fs/proc: fix softlockup in __read_vmcore

commit 5cbcb62ddd upstream.

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@imladris.surriel.com
Signed-off-by: Rik van Riel <riel@surriel.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This commit is contained in:

Rik van Riel

2024-05-07 09:18:58 -04:00

committed by

Greg Kroah-Hartman

parent 4f2fd2a378

commit e1b160a50c

1 changed files with 2 additions and 0 deletions

									
										fs/proc/vmcore.c
									
		+2
		
												View File
												
				@@ -373,6 +373,8 @@ static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,

						/* leave now if filled buffer already */

						if (buflen == 0)

							return acc;

						cond_resched();

					}

					list_for_each_entry(m, &vmcore_list, list) {