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Samuel Cabrero 76e752701a cifs: Check for timeout on Negotiate stage
Some servers seem to accept connections while booting but never send
the SMBNegotiate response neither close the connection, causing all
processes accessing the share hang on uninterruptible sleep state.

This happens when the cifs_demultiplex_thread detects the server is
unresponsive so releases the socket and start trying to reconnect.
At some point, the faulty server will accept the socket and the TCP
status will be set to NeedNegotiate. The first issued command accessing
the share will start the negotiation (pid 5828 below), but the response
will never arrive so other commands will be blocked waiting on the mutex
(pid 55352).

This patch checks for unresponsive servers also on the negotiate stage
releasing the socket and reconnecting if the response is not received
and checking again the tcp state when the mutex is acquired.

PID: 55352  TASK: ffff880fd6cc02c0  CPU: 0   COMMAND: "ls"
 #0 [ffff880fd9add9f0] schedule at ffffffff81467eb9
 #1 [ffff880fd9addb38] __mutex_lock_slowpath at ffffffff81468fe0
 #2 [ffff880fd9addba8] mutex_lock at ffffffff81468b1a
 #3 [ffff880fd9addbc0] cifs_reconnect_tcon at ffffffffa042f905 [cifs]
 #4 [ffff880fd9addc60] smb_init at ffffffffa042faeb [cifs]
 #5 [ffff880fd9addca0] CIFSSMBQPathInfo at ffffffffa04360b5 [cifs]
 ....

Which is waiting a mutex owned by:

PID: 5828   TASK: ffff880fcc55e400  CPU: 0   COMMAND: "xxxx"
 #0 [ffff880fbfdc19b8] schedule at ffffffff81467eb9
 #1 [ffff880fbfdc1b00] wait_for_response at ffffffffa044f96d [cifs]
 #2 [ffff880fbfdc1b60] SendReceive at ffffffffa04505ce [cifs]
 #3 [ffff880fbfdc1bb0] CIFSSMBNegotiate at ffffffffa0438d79 [cifs]
 #4 [ffff880fbfdc1c50] cifs_negotiate_protocol at ffffffffa043b383 [cifs]
 #5 [ffff880fbfdc1c80] cifs_reconnect_tcon at ffffffffa042f911 [cifs]
 #6 [ffff880fbfdc1d20] smb_init at ffffffffa042faeb [cifs]
 #7 [ffff880fbfdc1d60] CIFSSMBQFSInfo at ffffffffa0434eb0 [cifs]
 ....

Signed-off-by: Samuel Cabrero <scabrero@suse.de>
Reviewed-by: Aurélien Aptel <aaptel@suse.de>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
2017-09-04 20:55:29 -05:00
arch main drm pull request for 4.14 merge window 2017-09-03 17:02:26 -07:00
block Updates for 4.14 kernel merge window 2017-09-03 17:49:17 -07:00
certs modsign: add markers to endif-statements in certs/Makefile 2017-07-14 11:01:37 +10:00
crypto crypto: algif_skcipher - only call put_page on referenced and used pages 2017-08-22 14:45:48 +08:00
Documentation Merge branch 'docs-next' of git://git.lwn.net/linux 2017-09-03 21:07:29 -07:00
drivers hwmon updates for v4.14 2017-09-03 18:43:20 -07:00
firmware firmware/Makefile: force recompilation if makefile changes 2017-05-08 17:15:10 -07:00
fs cifs: Check for timeout on Negotiate stage 2017-09-04 20:55:29 -05:00
include Merge branch 'docs-next' of git://git.lwn.net/linux 2017-09-03 21:07:29 -07:00
init random: do not ignore early device randomness 2017-07-12 16:26:00 -07:00
ipc ipc: add missing container_of()s for randstruct 2017-08-02 17:16:12 -07:00
kernel Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-09-03 09:30:40 -07:00
lib Merge branch 'docs-next' of git://git.lwn.net/linux 2017-09-03 21:07:29 -07:00
mm Merge branch 'akpm' (patches from Andrew) 2017-08-31 17:56:56 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-09-01 12:49:03 -07:00
samples samples/bpf: fix bpf tunnel cleanup 2017-07-31 22:02:47 -07:00
scripts Merge branch 'docs-next' of git://git.lwn.net/linux 2017-09-03 21:07:29 -07:00
security Now that IPC and other changes have landed, enable manual markings for 2017-07-19 08:55:18 -07:00
sound main drm pull request for 4.14 merge window 2017-09-03 17:02:26 -07:00
tools NTB bug fixes to address an incorrect ntb_mw_count reference in the NTB 2017-08-27 17:01:54 -07:00
usr ramfs: clarify help text that compression applies to ramfs as well as legacy ramdisk. 2017-07-06 16:24:30 -07:00
virt KVM: update to new mmu_notifier semantic v2 2017-08-31 16:13:00 -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: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap power supply and reset changes for the v4.12 series (part 2) 2017-05-12 12:02:21 -07:00
COPYING
CREDITS avr32: remove support for AVR32 architecture 2017-05-01 09:27:15 +02:00
Kbuild kbuild: Consolidate header generation from ASM offset information 2017-04-13 05:43:37 +09:00
Kconfig
MAINTAINERS main drm pull request for 4.14 merge window 2017-09-03 17:02:26 -07:00
Makefile Merge branch 'docs-next' of git://git.lwn.net/linux 2017-09-03 21:07:29 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

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.