From 70c1835e776c8447c1aca87ddb38cfe764fe756a Mon Sep 17 00:00:00 2001 From: Rik van Riel Date: Tue, 7 May 2024 09:18:58 -0400 Subject: [PATCH] fs/proc: fix softlockup in __read_vmcore commit 5cbcb62dddf5346077feb82b7b0c9254222d3445 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 Acked-by: Baoquan He Cc: Dave Young Cc: Vivek Goyal Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- fs/proc/vmcore.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c index 0e4278d4a769..0833676da5f4 100644 --- a/fs/proc/vmcore.c +++ b/fs/proc/vmcore.c @@ -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) {