linux-stable.git/drivers/infiniband, branch v4.4.201

RDMA/iwcm: Fix a lock inversion issue

2019-11-06T11:09:13+00:00

[ Upstream commit b66f31efbdad95ec274345721d99d1d835e6de01 ]

This patch fixes the lock inversion complaint:

============================================
WARNING: possible recursive locking detected
5.3.0-rc7-dbg+ #1 Not tainted
--------------------------------------------
kworker/u16:6/171 is trying to acquire lock:
00000000035c6e6c (&id_priv->handler_mutex){+.+.}, at: rdma_destroy_id+0x78/0x4a0 [rdma_cm]

but task is already holding lock:
00000000bc7c307d (&id_priv->handler_mutex){+.+.}, at: iw_conn_req_handler+0x151/0x680 [rdma_cm]

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&id_priv->handler_mutex);
  lock(&id_priv->handler_mutex);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

3 locks held by kworker/u16:6/171:
 #0: 00000000e2eaa773 ((wq_completion)iw_cm_wq){+.+.}, at: process_one_work+0x472/0xac0
 #1: 000000001efd357b ((work_completion)(&work->work)#3){+.+.}, at: process_one_work+0x476/0xac0
 #2: 00000000bc7c307d (&id_priv->handler_mutex){+.+.}, at: iw_conn_req_handler+0x151/0x680 [rdma_cm]

stack backtrace:
CPU: 3 PID: 171 Comm: kworker/u16:6 Not tainted 5.3.0-rc7-dbg+ #1
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
Workqueue: iw_cm_wq cm_work_handler [iw_cm]
Call Trace:
 dump_stack+0x8a/0xd6
 __lock_acquire.cold+0xe1/0x24d
 lock_acquire+0x106/0x240
 __mutex_lock+0x12e/0xcb0
 mutex_lock_nested+0x1f/0x30
 rdma_destroy_id+0x78/0x4a0 [rdma_cm]
 iw_conn_req_handler+0x5c9/0x680 [rdma_cm]
 cm_work_handler+0xe62/0x1100 [iw_cm]
 process_one_work+0x56d/0xac0
 worker_thread+0x7a/0x5d0
 kthread+0x1bc/0x210
 ret_from_fork+0x24/0x30

This is not a bug as there are actually two lock classes here.

Link: https://lore.kernel.org/r/20190930231707.48259-3-bvanassche@acm.org
Fixes: de910bd92137 ("RDMA/cma: Simplify locking needed for serialization of callbacks")
Signed-off-by: Bart Van Assche 
Reviewed-by: Jason Gunthorpe 
Signed-off-by: Jason Gunthorpe 
Signed-off-by: Sasha Levin

RDMA/cxgb4: Do not dma memory off of the stack

2019-10-29T08:13:33+00:00

commit 3840c5b78803b2b6cc1ff820100a74a092c40cbb upstream.

Nicolas pointed out that the cxgb4 driver is doing dma off of the stack,
which is generally considered a very bad thing.  On some architectures it
could be a security problem, but odds are none of them actually run this
driver, so it's just a "normal" bug.

Resolve this by allocating the memory for a message off of the heap
instead of the stack.  kmalloc() always will give us a proper memory
location that DMA will work correctly from.

Link: https://lore.kernel.org/r/20191001165611.GA3542072@kroah.com
Reported-by: Nicolas Waisman 
Tested-by: Potnuri Bharat Teja 
Signed-off-by: Jason Gunthorpe 
Signed-off-by: Greg Kroah-Hartman

IB/mlx4: Fix memory leaks

2019-09-10T09:29:48+00:00

[ Upstream commit 5c1baaa82cea2c815a5180ded402a7cd455d1810 ]

In mlx4_ib_alloc_pv_bufs(), 'tun_qp->tx_ring' is allocated through
kcalloc(). However, it is not always deallocated in the following execution
if an error occurs, leading to memory leaks. To fix this issue, free
'tun_qp->tx_ring' whenever an error occurs.

Signed-off-by: Wenwen Wang 
Acked-by: Leon Romanovsky 
Link: https://lore.kernel.org/r/1566159781-4642-1-git-send-email-wenwen@cs.uga.edu
Signed-off-by: Doug Ledford 
Signed-off-by: Sasha Levin

IB/mlx5: Make coding style more consistent

2019-08-25T08:53:04+00:00

commit 0025b0bdeae7c13b8ab1dce64b0108ed9c071e2e upstream.

