--- /dev/null
+From 734df5ab549ca44f40de0f07af1c8803856dfb18 Mon Sep 17 00:00:00 2001
+From: Jiri Olsa <jolsa@redhat.com>
+Date: Tue, 9 Jul 2013 17:44:10 +0200
+Subject: perf: Clone child context from parent context pmu
+
+From: Jiri Olsa <jolsa@redhat.com>
+
+commit 734df5ab549ca44f40de0f07af1c8803856dfb18 upstream.
+
+Currently when the child context for inherited events is
+created, it's based on the pmu object of the first event
+of the parent context.
+
+This is wrong for the following scenario:
+
+ - HW context having HW and SW event
+ - HW event got removed (closed)
+ - SW event stays in HW context as the only event
+ and its pmu is used to clone the child context
+
+The issue starts when the cpu context object is touched
+based on the pmu context object (__get_cpu_context). In
+this case the HW context will work with SW cpu context
+ending up with following WARN below.
+
+Fixing this by using parent context pmu object to clone
+from child context.
+
+Addresses the following warning reported by Vince Weaver:
+
+[ 2716.472065] ------------[ cut here ]------------
+[ 2716.476035] WARNING: at kernel/events/core.c:2122 task_ctx_sched_out+0x3c/0x)
+[ 2716.476035] Modules linked in: nfsd auth_rpcgss oid_registry nfs_acl nfs locn
+[ 2716.476035] CPU: 0 PID: 3164 Comm: perf_fuzzer Not tainted 3.10.0-rc4 #2
+[ 2716.476035] Hardware name: AOpen DE7000/nMCP7ALPx-DE R1.06 Oct.19.2012, BI2
+[ 2716.476035] 0000000000000000 ffffffff8102e215 0000000000000000 ffff88011fc18
+[ 2716.476035] ffff8801175557f0 0000000000000000 ffff880119fda88c ffffffff810ad
+[ 2716.476035] ffff880119fda880 ffffffff810af02a 0000000000000009 ffff880117550
+[ 2716.476035] Call Trace:
+[ 2716.476035] [<ffffffff8102e215>] ? warn_slowpath_common+0x5b/0x70
+[ 2716.476035] [<ffffffff810ab2bd>] ? task_ctx_sched_out+0x3c/0x5f
+[ 2716.476035] [<ffffffff810af02a>] ? perf_event_exit_task+0xbf/0x194
+[ 2716.476035] [<ffffffff81032a37>] ? do_exit+0x3e7/0x90c
+[ 2716.476035] [<ffffffff810cd5ab>] ? __do_fault+0x359/0x394
+[ 2716.476035] [<ffffffff81032fe6>] ? do_group_exit+0x66/0x98
+[ 2716.476035] [<ffffffff8103dbcd>] ? get_signal_to_deliver+0x479/0x4ad
+[ 2716.476035] [<ffffffff810ac05c>] ? __perf_event_task_sched_out+0x230/0x2d1
+[ 2716.476035] [<ffffffff8100205d>] ? do_signal+0x3c/0x432
+[ 2716.476035] [<ffffffff810abbf9>] ? ctx_sched_in+0x43/0x141
+[ 2716.476035] [<ffffffff810ac2ca>] ? perf_event_context_sched_in+0x7a/0x90
+[ 2716.476035] [<ffffffff810ac311>] ? __perf_event_task_sched_in+0x31/0x118
+[ 2716.476035] [<ffffffff81050dd9>] ? mmdrop+0xd/0x1c
+[ 2716.476035] [<ffffffff81051a39>] ? finish_task_switch+0x7d/0xa6
+[ 2716.476035] [<ffffffff81002473>] ? do_notify_resume+0x20/0x5d
+[ 2716.476035] [<ffffffff813654f5>] ? retint_signal+0x3d/0x78
+[ 2716.476035] ---[ end trace 827178d8a5966c3d ]---
+
+Reported-by: Vince Weaver <vincent.weaver@maine.edu>
+Signed-off-by: Jiri Olsa <jolsa@redhat.com>
+Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
+Cc: Frederic Weisbecker <fweisbec@gmail.com>
+Cc: Ingo Molnar <mingo@elte.hu>
+Cc: Namhyung Kim <namhyung@kernel.org>
+Cc: Paul Mackerras <paulus@samba.org>
+Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
+Signed-off-by: Peter Zijlstra <peterz@infradead.org>
+Link: http://lkml.kernel.org/r/1373384651-6109-1-git-send-email-jolsa@redhat.com
+Signed-off-by: Ingo Molnar <mingo@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ kernel/events/core.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/kernel/events/core.c
++++ b/kernel/events/core.c
+@@ -7064,7 +7064,7 @@ inherit_task_group(struct perf_event *ev
+ * child.
