linux-toradex.git/kernel/printk.c, branch v2.6.39-rc2

printk: allow setting DEFAULT_MESSAGE_LEVEL via Kconfig

2011-03-23T00:44:13+00:00

We've been burned by regressions/bugs which we later realized could have
been triaged quicker if only we'd paid closer attention to dmesg.  To make
it easier to audit dmesg, we'd like to make DEFAULT_MESSAGE_LEVEL
Kconfig-settable.  That way we can set it to KERN_NOTICE and audit any
messages <= KERN_WARNING.

Signed-off-by: Mandeep Singh Baines 
Cc: Ingo Molnar 
Cc: Joe Perches 
Cc: Olof Johansson 
Cc: Randy Dunlap 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

console: prevent registered consoles from dumping old kernel message over again

2011-03-23T00:44:12+00:00

For a platform with many consoles like:
 "console=tty1 console=ttyMFD2 console=ttyS0 earlyprintk=mrst"

Each time when the non "selected_console" (tty1 and ttyMFD2 here) get
registered, the existing kernel message will be printed out on registered
consoles again, the "mrst" early console will get some same message for 3
times, and "tty1" will get some for twice.

As suggested by Andrew Morton, every time a new console is registered, it
will be set as the "exclusive" console which will dump the already
existing kernel messages.

Signed-off-by: Feng Tang 
Cc: Greg KH 
Cc: Alan Cox 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

console: allow to retain boot console via boot option keep_bootcon

2011-03-23T00:44:12+00:00

On some architectures, the boot process involves de-registering the boot
console (early boot), initialize drivers and then re-register the console.

This mechanism introduces a window in which no printk can happen on the
console and messages are buffered and then printed once the new console is
available.

If a kernel crashes during this window, all it's left on the boot console
is "console [foo] enabled, bootconsole disabled" making debug of the crash
rather 'interesting'.

By adding "keep_bootcon" option, do not unregister the boot console, that
will allow to printk everything that is happening up to the crash.

The option is clearly meant only for debugging purposes as it introduces
lots of duplicated info printed on console, but will make bug report from
users easier as it doesn't require a kernel build just to figure out where
we crash.

Signed-off-by: Fabio M. Di Nitto 
Acked-by: David S. Miller 
Cc: Alan Cox 
Cc: Greg KH 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6

2011-03-16T22:05:40+00:00

* 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6: (50 commits)
  printk: do not mangle valid userspace syslog prefixes
  efivars: Add Documentation
  efivars: Expose efivars functionality to external drivers.
  efivars: Parameterize operations.
  efivars: Split out variable registration
  efivars: parameterize efivars
  efivars: Make efivars bin_attributes dynamic
  efivars: move efivars globals into struct efivars
  drivers:misc: ti-st: fix debugging code
  kref: Fix typo in kref documentation
  UIO: add PRUSS UIO driver support
  Fix spelling mistakes in Documentation/zh_CN/SubmittingPatches
  firmware: Fix unaligned memory accesses in dmi-sysfs
  firmware: Add documentation for /sys/firmware/dmi
  firmware: Expose DMI type 15 System Event Log
  firmware: Break out system_event_log in dmi-sysfs
  firmware: Basic dmi-sysfs support
  firmware: Add DMI entry types to the headers
  Driver core: convert platform_{get,set}_drvdata to static inline functions
  Translate linux-2.6/Documentation/magic-number.txt into Chinese
  ...

printk: do not mangle valid userspace syslog prefixes

2011-03-14T15:49:16+00:00

printk: do not mangle valid userspace syslog prefixes with /dev/kmsg

Log messages passed to the kernel log by using /dev/kmsg or /dev/ttyprintk
might contain a syslog prefix including the syslog facility value.

This makes printk to recognize these headers properly, extract the real log
level from it to use, and add the prefix as a proper prefix to the
log buffer, instead of wrongly printing it as the log message text.

Before:
  $ echo '<14>text' > /dev/kmsg
  $ dmesg -r
  <4>[135159.594810] <14>text

After:
  $ echo '<14>text' > /dev/kmsg
  $ dmesg -r
  <14>[   50.750654] text

Cc: Lennart Poettering 
Signed-off-by: Kay Sievers 
Signed-off-by: Greg Kroah-Hartman

cap_syslog: accept CAP_SYS_ADMIN for now

2011-02-11T01:53:55+00:00

In commit ce6ada35bdf7 ("security: Define CAP_SYSLOG") Serge Hallyn
introduced CAP_SYSLOG, but broke backwards compatibility by no longer
accepting CAP_SYS_ADMIN as an override (it would cause a warning and
then reject the operation).

Re-instate CAP_SYS_ADMIN - but keeping the warning - as an acceptable
capability until any legacy applications have been updated.  There are
apparently applications out there that drop all capabilities except for
CAP_SYS_ADMIN in order to access the syslog.

(This is a re-implementation of a patch by Serge, cleaning the logic up
and making the code more readable)

Acked-by: Serge Hallyn 
Reviewed-by: James Morris 
Signed-off-by: Linus Torvalds

console: rename acquire/release_console_sem() to console_lock/unlock()

2011-01-26T00:50:06+00:00

The -rt patches change the console_semaphore to console_mutex.  As a
result, a quite large chunk of the patches changes all
acquire/release_console_sem() to acquire/release_console_mutex()

This commit makes things use more neutral function names which dont make
implications about the underlying lock.

The only real change is the return value of console_trylock which is
inverted from try_acquire_console_sem()

This patch also paves the way to switching console_sem from a semaphore to
a mutex.

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: make console_trylock return 1 on success, per Geert]
Signed-off-by: Torben Hohn 
Cc: Thomas Gleixner 
Cc: Greg KH 
Cc: Ingo Molnar 
Cc: Geert Uytterhoeven 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

printk: use RCU to prevent potential lock contention in kmsg_dump

2011-01-13T16:03:09+00:00

dump_list_lock is used to protect dump_list in kmsg_dumper implementation,
kmsg_dump() uses it to traverse dump_list too.  But if there is contention
on the lock, kmsg_dump() will fail, and the valuable kernel message may be
lost.

This patch solves this issue with RCU.  Because kmsg_dump() only read the
list, no lock is needed in kmsg_dump().  So that kmsg_dump() will never
fail because of lock contention.

Signed-off-by: Huang Ying 
Cc: "Paul E. McKenney" 
Cc: Ingo Molnar 
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

Merge branch 'master' into next

2011-01-09T22:46:24+00:00

Conflicts:
	security/smack/smack_lsm.c

Verified and added fix by Stephen Rothwell 
Ok'd by Casey Schaufler 

Signed-off-by: James Morris