These three related functions can't agree whether to put the
umrwr on the stack dirty and then memset it, or to initialize
it on the stack.  Make them all agree.

Signed-off-by: Doug Ledford 
Signed-off-by: Greg Kroah-Hartman

RDMA: Directly cast the sockaddr union to sockaddr

2019-08-25T08:53:04+00:00

commit 641114d2af312d39ca9bbc2369d18a5823da51c6 upstream.

gcc 9 now does allocation size tracking and thinks that passing the member
of a union and then accessing beyond that member's bounds is an overflow.

Instead of using the union member, use the entire union with a cast to
get to the sockaddr. gcc will now know that the memory extends the full
size of the union.

Signed-off-by: Jason Gunthorpe 
Signed-off-by: Greg Kroah-Hartman

IB/core: Add mitigation for Spectre V1

2019-08-25T08:53:00+00:00

[ Upstream commit 61f259821dd3306e49b7d42a3f90fb5a4ff3351b ]

Some processors may mispredict an array bounds check and
speculatively access memory that they should not. With
a user supplied array index we like to play things safe
by masking the value with the array size before it is
used as an index.

Signed-off-by: Tony Luck 
Link: https://lore.kernel.org/r/20190731043957.GA1600@agluck-desk2.amr.corp.intel.com
Signed-off-by: Doug Ledford 
Signed-off-by: Sasha Levin

coredump: fix race condition between mmget_not_zero()/get_task_mm() and core dumping

2019-06-22T06:18:27+00:00

commit 04f5866e41fb70690e28397487d8bd8eea7d712a upstream.

The core dumping code has always run without holding the mmap_sem for
writing, despite that is the only way to ensure that the entire vma
layout will not change from under it.  Only using some signal
serialization on the processes belonging to the mm is not nearly enough.
This was pointed out earlier.  For example in Hugh's post from Jul 2017:

  https://lkml.kernel.org/r/alpine.LSU.2.11.1707191716030.2055@eggly.anvils

  "Not strictly relevant here, but a related note: I was very surprised
   to discover, only quite recently, how handle_mm_fault() may be called
   without down_read(mmap_sem) - when core dumping. That seems a
   misguided optimization to me, which would also be nice to correct"

In particular because the growsdown and growsup can move the
vm_start/vm_end the various loops the core dump does around the vma will
not be consistent if page faults can happen concurrently.

Pretty much all users calling mmget_not_zero()/get_task_mm() and then
taking the mmap_sem had the potential to introduce unexpected side
effects in the core dumping code.

Adding mmap_sem for writing around the ->core_dump invocation is a
viable long term fix, but it requires removing all copy user and page
faults and to replace them with get_dump_page() for all binary formats
which is not suitable as a short term fix.

For the time being this solution manually covers the places that can
confuse the core dump either by altering the vma layout or the vma flags
while it runs.  Once ->core_dump runs under mmap_sem for writing the
function mmget_still_valid() can be dropped.

Allowing mmap_sem protected sections to run in parallel with the
coredump provides some minor parallelism advantage to the swapoff code
(which seems to be safe enough by never mangling any vma field and can
keep doing swapins in parallel to the core dumping) and to some other
corner case.

In order to facilitate the backporting I added "Fixes: 86039bd3b4e6"
however the side effect of this same race condition in /proc/pid/mem
should be reproducible since before 2.6.12-rc2 so I couldn't add any
other "Fixes:" because there's no hash beyond the git genesis commit.

Because find_extend_vma() is the only location outside of the process
context that could modify the "mm" structures under mmap_sem for
reading, by adding the mmget_still_valid() check to it, all other cases
that take the mmap_sem for reading don't need the new check after
mmget_not_zero()/get_task_mm().  The expand_stack() in page fault
context also doesn't need the new check, because all tasks under core
dumping are frozen.

