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FS#70663 - [linux] 5.12.0-arch1-1 - fails to boot - watchdog: BUG: soft lockup - CPU#0 stuck for 23s! [systemd-

Attached to Project: Arch Linux
Opened by James (thx1138) - Friday, 30 April 2021, 15:45 GMT
Last edited by Andreas Radke (AndyRTR) - Friday, 30 April 2021, 18:34 GMT
Task Type Bug Report
Category Packages: Testing
Status Assigned
Assigned To Jan Alexander Steffens (heftig)
Architecture All
Severity Critical
Priority Normal
Reported Version
Due in Version Undecided
Due Date Undecided
Percent Complete 0%
Votes 0
Private No


Upgrade to linux 5.12.arch1-1

System log throws:

watchdog: BUG: soft lockup - CPU#0 stuck for 23s! [systemd-udevd: 241]
RIP: 0010:smp_call_function_single+0xf7/0x140
Call Trace:
? __flush_tlb_all+0x30/0x30
? __flush_tlb_all+0x30/0x30

and repeats indefinitely.

smp_call_function_single is defined in kernel/smp.c

For now, reverting to 5.11 or lts.
This task depends upon

Comment by James (thx1138) - Friday, 30 April 2021, 15:53 GMT
Intel Core2 T7200
Mobile Intel 945PM Express Chipset
Comment by James (thx1138) - Friday, 30 April 2021, 17:05 GMT
Bug posted to linux-smp
Comment by env (ENV25) - Monday, 03 May 2021, 08:31 GMT Comment by James (thx1138) - Monday, 03 May 2021, 09:43 GMT
$ git bisect bad
7c70f3a7488d2fa62d32849d138bf2b8420fe788 is the first bad commit
commit 7c70f3a7488d2fa62d32849d138bf2b8420fe788
Merge: 20bf195e9391 4d12b7275386
Author: Linus Torvalds <>
Date: Mon Feb 22 13:29:55 2021 -0800

Merge tag 'nfsd-5.12-1' of git://

Pull more nfsd updates from Chuck Lever:
"Here are a few additional NFSD commits for the merge window:

- Cork the socket while there are queued replies

- DRC shutdown ordering
- svc_rdma_accept() lockdep splat"

* tag 'nfsd-5.12-1' of git://
SUNRPC: Further clean up svc_tcp_sendmsg()
SUNRPC: Remove redundant socket flags from svc_tcp_sendmsg()
SUNRPC: Use TCP_CORK to optimise send performance on the server
svcrdma: Hold private mutex while invoking rdma_accept()
nfsd: register pernet ops last, unregister first

fs/nfsd/nfsctl.c | 14 ++++++-------
include/linux/sunrpc/svcsock.h | 2 ++
net/sunrpc/svcsock.c | 35 ++++++++++++++++----------------
net/sunrpc/xprtrdma/svc_rdma_transport.c | 6 +++---
4 files changed, 29 insertions(+), 28 deletions(-)


There is a small chance that this bisect is not precise, because sometimes the system can boot to a temporarily working state, then lock-up after a short time. I did not test every successful initial boot extensively.

This particular commit does not produce the same "watchdog: BUG: soft lockup" log message. Instead, after sometimes booting to an Xorg display, the system just completely freezes, with not so much as the system log still working.