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Jack Morgenstein e15ce4b8d1 net/mlx4_core: Fix reset flow when in command polling mode
As part of unloading a device, the driver switches from
FW command event mode to FW command polling mode.

Part of switching over to polling mode is freeing the command context array
memory (unfortunately, currently, without NULLing the command context array
pointer).

The reset flow calls "complete" to complete all outstanding fw commands
(if we are in event mode). The check for event vs. polling mode here
is to test if the command context array pointer is NULL.

If the reset flow is activated after the switch to polling mode, it will
attempt (incorrectly) to complete all the commands in the context array --
because the pointer was not NULLed when the driver switched over to polling
mode.

As a result, we have a use-after-free situation, which results in a
kernel crash.

For example:
BUG: unable to handle kernel NULL pointer dereference at           (null)
IP: [<ffffffff876c4a8e>] __wake_up_common+0x2e/0x90
PGD 0
Oops: 0000 [#1] SMP
Modules linked in: netconsole nfsv3 nfs_acl nfs lockd grace ...
CPU: 2 PID: 940 Comm: kworker/2:3 Kdump: loaded Not tainted 3.10.0-862.el7.x86_64 #1
Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS 090006  04/28/2016
Workqueue: events hv_eject_device_work [pci_hyperv]
task: ffff8d1734ca0fd0 ti: ffff8d17354bc000 task.ti: ffff8d17354bc000
RIP: 0010:[<ffffffff876c4a8e>]  [<ffffffff876c4a8e>] __wake_up_common+0x2e/0x90
RSP: 0018:ffff8d17354bfa38  EFLAGS: 00010082
RAX: 0000000000000000 RBX: ffff8d17362d42c8 RCX: 0000000000000000
RDX: 0000000000000001 RSI: 0000000000000003 RDI: ffff8d17362d42c8
RBP: ffff8d17354bfa70 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000298 R11: ffff8d173610e000 R12: ffff8d17362d42d0
R13: 0000000000000246 R14: 0000000000000000 R15: 0000000000000003
FS:  0000000000000000(0000) GS:ffff8d1802680000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000f16d8000 CR4: 00000000001406e0
Call Trace:
 [<ffffffff876c7adc>] complete+0x3c/0x50
 [<ffffffffc04242f0>] mlx4_cmd_wake_completions+0x70/0x90 [mlx4_core]
 [<ffffffffc041e7b1>] mlx4_enter_error_state+0xe1/0x380 [mlx4_core]
 [<ffffffffc041fa4b>] mlx4_comm_cmd+0x29b/0x360 [mlx4_core]
 [<ffffffffc041ff51>] __mlx4_cmd+0x441/0x920 [mlx4_core]
 [<ffffffff877f62b1>] ? __slab_free+0x81/0x2f0
 [<ffffffff87951384>] ? __radix_tree_lookup+0x84/0xf0
 [<ffffffffc043a8eb>] mlx4_free_mtt_range+0x5b/0xb0 [mlx4_core]
 [<ffffffffc043a957>] mlx4_mtt_cleanup+0x17/0x20 [mlx4_core]
 [<ffffffffc04272c7>] mlx4_free_eq+0xa7/0x1c0 [mlx4_core]
 [<ffffffffc042803e>] mlx4_cleanup_eq_table+0xde/0x130 [mlx4_core]
 [<ffffffffc0433e08>] mlx4_unload_one+0x118/0x300 [mlx4_core]
 [<ffffffffc0434191>] mlx4_remove_one+0x91/0x1f0 [mlx4_core]

The fix is to set the command context array pointer to NULL after freeing
the array.

Fixes: f5aef5aa35 ("net/mlx4_core: Activate reset flow upon fatal command cases")
Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-03-12 15:00:15 -07:00
arch y2038: fix socket.h header inclusion 2019-03-11 11:06:00 -07:00
block
certs
crypto
Documentation Documentation: devicetree: add a new optional property for port mac address 2019-03-11 16:21:09 -07:00
drivers net/mlx4_core: Fix reset flow when in command polling mode 2019-03-12 15:00:15 -07:00
firmware
fs a.out: remove core dumping support 2019-03-05 10:00:35 -08:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf 2019-03-11 16:14:14 -07:00
init
ipc
kernel bpf: fix replace_map_fd_with_map_ptr's ldimm64 second imm field 2019-03-07 08:47:13 -08:00
lib
LICENSES
mm
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf 2019-03-11 16:14:14 -07:00
samples bpf: hbm: fix spelling mistake "deault" -> "default" 2019-03-07 10:35:00 +01:00
scripts
security
sound
tools bpf, libbpf: fixing leak when kernel does not support btf 2019-03-08 21:16:36 +01:00
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS appletalk: Add atalk.h header files to MAINTAINERS file 2019-03-06 10:46:43 -08:00
Makefile
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.