[PATCH v3 2/6] pstore/platform: Pass max_reason to kmesg dump

Kees Cook
2020-05-06T21:15:37Z

From: Pavel Tatashin <pasha.tatashin@soleen.com>

Add a new member to struct pstore_info for passing information about
kmesg dump maximum reason. This allows a finer control of what kmesg
dumps are sent to pstore storage backends.

Those backends that do not explicitly set this field (keeping it equal to
0), get the default behavior: store only Oopses and Panics, or everything
if the printk.always_kmsg_dump boot param is set.

Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Link: https://lore.kernel.org/r/20200505154510.93506-3-pasha.tatashin@soleen.com
Co-developed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
fs/pstore/platform.c | 4 +++-
include/linux/pstore.h | 7 +++++++
2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 6fb526187953..3a3906173534 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -606,8 +606,10 @@ int pstore_register(struct pstore_info *psi)

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();
+ }
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..e78d5c29aa8b 100644
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -96,6 +96,12 @@ struct pstore_record {
*
* @read_mutex: serializes @open, @read, @close, and @erase callbacks
* @flags: bitfield of frontends the backend can accept writes for
+ * @max_reason: Used when PSTORE_FLAGS_DMESG is set. Contains the
+ * kmsg_dump_reason enum value. KMSG_DUMP_UNDEF means
+ * "use existing kmsg_dump() filtering, based on the
+ * printk.always_kmsg_dump boot param" (which is either
+ * KMSG_DUMP_OOPS when false, or KMSG_DUMP_MAX when
+ * tree); see printk.always_kmsg_dump for more details.
* @data: backend-private pointer passed back during callbacks
*
* Callbacks:
@@ -179,6 +185,7 @@ struct pstore_info {
struct mutex read_mutex;

int flags;
+ int max_reason;
void *data;

int (*open)(struct pstore_info *psi);
--
2.20.1