On 2020-05-06 14:15:21, 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; > +module_param_named(max_reason, ramoops_max_reason, int, 0400); > +MODULE_PARM_DESC(max_reason, > + "maximum reason for kmsg dump (default 2: Oops and Panic) "); > > static int ramoops_ecc; > module_param_named(ecc, ramoops_ecc, int, 0600); > @@ -81,7 +86,6 @@ struct ramoops_context { > size_t console_size; > size_t ftrace_size; > size_t pmsg_size; > - int dump_oops; > u32 flags; > struct persistent_ram_ecc_info ecc_info; > unsigned int max_dump_cnt; > @@ -382,16 +386,14 @@ static int notrace ramoops_pstore_write(struct pstore_record *record) > return -EINVAL; > > /* > - * Out of the various dmesg dump types, ramoops is currently designed > - * to only store crash logs, rather than storing general kernel logs. > + * We could filter on record->reason here if we wanted to (which > + * would duplicate what happened before the "max_reason" setting > + * was added), but that would defeat the purpose of a system > + * changing printk.always_kmsg_dump, so instead log everything that > + * the kmsg dumper sends us, since it should be doing the filtering > + * based on the combination of printk.always_kmsg_dump and our > + * requested "max_reason". > */ > - if (record->reason != KMSG_DUMP_OOPS && > - record->reason != KMSG_DUMP_PANIC) > - return -EINVAL; > - > - /* Skip Oopes when configured to do so. */ > - if (record->reason == KMSG_DUMP_OOPS && !cxt->dump_oops) > - return -EINVAL; > > /* > * Explicitly only take the first part of any new crash. > @@ -692,7 +694,14 @@ static int ramoops_parse_dt(struct platform_device *pdev, > pdata->mem_size = resource_size(res); > pdata->mem_address = res->start; > pdata->mem_type = of_property_read_bool(of_node, "unbuffered"); > - pdata->dump_oops = !of_property_read_bool(of_node, "no-dump-oops"); > + /* > + * Setting "no-dump-oops" is deprecated and will be ignored if > + * "max_reason" is also specified. > + */ > + if (of_property_read_bool(of_node, "no-dump-oops")) > + pdata->max_reason = KMSG_DUMP_PANIC; > + else > + pdata->max_reason = KMSG_DUMP_OOPS; > > #define parse_size(name, field, default_value) { \ > ret = ramoops_parse_dt_size(pdev, name, default_value, \ > @@ -708,6 +717,7 @@ static int ramoops_parse_dt(struct platform_device *pdev, > parse_size("pmsg-size", pdata->pmsg_size, 0); > parse_size("ecc-size", pdata->ecc_info.ecc_size, 0); > parse_size("flags", pdata->flags, 0); > + parse_size("max-reason", pdata->max_reason, pdata->max_reason); > > #undef parse_size > > @@ -791,7 +801,6 @@ static int ramoops_probe(struct platform_device *pdev) > cxt->console_size = pdata->console_size; > cxt->ftrace_size = pdata->ftrace_size; > cxt->pmsg_size = pdata->pmsg_size; > - cxt->dump_oops = pdata->dump_oops; > cxt->flags = pdata->flags; > cxt->ecc_info = pdata->ecc_info; > > @@ -834,8 +843,10 @@ static int ramoops_probe(struct platform_device *pdev) > * the single region size is how to check. > */ > cxt->pstore.flags = 0; > - if (cxt->max_dump_cnt) > + if (cxt->max_dump_cnt) { > cxt->pstore.flags |= PSTORE_FLAGS_DMESG; > + cxt->pstore.max_reason = pdata->max_reason; > + } > if (cxt->console_size) > cxt->pstore.flags |= PSTORE_FLAGS_CONSOLE; > if (cxt->max_ftrace_cnt) > @@ -871,7 +882,7 @@ static int ramoops_probe(struct platform_device *pdev) > mem_size = pdata->mem_size; > mem_address = pdata->mem_address; > record_size = pdata->record_size; > - dump_oops = pdata->dump_oops; > + ramoops_max_reason = pdata->max_reason; > ramoops_console_size = pdata->console_size; > ramoops_pmsg_size = pdata->pmsg_size; > ramoops_ftrace_size = pdata->ftrace_size; > @@ -954,7 +965,11 @@ static void __init ramoops_register_dummy(void) > pdata.console_size = ramoops_console_size; > pdata.ftrace_size = ramoops_ftrace_size; > pdata.pmsg_size = ramoops_pmsg_size; > - pdata.dump_oops = dump_oops; > + /* Parse deprecated module param "dump_oops" into "max_reason". */ > + if (ramoops_dump_oops != -1) > + pdata.max_reason = ramoops_dump_oops ? KMSG_DUMP_OOPS > + : KMSG_DUMP_PANIC; > + pdata.max_reason = ramoops_max_reason; This isn't quite right. We're conditionally assigning pdata.max_reason and then immediately re-assigning it. IIUC, we're just missing an else block and it should look like this: /* Parse deprecated module param "dump_oops" into "max_reason". */ if (ramoops_dump_oops != -1) pdata.max_reason = ramoops_dump_oops ? KMSG_DUMP_OOPS : KMSG_DUMP_PANIC; else pdata.max_reason = ramoops_max_reason; Tyler > pdata.flags = RAMOOPS_FLAG_FTRACE_PER_CPU; > > /* > diff --git a/include/linux/pstore_ram.h b/include/linux/pstore_ram.h > index 9cb9b9067298..9f16afec7290 100644 > --- a/include/linux/pstore_ram.h > +++ b/include/linux/pstore_ram.h > @@ -133,7 +133,7 @@ struct ramoops_platform_data { > unsigned long console_size; > unsigned long ftrace_size; > unsigned long pmsg_size; > - int dump_oops; > + int max_reason; > u32 flags; > struct persistent_ram_ecc_info ecc_info; > }; > -- > 2.20.1 >
