Hello, I am experiencing crashes in dnsmasq (2.86). I am able to reproduce it though I am not sure about the exact sequence of events -- it happens when I enable/disable my Ethernet NIC and disable/enable my wireless NIC.
In this use case, dnsmasq provides DNS and DHCP for a virtual machine (VM) running on KVM. Something like this: +-- (Ethernet)-+ | | Internet + Hypervisor (virbr0) --- VM | | +--- (Wi-fi)---+ The interfaces I am enabling and disabling are on the hypervisor ("Ethernet" and "Wi-fi" above; virbr0 never goes down). I guess dnsmasq does not handle gracefully receiving a DNS request from the VM when the external interfaces of the hypervisor (Ethernet or wi-fi) go down? Some details below; happy to provide more information if that's not enough to get to the bottom of it. Cheers, Eloy Paris.- ---------------------------------------------------------------------- elparis@chapilu[0]:~$ sudo coredumpctl debug dnsmasq [sudo] Mot de passe de elparis : PID: 46002 (dnsmasq) UID: 65534 (nobody) GID: 65534 (nobody) Signal: 11 (SEGV) Timestamp: Tue 2021-10-12 22:17:33 EDT (11min ago) Command Line: /usr/bin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper Executable: /usr/bin/dnsmasq Control Group: /system.slice/libvirtd.service Unit: libvirtd.service Slice: system.slice Boot ID: a42fe0fbd18649ad8a6951687e2855d8 Machine ID: 3d34409507634591951da9abb51a3942 Hostname: chapilu Storage: /var/lib/systemd/coredump/core.dnsmasq.65534.a42fe0fbd18649ad8a6951687e2855d8.46002.1634091453000000.zst (present) Disk Size: 204.6K Message: Process 46002 (dnsmasq) of user 65534 dumped core. Found module linux-vdso.so.1 with build-id: c6d7bcf242640b81aef03f231535fa4c2486c744 Found module libffi.so.7 with build-id: de60e99f39569d11d09160bbdcd486cedc87d2b6 Found module libp11-kit.so.0 with build-id: 5314ec746546ada6f442b6fdfae15eab9f6d3cdc Found module libcrypto.so.1.1 with build-id: 6d23f0a3f354825868d044684fad31d482cc9210 Found module libdl.so.2 with build-id: 5abc547e7b0949f89f3c0e21ab0c8331a7440a8a Found module libcrypt.so.2 with build-id: 3743451bdaf36f951f926927633fd964813025d0 Found module libnss_systemd.so.2 with build-id: 22990ff716d182c427e26b7a3cf94048b55b3e75 Found module libnss_files.so.2 with build-id: 1a36dfc01d3a1010b2ee79766a24a8090a3266d5 Found module libgpg-error.so.0 with build-id: ba85170c2d9343ea05eea8fa2048c212ff4ef552 Found module libgcrypt.so.20 with build-id: db45f5d5e0f7af1e77324fea1885f974619ad268 Found module libcap.so.2 with build-id: c1674f9082fedd415876b9f7d9712269163259b5 Found module liblz4.so.1 with build-id: e63600ab23b2f6997f42fac2fa56e1f02ce159a1 Found module libzstd.so.1 with build-id: 4b10444c1560ebc574af4d5f488b7408b22d450e Found module liblzma.so.5 with build-id: 8b615460aa230708c5183f16bede67aa0437d95e Found module librt.so.1 with build-id: 75484da2d6f1515189eefa076e0a40328834cd16 Found module ld-linux-x86-64.so.2 with build-id: 040cc3dd10461562f177df39e3be2f3704258c3c Found module libmnl.so.0 with build-id: fdf3a318247060fa3e451d511ebaf23a7396d1dd Found module libnfnetlink.so.0 with build-id: 273cc877c7b2ff41e88753edda777d7f1c4017ca Found module libunistring.so.2 with build-id: 015ac6d6bcb60b7d8bea31a80d1941b06e8636ab Found module libsystemd.so.0 with build-id: f776aaa16b4e2ba7056d01d928e4b2726ffe2b8b Found module libpthread.so.0 with build-id: 07c8f95b4f3251d08550217ad8a1f31066229996 Found module libc.so.6 with build-id: 4b406737057708c0e4c642345a703c47a61c73dc Found module libgmp.so.10 with build-id: e58d34ab389d1b649c24195c2d145e3ff2e58290 Found module libhogweed.so.6 with build-id: 2d70cff7b1841b4d9ca4e8e7726cd4b944c07fdc Found module libnettle.so.8 with build-id: 9a878e513c02007598fcf1e2e286c2203f13536e Found module libnetfilter_conntrack.so.3 with build-id: 0ad526380b1a1986a1e471a84d88d5f2a7fedd80 Found module libidn2.so.0 with build-id: 1ce2b50ad9f9821c2c629b521cf5a3c99593d332 Found module libdbus-1.so.3 with build-id: 74f2ab9c60512f3a93c932c3f627564d42e0b11e Found module dnsmasq with build-id: 17b49d0999133997748526c51d99bf8b932fb79d Stack trace of thread 46002: #0 0x0000561772564d46 lookup_domain (dnsmasq + 0x55d46) #1 0x0000561772532b1e forward_query (dnsmasq + 0x23b1e) #2 0x000056177253387e receive_query (dnsmasq + 0x2487e) #3 0x0000561772538b7c check_dns_listeners (dnsmasq + 0x29b7c) #4 0x000056177251888b main (dnsmasq + 0x988b) #5 0x00007f85147e4b25 __libc_start_main (libc.so.6 + 0x27b25) #6 0x00005617725197ae _start (dnsmasq + 0xa7ae) GNU gdb (GDB) 11.1 Copyright (C) 2021 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64-pc-linux-gnu". Type "show configuration" for configuration details. For bug reporting instructions, please see: <https://www.gnu.org/software/gdb/bugs/>. Find the GDB manual and other documentation resources online at: <http://www.gnu.org/software/gdb/documentation/>. For help, type "help". Type "apropos word" to search for commands related to "word"... Reading symbols from /usr/bin/dnsmasq... [New LWP 46002] [Thread debugging using libthread_db enabled] Using host libthread_db library "/usr/lib/libthread_db.so.1". Core was generated by `/usr/bin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-'. Program terminated with signal SIGSEGV, Segmentation fault. #0 0x0000561772564d46 in lookup_domain (domain=0x561772b1d7a0 "enterprise.activity.windows.com", flags=flags@entry=128, lowout=lowout@entry=0x7ffe8a4b63ac, highout=highout@entry=0x7ffe8a4b63b0) at domain-match.c:234 234 domain-match.c: Aucun fichier ou dossier de ce type. (gdb) _______________________________________________ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk https://lists.thekelleys.org.uk/cgi-bin/mailman/listinfo/dnsmasq-discuss