From 2852b559afdfe9f29ec36a73b4410440aa749caa Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Tue, 12 Nov 2019 11:47:34 +0100 Subject: [PATCH] PM / devfreq: Add missing locking while setting suspend_freq commit e1e047ace8cef6d143f38c7d769753f133becbe6 upstream. Commit 2abb0d5268ae ("PM / devfreq: Lock devfreq in trans_stat_show") revealed a missing locking while calling devfreq_update_status() function during suspend/resume cycle. Code analysis revealed that devfreq_set_target() function was called without needed locks held for setting device specific suspend_freq if such has been defined. This patch fixes that by adding the needed locking, what fixes following kernel warning on Exynos4412-based OdroidU3 board during system suspend: PM: suspend entry (deep) Filesystems sync: 0.002 seconds Freezing user space processes ... (elapsed 0.001 seconds) done. OOM killer disabled. Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done. ------------[ cut here ]------------ WARNING: CPU: 2 PID: 1385 at drivers/devfreq/devfreq.c:204 devfreq_update_status+0xc0/0x188 Modules linked in: CPU: 2 PID: 1385 Comm: rtcwake Not tainted 5.4.0-rc6-next-20191111 #6848 Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [] (unwind_backtrace) from [] (show_stack+0x10/0x14) [] (show_stack) from [] (dump_stack+0xb4/0xe0) [] (dump_stack) from [] (__warn+0xf4/0x10c) [] (__warn) from [] (warn_slowpath_fmt+0xb0/0xb8) [] (warn_slowpath_fmt) from [] (devfreq_update_status+0xc0/0x188) [] (devfreq_update_status) from [] (devfreq_set_target+0xb0/0x15c) [] (devfreq_set_target) from [] (devfreq_suspend+0x2c/0x64) [] (devfreq_suspend) from [] (dpm_suspend+0xa4/0x57c) [] (dpm_suspend) from [] (dpm_suspend_start+0x98/0xa0) [] (dpm_suspend_start) from [] (suspend_devices_and_enter+0xec/0xc74) [] (suspend_devices_and_enter) from [] (pm_suspend+0x340/0x410) [] (pm_suspend) from [] (state_store+0x6c/0xc8) [] (state_store) from [] (kernfs_fop_write+0x10c/0x228) [] (kernfs_fop_write) from [] (__vfs_write+0x30/0x1d0) [] (__vfs_write) from [] (vfs_write+0xa4/0x180) [] (vfs_write) from [] (ksys_write+0x60/0xd8) [] (ksys_write) from [] (ret_fast_syscall+0x0/0x28) Exception stack(0xed3d7fa8 to 0xed3d7ff0) ... irq event stamp: 9667 hardirqs last enabled at (9679): [] _raw_spin_unlock_irq+0x20/0x58 hardirqs last disabled at (9698): [] __schedule+0xd8/0x818 softirqs last enabled at (9694): [] __do_softirq+0x4fc/0x5fc softirqs last disabled at (9719): [] irq_exit+0x16c/0x170 ---[ end trace 41ac5b57d046bdbc ]--- ------------[ cut here ]------------ Signed-off-by: Marek Szyprowski Acked-by: Chanwoo Choi Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- drivers/devfreq/devfreq.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index ff81b7cdab71..dce45f7a497d 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -902,7 +902,9 @@ int devfreq_suspend_device(struct devfreq *devfreq) } if (devfreq->suspend_freq) { + mutex_lock(&devfreq->lock); ret = devfreq_set_target(devfreq, devfreq->suspend_freq, 0); + mutex_unlock(&devfreq->lock); if (ret) return ret; } @@ -930,7 +932,9 @@ int devfreq_resume_device(struct devfreq *devfreq) return 0; if (devfreq->resume_freq) { + mutex_lock(&devfreq->lock); ret = devfreq_set_target(devfreq, devfreq->resume_freq, 0); + mutex_unlock(&devfreq->lock); if (ret) return ret; }