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Hans de Goede 8f4347081b staging: rtl8723bs: Fix access-point mode deadlock Commit `54659ca026` ("staging: rtl8723bs: remove possible deadlock when disconnect (v2)") split the locking of pxmitpriv->lock vs sleep_q/lock into 2 locks in attempt to fix a lockdep reported issue with the locking order of the sta_hash_lock vs pxmitpriv->lock. But in the end this turned out to not fully solve the sta_hash_lock issue so commit `a7ac783c33` ("staging: rtl8723bs: remove a second possible deadlock") was added to fix this in another way. The original fix was kept as it was still seen as a good thing to have, but now it turns out that it creates a deadlock in access-point mode: [Feb20 23:47] ====================================================== [ +0.074085] WARNING: possible circular locking dependency detected [ +0.074077] 5.16.0-1-amd64 #1 Tainted: G C E [ +0.064710] ------------------------------------------------------ [ +0.074075] ksoftirqd/3/29 is trying to acquire lock: [ +0.060542] ffffb8b30062ab00 (&pxmitpriv->lock){+.-.}-{2:2}, at: rtw_xmit_classifier+0x8a/0x140 [r8723bs] [ +0.114921] but task is already holding lock: [ +0.069908] ffffb8b3007ab704 (&psta->sleep_q.lock){+.-.}-{2:2}, at: wakeup_sta_to_xmit+0x3b/0x300 [r8723bs] [ +0.116976] which lock already depends on the new lock. [ +0.098037] the existing dependency chain (in reverse order) is: [ +0.089704] -> #1 (&psta->sleep_q.lock){+.-.}-{2:2}: [ +0.077232] _raw_spin_lock_bh+0x34/0x40 [ +0.053261] xmitframe_enqueue_for_sleeping_sta+0xc1/0x2f0 [r8723bs] [ +0.082572] rtw_xmit+0x58b/0x940 [r8723bs] [ +0.056528] _rtw_xmit_entry+0xba/0x350 [r8723bs] [ +0.062755] dev_hard_start_xmit+0xf1/0x320 [ +0.056381] sch_direct_xmit+0x9e/0x360 [ +0.052212] __dev_queue_xmit+0xce4/0x1080 [ +0.055334] ip6_finish_output2+0x18f/0x6e0 [ +0.056378] ndisc_send_skb+0x2c8/0x870 [ +0.052209] ndisc_send_ns+0xd3/0x210 [ +0.050130] addrconf_dad_work+0x3df/0x5a0 [ +0.055338] process_one_work+0x274/0x5a0 [ +0.054296] worker_thread+0x52/0x3b0 [ +0.050124] kthread+0x16c/0x1a0 [ +0.044925] ret_from_fork+0x1f/0x30 [ +0.049092] -> #0 (&pxmitpriv->lock){+.-.}-{2:2}: [ +0.074101] __lock_acquire+0x10f5/0x1d80 [ +0.054298] lock_acquire+0xd7/0x300 [ +0.049088] _raw_spin_lock_bh+0x34/0x40 [ +0.053248] rtw_xmit_classifier+0x8a/0x140 [r8723bs] [ +0.066949] rtw_xmitframe_enqueue+0xa/0x20 [r8723bs] [ +0.066946] rtl8723bs_hal_xmitframe_enqueue+0x14/0x50 [r8723bs] [ +0.078386] wakeup_sta_to_xmit+0xa6/0x300 [r8723bs] [ +0.065903] rtw_recv_entry+0xe36/0x1160 [r8723bs] [ +0.063809] rtl8723bs_recv_tasklet+0x349/0x6c0 [r8723bs] [ +0.071093] tasklet_action_common.constprop.0+0xe5/0x110 [ +0.070966] __do_softirq+0x16f/0x50a [ +0.050134] __irq_exit_rcu+0xeb/0x140 [ +0.051172] irq_exit_rcu+0xa/0x20 [ +0.047006] common_interrupt+0xb8/0xd0 [ +0.052214] asm_common_interrupt+0x1e/0x40 [ +0.056381] finish_task_switch.isra.0+0x100/0x3a0 [ +0.063670] __schedule+0x3ad/0xd20 [ +0.048047] schedule+0x4e/0xc0 [ +0.043880] smpboot_thread_fn+0xc4/0x220 [ +0.054298] kthread+0x16c/0x1a0 [ +0.044922] ret_from_fork+0x1f/0x30 [ +0.049088] other info that might help us debug this: [ +0.095950] Possible unsafe locking scenario: [ +0.070952] CPU0 CPU1 [ +0.054282] ---- ---- [ +0.054285] lock(&psta->sleep_q.lock); [ +0.047004] lock(&pxmitpriv->lock); [ +0.074082] lock(&psta->sleep_q.lock); [ +0.077209] lock(&pxmitpriv->lock); [ +0.043873] * DEADLOCK * [ +0.070950] 1 lock held by ksoftirqd/3/29: [ +0.049082] #0: ffffb8b3007ab704 (&psta->sleep_q.lock){+.