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Date: Mon, 18 Feb 2019 14:43:21 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Vince Weaver <vincent.weaver@...ne.edu>,
Jiri Olsa <jolsa@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Arnaldo Carvalho de Melo <acme@...hat.com>,
Jiri Olsa <jolsa@...hat.com>,
Linus Torvalds <torvalds@...ux-foundation.org>,
"Naveen N. Rao" <naveen.n.rao@...ux.vnet.ibm.com>,
Ravi Bangoria <ravi.bangoria@...ux.ibm.com>,
Stephane Eranian <eranian@...gle.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...nel.org>
Subject: [PATCH 4.19 55/85] perf/x86: Add check_period PMU callback
4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jiri Olsa <jolsa@...hat.com>
commit 81ec3f3c4c4d78f2d3b6689c9816bfbdf7417dbb upstream.
Vince (and later on Ravi) reported crashes in the BTS code during
fuzzing with the following backtrace:
general protection fault: 0000 [#1] SMP PTI
...
RIP: 0010:perf_prepare_sample+0x8f/0x510
...
Call Trace:
<IRQ>
? intel_pmu_drain_bts_buffer+0x194/0x230
intel_pmu_drain_bts_buffer+0x160/0x230
? tick_nohz_irq_exit+0x31/0x40
? smp_call_function_single_interrupt+0x48/0xe0
? call_function_single_interrupt+0xf/0x20
? call_function_single_interrupt+0xa/0x20
? x86_schedule_events+0x1a0/0x2f0
? x86_pmu_commit_txn+0xb4/0x100
? find_busiest_group+0x47/0x5d0
? perf_event_set_state.part.42+0x12/0x50
? perf_mux_hrtimer_restart+0x40/0xb0
intel_pmu_disable_event+0xae/0x100
? intel_pmu_disable_event+0xae/0x100
x86_pmu_stop+0x7a/0xb0
x86_pmu_del+0x57/0x120
event_sched_out.isra.101+0x83/0x180
group_sched_out.part.103+0x57/0xe0
ctx_sched_out+0x188/0x240
ctx_resched+0xa8/0xd0
__perf_event_enable+0x193/0x1e0
event_function+0x8e/0xc0
remote_function+0x41/0x50
flush_smp_call_function_queue+0x68/0x100
generic_smp_call_function_single_interrupt+0x13/0x30
smp_call_function_single_interrupt+0x3e/0xe0
call_function_single_interrupt+0xf/0x20
</IRQ>
The reason is that while event init code does several checks
for BTS events and prevents several unwanted config bits for
BTS event (like precise_ip), the PERF_EVENT_IOC_PERIOD allows
to create BTS event without those checks being done.
Following sequence will cause the crash:
If we create an 'almost' BTS event with precise_ip and callchains,
and it into a BTS event it will crash the perf_prepare_sample()
function because precise_ip events are expected to come
in with callchain data initialized, but that's not the
case for intel_pmu_drain_bts_buffer() caller.
Adding a check_period callback to be called before the period
is changed via PERF_EVENT_IOC_PERIOD. It will deny the change
if the event would become BTS. Plus adding also the limit_period
check as well.
Reported-by: Vince Weaver <vincent.weaver@...ne.edu>
Signed-off-by: Jiri Olsa <jolsa@...nel.org>
Acked-by: Peter Zijlstra <peterz@...radead.org>
Cc: <stable@...r.kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Naveen N. Rao <naveen.n.rao@...ux.vnet.ibm.com>
Cc: Ravi Bangoria <ravi.bangoria@...ux.ibm.com>
Cc: Stephane Eranian <eranian@...gle.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Link: http://lkml.kernel.org/r/20190204123532.GA4794@krava
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
arch/x86/events/core.c | 14 ++++++++++++++
arch/x86/events/intel/core.c | 9 +++++++++
arch/x86/events/perf_event.h | 16 ++++++++++++++--
include/linux/perf_event.h | 5 +++++
kernel/events/core.c | 16 ++++++++++++++++
5 files changed, 58 insertions(+), 2 deletions(-)
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -2253,6 +2253,19 @@ void perf_check_microcode(void)
x86_pmu.check_microcode();
}
+static int x86_pmu_check_period(struct perf_event *event, u64 value)
+{
+ if (x86_pmu.check_period && x86_pmu.check_period(event, value))
+ return -EINVAL;
+
+ if (value && x86_pmu.limit_period) {
+ if (x86_pmu.limit_period(event, value) > value)
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static struct pmu pmu = {
