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Mon, 30 Sep 2024 19:58:45 +0000 (GMT) Received: from pps.filterd (phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com [127.0.0.1]) by phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com (8.18.1.2/8.18.1.2) with ESMTP id 48UJkuIo028453; Mon, 30 Sep 2024 19:58:44 GMT Received: from pps.reinject (localhost [127.0.0.1]) by phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com (PPS) with ESMTPS id 41x886sa9e-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 30 Sep 2024 19:58:44 +0000 Received: from phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com (phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 48UJu2cs033321; Mon, 30 Sep 2024 19:58:44 GMT Received: from gkennedy-linux.us.oracle.com (gkennedy-linux.us.oracle.com [10.152.170.45]) by phxpaimrmta02.imrmtpd1.prodappphxaev1.oraclevcn.com (PPS) with ESMTP id 41x886sa6q-1; Mon, 30 Sep 2024 19:58:43 +0000 From: George Kennedy To: ravi.bangoria@amd.com Cc: george.kennedy@oracle.com, harshit.m.mogalapalli@oracle.com, peterz@infradead.org, mingo@redhat.com, acme@kernel.org, namhyung@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, irogers@google.com, adrian.hunter@intel.com, kan.liang@linux.intel.com, tglx@linutronix.de, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, dongli.zhang@oracle.com Subject: [PATCH] [PATCH v2] perf/x86/amd: check event before enable to avoid GPF Date: Mon, 30 Sep 2024 14:52:27 -0500 Message-Id: <1727725947-18058-1-git-send-email-george.kennedy@oracle.com> X-Mailer: git-send-email 1.8.3.1 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1051,Hydra:6.0.680,FMLib:17.12.62.30 definitions=2024-09-30_19,2024-09-30_01,2024-09-30_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 mlxscore=0 malwarescore=0 mlxlogscore=901 phishscore=0 suspectscore=0 spamscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2408220000 definitions=main-2409300144 X-Proofpoint-GUID: focYdnfSSzFjVpzzfX-Rnspnb2JJ5py3 X-Proofpoint-ORIG-GUID: focYdnfSSzFjVpzzfX-Rnspnb2JJ5py3 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" On AMD machines cpuc->events[idx] can become NULL in a subtle race condition with NMI->throttle->x86_pmu_stop(). Check event for NULL in amd_pmu_enable_all() before enable to avoid a GPF. This appears to be an AMD only issue. Syzkaller reported a GPF in amd_pmu_enable_all. INFO: NMI handler (perf_event_nmi_handler) took too long to run: 13.143 msecs Oops: general protection fault, probably for non-canonical address 0xdffffc0000000034: 0000 PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x00000000000001a0-0x00000000000001a7] CPU: 0 UID: 0 PID: 328415 Comm: repro_36674776 Not tainted 6.12.0-rc1-syzk RIP: 0010:x86_pmu_enable_event (arch/x86/events/perf_event.h:1195 arch/x86/events/core.c:1430) RSP: 0018:ffff888118009d60 EFLAGS: 00010012 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000034 RSI: 0000000000000000 RDI: 00000000000001a0 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000002 R13: ffff88811802a440 R14: ffff88811802a240 R15: ffff8881132d8601 FS: 00007f097dfaa700(0000) GS:ffff888118000000(0000) GS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000200001c0 CR3: 0000000103d56000 CR4: 00000000000006f0 Call Trace: amd_pmu_enable_all (arch/x86/events/amd/core.c:760 (discriminator 2)) x86_pmu_enable (arch/x86/events/core.c:1360) event_sched_out (kernel/events/core.c:1191 kernel/events/core.c:1186 kernel/events/core.c:2346) __perf_remove_from_context (kernel/events/core.c:2435) event_function (kernel/events/core.c:259) remote_function (kernel/events/core.c:92 (discriminator 1) kernel/events/core.c:72 (discriminator 1)) __flush_smp_call_function_queue (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./include/trace/events/csd.h:64 kernel/smp.c:135 kernel/smp.c:540) __sysvec_call_function_single (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./arch/x86/include/asm/trace/irq_vectors.h:99 arch/x86/kernel/smp.c:272) sysvec_call_function_single (arch/x86/kernel/smp.c:266 (discriminator 47) arch/x86/kernel/smp.c:266 (discriminator 47)) Reported-by: syzkaller Signed-off-by: George Kennedy Acked-by: Ravi Bangoria --- Ravi requested patch resend with the following: /* * FIXME: cpuc->events[idx] can become NULL in a subtle race * condition with NMI->throttle->x86_pmu_stop(). */ arch/x86/events/amd/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c index 920e3a640cad..3a8b8db878f6 100644 --- a/arch/x86/events/amd/core.c +++ b/arch/x86/events/amd/core.c @@ -762,7 +762,8 @@ static void amd_pmu_enable_all(int added) if (!test_bit(idx, cpuc->active_mask)) continue; =20 - amd_pmu_enable_event(cpuc->events[idx]); + if (cpuc->events[idx]) + amd_pmu_enable_event(cpuc->events[idx]); } } =20 --=20 2.39.3