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AJvYcCXQMr8K/oRz6rga57DdDAhdlxQ1i/HeKhReWxi5s8ebZfzY81fA8IUvL1fDrWp293DqHk31nmRXtkk=@vger.kernel.org X-Gm-Message-State: AOJu0Yy3ux5jMfs7X4u8LGLxx8z9QSki1g7SrQ87UH1sYPZac7t09ODt LG+uHiEb4mwRAyNr897Z+wLu0213coEMZjDWNiegnnDK8Evob6W0X2jnbWgNBRXEywkbMJKgUco NdGZ+wLShIJ2QjbrDT1qz9Gq6YOuF8pjMXDYekZwm X-Gm-Gg: ASbGnct+4okWnopQSCJ9lZiumjNhf/aB8sBV8s1PhfoQ1YFW78iZ5/WERLhhVGEe7Kp FCa1R3EBhFKkfLg1NBlLLxb2YIiIwq9qeS7AVfOF/PrGd50bNo3jk/P9Wt0KOaJsrxyGNO6c4bE xOonILpHa9jzyt11OkhCSLleXlSv3YkZEDsFDvCXnZb2WZkagE+8PTDFiipYcM3vIO5R066rgnD A== X-Google-Smtp-Source: AGHT+IGOsLPlFlEvlYkCbus5+x3MBMYKoCe7UkbI/PuCUN4NG3EUAT4RU2knzTA5Ul1WnnYLmtViQvSgi4fXiCoywyw= X-Received: by 2002:a17:907:6eab:b0:ad5:822d:b00d with SMTP id a640c23a62f3a-ad85b2119damr754537866b.45.1748252900886; Mon, 26 May 2025 02:48:20 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <6a2cdedc0b2bf7e3da82d453b0104b46a2e85529.1747349530.git.babu.moger@amd.com> In-Reply-To: <6a2cdedc0b2bf7e3da82d453b0104b46a2e85529.1747349530.git.babu.moger@amd.com> From: Peter Newman Date: Mon, 26 May 2025 11:48:10 +0200 X-Gm-Features: AX0GCFs5QnLJ7LzQu3TrunXdv4Y7Ov3b367Y6o1OV9QQKODd-523j7ZA10IRPKc Message-ID: Subject: Re: [PATCH v13 24/27] x86/resctrl: Introduce the interface to modify assignments in a group To: Babu Moger Cc: corbet@lwn.net, tony.luck@intel.com, reinette.chatre@intel.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, james.morse@arm.com, dave.martin@arm.com, fenghuay@nvidia.com, x86@kernel.org, hpa@zytor.com, paulmck@kernel.org, akpm@linux-foundation.org, thuth@redhat.com, rostedt@goodmis.org, ardb@kernel.org, gregkh@linuxfoundation.org, daniel.sneddon@linux.intel.com, jpoimboe@kernel.org, alexandre.chartre@oracle.com, pawan.kumar.gupta@linux.intel.com, thomas.lendacky@amd.com, perry.yuan@amd.com, seanjc@google.com, kai.huang@intel.com, xiaoyao.li@intel.com, kan.liang@linux.intel.com, xin3.li@intel.com, ebiggers@google.com, xin@zytor.com, sohil.mehta@intel.com, andrew.cooper3@citrix.com, mario.limonciello@amd.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, maciej.wieczor-retman@intel.com, eranian@google.com, Xiaojian.Du@amd.com, gautham.shenoy@amd.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi Babu, On Fri, May 16, 2025 at 12:56=E2=80=AFAM Babu Moger wr= ote: > diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c > index 8d970b99bbbd..ea1782723f81 100644 > --- a/fs/resctrl/rdtgroup.c > +++ b/fs/resctrl/rdtgroup.c > @@ -2126,6 +2126,168 @@ static int mbm_L3_assignments_show(struct kernfs_= open_file *of, struct seq_file > return ret; > } > > +/* > + * mbm_get_mon_event_by_name() - Return the mon_evt entry for the matchi= ng > + * event name. > + */ > +static struct mon_evt *mbm_get_mon_event_by_name(struct rdt_resource *r, > + char *name) > +{ > + struct mon_evt *mevt; > + > + list_for_each_entry(mevt, &r->mon.evt_list, list) { > + if (!strcmp(mevt->name, name)) > + return mevt; > + } > + > + return NULL; > +} > + > +static unsigned int resctrl_get_assing_type(char *assign) > +{ > + unsigned int mon_state =3D ASSIGN_NONE; > + int len =3D strlen(assign); [ 395.013183] BUG: kernel NULL pointer dereference, address: 0000000000000= 000 [ 395.013426] #PF: supervisor read access in kernel mode [ 395.013600] #PF: error_code(0x0000) - not-present page [ 395.013779] PGD 39322c067 P4D 2a4f49067 PUD 2a4f4a067 PMD 0 [ 395.013973] Oops: Oops: 0000 [#1] SMP DEBUG_PAGEALLOC NOPTI [ 395.014156] CPU: 37 UID: 0 PID: 24147 Comm: bash Not tainted 6.15.0-dbg-DEV #13 NONE [ 395.014403] Hardware name: Google Astoria-Turin/astoria, BIOS 0.20241223.2-0 01/17/2025 [ 395.014652] RIP: 0010:strlen+0xb/0x20 [ 395.014778] Code: 66 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 