From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-x435.google.com ([2607:f8b0:4864:20::435]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1lESiL-0006Ou-JD for linux-um@lists.infradead.org; Tue, 23 Feb 2021 08:06:39 +0000 Received: by mail-pf1-x435.google.com with SMTP id w18so8286521pfu.9 for ; Tue, 23 Feb 2021 00:06:35 -0800 (PST) Received: from priyasi.researchut.com ([157.45.194.32]) by smtp.gmail.com with ESMTPSA id q7sm2139502pjl.53.2021.02.23.00.06.32 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 23 Feb 2021 00:06:32 -0800 (PST) Received: from [IPv6:::1] (localhost [IPv6:::1]) by priyasi.researchut.com (Postfix) with ESMTP id 87E0D164024C for ; Tue, 23 Feb 2021 13:36:28 +0530 (IST) Message-ID: <3448a70e7a39b9c3202aeefa7858ace265b8a978.camel@debian.org> Subject: linux uml segfault From: Ritesh Raj Sarraf Date: Tue, 23 Feb 2021 13:36:28 +0530 MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: rrs@debian.org Content-Type: multipart/mixed; boundary="===============0401790187433786201==" Sender: "linux-um" Errors-To: linux-um-bounces+geert=linux-m68k.org@lists.infradead.org To: "linux-um@lists.infradead.org" --===============0401790187433786201== Content-Type: multipart/signed; micalg="pgp-sha512"; protocol="application/pgp-signature"; boundary="=-SrfOFmCwJB0TupZC7CKZ" --=-SrfOFmCwJB0TupZC7CKZ Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi, Recently, with the Linux 5.10 release, I have run into the following segfault on UML. I was a little disappointed in myself that this slipped my regular set of tests, before being pushed to Debian. It is right now part of Debian Testing too and I'd hate to have it removed from the Bullseye release. What is worse is that (to do some quick tests) I reverted to an older UML (5.9) which I recollect to have working, and that too failed on the setups. In regard to setups, I tried and reproduced the issue on 3 different machines, but all running Intel hardware. And all running 5.10 host kernel It would really help if others on this mailing list can check and validate if they run into this problem. So far I have had 1 report of being able to reproduce this bug other than me. I have also had 1 report of not being able to reproduce this bug. Thanks, Ritesh ``` rrs@priyasi:~$ linux ubd0=3D~/rrs-home/Libvirt-Images/uml.img vec0:transport=3Dtap,ifname=3Dtap0,gro=3D1 mem=3D1024M rw Core dump limits : soft - 0 hard - NONE Checking that ptrace can change system call numbers...OK Checking syscall emulation patch for ptrace...OK Checking advanced syscall emulation patch for ptrace...OK Checking environment variables for a tempdir...none found Checking if /dev/shm is on tmpfs...OK Checking PROT_EXEC mmap in /dev/shm...OK Adding 5906432 bytes to physical memory to account for exec-shield gap kmsg_dump: <5>Linux version 5.10.5 (buildd@x86-conova-01) (gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1) #1 Mon Jan 11 20:40:53 UTC 2021 <6>Zone ranges: <6> Normal [mem 0x0000000000000000-0x00000000a05a1fff] <6>Movable zone start for each node <6>Early memory node ranges <6> node 0: [mem 0x0000000000000000-0x00000000405a1fff] <6>Initmem setup node 0 [mem 0x0000000000000000-0x00000000405a1fff] <7>On node 0 totalpages: 263586 <7> Normal zone: 4119 pages used for memmap <7> Normal zone: 0 pages reserved <7> Normal zone: 263586 pages, LIFO batch:63 <7>pcpu-alloc: s0 r0 d32768 u32768 alloc=3D1*32768 <7>pcpu-alloc: [0] 0=20 <6>Built 1 zonelists, mobility grouping on. Total pages: 259467 <5>Kernel command line: ubd0=3D/home/rrs/rrs-home/Libvirt-Images/uml.img vec0:transport=3Dtap,ifname=3Dtap0,gro=3D1 mem=3D1024M rw root=3D98:0 <6>Dentry cache hash table entries: 131072 (order: 8, 1048576 bytes, linear) <6>Inode-cache hash table entries: 65536 (order: 7, 524288 bytes, linear) <6>mem auto-init: stack:off, heap alloc:off, heap free:off <6>Memory: 1016464K/1054344K available (5830K kernel code, 1535K rwdata, 1744K rodata, 191K init, 225K bss, 37880K reserved, 0K cma- reserved) <6>SLUB: HWalign=3D64, Order=3D0-3, MinObjects=3D0, CPUs=3D1, Nodes=3D1 <6>NR_IRQS: 24 <6>clocksource: timer: mask: 0xffffffffffffffff max_cycles: 0x1cd42e205, max_idle_ns: 881590404426 ns <6>Calibrating delay loop... 5731.94 BogoMIPS (lpj=3D28659712) <6>pid_max: default: 32768 minimum: 301 <6>LSM: Security Framework initializing <6>Yama: disabled by default; enable with sysctl kernel.yama.