5.4-stable patches

added patches:
	powerpc-imc-pmu-revert-nest_init_lock-to-being-a-mutex.patch

diff --git a/queue-5.4/powerpc-imc-pmu-revert-nest_init_lock-to-being-a-mutex.patch b/queue-5.4/powerpc-imc-pmu-revert-nest_init_lock-to-being-a-mutex.patch
new file mode 100644 (file)
index 0000000..4176f0d
--- /dev/null
+++ b/queue-5.4/powerpc-imc-pmu-revert-nest_init_lock-to-being-a-mutex.patch
@@ -0,0 +1,121 @@
+From ad53db4acb415976761d7302f5b02e97f2bd097e Mon Sep 17 00:00:00 2001
+From: Michael Ellerman <mpe@ellerman.id.au>
+Date: Mon, 30 Jan 2023 12:44:01 +1100
+Subject: powerpc/imc-pmu: Revert nest_init_lock to being a mutex
+
+From: Michael Ellerman <mpe@ellerman.id.au>
+
+commit ad53db4acb415976761d7302f5b02e97f2bd097e upstream.
+
+The recent commit 76d588dddc45 ("powerpc/imc-pmu: Fix use of mutex in
+IRQs disabled section") fixed warnings (and possible deadlocks) in the
+IMC PMU driver by converting the locking to use spinlocks.
+
+It also converted the init-time nest_init_lock to a spinlock, even
+though it's not used at runtime in IRQ disabled sections or while
+holding other spinlocks.
+
+This leads to warnings such as:
+
+  BUG: sleeping function called from invalid context at include/linux/percpu-rwsem.h:49
+  in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper/0
+  preempt_count: 1, expected: 0
+  CPU: 7 PID: 1 Comm: swapper/0 Not tainted 6.2.0-rc2-14719-gf12cd06109f4-dirty #1
+  Hardware name: Mambo,Simulated-System POWER9 0x4e1203 opal:v6.6.6 PowerNV
+  Call Trace:
+    dump_stack_lvl+0x74/0xa8 (unreliable)
+    __might_resched+0x178/0x1a0
+    __cpuhp_setup_state+0x64/0x1e0
+    init_imc_pmu+0xe48/0x1250
+    opal_imc_counters_probe+0x30c/0x6a0
+    platform_probe+0x78/0x110
+    really_probe+0x104/0x420
+    __driver_probe_device+0xb0/0x170
+    driver_probe_device+0x58/0x180
+    __driver_attach+0xd8/0x250
+    bus_for_each_dev+0xb4/0x140
+    driver_attach+0x34/0x50
+    bus_add_driver+0x1e8/0x2d0
+    driver_register+0xb4/0x1c0
+    __platform_driver_register+0x38/0x50
+    opal_imc_driver_init+0x2c/0x40
+    do_one_initcall+0x80/0x360
+    kernel_init_freeable+0x310/0x3b8
+    kernel_init+0x30/0x1a0
+    ret_from_kernel_thread+0x5c/0x64
+
+Fix it by converting nest_init_lock back to a mutex, so that we can call
+sleeping functions while holding it. There is no interaction between
+nest_init_lock and the runtime spinlocks used by the actual PMU routines.
+
+Fixes: 76d588dddc45 ("powerpc/imc-pmu: Fix use of mutex in IRQs disabled section")
+Tested-by: Kajol Jain<kjain@linux.ibm.com>
+Reviewed-by: Kajol Jain<kjain@linux.ibm.com>
+Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
+Link: https://lore.kernel.org/r/20230130014401.540543-1-mpe@ellerman.id.au
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/powerpc/perf/imc-pmu.c |   14 +++++++-------
+ 1 file changed, 7 insertions(+), 7 deletions(-)
+
+--- a/arch/powerpc/perf/imc-pmu.c
++++ b/arch/powerpc/perf/imc-pmu.c
+@@ -21,7 +21,7 @@
+  * Used to avoid races in counting the nest-pmu units during hotplug
+  * register and unregister
+  */
+-static DEFINE_SPINLOCK(nest_init_lock);
++static DEFINE_MUTEX(nest_init_lock);
+ static DEFINE_PER_CPU(struct imc_pmu_ref *, local_nest_imc_refc);
+ static struct imc_pmu **per_nest_pmu_arr;
+ static cpumask_t nest_imc_cpumask;
+@@ -1605,7 +1605,7 @@ static void imc_common_mem_free(struct i
+ static void imc_common_cpuhp_mem_free(struct imc_pmu *pmu_ptr)
+ {
+       if (pmu_ptr->domain == IMC_DOMAIN_NEST) {
+-              spin_lock(&nest_init_lock);
++              mutex_lock(&nest_init_lock);
+               if (nest_pmus == 1) {
+                       cpuhp_remove_state(CPUHP_AP_PERF_POWERPC_NEST_IMC_ONLINE);
+                       kfree(nest_imc_refc);
+@@ -1615,7 +1615,7 @@ static void imc_common_cpuhp_mem_free(st
+ 
+               if (nest_pmus > 0)
+                       nest_pmus--;
+-              spin_unlock(&nest_init_lock);
++              mutex_unlock(&nest_init_lock);
+       }
+ 
+       /* Free core_imc memory */
+@@ -1772,11 +1772,11 @@ int init_imc_pmu(struct device_node *par
+               * rest. To handle the cpuhotplug callback unregister, we track
+               * the number of nest pmus in "nest_pmus".
+               */
+-              spin_lock(&nest_init_lock);
++              mutex_lock(&nest_init_lock);
+               if (nest_pmus == 0) {
+                       ret = init_nest_pmu_ref();
+                       if (ret) {
+-                              spin_unlock(&nest_init_lock);
++                              mutex_unlock(&nest_init_lock);
+                               kfree(per_nest_pmu_arr);
+                               per_nest_pmu_arr = NULL;
+                               goto err_free_mem;
+@@ -1784,7 +1784,7 @@ int init_imc_pmu(struct device_node *par
+                       /* Register for cpu hotplug notification. */
+                       ret = nest_pmu_cpumask_init();
+                       if (ret) {
+-                              spin_unlock(&nest_init_lock);
++                              mutex_unlock(&nest_init_lock);
+                               kfree(nest_imc_refc);
+                               kfree(per_nest_pmu_arr);
+                               per_nest_pmu_arr = NULL;
+@@ -1792,7 +1792,7 @@ int init_imc_pmu(struct device_node *par
+                       }
+               }
+               nest_pmus++;
+-              spin_unlock(&nest_init_lock);
++              mutex_unlock(&nest_init_lock);
+               break;
+       case IMC_DOMAIN_CORE:
+               ret = core_imc_pmu_cpumask_init();

diff --git a/queue-5.4/series b/queue-5.4/series
index dbd5f0624e74f12d88fc703aadbcf4033c312811..72edcae7e12fab038a9017f0a96b072ed85dd3e1 100644 (file)
--- a/queue-5.4/series
+++ b/queue-5.4/series
@@ -53,3 +53,4 @@ xprtrdma-fix-regbuf-data-not-freed-in-rpcrdma_req_create.patch
 udf-avoid-using-stale-lengthofimpuse.patch
 serial-8250_dma-fix-dma-rx-completion-race.patch
 serial-8250_dma-fix-dma-rx-rearm-race.patch
+powerpc-imc-pmu-revert-nest_init_lock-to-being-a-mutex.patch