c7 c0 ff ff ff ff <80> 7c 07 01 00 48 8d 40 01 75 f5 c3 cc cc cc cc cc 0f 1f 40 00 90 [ 395.015356] RSP: 0018:ffa000002f743d58 EFLAGS: 00010246 [ 395.015522] RAX: ffffffffffffffff RBX: ff11000129a00600 RCX: 00000000000= 00000 [ 395.015747] RDX: ff110001299f5253 RSI: ffffffff827b9651 RDI: 00000000000= 00000 [ 395.015968] RBP: 0000000000000000 R08: 000000000000003d R09: 00000000000= 00000 [ 395.016202] R10: ffffffff827b9652 R11: 0000000000000000 R12: ffffffff830= 5b7f8 [ 395.016421] R13: ff110001299f5240 R14: 0000000000000014 R15: 00000000000= 00000 [ 395.016644] FS: 00007f1281ff8b80(0000) GS:ff1100bdc8276000(0000) knlGS:0000000000000000 [ 395.016893] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 395.017071] CR2: 0000000000000000 CR3: 0000000420bc8002 CR4: 00000000007= 71ef0 [ 395.017298] PKRU: 55555554 [ 395.017388] Call Trace: [ 395.017471] [ 395.017545] mbm_L3_assignments_write+0x2d4/0x4e0 [ 395.017700] kernfs_fop_write_iter+0x132/0x1c0 [ 395.017851] vfs_write+0x2bf/0x3c0 [ 395.017963] ksys_write+0x82/0x100 [ 395.018074] do_syscall_64+0xee/0x210 [ 395.018198] ? exc_page_fault+0x81/0xe0 [ 395.018321] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 395.018482] RIP: 0033:0x7f128177f8b3 [ 395.018598] Code: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 48 8b 05 99 91 07 00 83 38 00 75 10 b8 01 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 4d c3 55 48 89 e5 41 57 41 56 53 50 48 89 d3 [ 395.019167] RSP: 002b:00007ffff66e80f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 395.019409] RAX: ffffffffffffffda RBX: 0000000000000014 RCX: 00007f12817= 7f8b3 [ 395.019636] RDX: 0000000000000014 RSI: 0000000001eedb60 RDI: 00000000000= 00001 [ 395.019861] RBP: 00007ffff66e8120 R08: 0000000000000000 R09: 00000000000= 00000 [ 395.020081] R10: 00007ffff66e81b0 R11: 0000000000000246 R12: 0000000001e= edb60 [ 395.020303] R13: 0000000000000001 R14: 00007f12817fa650 R15: 00000000000= 00014 [ 395.020532] > + > + if (!len || len > 1) > + return ASSIGN_INVALID; > + > + switch (*assign) { > + case 'e': > + mon_state =3D ASSIGN_EXCLUSIVE; > + break; > + case '_': > + mon_state =3D ASSIGN_NONE; > + break; > + default: > + mon_state =3D ASSIGN_INVALID; > + break; > + } > + > + return mon_state; > +} > + > +static int resctrl_process_assign(struct rdt_resource *r, struct rdtgrou= p *rdtgrp, > + char *config, char *tok) > +{ > + struct rdt_mon_domain *d; > + char *dom_str, *id_str; > + unsigned long dom_id =3D 0; > + struct mon_evt *mevt; > + int assign_type; > + char domain[10]; > + bool found; > + int ret; > + > + mevt =3D mbm_get_mon_event_by_name(r, config); > + if (!mevt) { > + rdt_last_cmd_printf("Invalid assign configuration %s\n", = config); > + return -ENOENT; > + } > + > +next: > + if (!tok || tok[0] =3D=3D '\0') > + return 0; > + > + /* Start processing the strings for each domain */ > + dom_str =3D strim(strsep(&tok, ";")); > + > + id_str =3D strsep(&dom_str, "=3D"); If there's no '=3D' then dom_str becomes NULL... > + > + /* Check for domain id '*' which means all domains */ > + if (id_str && *id_str =3D=3D '*') { > + d =3D NULL; > + goto check_state; > + } else if (!id_str || kstrtoul(id_str, 10, &dom_id)) { > + rdt_last_cmd_puts("Missing domain id\n"); > + return -EINVAL; > + } > + > + /* Verify if the dom_id is valid */ > + found =3D false; > + list_for_each_entry(d, &r->mon_domains, hdr.list) { > + if (d->hdr.id =3D=3D dom_id) { > + found =3D true; > + break; > + } > + } > + > + if (!found) { > + rdt_last_cmd_printf("Invalid domain id %ld\n", dom_id); > + return -EINVAL; > + } > + > +check_state: > + assign_type =3D resctrl_get_assing_type(dom_str); then the resulting type of whatever this is supposed to mean is "panic" Thanks, -Peter