The default behavior of page table check was changed from panicking kernel to printing a warning. Add a note how to still panic the kernel when error is detected. Signed-off-by: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx> --- Documentation/mm/page_table_check.rst | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/Documentation/mm/page_table_check.rst b/Documentation/mm/page_table_check.rst index 1a09472f10a3..9306cd75647c 100644 --- a/Documentation/mm/page_table_check.rst +++ b/Documentation/mm/page_table_check.rst @@ -16,13 +16,13 @@ Page table check performs extra verifications at the time when new pages become accessible from the userspace by getting their page table entries (PTEs PMDs etc.) added into the table. -In case of detected corruption, the kernel is crashed. There is a small -performance and memory overhead associated with the page table check. Therefore, -it is disabled by default, but can be optionally enabled on systems where the -extra hardening outweighs the performance costs. Also, because page table check -is synchronous, it can help with debugging double map memory corruption issues, -by crashing kernel at the time wrong mapping occurs instead of later which is -often the case with memory corruptions bugs. +In case of detected corruption, a warning is printed or kernel is crashed. There +is a small performance and memory overhead associated with the page table check. +Therefore, it is disabled by default, but can be optionally enabled on systems +where the extra hardening outweighs the performance costs. Also, because page +table check is synchronous, it can help with debugging double map memory +corruption issues, by crashing kernel at the time wrong mapping occurs instead +of later which is often the case with memory corruptions bugs. Double mapping detection logic ============================== @@ -52,5 +52,7 @@ Build kernel with: - Boot with 'page_table_check=on' kernel parameter. +- Boot with 'page_table_check=panic' in order to panic when error is detected. + Optionally, build kernel with PAGE_TABLE_CHECK_ENFORCED in order to have page table support without extra kernel parameter. -- 2.37.2.789.g6183377224-goog
