On Fri, Mar 12, 2021 at 03:24PM +0100, Andrey Konovalov wrote: > Update the "Boot parameters" section in KASAN documentation: > > - Mention panic_on_warn. > - Mention kasan_multi_shot and its interaction with panic_on_warn. > - Clarify kasan.fault=panic interaction with panic_on_warn. > - A readability clean-up. > > Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Reviewed-by: Marco Elver <elver@xxxxxxxxxx> > --- > Documentation/dev-tools/kasan.rst | 14 ++++++++++---- > 1 file changed, 10 insertions(+), 4 deletions(-) > > diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst > index cd12c890b888..1189be9b4cb5 100644 > --- a/Documentation/dev-tools/kasan.rst > +++ b/Documentation/dev-tools/kasan.rst > @@ -174,10 +174,16 @@ call_rcu() and workqueue queuing. > Boot parameters > ~~~~~~~~~~~~~~~ > > +KASAN is affected by the generic ``panic_on_warn`` command line parameter. > +When it is enabled, KASAN panics the kernel after printing a bug report. > + > +By default, KASAN prints a bug report only for the first invalid memory access. > +With ``kasan_multi_shot``, KASAN prints a report on every invalid access. This > +effectively disables ``panic_on_warn`` for KASAN reports. > + > Hardware tag-based KASAN mode (see the section about various modes below) is > intended for use in production as a security mitigation. Therefore, it supports > -boot parameters that allow to disable KASAN competely or otherwise control > -particular KASAN features. > +boot parameters that allow disabling KASAN or controlling its features. > > - ``kasan=off`` or ``=on`` controls whether KASAN is enabled (default: ``on``). > > @@ -185,8 +191,8 @@ particular KASAN features. > traces collection (default: ``on``). > > - ``kasan.fault=report`` or ``=panic`` controls whether to only print a KASAN > - report or also panic the kernel (default: ``report``). Note, that tag > - checking gets disabled after the first reported bug. > + report or also panic the kernel (default: ``report``). The panic happens even > + if ``kasan_multi_shot`` is enabled. > > Implementation details > ---------------------- > -- > 2.31.0.rc2.261.g7f71774620-goog >
