On Wednesday, November 13, 2019 3:17:17 AM CET Chanwoo Choi wrote: > Dear Rafael, > > Could you take this patch directly into linux-pm.git for v5.5-rc1? > > Because the devfreq pull-request for v5.5-rc1 contained issue. This patch > fix the issue of following patch[1]. > [1] https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git/commit/?h=linux-next&id=2abb0d5268ae7b5ddf82099b1f8d5aa8414637d4 I missed this previously, sorry. Now applied as a fix for 5.5, thanks! > --- > Hi Marek, > > Thanks for the fixup. > Acked-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx> > > Regards, > Chanwoo Choi > > > On 11/12/19 7:47 PM, Marek Szyprowski wrote: > > 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) > > [<c0112588>] (unwind_backtrace) from [<c010e070>] (show_stack+0x10/0x14) > > [<c010e070>] (show_stack) from [<c0afb010>] (dump_stack+0xb4/0xe0) > > [<c0afb010>] (dump_stack) from [<c01272e0>] (__warn+0xf4/0x10c) > > [<c01272e0>] (__warn) from [<c01273a8>] (warn_slowpath_fmt+0xb0/0xb8) > > [<c01273a8>] (warn_slowpath_fmt) from [<c07d105c>] (devfreq_update_status+0xc0/0x188) > > [<c07d105c>] (devfreq_update_status) from [<c07d2d70>] (devfreq_set_target+0xb0/0x15c) > > [<c07d2d70>] (devfreq_set_target) from [<c07d3598>] (devfreq_suspend+0x2c/0x64) > > [<c07d3598>] (devfreq_suspend) from [<c05de0b0>] (dpm_suspend+0xa4/0x57c) > > [<c05de0b0>] (dpm_suspend) from [<c05def74>] (dpm_suspend_start+0x98/0xa0) > > [<c05def74>] (dpm_suspend_start) from [<c0195b58>] (suspend_devices_and_enter+0xec/0xc74) > > [<c0195b58>] (suspend_devices_and_enter) from [<c0196a20>] (pm_suspend+0x340/0x410) > > [<c0196a20>] (pm_suspend) from [<c019480c>] (state_store+0x6c/0xc8) > > [<c019480c>] (state_store) from [<c033fc50>] (kernfs_fop_write+0x10c/0x228) > > [<c033fc50>] (kernfs_fop_write) from [<c02a6d3c>] (__vfs_write+0x30/0x1d0) > > [<c02a6d3c>] (__vfs_write) from [<c02a9afc>] (vfs_write+0xa4/0x180) > > [<c02a9afc>] (vfs_write) from [<c02a9d58>] (ksys_write+0x60/0xd8) > > [<c02a9d58>] (ksys_write) from [<c0101000>] (ret_fast_syscall+0x0/0x28) > > Exception stack(0xed3d7fa8 to 0xed3d7ff0) > > ... > > irq event stamp: 9667 > > hardirqs last enabled at (9679): [<c0b1e7c4>] _raw_spin_unlock_irq+0x20/0x58 > > hardirqs last disabled at (9698): [<c0b16a20>] __schedule+0xd8/0x818 > > softirqs last enabled at (9694): [<c01026fc>] __do_softirq+0x4fc/0x5fc > > softirqs last disabled at (9719): [<c012fe68>] irq_exit+0x16c/0x170 > > ---[ end trace 41ac5b57d046bdbc ]--- > > ------------[ cut here ]------------ > > > > Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> > > --- > > drivers/devfreq/devfreq.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c > > index 94fb8e821e12..65a4b6cf3fa5 100644 > > --- a/drivers/devfreq/devfreq.c > > +++ b/drivers/devfreq/devfreq.c > > @@ -957,7 +957,9 @@ 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; > > } > > @@ -985,7 +987,9 @@ 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; > > } > > > > >