.pmu_enable = x86_pmu_enable,
.pmu_disable = x86_pmu_disable,
@@ -2277,6 +2290,7 @@ static struct pmu pmu = {
.event_idx = x86_pmu_event_idx,
.sched_task = x86_pmu_sched_task,
.task_ctx_size = sizeof(struct x86_perf_task_context),
+ .check_period = x86_pmu_check_period,
};
void arch_perf_update_userpage(struct perf_event *event,
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -3465,6 +3465,11 @@ static void intel_pmu_sched_task(struct
intel_pmu_lbr_sched_task(ctx, sched_in);
}
+static int intel_pmu_check_period(struct perf_event *event, u64 value)
+{
+ return intel_pmu_has_bts_period(event, value) ? -EINVAL : 0;
+}
+
PMU_FORMAT_ATTR(offcore_rsp, "config1:0-63");
PMU_FORMAT_ATTR(ldlat, "config1:0-15");
@@ -3545,6 +3550,8 @@ static __initconst const struct x86_pmu
.cpu_starting = intel_pmu_cpu_starting,
.cpu_dying = intel_pmu_cpu_dying,
.cpu_dead = intel_pmu_cpu_dead,
+
+ .check_period = intel_pmu_check_period,
};
static struct attribute *intel_pmu_attrs[];
@@ -3589,6 +3596,8 @@ static __initconst const struct x86_pmu
.guest_get_msrs = intel_guest_get_msrs,
.sched_task = intel_pmu_sched_task,
+
+ .check_period = intel_pmu_check_period,
};
static __init void intel_clovertown_quirk(void)
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -644,6 +644,11 @@ struct x86_pmu {
* Intel host/guest support (KVM)
*/
struct perf_guest_switch_msr *(*guest_get_msrs)(int *nr);
+
+ /*
+ * Check period value for PERF_EVENT_IOC_PERIOD ioctl.
+ */
+ int (*check_period) (struct perf_event *event, u64 period);
};
struct x86_perf_task_context {
@@ -855,7 +860,7 @@ static inline int amd_pmu_init(void)
#ifdef CONFIG_CPU_SUP_INTEL
-static inline bool intel_pmu_has_bts(struct perf_event *event)
+static inline bool intel_pmu_has_bts_period(struct perf_event *event, u64 period)
{
struct hw_perf_event *hwc = &event->hw;
unsigned int hw_event, bts_event;
@@ -866,7 +871,14 @@ static inline bool intel_pmu_has_bts(str
hw_event = hwc->config & INTEL_ARCH_EVENT_MASK;
bts_event = x86_pmu.event_map(PERF_COUNT_HW_BRANCH_INSTRUCTIONS);
- return hw_event == bts_event && hwc->sample_period == 1;
+ return hw_event == bts_event && period == 1;
+}
+
+static inline bool intel_pmu_has_bts(struct perf_event *event)
+{
+ struct hw_perf_event *hwc = &event->hw;
+
+ return intel_pmu_has_bts_period(event, hwc->sample_period);
}
int intel_pmu_save_and_restart(struct perf_event *event);
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -447,6 +447,11 @@ struct pmu {
* Filter events for PMU-specific reasons.
*/
int (*filter_match) (struct perf_event *event); /* optional */
+
+ /*
+ * Check period value for PERF_EVENT_IOC_PERIOD ioctl.
+ */
+ int (*check_period) (struct perf_event *event, u64 value); /* optional */
};
enum perf_addr_filter_action_t {
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -4963,6 +4963,11 @@ static void __perf_event_period(struct p
}
}
+static int perf_event_check_period(struct perf_event *event, u64 value)
+{
+ return event->pmu->check_period(event, value);
+}
+
static int perf_event_period(struct perf_event *event, u64 __user *arg)
{
u64 value;
@@ -4979,6 +4984,9 @@ static int perf_event_period(struct perf
if (event->attr.freq && value > sysctl_perf_event_sample_rate)
return -EINVAL;
+ if (perf_event_check_period(event, value))
+ return -EINVAL;
+
event_function_call(event, __perf_event_period, &value);
return 0;
@@ -9362,6 +9370,11 @@ static int perf_pmu_nop_int(struct pmu *
return 0;
}
+static int perf_event_nop_int(struct perf_event *event, u64 value)
+{
+ return 0;
+}
+
static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
@@ -9662,6 +9675,9 @@ got_cpu_context:
pmu->pmu_disable = perf_pmu_nop_void;
}
+ if (!pmu->check_period)
+ pmu->check_period = perf_event_nop_int;
+
if (!pmu->event_idx)
pmu->event_idx = perf_event_idx_default;
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