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Paulo Alcantara 662bf5bc0a cifs: Fix kernel oops when traceSMB is enabled
When traceSMB is enabled through 'echo 1 > /proc/fs/cifs/traceSMB', after a
mount, the following oops is triggered:

[   27.137943] BUG: unable to handle kernel paging request at
ffff8800f80c268b
[   27.143396] PGD 2c6b067 P4D 2c6b067 PUD 0
[   27.145386] Oops: 0000 [#1] SMP PTI
[   27.146186] CPU: 2 PID: 2655 Comm: mount.cifs Not tainted 4.17.0+ #39
[   27.147174] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS
1.0.0-prebuilt.qemu-project.org 04/01/2014
[   27.148969] RIP: 0010:hex_dump_to_buffer+0x413/0x4b0
[   27.149738] Code: 48 8b 44 24 08 31 db 45 31 d2 48 89 6c 24 18 44 89
6c 24 24 48 c7 c1 78 b5 23 82 4c 89 64 24 10 44 89 d5 41 89 dc 4c 8d 58
02 <44> 0f b7 00 4d 89 dd eb 1f 83 c5 01 41 01 c4 41 39 ef 0f 84 48 fe
[   27.152396] RSP: 0018:ffffc9000058f8c0 EFLAGS: 00010246
[   27.153129] RAX: ffff8800f80c268b RBX: 0000000000000000 RCX:
ffffffff8223b578
[   27.153867] RDX: 0000000000000000 RSI: ffffffff81a55496 RDI:
0000000000000008
[   27.154612] RBP: 0000000000000000 R08: 0000000000000020 R09:
0000000000000083
[   27.155355] R10: 0000000000000000 R11: ffff8800f80c268d R12:
0000000000000000
[   27.156101] R13: 0000000000000002 R14: ffffc9000058f94d R15:
0000000000000008
[   27.156838] FS:  00007f1693a6b740(0000) GS:ffff88007fd00000(0000)
knlGS:0000000000000000
[   27.158354] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   27.159093] CR2: ffff8800f80c268b CR3: 00000000798fa001 CR4:
0000000000360ee0
[   27.159892] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
0000000000000000
[   27.160661] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7:
0000000000000400
[   27.161464] Call Trace:
[   27.162123]  print_hex_dump+0xd3/0x160
[   27.162814] journal-offline (2658) used greatest stack depth: 13144
bytes left
[   27.162824]  ? __release_sock+0x60/0xd0
[   27.165344]  ? tcp_sendmsg+0x31/0x40
[   27.166177]  dump_smb+0x39/0x40
[   27.166972]  ? vsnprintf+0x236/0x490
[   27.167807]  __smb_send_rqst.constprop.12+0x103/0x430
[   27.168554]  ? apic_timer_interrupt+0xa/0x20
[   27.169306]  smb_send_rqst+0x48/0xc0
[   27.169984]  cifs_send_recv+0xda/0x420
[   27.170639]  SMB2_negotiate+0x23d/0xfa0
[   27.171301]  ? vsnprintf+0x236/0x490
[   27.171961]  ? smb2_negotiate+0x19/0x30
[   27.172586]  smb2_negotiate+0x19/0x30
[   27.173257]  cifs_negotiate_protocol+0x70/0xd0
[   27.173935]  ? kstrdup+0x43/0x60
[   27.174551]  cifs_get_smb_ses+0x295/0xbe0
[   27.175260]  ? lock_timer_base+0x67/0x80
[   27.175936]  ? __internal_add_timer+0x1a/0x50
[   27.176575]  ? add_timer+0x10f/0x230
[   27.177267]  cifs_mount+0x101/0x1190
[   27.177940]  ? cifs_smb3_do_mount+0x144/0x5c0
[   27.178575]  cifs_smb3_do_mount+0x144/0x5c0
[   27.179270]  mount_fs+0x35/0x150
[   27.179930]  vfs_kern_mount.part.28+0x54/0xf0
[   27.180567]  do_mount+0x5ad/0xc40
[   27.181234]  ? kmem_cache_alloc_trace+0xed/0x1a0
[   27.181916]  ksys_mount+0x80/0xd0
[   27.182535]  __x64_sys_mount+0x21/0x30
[   27.183220]  do_syscall_64+0x4e/0x100
[   27.183882]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[   27.184535] RIP: 0033:0x7f169339055a
[   27.185192] Code: 48 8b 0d 41 d9 2b 00 f7 d8 64 89 01 48 83 c8 ff c3
66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 00 0f
05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 0e d9 2b 00 f7 d8 64 89 01 48
[   27.187268] RSP: 002b:00007fff7b44eb58 EFLAGS: 00000202 ORIG_RAX:
00000000000000a5
[   27.188515] RAX: ffffffffffffffda RBX: 00007f1693a7e70e RCX:
00007f169339055a
[   27.189244] RDX: 000055b9f97f64e5 RSI: 000055b9f97f652c RDI:
00007fff7b45074f
[   27.189974] RBP: 000055b9fb8c9260 R08: 000055b9fb8ca8f0 R09:
0000000000000000
[   27.190721] R10: 0000000000000000 R11: 0000000000000202 R12:
000055b9fb8ca8f0
[   27.191429] R13: 0000000000000000 R14: 00007f1693a7c000 R15:
00007f1693a7e91d
[   27.192167] Modules linked in:
[   27.192797] CR2: ffff8800f80c268b
[   27.193435] ---[ end trace 67404c618badf323 ]---

