Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | From | Björn Töpel <> | Subject | [PATCH v3 6/9] riscv: mm: Take memory hotplug read-lock during kernel page table dump | Date | Tue, 21 May 2024 13:48:27 +0200 |
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From: Björn Töpel <bjorn@rivosinc.com>
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 bf2b59f60ee1 ("arm64/mm: Hold memory hotplug lock while walking for kernel page table dump").
Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Signed-off-by: Björn Töpel <bjorn@rivosinc.com> --- arch/riscv/mm/ptdump.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/arch/riscv/mm/ptdump.c b/arch/riscv/mm/ptdump.c index 1289cc6d3700..9d5f657a251b 100644 --- a/arch/riscv/mm/ptdump.c +++ b/arch/riscv/mm/ptdump.c @@ -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; } -- 2.40.1
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