Cc: Ahmed S. Darwish <darwish.07@gmail.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Marco Stornelli <marco.stornelli@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This series aims to develop logging facility for enterprise use.
It is important to save kernel messages reliably on enterprise system
because they are helpful for diagnosing system.
This series add kmsg_dump() to the paths loosing kernel messages. The use
case is the following.
[Use case of reboot/poweroff/halt/emergency_restart]
My company has often experienced the followings in our support service.
- Customer's system suddenly reboots.
- Customers ask us to investigate the reason of the reboot.
We recognize the fact itself because boot messages remain in
/var/log/messages. However, we can't investigate the reason why the
system rebooted, because the last messages don't remain. And off course
we can't explain the reason.
We can solve above problem with this patch as follows.
Case1: reboot with command
- We can see "Restarting system with command:" or ""Restarting system.".
Case2: halt with command
- We can see "System halted.".
Case3: poweroff with command
- We can see " Power down.".
Case4: emergency_restart with sysrq.
- We can see "Sysrq:" outputted in __handle_sysrq().
Case5: emergency_restart with softdog.
- We can see "Initiating system reboot" in watchdog_fire().
So, we can distinguish the reason of reboot, poweroff, halt and emergency_restart.
If customer executed reboot command, you may think the customer should
know the fact. However, they often claim they don't execute the command
when they rebooted system by mistake.
No message remains on the current Linux kernel, so we can't show the proof
to the customer. This patch improves this situation.
This patch:
Alters mtdoops and ramoops to perform their actions only for
KMSG_DUMP_PANIC, KMSG_DUMP_OOPS and KMSG_DUMP_KEXEC because they would
like to log crashes only.
Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Marco Stornelli <marco.stornelli@gmail.com>
Reviewed-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The current code mis-calculates the ramoops header size, leading to an
overflow over the next record at best, or over a non-allocated region at
worst. Fix that calculation.
Signed-off-by: Ahmed S. Darwish <darwish.07@gmail.com>
Acked-by: Marco Stornelli <marco.stornelli@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As each board and system has different memory for ramoops. It's better to
define the platform data instead of module params.
[akpm@linux-foundation.org: fix ramoops_remove() return type]
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Marco Stornelli <marco.stornelli@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ramoops, like mtdoops, can log oops/panic information but in RAM. It can
be used with persistent RAM for systems without flash support. In
addition, for this systems, with this driver, it's no more needed add to
the kernel the mtd subsystem with advantage in footprint.
It can be used in a very easy way with persistent RAM for systems without
flash support. For these systems, with this driver, it is no longer
required to cinlude mtd subsystem with an advantage in footprint. In
addition, you can save flash space and store this information only in RAM.
Signed-off-by: Marco Stornelli <marco.stornelli@gmail.com>
Cc: Simon Kagstrom <simon.kagstrom@netinsight.net>
Cc: David Woodhouse <David.Woodhouse@intel.com>
Cc; Anders Grafstrom <anders.grafstrom@netinsight.net>
Cc: Yuasa Yoichi <yuasa@linux-mips.org>
Cc: Jamie Lokier <jamie@shareable.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
