbypass crct10dif_pclmul crct10dif_common crc32_pclmul ghash_clmulni_intel aesni_intel lrw gf128mul glue_helper ablk_helper cryptd ast ttm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm pcspkr joydev drm_panel_orientation_quirks i2c_i801 mei_me lpc_ich mei wmi ipmi_si ipmi_devintf ipmi_msghandler nfit libnvdimm acpi_power_meter acpi_pad hfi1(OE) rdmavt(OE) rdma_ucm ib_ucm ib_uverbs ib_umad rdma_cm ib_cm iw_cm ib_core binfmt_misc numatools(OE) xpmem(OE) ip_tables
  nfsv3 nfs_acl nfs lockd grace sunrpc fscache igb ahci libahci i2c_algo_bit dca libata ptp pps_core crc32c_intel [last unloaded: i2c_algo_bit]
  CPU: 47 PID: 3546 Comm: wrf.exe Kdump: loaded Tainted: G W OE ------------ 3.10.0-957.41.1.el7.x86_64 #1
  Hardware name: HPE.COM HPE SGI 8600-XA730i Gen10/X11DPT-SB-SG007, BIOS SBED1229 01/22/2019
  Call Trace:
  [<ffffffff91f65ac0>] dump_stack+0x19/0x1b
  [<ffffffff91898b78>] __warn+0xd8/0x100
  [<ffffffff91898bff>] warn_slowpath_fmt+0x5f/0x80
  [<ffffffff91a1dabe>] ? ___slab_alloc+0x24e/0x4f0
  [<ffffffff91b97025>] __list_add+0x65/0xc0
  [<ffffffffc03926a5>] defer_packet_queue+0x145/0x1a0 [hfi1]
  [<ffffffffc0372987>] sdma_check_progress+0x67/0xa0 [hfi1]
  [<ffffffffc03779d2>] sdma_send_txlist+0x432/0x550 [hfi1]
  [<ffffffff91a20009>] ? kmem_cache_alloc+0x179/0x1f0
  [<ffffffffc0392973>] ? user_sdma_send_pkts+0xc3/0x1990 [hfi1]
  [<ffffffffc0393e3a>] user_sdma_send_pkts+0x158a/0x1990 [hfi1]
  [<ffffffff918ab65e>] ? try_to_del_timer_sync+0x5e/0x90
  [<ffffffff91a3fe1a>] ? __check_object_size+0x1ca/0x250
  [<ffffffffc0395546>] hfi1_user_sdma_process_request+0xd66/0x1280 [hfi1]
  [<ffffffffc034e0da>] hfi1_aio_write+0xca/0x120 [hfi1]
  [<ffffffff91a4245b>] do_sync_readv_writev+0x7b/0xd0
  [<ffffffff91a4409e>] do_readv_writev+0xce/0x260
  [<ffffffff918df69f>] ? pick_next_task_fair+0x5f/0x1b0
  [<ffffffff918db535>] ? sched_clock_cpu+0x85/0xc0
  [<ffffffff91f6b16a>] ? __schedule+0x13a/0x860
  [<ffffffff91a442c5>] vfs_writev+0x35/0x60
  [<ffffffff91a4447f>] SyS_writev+0x7f/0x110
  [<ffffffff91f78ddb>] system_call_fastpath+0x22/0x27

The issue happens when wait_event_interruptible_timeout() returns a value
<= 0.

In that case, the pq is left on the list. The code continues sending
packets and potentially can complete the current request with the pq still
on the dmawait list provided no descriptor shortage is seen.

If the pq is torn down in that state, the sdma interrupt handler could
find the now freed pq on the list with list corruption or memory
corruption resulting.

Fix by adding a flush routine to ensure that the pq is never on a list
after processing a request.

A follow-up patch series will address issues with seqlock surfaced in:
https://lore.kernel.org/r/20200320003129.GP20941@ziepe.ca

The seqlock use for sdma will then be converted to a spin lock since the
list_empty() doesn't need the protection afforded by the sequence lock
currently in use.

Fixes: a0d406934a ("staging/rdma/hfi1: Add page lock limit check for SDMA requests")
Link: https://lore.kernel.org/r/20200320200200.23203.37777.stgit@awfm-01.aw.intel.com
Reviewed-by: Kaike Wan <kaike.wan@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2020-03-23 21:57:57 -03:00
arch ARM: SoC fixes 2020-03-08 17:36:22 -07:00
block block, bfq: fix overwrite of bfq_group pointer in bfq_find_set_group() 2020-03-06 07:00:58 -07:00
certs certs: Add wrapper function to check blacklisted binary hash 2019-11-12 12:25:50 +11:00
crypto Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2020-02-20 15:15:16 -08:00
Documentation ARM: SoC fixes 2020-03-08 17:36:22 -07:00
drivers IB/hfi1: Ensure pq is not left on waitlist 2020-03-23 21:57:57 -03:00
fs Driver core / debugfs fixes for 5.6-rc5 2020-03-08 10:39:40 -05:00
include Driver core / debugfs fixes for 5.6-rc5 2020-03-08 10:39:40 -05:00
init Tracing updates: 2020-02-26 10:34:42 -08:00
ipc Revert "ipc,sem: remove uneeded sem_undo_list lock usage in exit_sem()" 2020-02-21 11:22:15 -08:00
kernel block-5.6-2020-03-07 2020-03-07 14:14:38 -06:00
lib Tracing updates: 2020-02-26 10:34:42 -08:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm, hotplug: fix page online with DEBUG_PAGEALLOC compiled but not enabled 2020-03-06 07:06:09 -06:00
net vsock: fix potential deadlock in transport->release() 2020-02-27 12:03:56 -08:00
samples Kbuild updates for v5.6 (2nd) 2020-02-09 16:05:50 -08:00
scripts parse-maintainers: Mark as executable 2020-03-06 16:29:21 -06:00
security Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2020-02-20 15:15:16 -08:00
sound ASoC: Fixes for v5.6 2020-03-07 07:24:36 +01:00
tools for-linus-2020-03-07 2020-03-07 08:01:43 -06:00
usr Kbuild updates for v5.6 (2nd) 2020-02-09 16:05:50 -08:00
virt KVM/arm fixes for 5.6, take #1 2020-02-28 11:50:06 +01:00
.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: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore selftest/lkdtm: Use local .gitignore 2020-03-02 08:39:39 -07:00
.mailmap A handful of small documentation fixes that wandered in. 2020-02-07 13:03:10 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Hand MIPS over to Thomas 2020-02-24 22:43:18 -08:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS MAINTAINERS: Update maintainers for HISILICON ROCE DRIVER 2020-03-10 14:30:52 -03:00
Makefile Linux 5.6-rc5 2020-03-08 17:44:44 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.