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zhuoliang zhang 243a16469c net: xfrm: fix a race condition during allocing spi [ Upstream commit `a779d91314` ] we found that the following race condition exists in xfrm_alloc_userspi flow: user thread state_hash_work thread ---- ---- xfrm_alloc_userspi() __find_acq_core() /alloc new xfrm_state:x/ xfrm_state_alloc() /schedule state_hash_work thread/ xfrm_hash_grow_check() xfrm_hash_resize() xfrm_alloc_spi /hold lock/ x->id.spi = htonl(spi) spin_lock_bh(&net->xfrm.xfrm_state_lock) /waiting lock release/ xfrm_hash_transfer() spin_lock_bh(&net->xfrm.xfrm_state_lock) /add x into hlist:net->xfrm.state_byspi/ hlist_add_head_rcu(&x->byspi) spin_unlock_bh(&net->xfrm.xfrm_state_lock) /add x into hlist:net->xfrm.state_byspi 2 times/ hlist_add_head_rcu(&x->byspi) 1. a new state x is alloced in xfrm_state_alloc() and added into the bydst hlist in __find_acq_core() on the LHS; 2. on the RHS, state_hash_work thread travels the old bydst and tranfers every xfrm_state (include x) into the new bydst hlist and new byspi hlist; 3. user thread on the LHS gets the lock and adds x into the new byspi hlist again. So the same xfrm_state (x) is added into the same list_hash (net->xfrm.state_byspi) 2 times that makes the list_hash become an inifite loop. To fix the race, x->id.spi = htonl(spi) in the xfrm_alloc_spi() is moved to the back of spin_lock_bh, sothat state_hash_work thread no longer add x which id.spi is zero into the hash_list. Fixes: `f034b5d4ef` ("[XFRM]: Dynamic xfrm_state hash table sizing.") Signed-off-by: zhuoliang zhang <zhuoliang.zhang@mediatek.com> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Sasha Levin <sashal@kernel.org>		2020-11-18 19:18:41 +01:00
arch	arm64: dts: marvell: espressobin: Add ethernet switch aliases	2020-11-10 12:36:02 +01:00
block	blk-cgroup: Pre-allocate tree node on blkg_conf_prep	2020-11-10 12:35:59 +01:00
certs	export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR()	2018-08-22 23:21:44 +09:00
crypto	crypto: algif_skcipher - EBUSY on aio should be an error	2020-10-29 09:55:01 +01:00
Documentation	media: videodev2.h: RGB BT2020 and HSV are always full range	2020-11-05 11:08:40 +01:00
drivers	hv_balloon: disable warning when floor reached	2020-11-18 19:18:41 +01:00
firmware	Fix built-in early-load Intel microcode alignment	2020-01-23 08:21:29 +01:00
fs	btrfs: reschedule when cloning lots of extents	2020-11-18 19:18:41 +01:00
include	time: Prevent undefined behaviour in timespec64_to_ns()	2020-11-18 19:18:40 +01:00
init	printk: reduce LOG_BUF_SHIFT range for H8300	2020-11-05 11:08:41 +01:00
ipc	ipc/util.c: sysvipc_find_ipc() incorrectly updates position index	2020-05-20 08:18:40 +02:00
kernel	genirq: Let GENERIC_IRQ_IPI select IRQ_DOMAIN_HIERARCHY	2020-11-18 19:18:41 +01:00
lib	lib/crc32test: remove extra local_irq_disable/enable	2020-11-10 12:35:57 +01:00
LICENSES	LICENSES: Remove CC-BY-SA-4.0 license text	2018-10-18 11:28:50 +02:00
mm	mm: mempolicy: fix potential pte_unmap_unlock pte error	2020-11-10 12:35:57 +01:00
net	net: xfrm: fix a race condition during allocing spi	2020-11-18 19:18:41 +01:00
samples	misc: vop: add round_up(x,4) for vring_size to avoid kernel panic	2020-10-30 10:38:29 +01:00
scripts	scripts/setlocalversion: make git describe output more reliable	2020-11-05 11:08:31 +01:00
security	evm: Check size of security.evm before using it	2020-11-05 11:08:34 +01:00
sound	ALSA: usb-audio: Add implicit feedback quirk for MODX	2020-11-10 12:35:57 +01:00
tools	tools: perf: Fix build error in v4.19.y	2020-11-10 12:36:02 +01:00
usr	initramfs: restore default compression behavior	2020-04-13 10:44:59 +02:00
virt	KVM: arm64: Assume write fault on S1PTW permission fault on instruction fetch	2020-10-01 13:14:54 +02:00
.clang-format	clang-format: Set IndentWrappedFunctionNames false	2018-08-01 18:38:51 +02:00
.cocciconfig
.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	libnvdimm-for-4.19_misc	2018-08-25 18:13:10 -07:00
COPYING	COPYING: use the new text with points to the license files	2018-03-23 12:41:45 -06:00
CREDITS	9p: remove Ron Minnich from MAINTAINERS	2018-08-17 16:20:26 -07:00
Kbuild	Kbuild updates for v4.15	2017-11-17 17:45:29 -08:00
Kconfig	kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt	2018-08-02 08:06:55 +09:00
MAINTAINERS	Documentation/llvm: add documentation on building w/ Clang/LLVM	2020-09-26 18:01:31 +02:00
Makefile	Linux 4.19.157	2020-11-10 21:11:27 +01:00
README	Docs: Added a pointer to the formatted docs to README	2018-03-21 09:02:53 -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.
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.