perf/x86/intel/lbr: Fix unchecked MSR access error on HSW - linux-dev - Linux kernel development work

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author	Kan Liang <kan.liang@linux.intel.com>	2022-07-14 11:26:30 -0700
committer	Peter Zijlstra <peterz@infradead.org>	2022-07-20 19:24:55 +0200
commit	b0380e13502adf7dd8be4c47d622c3522aae6c63 (patch)
tree	2fd5198579d400115220d5763424e8520fe00eb6 /drivers/fc4/ssh:/git:/git.zx2c4.com
parent	Linux 5.19-rc7 (diff)

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: 1ac7fd8159a8 ("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

Diffstat (limited to 'drivers/fc4/ssh:/git:/git.zx2c4.com')

0 files changed, 0 insertions, 0 deletions

/* Copyright (C) 2004-2021 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, see <https://www.gnu.org/licenses/>. */ #include <errno.h> #include <mqueue.h> #include <sysdep.h> /* Remove message queue named NAME. */ int mq_unlink (const char *name) { if (name[0] != '/') return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL); int ret = INTERNAL_SYSCALL_CALL (mq_unlink, name + 1); /* While unlink can return either EPERM or EACCES, mq_unlink should return just EACCES. */ if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (ret))) { ret = INTERNAL_SYSCALL_ERRNO (ret); if (ret == EPERM) ret = EACCES; return INLINE_SYSCALL_ERROR_RETURN_VALUE (ret); } return ret; }


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