The patch titled
Subject: fs/proc: fix softlockup in __read_vmcore
has been added to the -mm mm-nonmm-unstable branch. Its filename is
fs-proc-fix-softlockup-in-__read_vmcore.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/fs-proc-fix-softlockup-in-__read_vmcore.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Rik van Riel <riel@xxxxxxxxxxx>
Subject: fs/proc: fix softlockup in __read_vmcore
Date: Tue, 7 May 2024 09:18:58 -0400
While taking a kernel core dump with makedumpfile on a larger system,
softlockup messages often appear.
While softlockup warnings can be harmless, they can also interfere with
things like RCU freeing memory, which can be problematic when the kdump
kexec image is configured with as little memory as possible.
Avoid the softlockup, and give things like work items and RCU a chance to
do their thing during __read_vmcore by adding a cond_resched.
Link: https://lkml.kernel.org/r/20240507091858.36ff767f@xxxxxxxxxxxxxxxxxxxx
Signed-off-by: Rik van Riel <riel@xxxxxxxxxxx>
Acked-by: Baoquan He <bhe@xxxxxxxxxx>
Cc: Dave Young <dyoung@xxxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/vmcore.c | 2 ++
1 file changed, 2 insertions(+)
--- a/fs/proc/vmcore.c~fs-proc-fix-softlockup-in-__read_vmcore
+++ a/fs/proc/vmcore.c
@@ -383,6 +383,8 @@ static ssize_t __read_vmcore(struct iov_
/* leave now if filled buffer already */
if (!iov_iter_count(iter))
return acc;
+
+ cond_resched();
}
list_for_each_entry(m, &vmcore_list, list) {
_
Patches currently in -mm which might be from riel@xxxxxxxxxxx are
fs-proc-fix-softlockup-in-__read_vmcore.patch