+ */
+
+- child_ctx = alloc_perf_context(event->pmu, child);
++ child_ctx = alloc_perf_context(parent_ctx->pmu, child);
+ if (!child_ctx)
+ return -ENOMEM;
+
--- /dev/null
+From 058ebd0eba3aff16b144eabf4510ed9510e1416e Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Fri, 12 Jul 2013 11:08:33 +0200
+Subject: perf: Fix perf_lock_task_context() vs RCU
+
+From: Peter Zijlstra <peterz@infradead.org>
+
+commit 058ebd0eba3aff16b144eabf4510ed9510e1416e upstream.
+
+Jiri managed to trigger this warning:
+
+ [] ======================================================
+ [] [ INFO: possible circular locking dependency detected ]
+ [] 3.10.0+ #228 Tainted: G W
+ [] -------------------------------------------------------
+ [] p/6613 is trying to acquire lock:
+ [] (rcu_node_0){..-...}, at: [<ffffffff810ca797>] rcu_read_unlock_special+0xa7/0x250
+ []
+ [] but task is already holding lock:
+ [] (&ctx->lock){-.-...}, at: [<ffffffff810f2879>] perf_lock_task_context+0xd9/0x2c0
+ []
+ [] which lock already depends on the new lock.
+ []
+ [] the existing dependency chain (in reverse order) is:
+ []
+ [] -> #4 (&ctx->lock){-.-...}:
+ [] -> #3 (&rq->lock){-.-.-.}:
+ [] -> #2 (&p->pi_lock){-.-.-.}:
+ [] -> #1 (&rnp->nocb_gp_wq[1]){......}:
+ [] -> #0 (rcu_node_0){..-...}:
+
+Paul was quick to explain that due to preemptible RCU we cannot call
+rcu_read_unlock() while holding scheduler (or nested) locks when part
+of the read side critical section was preemptible.
+
+Therefore solve it by making the entire RCU read side non-preemptible.
+
+Also pull out the retry from under the non-preempt to play nice with RT.
+
+Reported-by: Jiri Olsa <jolsa@redhat.com>
+Helped-out-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+Signed-off-by: Peter Zijlstra <peterz@infradead.org>
+Signed-off-by: Ingo Molnar <mingo@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ kernel/events/core.c | 15 ++++++++++++++-
+ 1 file changed, 14 insertions(+), 1 deletion(-)
+
+--- a/kernel/events/core.c
++++ b/kernel/events/core.c
+@@ -651,8 +651,18 @@ perf_lock_task_context(struct task_struc
+ {
+ struct perf_event_context *ctx;
+
+- rcu_read_lock();
+ retry:
++ /*
++ * One of the few rules of preemptible RCU is that one cannot do
++ * rcu_read_unlock() while holding a scheduler (or nested) lock when
++ * part of the read side critical section was preemptible -- see
++ * rcu_read_unlock_special().
++ *
++ * Since ctx->lock nests under rq->lock we must ensure the entire read
++ * side critical section is non-preemptible.
++ */
++ preempt_disable();
++ rcu_read_lock();
+ ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
+ if (ctx) {
+ /*
+@@ -668,6 +678,8 @@ retry:
+ raw_spin_lock_irqsave(&ctx->lock, *flags);
+ if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
+ raw_spin_unlock_irqrestore(&ctx->lock, *flags);
++ rcu_read_unlock();
++ preempt_enable();
+ goto retry;
+ }
+
+@@ -677,6 +689,7 @@ retry:
+ }
+ }
+ rcu_read_unlock();
++ preempt_enable();
+ return ctx;
+ }
+
--- /dev/null
+From 06f417968beac6e6b614e17b37d347aa6a6b1d30 Mon Sep 17 00:00:00 2001
+From: Jiri Olsa <jolsa@redhat.com>
+Date: Tue, 9 Jul 2013 17:44:11 +0200
+Subject: perf: Remove WARN_ON_ONCE() check in __perf_event_enable() for valid scenario
+
+From: Jiri Olsa <jolsa@redhat.com>
+
+commit 06f417968beac6e6b614e17b37d347aa6a6b1d30 upstream.
+
+The '!ctx->is_active' check has a valid scenario, so
+there's no need for the warning.
+
+The reason is that there's a time window between the
+'ctx->is_active' check in the perf_event_enable() function
+and the __perf_event_enable() function having:
+
+ - IRQs on
+ - ctx->lock unlocked
+
+where the task could be killed and 'ctx' deactivated by
+perf_event_exit_task(), ending up with the warning below.
+
+So remove the WARN_ON_ONCE() check and add comments to
+explain it all.
