On Sat, Jul 22, 2023 at 7:59 PM Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote: > > Hi-- > > On 7/22/23 16:15, Pasha Tatashin wrote: > > 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 | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > diff --git a/Documentation/mm/page_table_check.rst b/Documentation/mm/page_table_check.rst > > index c12838ce6b8d..f534c80ee9c9 100644 > > --- a/Documentation/mm/page_table_check.rst > > +++ b/Documentation/mm/page_table_check.rst > > @@ -14,13 +14,14 @@ 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 > > +In case of detected corruption, a warning is printed. 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. > > +often the case with memory corruptions bugs. In order to crash kernel sysctl > > +panic_on_warn should be set to 1. > > Better as: > In order to crash the kernel, the sysctl panic_on_warn should be set > to 1. Will update in the next version. Thanks, Pasha >
