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Filename Latest commit message Latest commit date
Hou Pu a5bfcf2455 scsi: target: iscsi: Fix hang in iscsit_access_np() when getting tpg->np_login_sem
commit ed43ffea78dcc97db3f561da834f1a49c8961e33 upstream.

The iSCSI target login thread might get stuck with the following stack:

cat /proc/`pidof iscsi_np`/stack
[<0>] down_interruptible+0x42/0x50
[<0>] iscsit_access_np+0xe3/0x167
[<0>] iscsi_target_locate_portal+0x695/0x8ac
[<0>] __iscsi_target_login_thread+0x855/0xb82
[<0>] iscsi_target_login_thread+0x2f/0x5a
[<0>] kthread+0xfa/0x130
[<0>] ret_from_fork+0x1f/0x30

This can be reproduced via the following steps:

1. Initiator A tries to log in to iqn1-tpg1 on port 3260. After finishing
   PDU exchange in the login thread and before the negotiation is finished
   the the network link goes down. At this point A has not finished login
   and tpg->np_login_sem is held.

2. Initiator B tries to log in to iqn2-tpg1 on port 3260. After finishing
   PDU exchange in the login thread the target expects to process remaining
   login PDUs in workqueue context.

3. Initiator A' tries to log in to iqn1-tpg1 on port 3260 from a new
   socket. A' will wait for tpg->np_login_sem with np->np_login_timer
   loaded to wait for at most 15 seconds. The lock is held by A so A'
   eventually times out.

4. Before A' got timeout initiator B gets negotiation failed and calls
   iscsi_target_login_drop()->iscsi_target_login_sess_out().  The
   np->np_login_timer is canceled and initiator A' will hang forever.
   Because A' is now in the login thread, no new login requests can be
   serviced.

Fix this by moving iscsi_stop_login_thread_timer() out of
iscsi_target_login_sess_out(). Also remove iscsi_np parameter from
iscsi_target_login_sess_out().

Link: https://lore.kernel.org/r/20200729130343.24976-1-houpu@bytedance.com
Cc: stable@vger.kernel.org
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Hou Pu <houpu@bytedance.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-09-17 13:47:53 +02:00
arch arm64/module: set trampoline section flags regardless of CONFIG_DYNAMIC_FTRACE 2020-09-17 13:47:49 +02:00
block block: Set same_page to false in __bio_try_merge_page if ret is false 2020-09-17 13:47:44 +02:00
certs
crypto crypto: af_alg - Work around empty control messages without MSG_MORE 2020-09-03 11:27:05 +02:00
Documentation affs: fix basic permission bits to actually work 2020-09-09 19:12:34 +02:00
drivers scsi: target: iscsi: Fix hang in iscsit_access_np() when getting tpg->np_login_sem 2020-09-17 13:47:53 +02:00
fs btrfs: fix wrong address when faulting in pages in the search ioctl 2020-09-17 13:47:52 +02:00
include irqchip/eznps: Fix build error for !ARC700 builds 2020-09-17 13:47:47 +02:00
init
ipc
kernel gcov: Disable gcov build with GCC 10 2020-09-17 13:47:49 +02:00
lib kobject: Restore old behaviour of kobject_del(NULL) 2020-09-17 13:47:52 +02:00
LICENSES
mm mm/khugepaged.c: fix khugepaged's request size in collapse_file 2020-09-09 19:12:37 +02:00
net cfg80211: Adjust 6 GHz frequency to channel conversion 2020-09-17 13:47:46 +02:00
samples bpf: Fix fds_example SIGSEGV error 2020-08-19 08:16:03 +02:00
scripts checkpatch: fix the usage of capture group ( ... ) 2020-09-09 19:12:37 +02:00
security Smack: prevent underflow in smk_set_cipso() 2020-08-19 08:16:16 +02:00
sound ALSA: hda: fix a runtime pm issue in SOF when integrated GPU is disabled 2020-09-17 13:47:49 +02:00
tools selftests/timers: Turn off timeout setting 2020-09-17 13:47:41 +02:00
usr
virt KVM: arm64: Only reschedule if MMU_NOTIFIER_RANGE_BLOCKABLE is not set 2020-08-26 10:41:08 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-08-26 10:40:46 +02:00
Makefile Linux 5.4.65 2020-09-12 14:18:56 +02:00
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.