linux.git/drivers/devfreq, branch v6.1.168

PM / devfreq: mtk-cci: Fix potential error pointer dereference in probe()

2025-10-15T09:56:27+00:00

[ Upstream commit fc33bf0e097c6834646b98a7b3da0ae5b617f0f9 ]

The drv->sram_reg pointer could be set to ERR_PTR(-EPROBE_DEFER) which
would lead to a error pointer dereference.  Use IS_ERR_OR_NULL() to check
that the pointer is valid.

Fixes: e09bd5757b52 ("PM / devfreq: mtk-cci: Handle sram regulator probe deferral")
Signed-off-by: Dan Carpenter 
Signed-off-by: Chanwoo Choi 
Link: https://patchwork.kernel.org/project/linux-pm/patch/aJTNHz8kk8s6Q2os@stanley.mountain/
Signed-off-by: Sasha Levin

PM / devfreq: governor: Replace sscanf() with kstrtoul() in set_freq_store()

2025-08-28T14:25:52+00:00

[ Upstream commit 914cc799b28f17d369d5b4db3b941957d18157e8 ]

Replace sscanf() with kstrtoul() in set_freq_store() and check the result
to avoid invalid input.

Signed-off-by: Lifeng Zheng 
Link: https://lore.kernel.org/lkml/20250421030020.3108405-2-zhenglifeng1@huawei.com/
Signed-off-by: Chanwoo Choi 
Signed-off-by: Sasha Levin

PM / devfreq: Check governor before using governor->name

2025-08-15T10:04:55+00:00

[ Upstream commit bab7834c03820eb11269bc48f07c3800192460d2 ]

Commit 96ffcdf239de ("PM / devfreq: Remove redundant governor_name from
struct devfreq") removes governor_name and uses governor->name to replace
it. But devfreq->governor may be NULL and directly using
devfreq->governor->name may cause null pointer exception. Move the check of
governor to before using governor->name.

Fixes: 96ffcdf239de ("PM / devfreq: Remove redundant governor_name from struct devfreq")
Signed-off-by: Lifeng Zheng 
Link: https://lore.kernel.org/lkml/20250421030020.3108405-5-zhenglifeng1@huawei.com/
Signed-off-by: Chanwoo Choi 
Signed-off-by: Sasha Levin

PM / devfreq: Synchronize devfreq_monitor_[start/stop]

2024-02-05T20:12:47+00:00

[ 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]
...
..
-0    [003]   9436.209662:  timer_cancel   timer=0xffffff80444f0428
-0    [003]   9436.209664:  timer_expire_entry   timer=0xffffff80444f0428  now=0x10022da1c  function=__typeid__ZTSFvP10timer_listE_global_addr  baseclk=0x10022da1c
-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 
Acked-by: MyungJoo Ham 
Signed-off-by: Mukesh Ojha 
Signed-off-by: Chanwoo Choi 
Signed-off-by: Sasha Levin

PM / devfreq: Fix buffer overflow in trans_stat_show

2024-02-01T00:16:58+00:00

commit 08e23d05fa6dc4fc13da0ccf09defdd4bbc92ff4 upstream.

Fix buffer overflow in trans_stat_show().

Convert simple snprintf to the more secure scnprintf with size of
PAGE_SIZE.

Add condition checking if we are exceeding PAGE_SIZE and exit early from
loop. Also add at the end a warning that we exceeded PAGE_SIZE and that
stats is disabled.

Return -EFBIG in the case where we don't have enough space to write the
full transition table.

Also document in the ABI that this function can return -EFBIG error.

Link: https://lore.kernel.org/all/20231024183016.14648-2-ansuelsmth@gmail.com/
Cc: stable@vger.kernel.org
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218041
Fixes: e552bbaf5b98 ("PM / devfreq: Add sysfs node for representing frequency transition information.")
Signed-off-by: Christian Marangi 
Signed-off-by: Chanwoo Choi 
Signed-off-by: Greg Kroah-Hartman

PM / devfreq: rockchip-dfi: Make pmu regmap mandatory

2023-11-20T10:51:54+00:00

[ Upstream commit 1e0731c05c985deb68a97fa44c1adcd3305dda90 ]

As a matter of fact the regmap_pmu already is mandatory because
it is used unconditionally in the driver. Bail out gracefully in
probe() rather than crashing later.

