6.4-stable review patch. If anyone has any objections, please let me know.
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From: Swapnil Sapkal swapnil.sapkal@amd.com
[ Upstream commit 60dd283804479c4a52f995b713f448e2cd65b8c8 ]
After loading the amd-pstate-ut driver, amd_pstate_ut_check_perf() and amd_pstate_ut_check_freq() use cpufreq_cpu_get() to get the policy of the CPU and mark it as busy.
In these functions, cpufreq_cpu_put() should be used to release the policy, but it is not, so any other entity trying to access the policy is blocked indefinitely.
One such scenario is when amd_pstate mode is changed, leading to the following splat:
[ 1332.103727] INFO: task bash:2929 blocked for more than 120 seconds. [ 1332.110001] Not tainted 6.5.0-rc2-amd-pstate-ut #5 [ 1332.115315] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 1332.123140] task:bash state:D stack:0 pid:2929 ppid:2873 flags:0x00004006 [ 1332.123143] Call Trace: [ 1332.123145] <TASK> [ 1332.123148] __schedule+0x3c1/0x16a0 [ 1332.123154] ? _raw_read_lock_irqsave+0x2d/0x70 [ 1332.123157] schedule+0x6f/0x110 [ 1332.123160] schedule_timeout+0x14f/0x160 [ 1332.123162] ? preempt_count_add+0x86/0xd0 [ 1332.123165] __wait_for_common+0x92/0x190 [ 1332.123168] ? __pfx_schedule_timeout+0x10/0x10 [ 1332.123170] wait_for_completion+0x28/0x30 [ 1332.123173] cpufreq_policy_put_kobj+0x4d/0x90 [ 1332.123177] cpufreq_policy_free+0x157/0x1d0 [ 1332.123178] ? preempt_count_add+0x58/0xd0 [ 1332.123180] cpufreq_remove_dev+0xb6/0x100 [ 1332.123182] subsys_interface_unregister+0x114/0x120 [ 1332.123185] ? preempt_count_add+0x58/0xd0 [ 1332.123187] ? __pfx_amd_pstate_change_driver_mode+0x10/0x10 [ 1332.123190] cpufreq_unregister_driver+0x3b/0xd0 [ 1332.123192] amd_pstate_change_driver_mode+0x1e/0x50 [ 1332.123194] store_status+0xe9/0x180 [ 1332.123197] dev_attr_store+0x1b/0x30 [ 1332.123199] sysfs_kf_write+0x42/0x50 [ 1332.123202] kernfs_fop_write_iter+0x143/0x1d0 [ 1332.123204] vfs_write+0x2df/0x400 [ 1332.123208] ksys_write+0x6b/0xf0 [ 1332.123210] __x64_sys_write+0x1d/0x30 [ 1332.123213] do_syscall_64+0x60/0x90 [ 1332.123216] ? fpregs_assert_state_consistent+0x2e/0x50 [ 1332.123219] ? exit_to_user_mode_prepare+0x49/0x1a0 [ 1332.123223] ? irqentry_exit_to_user_mode+0xd/0x20 [ 1332.123225] ? irqentry_exit+0x3f/0x50 [ 1332.123226] ? exc_page_fault+0x8e/0x190 [ 1332.123228] entry_SYSCALL_64_after_hwframe+0x6e/0xd8 [ 1332.123232] RIP: 0033:0x7fa74c514a37 [ 1332.123234] RSP: 002b:00007ffe31dd0788 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 1332.123238] RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 00007fa74c514a37 [ 1332.123239] RDX: 0000000000000008 RSI: 000055e27c447aa0 RDI: 0000000000000001 [ 1332.123241] RBP: 000055e27c447aa0 R08: 00007fa74c5d1460 R09: 000000007fffffff [ 1332.123242] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000008 [ 1332.123244] R13: 00007fa74c61a780 R14: 00007fa74c616600 R15: 00007fa74c615a00 [ 1332.123247] </TASK>
Fix this by calling cpufreq_cpu_put() wherever necessary.
