linux-toradex.git/include/linux/kmsg_dump.h, branch v5.10-rc3

printk: Introduce kmsg_dump_reason_str()

2020-05-30T17:34:03+00:00

The pstore subsystem already had a private version of this function.
With the coming addition of the pstore/zone driver, this needs to be
shared. As it really should live with printk, move it there instead.

Link: https://lore.kernel.org/lkml/20200515184434.8470-4-keescook@chromium.org/
Acked-by: Petr Mladek 
Acked-by: Sergey Senozhatsky 
Reviewed-by: Pavel Tatashin 
Signed-off-by: Kees Cook

printk: honor the max_reason field in kmsg_dumper

2020-05-30T17:34:03+00:00

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.

Signed-off-by: Pavel Tatashin 
Link: https://lore.kernel.org/lkml/20200515184434.8470-3-keescook@chromium.org/
Reviewed-by: Petr Mladek 
Signed-off-by: Kees Cook

printk: Collapse shutdown types into a single dump reason

2020-05-30T17:34:03+00:00

To turn the KMSG_DUMP_* reasons into a more ordered list, collapse
the redundant KMSG_DUMP_(RESTART|HALT|POWEROFF) reasons into
KMSG_DUMP_SHUTDOWN. The current users already don't meaningfully
distinguish between them, so there's no need to, as discussed here:
https://lore.kernel.org/lkml/CA+CK2bAPv5u1ih5y9t5FUnTyximtFCtDYXJCpuyjOyHNOkRdqw@mail.gmail.com/

Link: https://lore.kernel.org/lkml/20200515184434.8470-2-keescook@chromium.org/
Reviewed-by: Pavel Tatashin 
Reviewed-by: Petr Mladek 
Acked-by: Michael Ellerman  (powerpc)
Signed-off-by: Kees Cook

printk: Implement some unlocked kmsg_dump functions

2012-07-21T17:34:00+00:00

If used from KDB, the locked variants are prone to deadlocks (suppose we
got to the debugger w/ the logbuf lock held).

So, we have to implement a few routines that grab no logbuf lock.

Yet we don't need these functions in modules, so we don't export them.

Signed-off-by: Anton Vorontsov 
Signed-off-by: Linus Torvalds

kmsg - kmsg_dump() fix CONFIG_PRINTK=n compilation

2012-06-18T22:55:21+00:00

Signed-off-by: Kay Sievers 
Cc: Stephen Rothwell 
Reported-by: Randy Dunlap 
Reported-by: Fengguang Wu 
Signed-off-by: Greg Kroah-Hartman

kmsg - kmsg_dump() use iterator to receive log buffer content

2012-06-15T21:53:59+00:00

Provide an iterator to receive the log buffer content, and convert all
kmsg_dump() users to it.

The structured data in the kmsg buffer now contains binary data, which
should no longer be copied verbatim to the kmsg_dump() users.

The iterator should provide reliable access to the buffer data, and also
supports proper log line-aware chunking of data while iterating.

Signed-off-by: Kay Sievers 
Tested-by: Tony Luck 
Reported-by: Anton Vorontsov 
Tested-by: Anton Vorontsov 
Signed-off-by: Greg Kroah-Hartman

kmsg_dump: don't run on non-error paths by default

2012-03-05T23:49:42+00:00

Since commit 04c6862c055f ("kmsg_dump: add kmsg_dump() calls to the
reboot, halt, poweroff and emergency_restart paths"), kmsg_dump() gets
run on normal paths including poweroff and reboot.

This is less than ideal given pstore implementations that can only
represent single backtraces, since a reboot may overwrite a stored oops
before it's been picked up by userspace.  In addition, some pstore
backends may have low performance and provide a significant delay in
reboot as a result.

This patch adds a printk.always_kmsg_dump kernel parameter (which can also
be changed from userspace).  Without it, the code will only be run on
failure paths rather than on normal paths.  The option can be enabled in
environments where there's a desire to attempt to audit whether or not a
reboot was cleanly requested or not.

Signed-off-by: Matthew Garrett 
Acked-by: Seiji Aguchi 
Cc: Seiji Aguchi 
Cc: David Woodhouse 
Cc: Marco Stornelli 
Cc: Artem Bityutskiy 
Cc: KOSAKI Motohiro 
Cc: Vivek Goyal 
Cc: Don Zickus 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kexec: remove KMSG_DUMP_KEXEC

2012-01-13T04:13:11+00:00

KMSG_DUMP_KEXEC is useless because we already save kernel messages inside
/proc/vmcore, and it is unsafe to allow modules to do other stuffs in a
crash dump scenario.

[akpm@linux-foundation.org: fix powerpc build]
Signed-off-by: WANG Cong 
Reported-by: Vivek Goyal 
Acked-by: Vivek Goyal 
Acked-by: Jarod Wilson 
Cc: "Eric W. Biederman" 
Cc: KOSAKI Motohiro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kmsg_dump.h: fix build when CONFIG_PRINTK is disabled

2011-06-16T03:03:59+00:00

Fix  when CONFIG_PRINTK is not enabled:

  include/linux/kmsg_dump.h:56: error: 'EINVAL' undeclared (first use in this function)
  include/linux/kmsg_dump.h:61: error: 'EINVAL' undeclared (first use in this function)

Looks like commit 595dd3d8bf95 ("kmsg_dump: fix build for
CONFIG_PRINTK=n") uses EINVAL without having the needed header file(s),
but I'm sure that I build tested that patch also.  oh well.

Signed-off-by: Randy Dunlap 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kmsg_dump: add kmsg_dump() calls to the reboot, halt, poweroff and emergency_restart paths

2011-01-13T16:03:07+00:00

We need to know the reason why system rebooted in support service.
However, we can't inform our customers of the reason because final
messages are lost on current Linux kernel.

This patch improves the situation above because the final messages are
saved by adding kmsg_dump() to reboot, halt, poweroff and
emergency_restart path.

Signed-off-by: Seiji Aguchi 
Cc: David Woodhouse 
Cc: Marco Stornelli 
Reviewed-by: Artem Bityutskiy 
Reviewed-by: KOSAKI Motohiro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds