提交 8396bae2 编写于 作者: K Kan Liang 提交者: Zheng Zengkai

perf/x86/intel: Fix unchecked MSR access error caused by VLBR_EVENT

stable inclusion
from stable-5.10.26
commit 4fdf5f4ba61f3f35912bb7de2a914ce6d4c1e223
bugzilla: 51363

--------------------------------

commit 2dc0572f upstream.

On a Haswell machine, the perf_fuzzer managed to trigger this message:

[117248.075892] unchecked MSR access error: WRMSR to 0x3f1 (tried to
write 0x0400000000000000) at rIP: 0xffffffff8106e4f4
(native_write_msr+0x4/0x20)
[117248.089957] Call Trace:
[117248.092685]  intel_pmu_pebs_enable_all+0x31/0x40
[117248.097737]  intel_pmu_enable_all+0xa/0x10
[117248.102210]  __perf_event_task_sched_in+0x2df/0x2f0
[117248.107511]  finish_task_switch.isra.0+0x15f/0x280
[117248.112765]  schedule_tail+0xc/0x40
[117248.116562]  ret_from_fork+0x8/0x30

A fake event called VLBR_EVENT may use the bit 58 of the PEBS_ENABLE, if
the precise_ip is set. The bit 58 is reserved by the HW. Accessing the
bit causes the unchecked MSR access error.

The fake event doesn't support PEBS. The case should be rejected.

Fixes: 097e4311 ("perf/x86: Add constraint to create guest LBR event without hw counter")
Reported-by: NVince Weaver <vincent.weaver@maine.edu>
Signed-off-by: NKan Liang <kan.liang@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1615555298-140216-2-git-send-email-kan.liang@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: N  Weilong Chen <chenweilong@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
上级 2f6bc0ad
...@@ -3562,6 +3562,9 @@ static int intel_pmu_hw_config(struct perf_event *event) ...@@ -3562,6 +3562,9 @@ static int intel_pmu_hw_config(struct perf_event *event)
return ret; return ret;
if (event->attr.precise_ip) { if (event->attr.precise_ip) {
if ((event->attr.config & INTEL_ARCH_EVENT_MASK) == INTEL_FIXED_VLBR_EVENT)
return -EINVAL;
if (!(event->attr.freq || (event->attr.wakeup_events && !event->attr.watermark))) { if (!(event->attr.freq || (event->attr.wakeup_events && !event->attr.watermark))) {
event->hw.flags |= PERF_X86_EVENT_AUTO_RELOAD; event->hw.flags |= PERF_X86_EVENT_AUTO_RELOAD;
if (!(event->attr.sample_type & if (!(event->attr.sample_type &
......
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