Link: http://lkml.kernel.org/r/20190325224949.11068-1-aarcange@redhat.com
Fixes: 86039bd3b4e6 ("userfaultfd: add new syscall to provide memory externalization")
Signed-off-by: Andrea Arcangeli 
Reported-by: Jann Horn 
Suggested-by: Oleg Nesterov 
Acked-by: Peter Xu 
Reviewed-by: Mike Rapoport 
Reviewed-by: Oleg Nesterov 
Reviewed-by: Jann Horn 
Acked-by: Jason Gunthorpe 
Acked-by: Michal Hocko 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Cc: Joel Fernandes (Google) 
[mhocko@suse.com: stable 4.4 backport
 - drop infiniband part because of missing 5f9794dc94f59
 - drop userfaultfd_event_wait_completion hunk because of
   missing 9cd75c3cd4c3d]
 - handle binder_update_page_range because of missing 720c241924046
 - handle mlx5_ib_disassociate_ucontext - akaher@vmware.com
]
Signed-off-by: Michal Hocko 
Signed-off-by: Greg Kroah-Hartman

RDMA/cxgb4: Fix null pointer dereference on alloc_skb failure

2019-06-11T10:23:59+00:00

[ Upstream commit a6d2a5a92e67d151c98886babdc86d530d27111c ]

Currently if alloc_skb fails to allocate the skb a null skb is passed to
t4_set_arp_err_handler and this ends up dereferencing the null skb.  Avoid
the NULL pointer dereference by checking for a NULL skb and returning
early.

Addresses-Coverity: ("Dereference null return")
Fixes: b38a0ad8ec11 ("RDMA/cxgb4: Set arp error handler for PASS_ACCEPT_RPL messages")
Signed-off-by: Colin Ian King 
Acked-by: Potnuri Bharat Teja 
Signed-off-by: Jason Gunthorpe 
Signed-off-by: Sasha Levin

IB/mlx4: Fix race condition between catas error reset and aliasguid flows

2019-04-27T07:33:56+00:00

[ Upstream commit 587443e7773e150ae29e643ee8f41a1eed226565 ]

Code review revealed a race condition which could allow the catas error
flow to interrupt the alias guid query post mechanism at random points.
Thiis is fixed by doing cancel_delayed_work_sync() instead of
cancel_delayed_work() during the alias guid mechanism destroy flow.

Fixes: a0c64a17aba8 ("mlx4: Add alias_guid mechanism")
Signed-off-by: Jack Morgenstein 
Signed-off-by: Leon Romanovsky 
Signed-off-by: Jason Gunthorpe 
Signed-off-by: Sasha Levin

IB/mlx4: Increase the timeout for CM cache

2019-04-27T07:33:50+00:00

[ Upstream commit 2612d723aadcf8281f9bf8305657129bd9f3cd57 ]

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 form the cache. But life is not perfect,
remote peers may die or be rebooted. Hence, it's a timeout to wipe out
a cache entry, when the PF driver assumes the remote peer has gone.

During workloads where a high number of QPs are destroyed concurrently,
excessive amount of CM DREQ retries has been observed

The problem can be demonstrated in a bare-metal environment, where two
nodes have instantiated 8 VFs each. This using dual ported HCAs, so we
have 16 vPorts per physical server.

64 processes are associated with each vPort and creates and destroys
one QP for each of the remote 64 processes. That is, 1024 QPs per
vPort, all in all 16K QPs. The QPs are created/destroyed using the
CM.

When tearing down these 16K QPs, excessive CM DREQ retries (and
duplicates) are observed. With some cat/paste/awk wizardry on the
infiniband_cm sysfs, we observe as sum of the 16 vPorts on one of the
nodes:

cm_rx_duplicates:
      dreq  2102
cm_rx_msgs:
      drep  1989
      dreq  6195
       rep  3968
       req  4224
       rtu  4224
cm_tx_msgs:
      drep  4093
      dreq 27568
       rep  4224
       req  3968
       rtu  3968
cm_tx_retries:
      dreq 23469

Note that the active/passive side is equally distributed between the
two nodes.

Enabling pr_debug in cm.c gives tons of:

[171778.814239]  mlx4_ib_multiplex_cm_handler: id{slave:
1,sl_cm_id: 0xd393089f} is NULL!

By increasing the CM_CLEANUP_CACHE_TIMEOUT from 5 to 30 seconds, the
tear-down phase of the application is reduced from approximately 90 to
50 seconds. Retries/duplicates are also significantly reduced:

cm_rx_duplicates:
      dreq  2460
[]
cm_tx_retries:
      dreq  3010
       req    47

Increasing the timeout further didn't help, as these duplicates and
retries stems from a too short CMA timeout, which was 20 (~4 seconds)
on the systems. By increasing the CMA timeout to 22 (~17 seconds), the
numbers fell down to about 10 for both of them.

Adjustment of the CMA timeout is not part of this commit.

Signed-off-by: Håkon Bugge 
Acked-by: Jack Morgenstein 
Signed-off-by: Jason Gunthorpe 
Signed-off-by: Sasha Levin