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Shiraz Saleem 7872168a83 RDMA/umem: Handle page combining avoidance correctly in ib_umem_add_sg_table()
The flag update_cur_sg tracks whether contiguous pages from a new set of
page_list pages can be merged into the SGE passed into
ib_umem_add_sg_table(). If this flag is true, but the total segment length
exceeds the max_seg_size supported by HW, we avoid combining to this SGE
and move to a new SGE (x) and merge 'len' pages to it. However, if i <
npages, the next iteration can incorrectly merge 'len' contiguous pages
into x instead of into a new SGE since update_cur_sg is still true.

Reset update_cur_sg to false always after the check to merge pages into
the first SGE passed in to ib_umem_add_sg_table().  Also, prevent a new
SGE's segment length from ever exceeding HW max_seg_sz.

There is a crash on hfi1 as result of this where-in max_seg_sz is
defaulting to 64K. Due to above bug, unfolding SGE's in __ib_umem_release
points to a bad page ptr.

 TEST comp-wfr.perfnative.STL-22166-WDT _ perftest native 2-Write_4097QP_4MB STARTING at 1555387093
 BUG: Bad page state in process ib_write_bw  pfn:7ebca0
 page:ffffcd675faf2800 count:0 mapcount:1 mapping:0000000000000000 index:0x1
 flags: 0x17ffffc0000000()
 raw: 0017ffffc0000000 dead000000000100 dead000000000200 0000000000000000
 raw: 0000000000000001 0000000000000000 0000000000000000 0000000000000000
 page dumped because: nonzero mapcount
 CPU: 18 PID: 15853 Comm: ib_write_bw Tainted: G    B             5.1.0-rc4 #1
 Hardware name: Intel Corporation S2600CWR/S2600CW, BIOS SE5C610.86B.01.01.0014.121820151719 12/18/2015
 Call Trace:
  dump_stack+0x5a/0x73
  bad_page+0xf5/0x10f
  free_pcppages_bulk+0x62c/0x680
  free_unref_page+0x54/0x70
  __ib_umem_release+0x148/0x1a0 [ib_uverbs]
  ib_umem_release+0x22/0x80 [ib_uverbs]
  rvt_dereg_mr+0x67/0xb0 [rdmavt]
  ib_dereg_mr_user+0x37/0x60 [ib_core]
  destroy_hw_idr_uobject+0x1c/0x50 [ib_uverbs]
  uverbs_destroy_uobject+0x2e/0x180 [ib_uverbs]
  uobj_destroy+0x4d/0x60 [ib_uverbs]
  __uobj_get_destroy+0x33/0x50 [ib_uverbs]
  __uobj_perform_destroy+0xa/0x30 [ib_uverbs]
  ib_uverbs_dereg_mr+0x66/0x90 [ib_uverbs]
  ib_uverbs_write+0x3e1/0x500 [ib_uverbs]
  vfs_write+0xad/0x1b0
  ksys_write+0x5a/0xd0
  do_syscall_64+0x5b/0x180
  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: d10bcf947a ("RDMA/umem: Combine contiguous PAGE_SIZE regions in SGEs")
Tested-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: Shiraz Saleem <shiraz.saleem@intel.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-05-02 16:50:12 -03:00
arch powerpc fixes for 5.1 #5 2019-04-13 09:03:09 -07:00
block block: do not leak memory in bio_copy_user_iov() 2019-04-10 16:14:40 -06:00
certs kexec, KEYS: Make use of platform keyring for signature verify 2019-02-04 17:34:07 -05:00
crypto lib/lzo: separate lzo-rle from lzo 2019-03-07 18:32:03 -08:00
Documentation ARM: SoC fixes 2019-04-07 13:46:17 -10:00
drivers RDMA/umem: Handle page combining avoidance correctly in ib_umem_add_sg_table() 2019-05-02 16:50:12 -03:00
fs Merge branch 'page-refs' (page ref overflow) 2019-04-14 15:09:40 -07:00
include RDMA/core: Introduce RDMA subsystem ibdev_* print functions 2019-05-01 12:29:28 -04:00
init init/main: add checks for the return value of memblock_alloc*() 2019-03-12 10:04:02 -07:00
ipc Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-03-12 14:08:19 -07:00
kernel Merge branch 'page-refs' (page ref overflow) 2019-04-14 15:09:40 -07:00
lib RDMA/core: Introduce RDMA subsystem ibdev_* print functions 2019-05-01 12:29:28 -04:00
LICENSES LICENSES: Add GCC runtime library exception text 2019-01-16 14:54:15 -07:00
mm Merge branch 'page-refs' (page ref overflow) 2019-04-14 15:09:40 -07:00
net Revert "SUNRPC: Micro-optimise when the task is known not to be sleeping" 2019-04-11 15:41:14 -04:00
samples BPF: Add sample code for new ib_umad tracepoint 2019-03-27 15:53:26 -03:00
scripts fs: stream_open - opener for stream-like files so that read and write can run simultaneously without deadlock 2019-04-06 07:01:55 -10:00
security apparmor: Restore Y/N in /sys for apparmor's "enabled" 2019-04-10 04:24:48 -07:00
sound ASoC: Fixes for v5.1 2019-04-11 14:36:30 +02:00
tools for-linus-20190412 2019-04-13 16:23:16 -07:00
usr user/Makefile: Fix typo and capitalization in comment section 2018-12-11 00:18:03 +09:00
virt KVM/ARM fixes for 5.1 2019-03-28 19:07:30 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2019-04-12 12:49:54 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support for DT binding schema checks 2018-12-13 09:41:32 -06:00
.mailmap Update Nicolas Pitre's email address 2019-04-02 18:12:44 -10:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Char/Misc driver patches for 5.1-rc1 2019-03-06 14:18:59 -08:00
Kbuild Kbuild updates for v5.1 2019-03-10 17:48:21 -07:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS Merge branch 'rdma_mmap' into rdma.git for-next 2019-04-24 16:20:34 -03:00
Makefile Linux 5.1-rc5 2019-04-14 15:17:41 -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.