Parav Pandit a379d1ce32 IB/core: Fix querying total rdma stats
rdma_counter_init() may fail for a device. In such case while calculating
total sum, ignore NULL hstats.

This fixes below observed call trace.

BUG: kernel NULL pointer dereference, address: 00000000000000a0
PGD 8000001009b30067 P4D 8000001009b30067 PUD 10549c9067 PMD 0
Oops: 0000 [#1] SMP PTI
CPU: 55 PID: 20887 Comm: cat Kdump: loaded Not tainted 5.2.0-rc6-jdc+ #13
RIP: 0010:rdma_counter_get_hwstat_value+0xf2/0x150 [ib_core]
Call Trace:
 show_hw_stats+0x5e/0x130 [ib_core]
 dev_attr_show+0x15/0x50
 sysfs_kf_seq_show+0xc6/0x1a0
 seq_read+0x132/0x370
 vfs_read+0x89/0x140
 ksys_read+0x5c/0xd0
 do_syscall_64+0x5a/0x240
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Fixes: f34a55e497 ("RDMA/core: Get sum value of all counters when perform a sysfs stat read")
Link: https://lore.kernel.org/r/20190723065733.4899-10-leon@kernel.org
Signed-off-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Mark Zhang <markz@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-07-25 11:39:38 -03:00
2019-06-18 14:37:27 +01:00
2019-07-19 12:22:04 -07:00
2019-07-21 14:05:38 -07:00

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.
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