On Wed, May 06, 2020 at 02:15:21PM -0700, Kees Cook wrote: > From: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> > > Now that pstore_register() can correctly pass max_reason to the kmesg > dump facility, introduce a new "max_reason" module parameter and > "max-reason" Device Tree field. > > The "dump_oops" module parameter and "dump-oops" Device > Tree field are now considered deprecated, but are now automatically > converted to their corresponding max_reason values when present, though > the new max_reason setting has precedence. > > For struct ramoops_platform_data, the "dump_oops" member is entirely > replaced by a new "max_reason" member, with the only existing user > updated in place. > > Additionally remove the "reason" filter logic from ramoops_pstore_write(), > as that is not specifically needed anymore, though technically > this is a change in behavior for any ramoops users also setting the > printk.always_kmsg_dump boot param, which will cause ramoops to behave as > if max_reason was set to KMSG_DUMP_MAX. > > Signed-off-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> > Link: https://lore.kernel.org/r/20200505154510.93506-4-pasha.tatashin@xxxxxxxxxx > Link: https://lore.kernel.org/r/20200505154510.93506-5-pasha.tatashin@xxxxxxxxxx > Co-developed-by: Kees Cook <keescook@xxxxxxxxxxxx> > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> > --- > Documentation/admin-guide/ramoops.rst | 14 +++++-- > drivers/platform/chrome/chromeos_pstore.c | 2 +- > fs/pstore/ram.c | 51 +++++++++++++++-------- > include/linux/pstore_ram.h | 2 +- > 4 files changed, 45 insertions(+), 24 deletions(-) > > diff --git a/Documentation/admin-guide/ramoops.rst b/Documentation/admin-guide/ramoops.rst > index 6dbcc5481000..a60a96218ba9 100644 > --- a/Documentation/admin-guide/ramoops.rst > +++ b/Documentation/admin-guide/ramoops.rst > @@ -32,11 +32,17 @@ memory to be mapped strongly ordered, and atomic operations on strongly ordered > memory are implementation defined, and won't work on many ARMs such as omaps. > > The memory area is divided into ``record_size`` chunks (also rounded down to > -power of two) and each oops/panic writes a ``record_size`` chunk of > +power of two) and each kmesg dump writes a ``record_size`` chunk of > information. > > -Dumping both oopses and panics can be done by setting 1 in the ``dump_oops`` > -variable while setting 0 in that variable dumps only the panics. > +Limiting which kinds of kmsg dumps are stored can be controlled via > +the ``max_reason`` value, as defined in include/linux/kmsg_dump.h's > +``enum kmsg_dump_reason``. For example, to store both Oopses and Panics, > +``max_reason`` should be set to 2 (KMSG_DUMP_OOPS), to store only Panics > +``max_reason`` should be set to 1 (KMSG_DUMP_PANIC). Setting this to 0 > +(KMSG_DUMP_UNDEF), means the reason filtering will be controlled by the > +``printk.always_kmsg_dump`` boot param: if unset, it'll be KMSG_DUMP_OOPS, > +otherwise KMSG_DUMP_MAX. > > The module uses a counter to record multiple dumps but the counter gets reset > on restart (i.e. new dumps after the restart will overwrite old ones). > @@ -90,7 +96,7 @@ Setting the ramoops parameters can be done in several different manners: > .mem_address = <...>, > .mem_type = <...>, > .record_size = <...>, > - .dump_oops = <...>, > + .max_reason = <...>, > .ecc = <...>, > }; > > diff --git a/drivers/platform/chrome/chromeos_pstore.c b/drivers/platform/chrome/chromeos_pstore.c > index d13770785fb5..fa51153688b4 100644 > --- a/drivers/platform/chrome/chromeos_pstore.c > +++ b/drivers/platform/chrome/chromeos_pstore.c > @@ -57,7 +57,7 @@ static struct ramoops_platform_data chromeos_ramoops_data = { > .record_size = 0x40000, > .console_size = 0x20000, > .ftrace_size = 0x20000, > - .dump_oops = 1, > + .max_reason = KMSG_DUMP_OOPS, > }; > > static struct platform_device chromeos_ramoops = { > diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c > index c2f76b650f91..b8dac1d04e96 100644 > --- a/fs/pstore/ram.c > +++ b/fs/pstore/ram.c > @@ -57,10 +57,15 @@ module_param(mem_type, uint, 0600); > MODULE_PARM_DESC(mem_type, > "set to 1 to try to use unbuffered memory (default 0)"); > > -static int dump_oops = 1; > -module_param(dump_oops, int, 0600); > +static int ramoops_dump_oops = -1; > +module_param_named(dump_oops, ramoops_dump_oops, int, 0400); > MODULE_PARM_DESC(dump_oops, > - "set to 1 to dump oopses, 0 to only dump panics (default 1)"); > + "set to 1 to dump oopses & panics, 0 to only dump panics (deprecated: use max_reason instead)"); > + > +static int ramoops_max_reason = KMESG_DUMP_OOPS; This is what I get for a "quick change right before sending". This is a typo and should be KMSG_DUMP_OOPS. :| -- Kees Cook