Link: https://lore.kernel.org/lkml/20230704093242.583575-2-s.hauer@pengutronix.de/
Fixes: b9d1262bca0af ("PM / devfreq: event: support rockchip dfi controller")
Reviewed-by: Sebastian Reichel 
Signed-off-by: Sascha Hauer 
Signed-off-by: Chanwoo Choi 
Signed-off-by: Sasha Levin

PM / devfreq: Fix leak in devfreq_dev_release()

2023-09-13T07:42:59+00:00

commit 5693d077595de721f9ddbf9d37f40e5409707dfe upstream.

srcu_init_notifier_head() allocates resources that need to be released
with a srcu_cleanup_notifier_head() call.

Reported by kmemleak.

Fixes: 0fe3a66410a3 ("PM / devfreq: Add new DEVFREQ_TRANSITION_NOTIFIER notifier")
Cc: 
Signed-off-by: Boris Brezillon 
Reviewed-by: Dhruva Gole 
Signed-off-by: Chanwoo Choi 
Signed-off-by: Greg Kroah-Hartman

PM/devfreq: governor: Add a private governor_data for governor

2023-01-07T10:11:40+00:00

commit 5fdded8448924e3631d466eea499b11606c43640 upstream.

The member void *data in the structure devfreq can be overwrite
by governor_userspace. For example:
1. The device driver assigned the devfreq governor to simple_ondemand
by the function devfreq_add_device() and init the devfreq member
void *data to a pointer of a static structure devfreq_simple_ondemand_data
by the function devfreq_add_device().
2. The user changed the devfreq governor to userspace by the command
"echo userspace > /sys/class/devfreq/.../governor".
3. The governor userspace alloced a dynamic memory for the struct
userspace_data and assigend the member void *data of devfreq to
this memory by the function userspace_init().
4. The user changed the devfreq governor back to simple_ondemand
by the command "echo simple_ondemand > /sys/class/devfreq/.../governor".
5. The governor userspace exited and assigned the member void *data
in the structure devfreq to NULL by the function userspace_exit().
6. The governor simple_ondemand fetched the static information of
devfreq_simple_ondemand_data in the function
devfreq_simple_ondemand_func() but the member void *data of devfreq was
assigned to NULL by the function userspace_exit().
7. The information of upthreshold and downdifferential is lost
and the governor simple_ondemand can't work correctly.

The member void *data in the structure devfreq is designed for
a static pointer used in a governor and inited by the function
devfreq_add_device(). This patch add an element named governor_data
in the devfreq structure which can be used by a governor(E.g userspace)
who want to assign a private data to do some private things.

Fixes: ce26c5bb9569 ("PM / devfreq: Add basic governors")
Cc: stable@vger.kernel.org # 5.10+
Reviewed-by: Chanwoo Choi 
Acked-by: MyungJoo Ham 
Signed-off-by: Kant Fan 
Signed-off-by: Chanwoo Choi 
Signed-off-by: Greg Kroah-Hartman

PM / devfreq: rockchip-dfi: Fix an error message

2022-09-25T18:59:43+00:00

There is a typo in the message. The clock name should be 'pclk_ddr_mon'.
Fix it.

While at it, switch to dev_err_probe() which is less verbose, filters
-EPROBE_DEFER, and log the error code in a human readable way.

Signed-off-by: Christophe JAILLET 
Signed-off-by: Chanwoo Choi

PM / devfreq: mtk-cci: Handle sram regulator probe deferral

2022-09-25T18:59:12+00:00

If the regulator_get_optional()	call for the SRAM regulator returns
a probe deferral, we must bail out and retry probing later: failing
to do this will	produce	unstabilities on platforms requiring the
handling for this regulator.

Fixes: b615b00c42da ("PM / devfreq: mediatek: Introduce MediaTek CCI devfreq driver")
Signed-off-by: AngeloGioacchino Del Regno 
Signed-off-by: Chanwoo Choi