From 2167e2399dc5e69c62db56d933e9c8cbe107620a Mon Sep 17 00:00:00 2001 From: =?utf8?q?Bj=C3=B8rn=20Mork?= Date: Tue, 3 Dec 2013 12:14:32 +0100 Subject: [PATCH] cpufreq: fix garbage kobjects on errors during suspend/resume MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit This is effectively a revert of commit 5302c3fb2e62 ("cpufreq: Perform light-weight init/teardown during suspend/resume"), which enabled suspend/resume optimizations leaving the sysfs files in place. Errors during suspend/resume are not handled properly, leaving dead sysfs attributes in case of failures. There are are number of functions with special code for the "frozen" case, and all these need to also have special error handling. The problem is easy to demonstrate by making cpufreq_driver->init() or cpufreq_driver->get() fail during resume. The code is too complex for a simple fix, with split code paths in multiple blocks within a number of functions. It is therefore best to revert the patch enabling this code until the error handling is in place. Examples of problems resulting from resume errors: WARNING: CPU: 0 PID: 6055 at fs/sysfs/file.c:343 sysfs_open_file+0x77/0x212() missing sysfs attribute operations for kobject: (null) Modules linked in: [stripped as irrelevant] CPU: 0 PID: 6055 Comm: grep Tainted: G D 3.13.0-rc2 #153 Hardware name: LENOVO 2776LEG/2776LEG, BIOS 6EET55WW (3.15 ) 12/19/2011 0000000000000009 ffff8802327ebb78 ffffffff81380b0e 0000000000000006 ffff8802327ebbc8 ffff8802327ebbb8 ffffffff81038635 0000000000000000 ffffffff811823c7 ffff88021a19e688 ffff88021a19e688 ffff8802302f9310 Call Trace: [] dump_stack+0x55/0x76 [] warn_slowpath_common+0x7c/0x96 [] ? sysfs_open_file+0x77/0x212 [] warn_slowpath_fmt+0x41/0x43 [] ? sysfs_get_active+0x6b/0x82 [] ? sysfs_open_file+0x32/0x212 [] sysfs_open_file+0x77/0x212 [] ? sysfs_schedule_callback+0x1ac/0x1ac [] do_dentry_open+0x17c/0x257 [] finish_open+0x41/0x4f [] do_last+0x80c/0x9ba [] ? inode_permission+0x40/0x42 [] path_openat+0x233/0x4a1 [] do_filp_open+0x35/0x85 [] ? __alloc_fd+0x172/0x184 [] do_sys_open+0x6b/0xfa [] SyS_openat+0xf/0x11 [] system_call_fastpath+0x16/0x1b The failure to restore cpufreq devices on cancelled hibernation is not a new bug. It is caused by the ACPI _PPC call failing unless the hibernate is completed. This makes the acpi_cpufreq driver fail its init. Previously, the cpufreq device could be restored by offlining the cpu temporarily. And as a complete hibernation cycle would do this, it would be automatically restored most of the time. But after commit 5302c3fb2e62 the leftover sysfs attributes will block any device add action. Therefore offlining and onlining CPU 1 will no longer restore the cpufreq object, and a complete suspend/resume cycle will replace it with garbage. Fixes: 5302c3fb2e62 ("cpufreq: Perform light-weight init/teardown during suspend/resume") Cc: 3.12+ # 3.12+ Signed-off-by: Bjørn Mork Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/cpufreq.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 606224a8abc2..81e9d4412db8 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -2119,9 +2119,6 @@ static int cpufreq_cpu_callback(struct notifier_block *nfb, dev = get_cpu_device(cpu); if (dev) { - if (action & CPU_TASKS_FROZEN) - frozen = true; - switch (action & ~CPU_TASKS_FROZEN) { case CPU_ONLINE: __cpufreq_add_dev(dev, NULL, frozen); -- 2.20.1