Messages in this thread | | | Date | Sat, 22 Jul 2023 16:59:15 -0700 | Subject | Re: [PATCH v2 2/3] doc/vm: add information about page_table_check warn_on behavior | From | Randy Dunlap <> |
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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@soleen.com> > --- > 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.
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