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Leon Romanovsky 4121fb0db6 RDMA/core: Check that type_attrs is not NULL prior access
In disassociate flow, the type_attrs is set to be NULL, which is in an
implicit way is checked in alloc_uobj() by "if (!attrs->context)".

Change the logic to rely on that check, to be consistent with other
alloc_uobj() places that will fix the following kernel splat.

 BUG: kernel NULL pointer dereference, address: 0000000000000018
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 0 P4D 0
 Oops: 0000 [#1] SMP PTI
 CPU: 3 PID: 2743 Comm: python3 Not tainted 5.7.0-rc6-for-upstream-perf-2020-05-23_19-04-38-5 #1
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
 RIP: 0010:alloc_begin_fd_uobject+0x18/0xf0 [ib_uverbs]
 Code: 89 43 48 eb 97 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 41 55 49 89 f5 41 54 55 48 89 fd 53 48 83 ec 08 48 8b 1f <48> 8b 43 18 48 8b 80 80 00 00 00 48 3d 20 10 33 a0 74 1c 48 3d 30
 RSP: 0018:ffffc90001127b70 EFLAGS: 00010282
 RAX: ffffffffa0339fe0 RBX: 0000000000000000 RCX: 8000000000000007
 RDX: fffffffffffffffb RSI: ffffc90001127d28 RDI: ffff88843fe1f600
 RBP: ffff88843fe1f600 R08: ffff888461eb06d8 R09: ffff888461eb06f8
 R10: ffff888461eb0700 R11: 0000000000000000 R12: ffff88846a5f6450
 R13: ffffc90001127d28 R14: ffff88845d7d6ea0 R15: ffffc90001127cb8
 FS: 00007f469bff1540(0000) GS:ffff88846f980000(0000) knlGS:0000000000000000
 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000018 CR3: 0000000450018003 CR4: 0000000000760ee0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 PKRU: 55555554
 Call Trace:
 ? xa_store+0x28/0x40
 rdma_alloc_begin_uobject+0x4f/0x90 [ib_uverbs]
 ib_uverbs_create_comp_channel+0x87/0xf0 [ib_uverbs]
 ib_uverbs_handler_UVERBS_METHOD_INVOKE_WRITE+0xb1/0xf0 [ib_uverbs]
 ib_uverbs_cmd_verbs.isra.8+0x96d/0xae0 [ib_uverbs]
 ? get_page_from_freelist+0x3bb/0xf70
 ? _copy_to_user+0x22/0x30
 ? uverbs_disassociate_api+0xd0/0xd0 [ib_uverbs]
 ? __wake_up_common_lock+0x87/0xc0
 ib_uverbs_ioctl+0xbc/0x130 [ib_uverbs]
 ksys_ioctl+0x83/0xc0
 ? ksys_write+0x55/0xd0
 __x64_sys_ioctl+0x16/0x20
 do_syscall_64+0x48/0x130
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
 RIP: 0033:0x7f469ac43267

Fixes: 849e149063 ("RDMA/core: Do not allow alloc_commit to fail")
Link: https://lore.kernel.org/r/20200617061826.2625359-1-leon@kernel.org
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2020-06-18 10:59:21 -03:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-06-13 16:27:13 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch Kbuild updates for v5.8 (2nd) 2020-06-13 13:29:16 -07:00
block Kbuild updates for v5.8 (2nd) 2020-06-13 13:29:16 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto Merge branch 'rwonce/rework' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux 2020-06-10 14:46:54 -07:00
drivers RDMA/core: Check that type_attrs is not NULL prior access 2020-06-18 10:59:21 -03:00
fs for-5.8-part2-tag 2020-06-14 09:47:25 -07:00
include RDMA/mlx5: Add missed RST2INIT and INIT2INIT steps during ECE handshake 2020-06-18 09:52:29 -03:00
init Kbuild updates for v5.8 (2nd) 2020-06-13 13:29:16 -07:00
ipc mmap locking API: use coccinelle to convert mmap_sem rwsem call sites 2020-06-09 09:39:14 -07:00
kernel Add additional LSM hooks for SafeSetID 2020-06-14 11:39:31 -07:00
lib Kbuild updates for v5.8 (2nd) 2020-06-13 13:29:16 -07:00
mm Kbuild updates for v5.8 (2nd) 2020-06-13 13:29:16 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-06-13 16:27:13 -07:00
samples binderfs: add gitignore for generated sample program 2020-06-13 13:41:24 -07:00
scripts Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-06-13 16:27:13 -07:00
security Add additional LSM hooks for SafeSetID 2020-06-14 11:39:31 -07:00
sound Kbuild updates for v5.8 (2nd) 2020-06-13 13:29:16 -07:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-06-13 16:27:13 -07:00
usr bpfilter: match bit size of bpfilter_umh to that of the kernel 2020-05-17 18:52:01 +09:00
virt MIPS: 2020-06-12 11:05:52 -07:00
.clang-format block: add bio_for_each_bvec_all() 2020-05-25 11:25:24 +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: generate vmlinux.symvers and reuse it for the second modpost 2020-06-06 23:38:12 +09:00
.mailmap A fair amount of stuff this time around, dominated by yet another massive 2020-06-01 15:45:27 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS mailmap: change email for Ricardo Ribalda 2020-05-25 18:59:59 -06:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge branch 'i2c/for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2020-06-13 13:12:38 -07:00
Makefile Linux 5.8-rc1 2020-06-14 12:45:04 -07:00
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.