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Mukesh Ojha 099f6a9edb PM / devfreq: Synchronize devfreq_monitor_[start/stop]
[ Upstream commit aed5ed595960c6d301dcd4ed31aeaa7a8054c0c6 ]

There is a chance if a frequent switch of the governor
done in a loop result in timer list corruption where
timer cancel being done from two place one from
cancel_delayed_work_sync() and followed by expire_timers()
can be seen from the traces[1].

while true
do
        echo "simple_ondemand" > /sys/class/devfreq/1d84000.ufshc/governor
        echo "performance" > /sys/class/devfreq/1d84000.ufshc/governor
done

It looks to be issue with devfreq driver where
device_monitor_[start/stop] need to synchronized so that
delayed work should get corrupted while it is either
being queued or running or being cancelled.

Let's use polling flag and devfreq lock to synchronize the
queueing the timer instance twice and work data being
corrupted.

[1]
...
..
<idle>-0    [003]   9436.209662:  timer_cancel   timer=0xffffff80444f0428
<idle>-0    [003]   9436.209664:  timer_expire_entry   timer=0xffffff80444f0428  now=0x10022da1c  function=__typeid__ZTSFvP10timer_listE_global_addr  baseclk=0x10022da1c
<idle>-0    [003]   9436.209718:  timer_expire_exit   timer=0xffffff80444f0428
kworker/u16:6-14217    [003]   9436.209863:  timer_start   timer=0xffffff80444f0428  function=__typeid__ZTSFvP10timer_listE_global_addr  expires=0x10022da2b  now=0x10022da1c  flags=182452227
vendor.xxxyyy.ha-1593    [004]   9436.209888:  timer_cancel   timer=0xffffff80444f0428
vendor.xxxyyy.ha-1593    [004]   9436.216390:  timer_init   timer=0xffffff80444f0428
vendor.xxxyyy.ha-1593    [004]   9436.216392:  timer_start   timer=0xffffff80444f0428  function=__typeid__ZTSFvP10timer_listE_global_addr  expires=0x10022da2c  now=0x10022da1d  flags=186646532
vendor.xxxyyy.ha-1593    [005]   9436.220992:  timer_cancel   timer=0xffffff80444f0428
xxxyyyTraceManag-7795    [004]   9436.261641:  timer_cancel   timer=0xffffff80444f0428

[2]

 9436.261653][    C4] Unable to handle kernel paging request at virtual address dead00000000012a
[ 9436.261664][    C4] Mem abort info:
[ 9436.261666][    C4]   ESR = 0x96000044
[ 9436.261669][    C4]   EC = 0x25: DABT (current EL), IL = 32 bits
[ 9436.261671][    C4]   SET = 0, FnV = 0
[ 9436.261673][    C4]   EA = 0, S1PTW = 0
[ 9436.261675][    C4] Data abort info:
[ 9436.261677][    C4]   ISV = 0, ISS = 0x00000044
[ 9436.261680][    C4]   CM = 0, WnR = 1
[ 9436.261682][    C4] [dead00000000012a] address between user and kernel address ranges
[ 9436.261685][    C4] Internal error: Oops: 96000044 [#1] PREEMPT SMP
[ 9436.261701][    C4] Skip md ftrace buffer dump for: 0x3a982d0
...

