Hello everyone, I found a core dump issue when I use dnsmasq as a DHCP server (Version 2.86, running on Linux). My setup and reproduction step is as follows. Dnsmasq main config
> # Common Configure > pid-file=/var/run/dnsmasq.pid > log-facility=/var/log/dnsmasq.log > user=root > group=root > interface=eth0 > > # DNS Server Configure > no-hosts > no-resolv > log-queries=extra > port=53 > > # DHCP Server Configure > log-dhcp > dhcp-range=172.17.12.128,static,255.255.255.192 # Change the network > address and subnet mask. > dhcp-hostsfile=/etc/dnsmasq/dhcp-hosts > dhcp-optsfile=/etc/dnsmasq/dhcp-options > dhcp-vendorclass=set:pxe-bios-x86,PXEClient:Arch:00000 > dhcp-vendorclass=set:pxe-uefi-amd64,PXEClient:Arch:00007 > dhcp-vendorclass=set:pxe-uefi-amd64,PXEClient:Arch:00009 > dhcp-boot=tag:pxe-bios-x86,pxelinux.0,pxeserver > dhcp-boot=tag:pxe-uefi-amd64,bootnetx64.efi,pxeserver > dhcp-ignore=tag:!known > External DHCP host file > 08:c0:eb:cb:MM:NN,id:*,set:mytag,172.17.12.XXX,XXX-01,5m External DHCP options file > tag:mytag,option:netmask,255.255.255.128 > tag:mytag,option:router,172.17.12.190 > tag:mytag,option:dns-server,172.16.0.XXX > tag:mytag,option:ntp-server,172.16.0.XXX > tag:mytag,option:domain-name,mydomain > Reproduction step is First start dnsmasq with the config shown above, Then use 08:c0:eb:cb:MM:NN to obtain an IP address from dnsmasq server. After we can see lease of 08:c0:eb:cb:MM:NN in dnsmasq.leases, send signal HUP to dnsmasq, Now I got dnsmasq core dumped and traceback is following > #0 __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50 > #1 0x00007f858837f535 in __GI_abort () at abort.c:79 > #2 0x00007f85883d6518 in __libc_message (action=action@entry=do_abort, > fmt=fmt@entry=0x7f85884e028d "%s\n") > at ../sysdeps/posix/libc_fatal.c:181 > #3 0x00007f85883dcc3a in malloc_printerr (str=str@entry=0x7f85884e1fe0 > "double free or corruption (out)") at malloc.c:5359 > #4 0x00007f85883de770 in _int_free (av=0x7f8588517c40 <main_arena>, > p=0x7ffd7d6e79a0, have_lock=<optimized out>) at malloc.c:4321 > #5 0x0000000000410187 in dhcp_netid_free (nid=0x7ffd7d6e79b0) at > option.c:1019 > #6 0x0000000000410258 in dhcp_netid_list_free (netid=0x0) at option.c:1050 > #7 0x00000000004102c9 in dhcp_config_free (config=0x2273950) at > option.c:1068 > #8 0x000000000041c313 in clear_dynamic_conf () at option.c:5186 > #9 0x000000000041c3bd in reread_dhcp () at option.c:5219 > #10 0x0000000000428a11 in clear_cache_and_reload (now=1650633404) at > dnsmasq.c:1694 > #11 0x0000000000428303 in async_event (pipe=10, now=1650633404) at > dnsmasq.c:1450 > #12 0x0000000000427cf4 in main (argc=3, argv=0x7ffd7d6e81a8) at > dnsmasq.c:1193 > It looks like there is some memory management issue about dhcp tag I found another related fact that if I just start dnsmasq and reload it, or dnsmasq only receive dhcp packet from UNKNOWN mac address and reload it, dnsmasq will NOT core dumped when reloading, so I guess that the issue maybe related to progress of DHCP packet That is all about I found about core dumped issue when reloading, I'm looking forward for someone found similar problem or have idea about this issue Thanks Han Bing
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