+
+This addresses the following warning reported by Vince Weaver:
+
+[ 324.983534] ------------[ cut here ]------------
+[ 324.984420] WARNING: at kernel/events/core.c:1953 __perf_event_enable+0x187/0x190()
+[ 324.984420] Modules linked in:
+[ 324.984420] CPU: 19 PID: 2715 Comm: nmi_bug_snb Not tainted 3.10.0+ #246
+[ 324.984420] Hardware name: Supermicro X8DTN/X8DTN, BIOS 4.6.3 01/08/2010
+[ 324.984420] 0000000000000009 ffff88043fce3ec8 ffffffff8160ea0b ffff88043fce3f00
+[ 324.984420] ffffffff81080ff0 ffff8802314fdc00 ffff880231a8f800 ffff88043fcf7860
+[ 324.984420] 0000000000000286 ffff880231a8f800 ffff88043fce3f10 ffffffff8108103a
+[ 324.984420] Call Trace:
+[ 324.984420] <IRQ> [<ffffffff8160ea0b>] dump_stack+0x19/0x1b
+[ 324.984420] [<ffffffff81080ff0>] warn_slowpath_common+0x70/0xa0
+[ 324.984420] [<ffffffff8108103a>] warn_slowpath_null+0x1a/0x20
+[ 324.984420] [<ffffffff81134437>] __perf_event_enable+0x187/0x190
+[ 324.984420] [<ffffffff81130030>] remote_function+0x40/0x50
+[ 324.984420] [<ffffffff810e51de>] generic_smp_call_function_single_interrupt+0xbe/0x130
+[ 324.984420] [<ffffffff81066a47>] smp_call_function_single_interrupt+0x27/0x40
+[ 324.984420] [<ffffffff8161fd2f>] call_function_single_interrupt+0x6f/0x80
+[ 324.984420] <EOI> [<ffffffff816161a1>] ? _raw_spin_unlock_irqrestore+0x41/0x70
+[ 324.984420] [<ffffffff8113799d>] perf_event_exit_task+0x14d/0x210
+[ 324.984420] [<ffffffff810acd04>] ? switch_task_namespaces+0x24/0x60
+[ 324.984420] [<ffffffff81086946>] do_exit+0x2b6/0xa40
+[ 324.984420] [<ffffffff8161615c>] ? _raw_spin_unlock_irq+0x2c/0x30
+[ 324.984420] [<ffffffff81087279>] do_group_exit+0x49/0xc0
+[ 324.984420] [<ffffffff81096854>] get_signal_to_deliver+0x254/0x620
+[ 324.984420] [<ffffffff81043057>] do_signal+0x57/0x5a0
+[ 324.984420] [<ffffffff8161a164>] ? __do_page_fault+0x2a4/0x4e0
+[ 324.984420] [<ffffffff8161665c>] ? retint_restore_args+0xe/0xe
+[ 324.984420] [<ffffffff816166cd>] ? retint_signal+0x11/0x84
+[ 324.984420] [<ffffffff81043605>] do_notify_resume+0x65/0x80
+[ 324.984420] [<ffffffff81616702>] retint_signal+0x46/0x84
+[ 324.984420] ---[ end trace 442ec2f04db3771a ]---
+
+Reported-by: Vince Weaver <vincent.weaver@maine.edu>
+Signed-off-by: Jiri Olsa <jolsa@redhat.com>
+Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
+Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
+Cc: Frederic Weisbecker <fweisbec@gmail.com>
+Cc: Ingo Molnar <mingo@elte.hu>
+Cc: Namhyung Kim <namhyung@kernel.org>
+Cc: Paul Mackerras <paulus@samba.org>
+Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
+Signed-off-by: Peter Zijlstra <peterz@infradead.org>
+Link: http://lkml.kernel.org/r/1373384651-6109-2-git-send-email-jolsa@redhat.com
+Signed-off-by: Ingo Molnar <mingo@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ kernel/events/core.c | 11 ++++++++++-
+ 1 file changed, 10 insertions(+), 1 deletion(-)
+
+--- a/kernel/events/core.c
++++ b/kernel/events/core.c
+@@ -1616,7 +1616,16 @@ static int __perf_event_enable(void *inf
+ struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
+ int err;
+
+- if (WARN_ON_ONCE(!ctx->is_active))
++ /*
++ * There's a time window between 'ctx->is_active' check
++ * in perf_event_enable function and this place having:
++ * - IRQs on
++ * - ctx->lock unlocked
++ *
++ * where the task could be killed and 'ctx' deactivated
++ * by perf_event_exit_task.
++ */
++ if (!ctx->is_active)
+ return -EINVAL;
+
+ raw_spin_lock(&ctx->lock);
scsi-zfcp-fix-adapter-re-open-recovery-while-link-to-san-is-down.patch
scsi-mpt2sas-fix-firmware-failure-with-wrong-task-attribute.patch
tracing-use-current_uid-for-critical-time-tracing.patch
+perf-clone-child-context-from-parent-context-pmu.patch
+perf-remove-warn_on_once-check-in-__perf_event_enable-for-valid-scenario.patch
+perf-fix-perf_lock_task_context-vs-rcu.patch
projects / thirdparty / kernel / stable-queue.git / commitdiff