The problem was that dump_smb() had been called with an invalid pointer,
that is, in __smb_send_rqst(), iov[1] doesn't exist (n_vec == 1).

This patch fixes it by relying on the n_vec value to dump out the smb
packets.

Signed-off-by: Paulo Alcantara <palcantara@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
2018-06-15 02:38:08 -05:00
arch Merge branch 'akpm' (patches from Andrew) 2018-06-15 08:51:42 +09:00
block treewide: Use array_size() in vzalloc() 2018-06-12 16:19:22 -07:00
certs certs/blacklist_nohashes.c: fix const confusion in certs blacklist 2018-02-21 15:35:43 -08:00
crypto treewide: Use array_size() in sock_kmalloc() 2018-06-12 16:19:22 -07:00
Documentation cifs: minor documentation updates 2018-06-15 02:38:07 -05:00
drivers Merge branch 'akpm' (patches from Andrew) 2018-06-15 08:51:42 +09:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs cifs: Fix kernel oops when traceSMB is enabled 2018-06-15 02:38:08 -05:00
include Merge branch 'akpm' (patches from Andrew) 2018-06-15 08:51:42 +09:00
init Kbuild updates for v4.18 (2nd) 2018-06-13 08:40:34 -07:00
ipc ipc: use new return type vm_fault_t 2018-06-15 07:55:25 +09:00
kernel Merge branch 'akpm' (patches from Andrew) 2018-06-15 08:51:42 +09:00
lib lib/test_printf.c: call wait_for_random_bytes() before plain %p tests 2018-06-15 07:55:25 +09:00
LICENSES LICENSES: Add Linux-OpenIB license text 2018-04-27 16:41:53 -06:00
mm mm: fix oom_kill event handling 2018-06-15 07:55:25 +09:00
net The main piece is a set of libceph changes that revamps how OSD 2018-06-15 07:24:58 +09:00
samples VFIO updates for v4.18 2018-06-12 13:11:26 -07:00
scripts Kbuild updates for v4.18 (2nd) 2018-06-13 08:40:34 -07:00
security + Features 2018-06-14 16:11:28 +09:00
sound - Error path bug fix for overflow tests (Dan) 2018-06-12 18:28:00 -07:00
tools Additional power management updates for 4.18-rc1 2018-06-13 07:24:18 -07:00
usr kbuild: rename built-in.o to built-in.a 2018-03-26 02:01:19 +09:00
virt - Error path bug fix for overflow tests (Dan) 2018-06-12 18:28:00 -07:00
.clang-format clang-format: add configuration file 2018-04-11 10:28:35 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap Merge branch 'asoc-4.17' into asoc-4.18 for compress dependencies 2018-04-26 12:24:28 +01:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS/CREDITS: Drop METAG ARCHITECTURE 2018-03-05 16:34:24 +00:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: add basic helper macros to scripts/Kconfig.include 2018-05-29 03:31:19 +09:00
MAINTAINERS Merge branch 'i2c/for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2018-06-14 16:21:46 +09:00
Makefile Kbuild: rename CC_STACKPROTECTOR[_STRONG] config variables 2018-06-14 12:21:18 +09:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -06:00

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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.