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Wed, 21 Aug 2024 17:28:32 GMT Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8589920043; Wed, 21 Aug 2024 17:28:30 +0000 (GMT) Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 28D1820040; Wed, 21 Aug 2024 17:28:30 +0000 (GMT) Received: from [127.0.0.1] (unknown [9.152.108.100]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 21 Aug 2024 17:28:30 +0000 (GMT) Message-ID: Subject: Re: Problem testing with S390x under QEMU on x86_64 From: Ilya Leoshkevich To: Tony Ambardar Cc: bpf@vger.kernel.org, linux-s390@vger.kernel.org, Alexei Starovoitov Date: Wed, 21 Aug 2024 19:28:29 +0200 In-Reply-To: References: <180f4c27ebfb954d6b0fd2303c9fb7d5f21dae04.camel@linux.ibm.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.52.4 (3.52.4-1.fc40) Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: ynu1xobkTL6GOEen_jrS_DW_RcAEpxex X-Proofpoint-GUID: Bzn5ENgkkz5CX9Sw2Sb7eLzV9i3PABMO X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1039,Hydra:6.0.680,FMLib:17.12.28.16 definitions=2024-08-21_11,2024-08-19_03,2024-05-17_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1011 spamscore=0 priorityscore=1501 adultscore=0 bulkscore=0 impostorscore=0 malwarescore=0 mlxlogscore=984 phishscore=0 mlxscore=0 lowpriorityscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2407110000 definitions=main-2408210124 On Tue, 2024-08-20 at 17:38 -0700, Tony Ambardar wrote: [...] > I used the command line: > =C2=A0=C2=A0=C2=A0 ./test_progs -d > get_stack_raw_tp,stacktrace_build_id,verifier_iterating_callbacks,tai > lcalls >=20 > which includes the current DENYLIST.s390x as well as 'tailcalls', > which > is also excluded by the kernel-patches/bpf s390x CI. I note the CI > excludes several more tests that seem to work. Any idea why that is? >=20 > For reference, the issue with 'tailcalls/tailcall_hierarchy_count' is > an > RCU stall and kernel hang: >=20 > root@(none):/usr/libexec/kselftests-bpf# ./test_progs -v --debug -n > 332/19 > bpf_testmod.ko is already unloaded. > Loading bpf_testmod.ko... > Successfully loaded bpf_testmod.ko. > test_tailcall_hierarchy_count:PASS:load obj 0 nsec > test_tailcall_hierarchy_count:PASS:find entry prog 0 nsec > test_tailcall_hierarchy_count:PASS:prog_fd 0 nsec > test_tailcall_hierarchy_count:PASS:find jmp_table 0 nsec > test_tailcall_hierarchy_count:PASS:map_fd 0 nsec > test_tailcall_hierarchy_count:PASS:update jmp_table 0 nsec > test_tailcall_hierarchy_count:PASS:find data_map 0 nsec > test_tailcall_hierarchy_count:PASS:open fentry_obj file 0 nsec > test_tailcall_hierarchy_count:PASS:find fentry prog 0 nsec > test_tailcall_hierarchy_count:PASS:set_attach_target subprog_tail 0 > nsec > test_tailcall_hierarchy_count:PASS:load fentry_obj 0 nsec > test_tailcall_hierarchy_count:PASS:attach_trace 0 nsec > rcu: INFO: rcu_sched self-detected stall on CPU > rcu:=C2=A0=C2=A0=C2=A0 0-....: (1 GPs behind) idle=3D4eb4/1/0x40000000000= 00000 > softirq=3D527/528 fqs=3D1050 > rcu:=C2=A0=C2=A0=C2=A0 (t=3D2100 jiffies g=3D-379 q=3D20 ncpus=3D2) > CPU: 0 UID: 0 PID: 84 Comm: test_progs Tainted: G=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 O=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 > 6.10.0-12706-g853081e84612-dirty #111 > Tainted: [O]=3DOOT_MODULE > Hardware name: QEMU 8561 QEMU (KVM/Linux) > Krnl PSW : 0704f00180000000 000003ffe00f8fca > (lock_release+0xf2/0x190) > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 R:0 T:1 IO:1= EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:3 PM:0 RI:0 > EA:3 > Krnl GPRS: 00000000b298dd12 