linux-stable.git/kernel/printk/printk.c, branch v5.2

treewide: Add SPDX license identifier for missed files

2019-05-21T08:50:45+00:00

Add SPDX license identifiers to all files which:

 - Have no license information of any form

 - Have EXPORT_.*_SYMBOL_GPL inside which was used in the
   initial scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

panic: add an option to replay all the printk message in buffer

2019-05-18T22:52:26+00:00

Currently on panic, kernel will lower the loglevel and print out pending
printk msg only with console_flush_on_panic().

Add an option for users to configure the "panic_print" to replay all
dmesg in buffer, some of which they may have never seen due to the
loglevel setting, which will help panic debugging .

[feng.tang@intel.com: keep the original console_flush_on_panic() inside panic()]
  Link: http://lkml.kernel.org/r/1556199137-14163-1-git-send-email-feng.tang@intel.com
[feng.tang@intel.com: use logbuf lock to protect the console log index]
  Link: http://lkml.kernel.org/r/1556269868-22654-1-git-send-email-feng.tang@intel.com
Link: http://lkml.kernel.org/r/1556095872-36838-1-git-send-email-feng.tang@intel.com
Signed-off-by: Feng Tang 
Reviewed-by: Petr Mladek 
Cc: Aaro Koskinen 
Cc: Petr Mladek 
Cc: Steven Rostedt 
Cc: Sergey Senozhatsky 
Cc: Kees Cook 
Cc: Borislav Petkov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

panic: avoid the extra noise dmesg

2019-05-15T02:52:51+00:00

When kernel panic happens, it will first print the panic call stack,
then the ending msg like:

[   35.743249] ---[ end Kernel panic - not syncing: Fatal exception
[   35.749975] ------------[ cut here ]------------

The above message are very useful for debugging.

But if system is configured to not reboot on panic, say the
"panic_timeout" parameter equals 0, it will likely print out many noisy
message like WARN() call stack for each and every CPU except the panic
one, messages like below:

	WARNING: CPU: 1 PID: 280 at kernel/sched/core.c:1198 set_task_cpu+0x183/0x190
	Call Trace:
	
	try_to_wake_up
	default_wake_function
	autoremove_wake_function
	__wake_up_common
	__wake_up_common_lock
	__wake_up
	wake_up_klogd_work_func
	irq_work_run_list
	irq_work_tick
	update_process_times
	tick_sched_timer
	__hrtimer_run_queues
	hrtimer_interrupt
	smp_apic_timer_interrupt
	apic_timer_interrupt

For people working in console mode, the screen will first show the panic
call stack, but immediately overridden by these noisy extra messages,
which makes debugging much more difficult, as the original context gets
lost on screen.

Also these noisy messages will confuse some users, as I have seen many bug
reporters posted the noisy message into bugzilla, instead of the real
panic call stack and context.

Adding a flag "suppress_printk" which gets set in panic() to avoid those
noisy messages, without changing current kernel behavior that both panic
blinking and sysrq magic key can work as is, suggested by Petr Mladek.

To verify this, make sure kernel is not configured to reboot on panic and
in console
 # echo c > /proc/sysrq-trigger
to see if console only prints out the panic call stack.

Link: http://lkml.kernel.org/r/1551430186-24169-1-git-send-email-feng.tang@intel.com
Signed-off-by: Feng Tang 
Suggested-by: Petr Mladek 
Reviewed-by: Petr Mladek 
Acked-by: Steven Rostedt (VMware) 
Acked-by: Sergey Senozhatsky 
Cc: Thomas Gleixner 
Cc: Kees Cook 
Cc: Borislav Petkov 
Cc: Andi Kleen 
Cc: Peter Zijlstra 
Cc: Greg Kroah-Hartman 
Cc: Jiri Slaby 
Cc: Sasha Levin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge tag 'fbdev-v5.1' of git://github.com/bzolnier/linux

2019-03-15T21:22:59+00:00

Pull fbdev updates from Bartlomiej Zolnierkiewicz:
 "Just a couple of small fixes and cleanups:

   - fix memory access if logo is bigger than the screen (Manfred
     Schlaegl)

   - silence fbcon logo on 'quiet' boots (Prarit Bhargava)

   - use kvmalloc() for scrollback buffer in fbcon (Konstantin Khorenko)

   - misc fixes (Colin Ian King, YueHaibing, Matteo Croce, Mathieu
     Malaterre, Anders Roxell, Arnd Bergmann)

