linux/arch/x86/events
Kan Liang b0380e1350 perf/x86/intel/lbr: Fix unchecked MSR access error on HSW
The fuzzer triggers the below trace.

[ 7763.384369] unchecked MSR access error: WRMSR to 0x689
(tried to write 0x1fffffff8101349e) at rIP: 0xffffffff810704a4
(native_write_msr+0x4/0x20)
[ 7763.397420] Call Trace:
[ 7763.399881]  <TASK>
[ 7763.401994]  intel_pmu_lbr_restore+0x9a/0x1f0
[ 7763.406363]  intel_pmu_lbr_sched_task+0x91/0x1c0
[ 7763.410992]  __perf_event_task_sched_in+0x1cd/0x240

On a machine with the LBR format LBR_FORMAT_EIP_FLAGS2, when the TSX is
disabled, a TSX quirk is required to access LBR from registers.
The lbr_from_signext_quirk_needed() is introduced to determine whether
the TSX quirk should be applied. However, the
lbr_from_signext_quirk_needed() is invoked before the
intel_pmu_lbr_init(), which parses the LBR format information. Without
the correct LBR format information, the TSX quirk never be applied.

Move the lbr_from_signext_quirk_needed() into the intel_pmu_lbr_init().
Checking x86_pmu.lbr_has_tsx in the lbr_from_signext_quirk_needed() is
not required anymore.

Both LBR_FORMAT_EIP_FLAGS2 and LBR_FORMAT_INFO have LBR_TSX flag, but
only the LBR_FORMAT_EIP_FLAGS2 requirs the quirk. Update the comments
accordingly.

Fixes: 1ac7fd8159 ("perf/x86/intel/lbr: Support LBR format V7")
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20220714182630.342107-1-kan.liang@linux.intel.com
2022-07-20 19:24:55 +02:00
..
amd perf/x86/amd/core: Fix reloading events for SVM 2022-05-19 23:46:14 +02:00
intel perf/x86/intel/lbr: Fix unchecked MSR access error on HSW 2022-07-20 19:24:55 +02:00
zhaoxin x86: Fix various typos in comments 2021-03-18 15:31:53 +01:00
core.c perf/x86/amd: Fix AMD BRS period adjustment 2022-05-18 00:08:25 +02:00
Kconfig perf/x86/Kconfig: Fix indentation in the Kconfig file 2022-05-25 15:54:26 +02:00
Makefile perf/x86/rapl: Fix RAPL config variable bug 2020-06-02 11:52:56 +02:00
msr.c perf/x86/msr: Add new Alder Lake and Raptor Lake support 2022-05-11 16:27:08 +02:00
perf_event.h perf/x86/amd: Fix AMD BRS period adjustment 2022-05-18 00:08:25 +02:00
probe.c perf/x86/rapl: Add msr mask support 2021-02-10 14:44:54 +01:00
probe.h perf/x86/rapl: Add msr mask support 2021-02-10 14:44:54 +01:00
rapl.c perf/x86/rapl: fix AMD event handling 2022-01-18 12:09:48 +01:00