Fixes: 14eb1c96e3a3 ("cpufreq: amd-pstate: Add test module for amd-pstate driver") Reviewed-by: Mario Limonciello mario.limonciello@amd.com Reviewed-by: Meng Li li.meng@amd.com Reviewed-by: Wyes Karny wyes.karny@amd.com Suggested-by: Wyes Karny wyes.karny@amd.com Signed-off-by: Swapnil Sapkal swapnil.sapkal@amd.com [ rjw: Subject and changelog edits ] Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/cpufreq/amd-pstate-ut.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-)
diff --git a/drivers/cpufreq/amd-pstate-ut.c b/drivers/cpufreq/amd-pstate-ut.c index cf07ee77d3ccf..502d494499ae8 100644 --- a/drivers/cpufreq/amd-pstate-ut.c +++ b/drivers/cpufreq/amd-pstate-ut.c @@ -140,7 +140,7 @@ static void amd_pstate_ut_check_perf(u32 index) if (ret) { amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_FAIL; pr_err("%s cppc_get_perf_caps ret=%d error!\n", __func__, ret); - return; + goto skip_test; }
nominal_perf = cppc_perf.nominal_perf; @@ -151,7 +151,7 @@ static void amd_pstate_ut_check_perf(u32 index) if (ret) { amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_FAIL; pr_err("%s read CPPC_CAP1 ret=%d error!\n", __func__, ret); - return; + goto skip_test; }
nominal_perf = AMD_CPPC_NOMINAL_PERF(cap1); @@ -169,7 +169,7 @@ static void amd_pstate_ut_check_perf(u32 index) nominal_perf, cpudata->nominal_perf, lowest_nonlinear_perf, cpudata->lowest_nonlinear_perf, lowest_perf, cpudata->lowest_perf); - return; + goto skip_test; }
if (!((highest_perf >= nominal_perf) && @@ -180,11 +180,15 @@ static void amd_pstate_ut_check_perf(u32 index) pr_err("%s cpu%d highest=%d >= nominal=%d > lowest_nonlinear=%d > lowest=%d > 0, the formula is incorrect!\n", __func__, cpu, highest_perf, nominal_perf, lowest_nonlinear_perf, lowest_perf); - return; + goto skip_test; } + cpufreq_cpu_put(policy); }
amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_PASS; + return; +skip_test: + cpufreq_cpu_put(policy); }
/* @@ -212,14 +216,14 @@ static void amd_pstate_ut_check_freq(u32 index) pr_err("%s cpu%d max=%d >= nominal=%d > lowest_nonlinear=%d > min=%d > 0, the formula is incorrect!\n", __func__, cpu, cpudata->max_freq, cpudata->nominal_freq, cpudata->lowest_nonlinear_freq, cpudata->min_freq); - return; + goto skip_test; }
if (cpudata->min_freq != policy->min) { amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_FAIL; pr_err("%s cpu%d cpudata_min_freq=%d policy_min=%d, they should be equal!\n", __func__, cpu, cpudata->min_freq, policy->min); - return; + goto skip_test; }
if (cpudata->boost_supported) { @@ -231,16 +235,20 @@ static void amd_pstate_ut_check_freq(u32 index) pr_err("%s cpu%d policy_max=%d should be equal cpu_max=%d or cpu_nominal=%d !\n", __func__, cpu, policy->max, cpudata->max_freq, cpudata->nominal_freq); - return; + goto skip_test; } } else { amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_FAIL; pr_err("%s cpu%d must support boost!\n", __func__, cpu); - return; + goto skip_test; } + cpufreq_cpu_put(policy); }
amd_pstate_ut_cases[index].result = AMD_PSTATE_UT_RESULT_PASS; + return; +skip_test: + cpufreq_cpu_put(policy); }
static int __init amd_pstate_ut_init(void)