On Tue, May 05, 2020 at 11:45:07AM -0400, Pavel Tatashin wrote:
> Add a new field to pstore_info that passes information about kmesg dump
> maximum reason.
>
> This allows a finer control of what kmesg dumps are stored on pstore
> device.
>
> Those clients that do not explicitly set this field (keep it equal to 0),
> get the default behavior: dump only Oops and Panics, and dump everything
> if printk.always_kmsg_dump is provided.
>
> Signed-off-by: Pavel Tatashin <pasha.tatas...@soleen.com>
> ---
> fs/pstore/platform.c | 4 +++-
> include/linux/pstore.h | 3 +++
> 2 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
> index 408277ee3cdb..75bf8a43f92a 100644
> --- a/fs/pstore/platform.c
> +++ b/fs/pstore/platform.c
> @@ -602,8 +602,10 @@ int pstore_register(struct pstore_info *psi)
> if (pstore_is_mounted())
> pstore_get_records(0);
>
> - if (psi->flags & PSTORE_FLAGS_DMESG)
> + if (psi->flags & PSTORE_FLAGS_DMESG) {
> + pstore_dumper.max_reason = psinfo->max_reason;
> pstore_register_kmsg();
> + }
I haven't finished reading the whole series carefully, but I think
something we can do here to make things a bit more user-friendly is to
do the KMSG_DUMP_UNDEF value here to get us the "all" instead of INT_MAX:
if (psi->flags & PSTORE_FLAGS_DMESG) {
pstore_dumper.max_reason = psinfo->max_reason;
if (pstore_dumper.max_reason == KMSG_DUMP_UNDEF)
pstore_dumper.max_reason = KMSG_DUMP_MAX;
pstore_register_kmsg();
}
That way setting max_reason to 0 without setting dump_oops at all will
get "all". I think it'll need some tweaks to the next patch.
> if (psi->flags & PSTORE_FLAGS_CONSOLE)
> pstore_register_console();
> if (psi->flags & PSTORE_FLAGS_FTRACE)
> diff --git a/include/linux/pstore.h b/include/linux/pstore.h
> index e779441e6d26..45ae424bfeb5 100644
> --- a/include/linux/pstore.h
> +++ b/include/linux/pstore.h
> @@ -97,6 +97,8 @@ struct pstore_record {
> * @read_mutex: serializes @open, @read, @close, and @erase callbacks
> * @flags: bitfield of frontends the backend can accept writes for
> * @data: backend-private pointer passed back during callbacks
> + * @max_reason: Used when PSTORE_FLAGS_DMESG is set. Contains the
> + * kmsg_dump_reason enum value.
Nit: please move this above @data since it has a @flags dependency.
> *
> * Callbacks:
> *
> @@ -180,6 +182,7 @@ struct pstore_info {
>
> int flags;
> void *data;
> + int max_reason;
>
> int (*open)(struct pstore_info *psi);
> int (*close)(struct pstore_info *psi);
> --
> 2.25.1
>
Looking good!
--
Kees Cook