[ 9436.262138][    C4] CPU: 4 PID: 7795 Comm: TraceManag Tainted: G S      W  O      5.10.149-android12-9-o-g17f915d29d0c #1
[ 9436.262141][    C4] Hardware name: Qualcomm Technologies, Inc.  (DT)
[ 9436.262144][    C4] pstate: 22400085 (nzCv daIf +PAN -UAO +TCO BTYPE=--)
[ 9436.262161][    C4] pc : expire_timers+0x9c/0x438
[ 9436.262164][    C4] lr : expire_timers+0x2a4/0x438
[ 9436.262168][    C4] sp : ffffffc010023dd0
[ 9436.262171][    C4] x29: ffffffc010023df0 x28: ffffffd0636fdc18
[ 9436.262178][    C4] x27: ffffffd063569dd0 x26: ffffffd063536008
[ 9436.262182][    C4] x25: 0000000000000001 x24: ffffff88f7c69280
[ 9436.262185][    C4] x23: 00000000000000e0 x22: dead000000000122
[ 9436.262188][    C4] x21: 000000010022da29 x20: ffffff8af72b4e80
[ 9436.262191][    C4] x19: ffffffc010023e50 x18: ffffffc010025038
[ 9436.262195][    C4] x17: 0000000000000240 x16: 0000000000000201
[ 9436.262199][    C4] x15: ffffffffffffffff x14: ffffff889f3c3100
[ 9436.262203][    C4] x13: ffffff889f3c3100 x12: 00000000049f56b8
[ 9436.262207][    C4] x11: 00000000049f56b8 x10: 00000000ffffffff
[ 9436.262212][    C4] x9 : ffffffc010023e50 x8 : dead000000000122
[ 9436.262216][    C4] x7 : ffffffffffffffff x6 : ffffffc0100239d8
[ 9436.262220][    C4] x5 : 0000000000000000 x4 : 0000000000000101
[ 9436.262223][    C4] x3 : 0000000000000080 x2 : ffffff889edc155c
[ 9436.262227][    C4] x1 : ffffff8001005200 x0 : ffffff80444f0428
[ 9436.262232][    C4] Call trace:
[ 9436.262236][    C4]  expire_timers+0x9c/0x438
[ 9436.262240][    C4]  __run_timers+0x1f0/0x330
[ 9436.262245][    C4]  run_timer_softirq+0x28/0x58
[ 9436.262255][    C4]  efi_header_end+0x168/0x5ec
[ 9436.262265][    C4]  __irq_exit_rcu+0x108/0x124
[ 9436.262274][    C4]  __handle_domain_irq+0x118/0x1e4
[ 9436.262282][    C4]  gic_handle_irq.30369+0x6c/0x2bc
[ 9436.262286][    C4]  el0_irq_naked+0x60/0x6c

Link: https://lore.kernel.org/all/1700860318-4025-1-git-send-email-quic_mojha@quicinc.com/
Reported-by: Joyyoung Huang <huangzaiyang@oppo.com>
Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Mukesh Ojha <quic_mojha@quicinc.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-02-23 08:54:38 +01:00
Documentation PM / devfreq: Fix buffer overflow in trans_stat_show 2024-02-23 08:54:34 +01:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
arch x86/mce: Mark fatal MCE's page as poison to avoid panic in the kdump kernel 2024-02-23 08:54:37 +01:00
block block: Move checking GENHD_FL_NO_PART to bdev_add_partition() 2024-02-23 08:54:35 +01:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:22:01 +02:00
crypto crypto: api - Disallow identical driver names 2024-02-23 08:54:23 +01:00
drivers PM / devfreq: Synchronize devfreq_monitor_[start/stop] 2024-02-23 08:54:38 +01:00
fs ksmbd: fix global oob in ksmbd_nl_policy 2024-02-23 08:54:35 +01:00
include arm64: irq: set the correct node for VMAP stack 2024-02-23 08:54:36 +01:00
init rootfs: Fix support for rootfstype= when root= is given 2024-01-25 14:52:48 -08:00
io_uring io_uring/rw: ensure io->bytes_done is always initialized 2024-01-25 14:52:48 -08:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:28:45 +01:00
kernel audit: Send netlink ACK before setting connection in auditd_set 2024-02-23 08:54:37 +01:00
lib debugobjects: Stop accessing objects after releasing hash bucket lock 2024-02-23 08:54:37 +01:00
mm mm/sparsemem: fix race in accessing memory_section->usage 2024-02-23 08:54:34 +01:00
net netfilter: nf_tables: reject QUEUE/DROP verdict parameters 2024-02-23 08:54:32 +01:00
samples samples/hw_breakpoint: fix building without module unloading 2023-09-23 11:10:01 +02:00
scripts scripts/get_abi: fix source path leak 2024-02-23 08:54:25 +01:00
security lsm: new security_file_ioctl_compat() hook 2024-02-23 08:54:25 +01:00
sound ALSA: hda/relatek: Enable Mute LED on HP Laptop 15s-fq2xxx 2024-01-25 14:52:48 -08:00
tools selftests: netdevsim: fix the udp_tunnel_nic test 2024-02-23 08:54:30 +01:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:27:15 +01:00
virt KVM: Grab a reference to KVM for VM and vCPU stats file descriptors 2023-08-03 10:22:40 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.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: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
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 iio: stx104: Move to addac subdirectory 2023-08-26 14:23:27 +02:00
Makefile Linux 5.15.148 2024-01-25 14:52:56 -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.