4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Rik van Riel <riel@xxxxxxxxxxx> 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@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> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/proc/vmcore.c | 2 ++ 1 file changed, 2 insertions(+) --- a/fs/proc/vmcore.c +++ b/fs/proc/vmcore.c @@ -359,6 +359,8 @@ static ssize_t __read_vmcore(char *buffe /* leave now if filled buffer already */ if (buflen == 0) return acc; + + cond_resched(); } list_for_each_entry(m, &vmcore_list, list) {
