| Message ID | 20210914165623.18972-1-james.morse@arm.com |
|---|---|
| State | Accepted |
| Commit | cdef1196608892b9a46caa5f2b64095a7f0be60c |
| Headers | show |
| Series | cpufreq: schedutil: Destroy mutex before kobject_put() frees the memory | expand |
diff --git a/drivers/cpufreq/cpufreq_governor_attr_set.c b/drivers/cpufreq/cpufreq_governor_attr_set.c index 66b05a326910..a6f365b9cc1a 100644 --- a/drivers/cpufreq/cpufreq_governor_attr_set.c +++ b/drivers/cpufreq/cpufreq_governor_attr_set.c @@ -74,8 +74,8 @@ unsigned int gov_attr_set_put(struct gov_attr_set *attr_set, struct list_head *l if (count) return count; - kobject_put(&attr_set->kobj); mutex_destroy(&attr_set->update_lock); + kobject_put(&attr_set->kobj); return 0; } EXPORT_SYMBOL_GPL(gov_attr_set_put);
Since commit e5c6b312ce3c ("cpufreq: schedutil: Use kobject release() method to free sugov_tunables") kobject_put() has kfree()d the attr_set before gov_attr_set_put() returns. kobject_put() isn't the last user of attr_set in gov_attr_set_put(), the subsequent mutex_destroy() triggers a use-after-free: | BUG: KASAN: use-after-free in mutex_is_locked+0x20/0x60 | Read of size 8 at addr ffff000800ca4250 by task cpuhp/2/20 | | CPU: 2 PID: 20 Comm: cpuhp/2 Not tainted 5.15.0-rc1 #12369 | Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development | Platform, BIOS EDK II Jul 30 2018 | Call trace: | dump_backtrace+0x0/0x380 | show_stack+0x1c/0x30 | dump_stack_lvl+0x8c/0xb8 | print_address_description.constprop.0+0x74/0x2b8 | kasan_report+0x1f4/0x210 | kasan_check_range+0xfc/0x1a4 | __kasan_check_read+0x38/0x60 | mutex_is_locked+0x20/0x60 | mutex_destroy+0x80/0x100 | gov_attr_set_put+0xfc/0x150 | sugov_exit+0x78/0x190 | cpufreq_offline.isra.0+0x2c0/0x660 | cpuhp_cpufreq_offline+0x14/0x24 | cpuhp_invoke_callback+0x430/0x6d0 | cpuhp_thread_fun+0x1b0/0x624 | smpboot_thread_fn+0x5e0/0xa6c | kthread+0x3a0/0x450 | ret_from_fork+0x10/0x20 Swap the order of the calls. Fixes: e5c6b312ce3c ("cpufreq: schedutil: Use kobject release() method to free sugov_tunables") Cc: 4.7+ <stable@vger.kernel.org> # 4.7+ CC: Kevin Hao <haokexin@gmail.com> CC: Viresh Kumar <viresh.kumar@linaro.org> CC: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: James Morse <james.morse@arm.com> --- drivers/cpufreq/cpufreq_governor_attr_set.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)