Date: Mon, 30 Jun 2025 17:17:24 +0000 (UTC) From: "Bjoern A. Zeeb" <bzeeb-lists@lists.zabbadoz.net> To: John Baldwin <jhb@FreeBSD.org> Cc: Zhenlei Huang <zlei@FreeBSD.org>, FreeBSD Current <current@freebsd.org>, Olivier Certner <olce@freebsd.org> Subject: Re: regression: memory issues on main/arm64 over sched/runq changes Message-ID: <2qp0845s-p0oq-qsr9-0n64-3snn4466s139@yvfgf.mnoonqbm.arg> In-Reply-To: <274774b0-9137-4fa7-a0a5-a0ce8976dc27@FreeBSD.org> References: <43005447-2rq0-6nn2-pnr5-4939s112npr4@yvfgf.mnoonqbm.arg> <0A01B9F5-C49C-41D8-BAB7-4378DEDBF647@FreeBSD.org> <28o26o81-so5r-qq79-6q6n-0q6746o7oo79@yvfgf.mnoonqbm.arg> <6A003013-415A-4594-AB04-AF5A9B2D660D@FreeBSD.org> <23n1773o-10o2-5p5o-25s4-r623rnn44649@yvfgf.mnoonqbm.arg> <907D042E-AE8A-4818-A807-AD45F36354FD@FreeBSD.org> <274774b0-9137-4fa7-a0a5-a0ce8976dc27@FreeBSD.org>
index | next in thread | previous in thread | raw e-mail
On Mon, 30 Jun 2025, John Baldwin wrote: > On 6/28/25 11:35, Zhenlei Huang wrote: >> I boot from disk. >> >> Updates on this locking issue, >> >> I think I finally figured out why. More stack trace from my video: >> >> ``` >> shared lock of (sx) ifnet_sx @/usr/home/zlei/freebsd-src/sys/net/if.c:1467 >> while exclusively locked from /usr/home/zlei/freebsd-src/sys/net/if.c:1416 >> panic: excl->share >> ... >> witness_checkorder() at ... >> _sx_slock_int() at _sx_slock_int+0x64/frame .... >> if_addgroup() at ... >> if_attach_internal() at ... >> ether_ifattach() at ... >> iflib_device_register() at ... >> iflib_device_attach() at ... >> device_attach() at ... >> ... >> root_bus_configure() at ... >> configure() at ... >> mi_startup() at ... >> ``` >> >> The ifnet_sx has flag bit SX_RECURSE then it can be recursively locked. >> >> iflib_device_register() acquired ifnet_sx exclusively and then calls >> ethernet_ifattach() which will then calls if_addgroup(). It is prohibited >> to re-acquire the same lock shared so the witness blames. >> >> I think the witness should show the first file location of the exclusively >> lock, i.e. sys/net/iflib.c rather than the sys/net/if.c:1416 . So that it >> is more straight forward to figure out how that happens. CC John to see if >> that can be improved. > > Hmm, I think we have stopped at the first lle we found walking > back up the lle list (find_instance() always works this way). > > You could add a 'find_last_instance' and use it in a few places > perhaps. I guess both the share->excl and excl->share are places > where you would maybe use it. Alternatively, you could have a > 'find_next_instance' and maybe output all of them before the > panic? Having the full chain would be really nice :) +1 from me for that. /bz -- Bjoern A. Zeeb r15:7home | help
Want to link to this message? Use this
URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?2qp0845s-p0oq-qsr9-0n64-3snn4466s139>