diff options
| author | Peter Zijlstra | 2021-07-29 11:14:57 +0200 |
|---|---|---|
| committer | Peter Zijlstra | 2021-08-04 15:16:33 +0200 |
| commit | f4b4b45652578357031fbbef7f7a1b04f6fa2dc3 (patch) | |
| tree | 962fc386974a3c2b13c1f0664ad24f3f9f7fc0aa /arch/x86 | |
| parent | b068fc04de10fff8974f6ef32b861ad134d94ba4 (diff) | |
perf/x86: Fix out of bound MSR access
On Wed, Jul 28, 2021 at 12:49:43PM -0400, Vince Weaver wrote:
> [32694.087403] unchecked MSR access error: WRMSR to 0x318 (tried to write 0x0000000000000000) at rIP: 0xffffffff8106f854 (native_write_msr+0x4/0x20)
> [32694.101374] Call Trace:
> [32694.103974] perf_clear_dirty_counters+0x86/0x100
The problem being that it doesn't filter out all fake counters, in
specific the above (erroneously) tries to use FIXED_BTS. Limit the
fixed counters indexes to the hardware supplied number.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Vince Weaver <vincent.weaver@maine.edu>
Tested-by: Like Xu <likexu@tencent.com>
Link: https://lkml.kernel.org/r/YQJxka3dxgdIdebG@hirez.programming.kicks-ass.net
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/events/core.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 1eb45139fcc6..3092fbf9dbe4 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -2489,13 +2489,15 @@ void perf_clear_dirty_counters(void) return; for_each_set_bit(i, cpuc->dirty, X86_PMC_IDX_MAX) { - /* Metrics and fake events don't have corresponding HW counters. */ - if (is_metric_idx(i) || (i == INTEL_PMC_IDX_FIXED_VLBR)) - continue; - else if (i >= INTEL_PMC_IDX_FIXED) + if (i >= INTEL_PMC_IDX_FIXED) { + /* Metrics and fake events don't have corresponding HW counters. */ + if ((i - INTEL_PMC_IDX_FIXED) >= hybrid(cpuc->pmu, num_counters_fixed)) + continue; + wrmsrl(MSR_ARCH_PERFMON_FIXED_CTR0 + (i - INTEL_PMC_IDX_FIXED), 0); - else + } else { wrmsrl(x86_pmu_event_addr(i), 0); + } } bitmap_zero(cpuc->dirty, X86_PMC_IDX_MAX); |