From: Kees Cook <keescook@chromium.org>
To: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Kees Cook <keescook@chromium.org>,
Anton Vorontsov <anton@enomsg.org>,
Colin Cross <ccross@android.com>, Tony Luck <tony.luck@intel.com>,
Jonathan Corbet <corbet@lwn.net>,
Rob Herring <robh+dt@kernel.org>,
Benson Leung <bleung@chromium.org>,
Enric Balletbo i Serra <enric.balletbo@collabora.com>,
Petr Mladek <pmladek@suse.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
jmorris@namei.org, sashal@kernel.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, devicetree@vger.kernel.org
Subject: [PATCH v3 1/6] printk: honor the max_reason field in kmsg_dumper
Date: Wed, 6 May 2020 14:15:18 -0700 [thread overview]
Message-ID: <20200506211523.15077-2-keescook@chromium.org> (raw)
In-Reply-To: <20200506211523.15077-1-keescook@chromium.org>
From: Pavel Tatashin <pasha.tatashin@soleen.com>
kmsg_dump() allows to dump kmesg buffer for various system events: oops,
panic, reboot, etc. It provides an interface to register a callback call
for clients, and in that callback interface there is a field "max_reason"
which gets ignored unless always_kmsg_dump is passed as kernel parameter.
Allow clients to decide max_reason, and keep the current behavior when
max_reason is not set.
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Link: https://lore.kernel.org/r/20200505154510.93506-2-pasha.tatashin@soleen.com
Signed-off-by: Kees Cook <keescook@chromium.org>
---
include/linux/kmsg_dump.h | 1 +
kernel/printk/printk.c | 15 +++++++++++----
2 files changed, 12 insertions(+), 4 deletions(-)
diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h
index 2e7a1e032c71..cfc042066be7 100644
--- a/include/linux/kmsg_dump.h
+++ b/include/linux/kmsg_dump.h
@@ -28,6 +28,7 @@ enum kmsg_dump_reason {
KMSG_DUMP_RESTART,
KMSG_DUMP_HALT,
KMSG_DUMP_POWEROFF,
+ KMSG_DUMP_MAX
};
/**
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 9a9b6156270b..1aab69a8a2bf 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -3157,12 +3157,19 @@ void kmsg_dump(enum kmsg_dump_reason reason)
struct kmsg_dumper *dumper;
unsigned long flags;
- if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump)
- return;
-
rcu_read_lock();
list_for_each_entry_rcu(dumper, &dump_list, list) {
- if (dumper->max_reason && reason > dumper->max_reason)
+ enum kmsg_dump_reason cur_reason = dumper->max_reason;
+
+ /*
+ * If client has not provided a specific max_reason, default
+ * to KMSG_DUMP_OOPS, unless always_kmsg_dump was set.
+ */
+ if (cur_reason == KMSG_DUMP_UNDEF) {
+ cur_reason = always_kmsg_dump ? KMSG_DUMP_MAX :
+ KMSG_DUMP_OOPS;
+ }
+ if (reason > cur_reason)
continue;
/* initialize iterator with data about the stored records */
--
2.20.1
next prev parent reply other threads:[~2020-05-06 21:16 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-06 21:15 [PATCH v3 0/6] allow ramoops to collect all kmesg_dump events Kees Cook
2020-05-06 21:15 ` Kees Cook [this message]
2020-05-06 21:15 ` [PATCH v3 2/6] pstore/platform: Pass max_reason to kmesg dump Kees Cook
2020-05-06 21:25 ` Joe Perches
2020-05-06 22:40 ` Kees Cook
2020-05-06 21:15 ` [PATCH v3 3/6] pstore/ram: Refactor DT size parsing Kees Cook
2020-05-07 12:57 ` Pavel Tatashin
2020-05-07 18:04 ` Kees Cook
2020-05-06 21:15 ` [PATCH v3 4/6] pstore/ram: Introduce max_reason and convert dump_oops Kees Cook
2020-05-06 21:17 ` Kees Cook
2020-05-12 23:35 ` Tyler Hicks
2020-05-12 23:57 ` Kees Cook
2020-05-16 2:43 ` Kees Cook
2020-05-06 21:15 ` [PATCH v3 5/6] ramoops: Add max_reason optional field to ramoops DT node Kees Cook
2020-05-06 21:15 ` [PATCH v3 6/6] pstore/ram: Adjust module param permissions to reflect reality Kees Cook
2020-05-12 13:16 ` [PATCH v3 0/6] allow ramoops to collect all kmesg_dump events Petr Mladek
2020-05-12 14:03 ` Pavel Tatashin
2020-05-12 15:52 ` Petr Mladek
2020-05-12 16:03 ` Steven Rostedt
2020-05-12 16:49 ` Pavel Tatashin
2020-05-12 18:53 ` Kees Cook
2020-05-12 18:45 ` Kees Cook
2020-05-13 7:34 ` Petr Mladek
2020-05-13 7:47 ` Kees Cook
2020-05-13 14:35 ` Pavel Tatashin
2020-05-13 20:15 ` Kees Cook
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