Login
Log in using an SSO provider:
Fedora Account System
Red Hat Associate
Red Hat Customer
Login using a Red Hat Bugzilla account
Forgot Password
Create an Account
Red Hat Bugzilla – Attachment 1750515 Details for
Bug 1916589
watchdog: use nmi registers snapshot in hardlockup handler
Home
New
Search
Simple Search
Advanced Search
My Links
Browse
Requests
Reports
Current State
Search
Tabular reports
Graphical reports
Duplicates
Other Reports
User Changes
Plotly Reports
Bug Status
Bug Severity
Non-Defaults
Product Dashboard
Help
Page Help!
Bug Writing Guidelines
What's new
Browser Support Policy
5.0.4.rh90 Release notes
FAQ
Guides index
User guide
Web Services
Contact
Legal
[?]
This site requires JavaScript to be enabled to function correctly, please enable it.
RHEL PATCH 1/1
0001-kernel-watchdog-use-nmi-registers-snapshot-in-hardlo.patch (text/plain), 2.50 KB, created by
Prarit Bhargava
on 2021-01-25 13:33:46 UTC
(
hide
)
Description:
RHEL PATCH 1/1
Filename:
MIME Type:
Creator:
Prarit Bhargava
Created:
2021-01-25 13:33:46 UTC
Size:
2.50 KB
patch
obsolete
>From aadb965b8c7bfed32ab24fc3c6ebbdb1d53531ec Mon Sep 17 00:00:00 2001 >From: Prarit Bhargava <prarit@redhat.com> >Date: Fri, 15 Jan 2021 08:39:55 -0500 >Subject: [PATCH] kernel/watchdog: use nmi registers snapshot in hardlockup > handler > >Bugzilla: http://bugzilla.redhat.com/1916589 > >This line was introduced in RHEL7 commit b7557e36b465 ("[kernel] watchdog: >perform all-CPU backtrace in case of hard lockup") and causes a regression >during panic where the regs are missing. As a result it is not possible >to debug in kdump. > >Tested: I've tried to reproduce locally, however, it appears >the the problem has low reproducibility. I have sanity tested this patch >and confirmed that kdump does work in RHEL7. > >commit 4d1f0fb096aedea7bb5489af93498a82e467c480 >Author: Konstantin Khlebnikov <koct9i@gmail.com> >Date: Wed Dec 14 15:04:04 2016 -0800 > > kernel/watchdog: use nmi registers snapshot in hardlockup handler > > NMI handler doesn't call set_irq_regs(), it's set only by normal IRQ. > Thus get_irq_regs() returns NULL or stale registers snapshot with IP/SP > pointing to the code interrupted by IRQ which was interrupted by NMI. > NULL isn't a problem: in this case watchdog calls dump_stack() and > prints full stack trace including NMI. But if we're stuck in IRQ > handler then NMI watchlog will print stack trace without IRQ part at > all. > > This patch uses registers snapshot passed into NMI handler as arguments: > these registers point exactly to the instruction interrupted by NMI. > > Fixes: 55537871ef66 ("kernel/watchdog.c: perform all-CPU backtrace in case of hard lockup") > Link: http://lkml.kernel.org/r/146771764784.86724.6006627197118544150.stgit@buzz > Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> > Cc: Jiri Kosina <jkosina@suse.cz> > Cc: Ulrich Obergfell <uobergfe@redhat.com> > Cc: Aaron Tomlin <atomlin@redhat.com> > Cc: <stable@vger.kernel.org> [4.4+] > Signed-off-by: Andrew Morton <akpm@linux-foundation.org> > Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> >--- > kernel/watchdog.c | 1 - > 1 file changed, 1 deletion(-) > >diff --git a/kernel/watchdog.c b/kernel/watchdog.c >index 669e77678318..a72e2aa21100 100644 >--- a/kernel/watchdog.c >+++ b/kernel/watchdog.c >@@ -414,7 +414,6 @@ static void watchdog_overflow_callback(struct perf_event *event, > */ > if (is_hardlockup()) { > int this_cpu = smp_processor_id(); >- struct pt_regs *regs = get_irq_regs(); > > /* only print hardlockups once */ > if (__this_cpu_read(hard_watchdog_warn) == true) >-- >2.29.2 >
You cannot view the attachment while viewing its details because your browser does not support IFRAMEs.
View the attachment on a separate page
.
View Attachment As Raw
Actions:
View
Attachments on
bug 1916589
: 1750515