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Håkon Bugge 295221bea3 IB/mlx4: Fix leak in id_map_find_del 
commit ea660ad7c1 upstream.

Using CX-3 virtual functions, either from a bare-metal machine or
pass-through from a VM, MAD packets are proxied through the PF driver.

Since the VF drivers have separate name spaces for MAD Transaction Ids
(TIDs), the PF driver has to re-map the TIDs and keep the book keeping in
a cache.

Following the RDMA Connection Manager (CM) protocol, it is clear when an
entry has to evicted from the cache. When a DREP is sent from
mlx4_ib_multiplex_cm_handler(), id_map_find_del() is called. Similar when
a REJ is received by the mlx4_ib_demux_cm_handler(), id_map_find_del() is
called.

This function wipes out the TID in use from the IDR or XArray and removes
the id_map_entry from the table.

In short, it does everything except the topping of the cake, which is to
remove the entry from the list and free it. In other words, for the REJ
case enumerated above, one id_map_entry will be leaked.

For the other case above, a DREQ has been received first. The reception of
the DREQ will trigger queuing of a delayed work to delete the
id_map_entry, for the case where the VM doesn't send back a DREP.

In the normal case, the VM _will_ send back a DREP, and id_map_find_del()
will be called.

But this scenario introduces a secondary leak. First, when the DREQ is
received, a delayed work is queued. The VM will then return a DREP, which
will call id_map_find_del(). As stated above, this will free the TID used
from the XArray or IDR. Now, there is window where that particular TID can
be re-allocated, lets say by an outgoing REQ. This TID will later be wiped
out by the delayed work, when the function id_map_ent_timeout() is
called. But the id_map_entry allocated by the outgoing REQ will not be
de-allocated, and we have a leak.

Both leaks are fixed by removing the id_map_find_del() function and only
using schedule_delayed(). Of course, a check in schedule_delayed() to see
if the work already has been queued, has been added.

Another benefit of always using the delayed version for deleting entries,
is that we do get a TimeWait effect; a TID no longer in use, will occupy
the XArray or IDR for CM_CLEANUP_CACHE_TIMEOUT time, without any ability
of being re-used for that time period.

Fixes: 3cf69cc8db ("IB/mlx4: Add CM paravirtualization")
Link: https://lore.kernel.org/r/20200123155521.1212288-1-haakon.bugge@oracle.com
Signed-off-by: Håkon Bugge <haakon.bugge@oracle.com>
Signed-off-by: Manjunath Patil <manjunath.b.patil@oracle.com>
Reviewed-by: Rama Nichanamatlu <rama.nichanamatlu@oracle.com>
Reviewed-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2020-02-14 16:52:56 -05:00
arch compat: ARM64: always include asm-generic/compat.h 2020-02-11 04:37:30 -08:00
block compat: scsi: sg: fix v3 compat read/write interface 2020-02-11 04:37:17 -08:00
certs certs: Add wrapper function to check blacklisted binary hash 2019-11-12 12:25:50 +11:00
crypto crypto: api - Fix race condition in crypto_spawn_alg 2020-02-11 04:37:01 -08:00
Documentation PM / devfreq: Add new name attribute for sysfs 2020-02-04 18:18:01 +00:00
drivers IB/mlx4: Fix leak in id_map_find_del 2020-02-14 16:52:56 -05:00
fs io_uring: prevent potential eventfd recursion on poll 2020-02-11 04:37:28 -08:00
include IB/mlx5: Return the administrative GUID if exists 2020-02-14 16:52:56 -05:00
init Revert "um: Enable CONFIG_CONSTRUCTORS" 2020-02-01 09:33:00 +00:00
ipc ipc/msg.c: consolidate all xxxctl_down() functions 2020-02-11 04:36:39 -08:00
kernel perf/cgroups: Install cgroup events to correct cpuctx 2020-02-11 04:37:28 -08:00
lib lib/test_kasan.c: fix memory leak in kmalloc_oob_krealloc_more() 2020-02-11 04:36:45 -08:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm/mmu_gather: invalidate TLB correctly on batch allocation failure and flush 2020-02-11 04:37:14 -08:00
net rxrpc: Fix service call disconnection 2020-02-11 04:37:29 -08:00
samples samples/bpf: Reintroduce missed build targets 2020-02-11 04:37:00 -08:00
scripts scripts/find-unused-docs: Fix massive false positives 2020-02-11 04:36:53 -08:00
security broken ping to ipv6 linklocal addresses on debian buster 2020-02-11 04:37:16 -08:00
sound ASoC: Intel: skl_hda_dsp_common: Fix global-out-of-bounds bug 2020-02-11 04:37:21 -08:00
tools libbpf: Extract and generalize CPU mask parsing logic 2020-02-11 04:37:22 -08:00
usr gen_initramfs_list.sh: fix 'bad variable name' error 2020-01-04 00:00:48 +09:00
virt KVM: Play nice with read-only memslots when querying host page size 2020-02-11 04:37:29 -08:00
.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 modpost: dump missing namespaces into a single modules.nsdeps file 2019-11-11 20:10:01 +09:00
.mailmap MAINTAINERS: update my email address 2020-01-11 14:33:39 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Linux 5.4-rc4 2019-10-29 04:43:29 -06:00
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: correct entries for ISDN/mISDN section 2020-02-11 04:36:38 -08:00
Makefile Linux 5.5.3 2020-02-11 04:37:31 -08:00
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.