From: Kees Cook <keescook@chromium.org>
To: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Kees Cook <keescook@chromium.org>, Petr Mladek <pmladek@suse.com>,
Anton Vorontsov <anton@enomsg.org>,
Colin Cross <ccross@android.com>, Tony Luck <tony.luck@intel.com>,
Jonathan Corbet <corbet@lwn.net>,
Benson Leung <bleung@chromium.org>,
Rob Herring <robh+dt@kernel.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Enric Balletbo i Serra <enric.balletbo@collabora.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
devicetree@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v4 2/6] printk: honor the max_reason field in kmsg_dumper
Date: Fri, 15 May 2020 11:44:30 -0700 [thread overview]
Message-ID: <20200515184434.8470-3-keescook@chromium.org> (raw)
In-Reply-To: <20200515184434.8470-1-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/lkml/20200506211523.15077-2-keescook@chromium.org/
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 3f82b5cb2d82..9826014771ab 100644
--- a/include/linux/kmsg_dump.h
+++ b/include/linux/kmsg_dump.h
@@ -26,6 +26,7 @@ enum kmsg_dump_reason {
KMSG_DUMP_OOPS,
KMSG_DUMP_EMERG,
KMSG_DUMP_SHUTDOWN,
+ KMSG_DUMP_MAX
};
/**
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 9a9b6156270b..a121c2255737 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 max_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 (max_reason == KMSG_DUMP_UNDEF) {
+ max_reason = always_kmsg_dump ? KMSG_DUMP_MAX :
+ KMSG_DUMP_OOPS;
+ }
+ if (reason > max_reason)
continue;
/* initialize iterator with data about the stored records */
--
2.20.1
next prev parent reply other threads:[~2020-05-15 18:44 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-15 18:44 [PATCH v4 0/6] allow ramoops to collect all kmesg_dump events Kees Cook
2020-05-15 18:44 ` [PATCH v4 1/6] printk: Collapse shutdown types into a single dump reason Kees Cook
2020-05-15 19:17 ` Pavel Tatashin
2020-05-22 16:21 ` Petr Mladek
2020-05-23 11:16 ` Michael Ellerman
2020-05-15 18:44 ` Kees Cook [this message]
2020-05-22 16:51 ` [PATCH v4 2/6] printk: honor the max_reason field in kmsg_dumper Petr Mladek
2020-05-22 17:34 ` Kees Cook
2020-05-15 18:44 ` [PATCH v4 3/6] printk: Introduce kmsg_dump_reason_str() Kees Cook
2020-05-15 19:23 ` Pavel Tatashin
2020-05-15 18:44 ` [PATCH v4 4/6] pstore/platform: Pass max_reason to kmesg dump Kees Cook
2020-05-15 18:44 ` [PATCH v4 5/6] pstore/ram: Introduce max_reason and convert dump_oops Kees Cook
2020-05-15 19:30 ` Pavel Tatashin
2020-05-15 19:48 ` Kees Cook
2020-05-15 19:40 ` Pavel Tatashin
2020-05-15 19:53 ` Kees Cook
2020-05-15 18:44 ` [PATCH v4 6/6] ramoops: Add max_reason optional field to ramoops DT node Kees Cook
2020-05-18 22:45 ` Rob Herring
2020-05-18 23:04 ` Kees Cook
2020-05-15 19:13 ` [PATCH v4 0/6] allow ramoops to collect all kmesg_dump events Pavel Tatashin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200515184434.8470-3-keescook@chromium.org \
--to=keescook@chromium.org \
--cc=anton@enomsg.org \
--cc=benh@kernel.crashing.org \
--cc=bleung@chromium.org \
--cc=ccross@android.com \
--cc=corbet@lwn.net \
--cc=devicetree@vger.kernel.org \
--cc=enric.balletbo@collabora.com \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mpe@ellerman.id.au \
--cc=pasha.tatashin@soleen.com \
--cc=paulus@samba.org \
--cc=pmladek@suse.com \
--cc=robh+dt@kernel.org \
--cc=rostedt@goodmis.org \
--cc=sergey.senozhatsky@gmail.com \
--cc=tony.luck@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).