Unverified Commit 37992b7f authored by Björn Töpel's avatar Björn Töpel Committed by Palmer Dabbelt
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riscv: mm: Take memory hotplug read-lock during kernel page table dump 



During memory hot remove, the ptdump functionality can end up touching
stale data. Avoid any potential crashes (or worse), by holding the
memory hotplug read-lock while traversing the page table.

This change is analogous to arm64's commit bf2b59f6 ("arm64/mm:
Hold memory hotplug lock while walking for kernel page table dump").

Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Reviewed-by: default avatarOscar Salvador <osalvador@suse.de>
Signed-off-by: default avatarBjörn Töpel <bjorn@rivosinc.com>
Link: https://lore.kernel.org/r/20240605114100.315918-8-bjorn@kernel.org


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent c75a74f4

arch/riscv/mm/ptdump.c

+3 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
#include <linux/efi.h>

#include <linux/init.h>

#include <linux/debugfs.h>

#include <linux/memory_hotplug.h>

#include <linux/seq_file.h>

#include <linux/ptdump.h>
@@ -370,7 +371,9 @@ bool ptdump_check_wx(void) 


static int ptdump_show(struct seq_file *m, void *v)

{

	get_online_mems();

	ptdump_walk(m, m->private);

	put_online_mems();



	return 0;

}