On Fri, Jan 20, 2023 at 12:26:50PM +0800, Kevin Hao wrote:
> commit a85ee6401a47ae3fc64ba506cacb3e7873823c65 upstream.
>
> The struct dbs_data embeds a struct gov_attr_set and
> the struct gov_attr_set embeds a kobject. Since every kobject must have
> a release() method and we can't use kfree() to free it directly,
> so introduce cpufreq_dbs_data_release() to release the dbs_data via
> the kobject::release() method. This fixes the calltrace like below:
>
> ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x34
> WARNING: CPU: 12 PID: 810 at lib/debugobjects.c:505 debug_print_object+0xb8/0x100
> Modules linked in:
> CPU: 12 PID: 810 Comm: sh Not tainted 5.16.0-next-20220120-yocto-standard+ #536
> Hardware name: Marvell OcteonTX CN96XX board (DT)
> pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> pc : debug_print_object+0xb8/0x100
> lr : debug_print_object+0xb8/0x100
> sp : ffff80001dfcf9a0
> x29: ffff80001dfcf9a0 x28: 0000000000000001 x27: ffff0001464f0000
> x26: 0000000000000000 x25: ffff8000090e3f00 x24: ffff80000af60210
> x23: ffff8000094dfb78 x22: ffff8000090e3f00 x21: ffff0001080b7118
> x20: ffff80000aeb2430 x19: ffff800009e8f5e0 x18: 0000000000000000
> x17: 0000000000000002 x16: 00004d62e58be040 x15: 013590470523aff8
> x14: ffff8000090e1828 x13: 0000000001359047 x12: 00000000f5257d14
> x11: 0000000000040591 x10: 0000000066c1ffea x9 : ffff8000080d15e0
> x8 : ffff80000a1765a8 x7 : 0000000000000000 x6 : 0000000000000001
> x5 : ffff800009e8c000 x4 : ffff800009e8c760 x3 : 0000000000000000
> x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0001474ed040
> Call trace:
> debug_print_object+0xb8/0x100
> __debug_check_no_obj_freed+0x1d0/0x25c
> debug_check_no_obj_freed+0x24/0xa0
> kfree+0x11c/0x440
> cpufreq_dbs_governor_exit+0xa8/0xac
> cpufreq_exit_governor+0x44/0x90
> cpufreq_set_policy+0x29c/0x570
> store_scaling_governor+0x110/0x154
> store+0xb0/0xe0
> sysfs_kf_write+0x58/0x84
> kernfs_fop_write_iter+0x12c/0x1c0
> new_sync_write+0xf0/0x18c
> vfs_write+0x1cc/0x220
> ksys_write+0x74/0x100
> __arm64_sys_write+0x28/0x3c
> invoke_syscall.constprop.0+0x58/0xf0
> do_el0_svc+0x70/0x170
> el0_svc+0x54/0x190
> el0t_64_sync_handler+0xa4/0x130
> el0t_64_sync+0x1a0/0x1a4
> irq event stamp: 189006
> hardirqs last enabled at (189005): [<ffff8000080849d0>] finish_task_switch.isra.0+0xe0/0x2c0
> hardirqs last disabled at (189006): [<ffff8000090667a4>] el1_dbg+0x24/0xa0
> softirqs last enabled at (188966): [<ffff8000080106d0>] __do_softirq+0x4b0/0x6a0
> softirqs last disabled at (188957): [<ffff80000804a618>] __irq_exit_rcu+0x108/0x1a4
>
> [ rjw: Because can be freed by the gov_attr_set_put() in
> cpufreq_dbs_governor_exit() now, it is also necessary to put the
> invocation of the governor ->exit() callback into the new
> cpufreq_dbs_data_release() function. ]
>
> Fixes: c4435630361d ("cpufreq: governor: New sysfs show/store callbacks for governor tunables")
> Signed-off-by: Kevin Hao <haokexin@xxxxxxxxx>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> ---
> Hi,
>
> The original upstream patch has the Fixes tag, but I have no idea why it
> wasn't picked up by the 5.15 stable kernel. So resend it to the linux stable.
> The original upstream patch can apply to the 5.15.y kernel cleanly.
applies but has build error:
/home/tsaeger/workspace/linux/linux-5.15.y/drivers/cpufreq/cpufreq_governor.c: In function ‘cpufreq_dbs_data_release’:
/home/tsaeger/workspace/linux/linux-5.15.y/drivers/cpufreq/cpufreq_governor.c:393:49: error: implicit declaration of function ‘to_gov_attr_set’ [-Werror=implicit-function-declaration]
393 | struct dbs_data *dbs_data = to_dbs_data(to_gov_attr_set(kobj));
| ^~~~~~~~~~~~~~~
/home/tsaeger/workspace/linux/linux-5.15.y/drivers/cpufreq/cpufreq_governor.c:393:49: warning: passing argument 1 of ‘to_dbs_data’ makes pointer from integer without a cast [-Wint-conversion]
393 | struct dbs_data *dbs_data = to_dbs_data(to_gov_attr_set(kobj));
| ^~~~~~~~~~~~~~~~~~~~~
| |
| int
In file included from /home/tsaeger/workspace/linux/linux-5.15.y/drivers/cpufreq/cpufreq_governor.c:20:
/home/tsaeger/workspace/linux/linux-5.15.y/drivers/cpufreq/cpufreq_governor.h:49:65: note: expected ‘struct gov_attr_set *’ but argument is of type ‘int’
49 | static inline struct dbs_data *to_dbs_data(struct gov_attr_set *attr_set)
| ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~
cc1: some warnings being treated as errors
5.15.y first with:
ae2650865127 ("cpufreq: Move to_gov_attr_set() to cpufreq.h")
then
a85ee6401a47 ("cpufreq: governor: Use kobject release() method to free dbs_data")
compiled clean
Regards,
--Tom
