From: Kees Cook <keescook@chromium.org> To: Petr Mladek <pmladek@suse.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.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: Re: [PATCH v4 2/6] printk: honor the max_reason field in kmsg_dumper Date: Fri, 22 May 2020 10:34:17 -0700 [thread overview] Message-ID: <202005221032.859452DFA0@keescook> (raw) In-Reply-To: <20200522165120.GL3464@linux-b0ei> On Fri, May 22, 2020 at 06:51:20PM +0200, Petr Mladek wrote: > On Fri 2020-05-15 11:44:30, Kees Cook wrote: > > 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. > > Strictly speaking, this is not fully true. "max_reason" field is not > ignored when set to KMSG_DUMP_PANIC even when always_kmsg_dump was not set. > > It should be something like: > > "which gets ignored for reason higher than KMSG_DUMP_OOPS unless > always_kmsg_dump is passed as kernel parameter". > > Heh, I wonder if anyone will be able to parse this ;-) Ah yeah, good point. I've reworded things like this: 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", but it was getting ignored when set to any "reason" higher than KMSG_DUMP_OOPS unless "always_kmsg_dump" was passed as kernel parameter. Allow clients to actually control their "max_reason", and keep the current behavior when "max_reason" is not set. > Otherwise, it looks good to me. With the updated commit message: > > Reviewed-by: Petr Mladek <pmladek@suse.com> Thanks! -- Kees Cook
WARNING: multiple messages have this Message-ID (diff)
From: Kees Cook <keescook@chromium.org> To: Petr Mladek <pmladek@suse.com> Cc: devicetree@vger.kernel.org, Tony Luck <tony.luck@intel.com>, Pavel Tatashin <pasha.tatashin@soleen.com>, Jonathan Corbet <corbet@lwn.net>, Anton Vorontsov <anton@enomsg.org>, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Steven Rostedt <rostedt@goodmis.org>, Sergey Senozhatsky <sergey.senozhatsky@gmail.com>, Rob Herring <robh+dt@kernel.org>, Paul Mackerras <paulus@samba.org>, Colin Cross <ccross@android.com>, Enric Balletbo i Serra <enric.balletbo@collabora.com>, linuxppc-dev@lists.ozlabs.org, Benson Leung <bleung@chromium.org> Subject: Re: [PATCH v4 2/6] printk: honor the max_reason field in kmsg_dumper Date: Fri, 22 May 2020 10:34:17 -0700 [thread overview] Message-ID: <202005221032.859452DFA0@keescook> (raw) In-Reply-To: <20200522165120.GL3464@linux-b0ei> On Fri, May 22, 2020 at 06:51:20PM +0200, Petr Mladek wrote: > On Fri 2020-05-15 11:44:30, Kees Cook wrote: > > 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. > > Strictly speaking, this is not fully true. "max_reason" field is not > ignored when set to KMSG_DUMP_PANIC even when always_kmsg_dump was not set. > > It should be something like: > > "which gets ignored for reason higher than KMSG_DUMP_OOPS unless > always_kmsg_dump is passed as kernel parameter". > > Heh, I wonder if anyone will be able to parse this ;-) Ah yeah, good point. I've reworded things like this: 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", but it was getting ignored when set to any "reason" higher than KMSG_DUMP_OOPS unless "always_kmsg_dump" was passed as kernel parameter. Allow clients to actually control their "max_reason", and keep the current behavior when "max_reason" is not set. > Otherwise, it looks good to me. With the updated commit message: > > Reviewed-by: Petr Mladek <pmladek@suse.com> Thanks! -- Kees Cook
next prev parent reply other threads:[~2020-05-22 17:34 UTC|newest] Thread overview: 40+ 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 ` 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 18:44 ` Kees Cook 2020-05-15 19:17 ` Pavel Tatashin 2020-05-15 19:17 ` Pavel Tatashin 2020-05-22 16:21 ` Petr Mladek 2020-05-22 16:21 ` Petr Mladek 2020-05-23 11:16 ` Michael Ellerman 2020-05-23 11:16 ` Michael Ellerman 2020-05-15 18:44 ` [PATCH v4 2/6] printk: honor the max_reason field in kmsg_dumper Kees Cook 2020-05-15 18:44 ` Kees Cook 2020-05-22 16:51 ` Petr Mladek 2020-05-22 16:51 ` Petr Mladek 2020-05-22 17:34 ` Kees Cook [this message] 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 18:44 ` Kees Cook 2020-05-15 19:23 ` Pavel Tatashin 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 ` 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 18:44 ` Kees Cook 2020-05-15 19:30 ` Pavel Tatashin 2020-05-15 19:30 ` Pavel Tatashin 2020-05-15 19:48 ` Kees Cook 2020-05-15 19:48 ` Kees Cook 2020-05-15 19:40 ` Pavel Tatashin 2020-05-15 19:40 ` Pavel Tatashin 2020-05-15 19:53 ` Kees Cook 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 2020-05-15 18:44 ` Kees Cook 2020-05-18 22:45 ` Rob Herring 2020-05-18 22:45 ` Rob Herring 2020-05-18 23:04 ` Kees Cook 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 2020-05-15 19:13 ` Pavel Tatashin
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