From: Raphael Norwitz <raphael.norwitz@nutanix.com>
To: qemu-devel@nongnu.org
Subject: Qemu master crashing on boot when using file backend for memory
Date: Thu, 12 Mar 2020 01:36:48 -0400 [thread overview]
Message-ID: <20200312053648.GA17365@localhost.localdomain> (raw)
When I try run master qemu I am hitting a divide by zero error. It seems
to be coming from util/oslib-posix.c in touch_all_pages(). see line 477:
numpages_per_thread = numpages / memset_num_threads;
Poking around the crash dumps, I can see that the smp_cpus parameter
passed in to touch_all_pages() is 0. Going up the stack to
host_memory_backend_memory_complete() I see backend->prealloc_threads is
also 0.
Here’s how I am running qemu
./x86_64-softmmu/qemu-system-x86_64 \
-kernel /boot/vmlinuz-3.10.0-1062.el7.x86_64 \
-netdev user,id=net0,hostfwd=tcp::2250-:22 \
-device e1000e,netdev=net0 \
-m 1G \
-initrd /boot/initramfs-3.10.0-1062.el7.x86_64.img \
-object memory-backend-file,id=ram-node0,prealloc=yes,mem-path=mem,share=yes,size=1G \
-numa node,nodeid=0,cpus=0,memdev=ram-node0
I don't see this error on a slightly older qemu, as of commit 105b07f1
(January 27th).
Interestingly when I remove the memory-backend-file parameter I don’t
see the error, i.e. this works:
./x86_64-softmmu/qemu-system-x86_64 \
-kernel /boot/vmlinuz-3.10.0-1062.el7.x86_64 \
-netdev user,id=net0,hostfwd=tcp::2250-:22 \
-device e1000e,netdev=net0 \
-m 1G \
-initrd /boot/initramfs-3.10.0-1062.el7.x86_64.img
Looking at the blame data for backends/hostmem.c I see commit ffac16fa
introduced some churn in this part of the code. Has anyone else seen
this issue? Could I be doing something wrong here?
next reply other threads:[~2020-03-12 5:37 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-12 5:36 Raphael Norwitz [this message]
2020-03-12 10:54 ` Qemu master crashing on boot when using file backend for memory Igor Mammedov
2020-03-25 2:50 ` Raphael Norwitz
2020-03-25 9:46 ` Igor Mammedov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200312053648.GA17365@localhost.localdomain \
--to=raphael.norwitz@nutanix.com \
--cc=qemu-devel@nongnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).