0000000000000000 000002f23fd767c8 > 000003ffe1848800 > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 000000000000= 0001 0000037fe034edbc 0000037fe034fd74 > 0000000000000001 > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 0700037fe034= edc8 000003ffe0249e48 000003ffe1848800 > 000003ffe19ba7c8 > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 000003ff9f7a= 7f90 0000037fe034ef00 000003ffe00f8f96 > 0000037fe034ed78 > Krnl Code: 000003ffe00f8fbe: a7820300=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0 tmhh=C2=A0=C2=A0=C2=A0 %r8,768 > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 000003ffe00f= 8fc2: a7840004=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 = brc=C2=A0=C2=A0=C2=A0=C2=A0 > 8,000003ffe00f8fca > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 #000003ffe00f8fc6:= ad03f0a0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 stosm= =C2=A0=C2=A0 160(%r15),3 > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 >000003ffe00f8fca:= eb8ff0a80004=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 lmg=C2=A0=C2=A0=C2=A0=C2= =A0 > %r8,%r15,168(%r15) > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 000003ffe00f= 8fd0: 07fe=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0 bcr=C2=A0=C2=A0=C2=A0=C2=A0 15,%r14 > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 000003ffe00f= 8fd2: c0e500011057=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 brasl=C2=A0=C2=A0 > %r14,000003ffe011b080 > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 000003ffe00f= 8fd8: ec26ffa6007e=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 cij=C2=A0=C2=A0=C2= =A0=C2=A0 > %r2,0,6,000003ffe00f8f24 > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 000003ffe00f= 8fde: c01000b78b96=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 larl=C2=A0=C2=A0=C2= =A0 > %r1,000003ffe17ea70a > Call Trace: > =C2=A0[<000003ffe00f8fca>] lock_release+0xf2/0x190 > ([<000003ffe00f8f96>] lock_release+0xbe/0x190) > =C2=A0[<000003ffe0249ea4>] __bpf_prog_exit_recur+0x5c/0x68 > =C2=A0[<000003ff6001e0b0>] bpf_trampoline_73014444060+0xb0/0xd2 > =C2=A0[<000003ff60024d14>] bpf_prog_eb7edc599e93dcc8_entry+0x5c/0xc8 > =C2=A0[<000003ff60024d14>] bpf_prog_eb7edc599e93dcc8_entry+0x5c/0xc8 > =C2=A0[<000003ff60024d14>] bpf_prog_eb7edc599e93dcc8_entry+0x5c/0xc8 > =C2=A0[<000003ff60024d2a>] bpf_prog_eb7edc599e93dcc8_entry+0x72/0xc8 > =C2=A0[<000003ff60024d2a>] bpf_prog_eb7edc599e93dcc8_entry+0x72/0xc8 > =C2=A0[<000003ff60024d14>] bpf_prog_eb7edc599e93dcc8_entry+0x5c/0xc8 > =C2=A0[<000003ff60024d14>] bpf_prog_eb7edc599e93dcc8_entry+0x5c/0xc8 > =C2=A0[<000003ff60024d14>] bpf_prog_eb7edc599e93dcc8_entry+0x5c/0xc8 > =C2=A0[<000003ffe084ecee>] bpf_test_run+0x216/0x3a8 > =C2=A0[<000003ffe084f9cc>] bpf_prog_test_run_skb+0x21c/0x630 > =C2=A0[<000003ffe0202ad2>] __sys_bpf+0x7ea/0xbb0 > =C2=A0[<000003ffe0203114>] __s390x_sys_bpf+0x44/0 Thanks for the detailed analysis! I will need to port commit 116e04ba1459fc08f80cf27b8c9f9f188be0fcb2 Author: Leon Hwang Date: Sun Jul 14 20:39:00 2024 +0800 bpf, x64: Fix tailcall hierarchy to s390x to fix this. > Another curiosity is with 'uprobe_multi_test/attach_uprobe_fails', > which usually succeeds but generates an inode warning in > kernel/events/uprobes.c: (with cross-compiled and native test_progs) >=20 > #416=C2=A0=C2=A0=C2=A0=C2=A0 uprobe_autoattach:OK > ref_ctr_offset mismatch. inode: 0x73c7 offset: 0x3c9b78 > ref_ctr_offset(old): 0x464d7be ref_ctr_offset(new): 0x464d7bc > #417/1=C2=A0=C2=A0 uprobe_multi_test/skel_api:OK > #417/2=C2=A0=C2=A0 