* <6>SELinux: Initializing. <6>TOMOYO Linux initialized <6>Mount-cache hash table entries: 2048 (order: 2, 16384 bytes, linear) <6>Mountpoint-cache hash table entries: 2048 (order: 2, 16384 bytes, linear) <4> <4>Modules linked in: <6>Pid: 0, comm: swapper Not tainted 5.10.5 <6>RIP: 0033:[<00000000604d4201>] <6>RSP: 00007ffca56a8890 EFLAGS: 00010206 <6>RAX: 0000000600000000 RBX: 0000000000000059 RCX: 00007ffca56a8000 <6>RDX: 0000000000000035 RSI: 0000000060b69a71 RDI: 0000000060d8ac3b <6>RBP: 0000000000000000 R08: 0000000060b69a72 R09: 0000000060d8abe2 <6>R10: 0000000080000000 R11: 3d74696e695f676e R12: 0000000000000002 <6>R13: 0000000000000005 R14: 0000000000000000 R15: 0000000000000001 <0>Kernel panic - not syncing: Segfault with no mm <4>CPU: 0 PID: 0 Comm: swapper Not tainted 5.10.5 #1 <4>Stack: <4> 61335b50 8000000000000000 7fae69465908 7fae69465ae5 <4> 7fae698ae9e8 00000000 7ffca56a88d0 00000400 <4> 7fae6985bf20 7fae698ae9e8 00000000 00000000Call Trace: <4> [<604d4fa3>] ? __printk_safe_enter+0x0/0x35 <4> [<604d154a>] ? arch_local_irq_save+0x0/0x22 <4> [<604d46f5>] ? vprintk_emit+0x9d/0x185 <4> [<604d49d3>] ? vprintk_deferred+0x1d/0x32 <4> [<60a26ee2>] ? printk_deferred+0x93/0x9b <4> [<6088f79f>] ? bucket_table_alloc.isra.0+0x115/0x13d <4> [<60a26e4f>] ? printk_deferred+0x0/0x9b <4> [<6049cddb>] ? set_signals+0x0/0x38 <4> [<60589588>] ? arch_local_irq_save+0x0/0x22 <4> [<6055c928>] ? kvmalloc_node+0x56/0x96 <4> [<6058d3c0>] ? __kmalloc+0x1e2/0x1f9 <4> [<608e3d32>] ? ___ratelimit+0xd0/0xde <4> [<6088f79f>] ? bucket_table_alloc.isra.0+0x115/0x13d <4> [<60901485>] ? _warn_unseeded_randomness+0x60/0x8f <4> [<6090295b>] ? get_random_u32+0x29/0x98 <4> [<6088f79f>] ? bucket_table_alloc.isra.0+0x115/0x13d <4> [<6088f68a>] ? bucket_table_alloc.isra.0+0x0/0x13d <4> [<6088ff7a>] ? rhashtable_init+0x175/0x1ca <4> [<607ef317>] ? ipc_init_ids+0x4e/0x6f <4> [<600153bd>] ? sem_init+0x17/0x45 <4> [<6049d0e5>] ? start_ptraced_child+0x0/0x180 <4> [<604a0ce0>] ? kernel_longjmp+0x0/0x20 <4> [<6049cc3d>] ? set_handler+0x123/0x15b <4> [<6049c9ee>] ? hard_handler+0x0/0xcd <4> [<604a0ce0>] ? kernel_longjmp+0x0/0x20 <4> [<6049c3a6>] ? openpty_cb+0x22/0x3b <4> [<6049fb4b>] ? start_idle_thread+0x66/0x116 <4> [<60004613>] ? linux_main+0x2e7/0x2f9 <4> [<6049cc86>] ? change_sig+0x0/0x6a <4> [<6000565e>] ? main+0x230/0x2dc <4> [<60a256b0>] ? __libc_csu_init+0x0/0x60 <4> [<604827d0>] ? _start+0x0/0x30 <4> [<6000542e>] ? main+0x0/0x2dc <4> [<604827d0>] ? _start+0x0/0x30 <4> [<604827d0>] ? _start+0x0/0x30 <4> [<604827fa>] ? _start+0x2a/0x30 <4> [<604827d0>] ? _start+0x0/0x30 Aborted (core dumped) ``` --=20 Ritesh Raj Sarraf | http://people.debian.org/~rrs Debian - The Universal Operating System --=-SrfOFmCwJB0TupZC7CKZ Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEQCVDstmIVAB/Yn02pjpYo/LhdWkFAmA0t4QACgkQpjpYo/Lh dWlPyQ//RjalYDNgZHz3pS3AFRXjTNW7hi0B47ZptKPKZVev0fK7QouA3gqldBpS 1XxBz2/VMRs0fhwD+mS3GsgyudIKSu8XS2tGYaT0H+qdOu059qhKuEeIlFWmVBqf juk/HdftF9wkAKkT+6SYPDaTiyLu/PaMiRi+e5r1YZpS5d90my9viNoJkywBbpxz 3RnpDmQbjjeVcVLOePCAPvv/xJ6mdMJI+UhQual1mSenM3EtPXnM4iIN/+yxt5UJ TdOsrSw5OyE5QAeeVzIrriS6GxL7XGjUBJPk3uVcJ4cWech9hazWVuWqdHnxLf3j HXEvk0xu5gXwm6LISB48S8lxXiWqGRJwqhnUTkYYSAs0xUkm21tY+Du7QeYMeQ3Z CQdX51SqpiM/kBsxC8ne/VTcIqssJRbP43t01OBxkneUdnFYA6PsT5MGUvdJcXdd BWSoC9SUtNDYqI+Wg3x8sjaImYmKxXKbq/Kt5jIAr3Epdh7ldshAtJ0Bo8r37/8z W5W77h+bgXyxeRZq/Fw05Gkt5pzFgoFO4JeqkOiVoiGA1AyfC33SH+TVkuphHXnl eUPqED/VkLecSF+oUN2hZ0Ys+Y1oC2wQm0klOZ3gky7Yfm4aQbZPTjeo1YmG5Gm3 OQVdyR1HJRO3vWzOQfvEj+K7rGzU7ADpNTziI1GFvpSum3Ls99M= =oL69 -----END PGP SIGNATURE----- --=-SrfOFmCwJB0TupZC7CKZ-- --===============0401790187433786201== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um --===============0401790187433786201==--