-.}-{2:2}, at: wakeup_sta_to_xmit+0x3b/0x300 [r8723bs] Analysis shows that in hindsight the splitting of the lock was not a good idea, so revert this to fix the access-point mode deadlock. Note this is a straight-forward revert done with git revert, the commented out "/* spin_lock_bh(&psta_bmc->sleep_q.lock); */" lines were part of the code before the reverted changes. Fixes: `54659ca026` ("staging: rtl8723bs: remove possible deadlock when disconnect (v2)") Cc: stable <stable@vger.kernel.org> Cc: Fabio Aiuto <fabioaiuto83@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com> BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=215542 Link: https://lore.kernel.org/r/20220302101637.26542-1-hdegoede@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		History 2022-03-02 16:38:19 +01:00
arch	RISC-V Fixes for 5.17-rc6	2022-02-26 10:26:24 -08:00
block	block: clear iocb->private in blkdev_bio_end_io_async()	2022-02-22 06:59:49 -07:00
certs	certs: Fix build error when CONFIG_MODULE_SIG_KEY is empty	2022-01-23 00:08:44 +09:00
crypto	crypto: af_alg - get rid of alg_memory_allocated	2022-02-15 14:29:04 +00:00
Documentation	dma-mapping fix for Linux 5.17	2022-02-27 12:42:37 -08:00
drivers	staging: rtl8723bs: Fix access-point mode deadlock	2022-03-02 16:38:19 +01:00
fs	Tracing fixes for 5.17:	2022-02-26 12:10:17 -08:00
include	dma-mapping fix for Linux 5.17	2022-02-27 12:42:37 -08:00
init	lib/stackdepot: allow optional init and stack_table allocation by kvmalloc()	2022-01-22 08:33:37 +02:00
ipc	ipc/sem: do not sleep with a spin lock held	2022-02-04 09:25:05 -08:00
kernel	dma-mapping fix for Linux 5.17	2022-02-27 12:42:37 -08:00
lib	kasan: test: prevent cache merging in kmem_cache_double_destroy	2022-02-26 09:51:17 -08:00
LICENSES	LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers	2021-12-16 14:33:10 +01:00
mm	memblock: use kfree() to release kmalloced memblock regions	2022-02-26 12:00:44 -08:00
net	ping: remove pr_err from ping_lookup	2022-02-24 09:18:29 -08:00
samples	samples/seccomp: Adjust sample to also provide kill option	2022-02-10 19:09:12 -08:00
scripts	kconfig: fix failing to generate auto.conf	2022-02-12 23:24:19 +09:00
security	selinux/stable-5.17 PR 20220223	2022-02-23 17:19:55 -08:00
sound	ASoC: intel: skylake: Set max DMA segment size	2022-02-17 09:39:44 +01:00
tools	Tracing fixes for 5.17:	2022-02-26 12:10:17 -08:00
usr	kbuild: remove include/linux/cyclades.h from header file check	2022-01-27 08:51:08 +01:00
virt	KVM: Fix lockdep false negative during host resume	2022-02-17 09:52:50 -05:00
.clang-format	genirq/msi: Make interrupt allocation less convoluted	2021-12-16 22:22:20 +01:00
.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	.gitignore: ignore only top-level modules.builtin	2021-05-02 00:43:35 +09:00
.mailmap	mailmap: update Roman Gushchin's email	2022-02-26 09:51:17 -08:00
COPYING	COPYING: state that all contributions really are covered by this file	2020-02-10 13:32:20 -08:00
CREDITS	MAINTAINERS: Removing Ohad from remoteproc/rpmsg maintenance	2021-12-08 10:09:40 -07:00
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	MAINTAINERS, SLAB: add Roman as reviewer, git tree	2022-02-26 09:51:17 -08:00
Makefile	Linux 5.17-rc6	2022-02-27 14:36:33 -08:00
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.