uprobe_multi_test/attach_api_pattern:OK > #417/3=C2=A0=C2=A0 uprobe_multi_test/attach_api_syms:OK > #417/4=C2=A0=C2=A0 uprobe_multi_test/link_api:OK > #417/5=C2=A0=C2=A0 uprobe_multi_test/bench_uprobe:OK > #417/6=C2=A0=C2=A0 uprobe_multi_test/bench_usdt:OK > #417/7=C2=A0=C2=A0 uprobe_multi_test/attach_api_fails:OK > #417/8=C2=A0=C2=A0 uprobe_multi_test/attach_uprobe_fails:OK > #417/9=C2=A0=C2=A0 uprobe_multi_test/consumers:OK > #417=C2=A0=C2=A0=C2=A0=C2=A0 uprobe_multi_test:OK >=20 > but occasionally I see this kernel fault: >=20 > #416=C2=A0=C2=A0=C2=A0=C2=A0 uprobe_autoattach:OK > User process fault: interruption code 0001 ilc:1 in > test_progs[3c9ba2,2aa3b580000+cc5000] > CPU: 0 UID: 0 PID: 165 Comm: new_name Tainted: G=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 OE=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 > 6.10.0-12707-g8189b8007d01 #114 > Tainted: [O]=3DOOT_MODULE, [E]=3DUNSIGNED_MODULE > Hardware name: QEMU 8561 QEMU (KVM/Linux) > User PSW : 0705000180000000 000002aa3b949ba2 > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 R:0 T:1 IO:1= EX:1 Key:0 M:1 W:0 P:1 AS:0 CC:0 PM:0 RI:0 > EA:3 > User GPRS: cccccccccccccccd 0000000000000000 000003ffbe080000 > 0000000000000000 > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 000003ffbeb7= 4828 0000000000000006 0000000000000000 > 000002aa3c245928 > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 000003ffbeb2= cbc0 000003ffbeb2d020 0000000000000003 > 000003ffdb379f20 > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 000003ffbeb2= cf98 0000000000000000 000002aa3b94a400 > 000003ffdb379f20 > User Code:>000002aa3b949ba2: 0000=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 illegal > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 000002aa3b94= 9ba4: 0700=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0 bcr=C2=A0=C2=A0=C2=A0=C2=A0 0,%r0 > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 000002aa3b94= 9ba6: b3cd00b0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 = lgdr=C2=A0=C2=A0=C2=A0 %r11,%f0 > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 000002aa3b94= 9baa: 07fe=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0 bcr=C2=A0=C2=A0=C2=A0=C2=A0 15,%r14 > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 000002aa3b94= 9bac: 0707=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0 bcr=C2=A0=C2=A0=C2=A0=C2=A0 0,%r7 > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 000002aa3b94= 9bae: 0707=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0 bcr=C2=A0=C2=A0=C2=A0=C2=A0 0,%r7 > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 000002aa3b94= 9bb0: ebbff0580024=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 stmg=C2=A0=C2=A0=C2= =A0 > %r11,%r15,88(%r15) > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 000002aa3b94= 9bb6: e3f0ff48ff71=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 lay=C2=A0=C2=A0=C2= =A0=C2=A0 %r15,- > 184(%r15) > Last Breaking-Event-Address: > =C2=A0[<000002aa3b94a3fa>] test_progs[3ca3fa,2aa3b580000+cc5000] >=20 >=20 > Have you seen this fault before? Is the inode warning expected by the > test? Yes, this is caused by: /* attach fail due to wrong ref_ctr_offs on one of the uprobes */ attach_uprobe_fail_refctr(skel); The fault is a user fault, not a kernel fault. I could not reproduce it on a real s390x machine. This may be an emulation problem, since apparently the kernel does not recognize that "0000 illegal" is an uprobe. Quite some time ago I fixed a similar issue in this area, perhaps it's a new flavour. I will investigate. [...] Best regards, Ilya