   - misc cleanups (Rob Herring, Lubomir Rintel, Greg Kroah-Hartman,
     Jani Nikula, Michal Vokáč)"

* tag 'fbdev-v5.1' of git://github.com/bzolnier/linux:
  fbdev: mbx: fix a misspelled variable name
  fbdev: omap2: fix warnings in dss core
  video: fbdev: Fix potential NULL pointer dereference
  fbcon: Silence fbcon logo on 'quiet' boots
  printk: Export console_printk
  ARM: dts: imx28-cfa10036: Fix the reset gpio signal polarity
  video: ssd1307fb: Do not hard code active-low reset sequence
  dt-bindings: display: ssd1307fb: Remove reset-active-low from examples
  fbdev: fbmem: fix memory access if logo is bigger than the screen
  video/fbdev: refactor video= cmdline parsing
  fbdev: mbx: fix up debugfs file creation
  fbdev: omap2: no need to check return value of debugfs_create functions
  video: fbdev: geode: remove ifdef OLPC noise
  video: offb: annotate implicit fall throughs
  omapfb: fix typo
  fbdev: Use of_node_name_eq for node name comparisons
  fbcon: use kvmalloc() for scrollback buffer
  fbdev: chipsfb: remove set but not used variable 'size'
  fbdev/via: fix spelling mistake "Expandsion" -> "Expansion"

memblock: drop memblock_alloc_*_nopanic() variants

2019-03-12T17:04:02+00:00

As all the memblock allocation functions return NULL in case of error
rather than panic(), the duplicates with _nopanic suffix can be removed.

Link: http://lkml.kernel.org/r/1548057848-15136-22-git-send-email-rppt@linux.ibm.com
Signed-off-by: Mike Rapoport 
Acked-by: Greg Kroah-Hartman 
Reviewed-by: Petr Mladek 		[printk]
Cc: Catalin Marinas 
Cc: Christophe Leroy 
Cc: Christoph Hellwig 
Cc: "David S. Miller" 
Cc: Dennis Zhou 
Cc: Geert Uytterhoeven 
Cc: Greentime Hu 
Cc: Guan Xuetao 
Cc: Guo Ren 
Cc: Guo Ren 				[c-sky]
Cc: Heiko Carstens 
Cc: Juergen Gross 			[Xen]
Cc: Mark Salter 
Cc: Matt Turner 
Cc: Max Filippov 
Cc: Michael Ellerman 
Cc: Michal Simek 
Cc: Paul Burton 
Cc: Richard Weinberger 
Cc: Rich Felker 
Cc: Rob Herring 
Cc: Rob Herring 
Cc: Russell King 
Cc: Stafford Horne 
Cc: Tony Luck 
Cc: Vineet Gupta 
Cc: Yoshinori Sato 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge tag 'printk-for-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk

2019-03-09T17:22:42+00:00

Pull printk updates from Petr Mladek:

 - Allow to sort mixed lines by an extra information about the caller

 - Remove no longer used LOG_PREFIX.

 - Some clean up and documentation update.

* tag 'printk-for-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
  printk/docs: Add extra integer types to printk-formats
  printk: Remove no longer used LOG_PREFIX.
  lib/vsprintf: Remove %pCr remnant in comment
  printk: Pass caller information to log_store().
  printk: Add caller information to printk() output.

printk: Remove no longer used LOG_PREFIX.

2019-03-04T12:42:05+00:00

When commit 5becfb1df5ac8e49 ("kmsg: merge continuation records while
printing") introduced LOG_PREFIX, we used KERN_DEFAULT etc. as a flag
for setting LOG_PREFIX in order to tell whether to call cont_add()
(i.e. whether to append the message to "struct cont").

But since commit 4bcc595ccd80decb ("printk: reinstate KERN_CONT for
printing continuation lines") inverted the behavior (i.e. don't append
the message to "struct cont" unless KERN_CONT is specified) and commit
5aa068ea4082b39e ("printk: remove games with previous record flags")
removed the last LOG_PREFIX check, setting LOG_PREFIX via KERN_DEFAULT
etc. is no longer meaningful.

Therefore, we can remove LOG_PREFIX and make KERN_DEFAULT empty string.

Link: http://lkml.kernel.org/r/1550829580-9189-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp
To: Steven Rostedt 
To: Linus Torvalds 
Cc: linux-kernel@vger.kernel.org
Cc: Tetsuo Handa 
Signed-off-by: Tetsuo Handa 
Reviewed-by: Sergey Senozhatsky 
Signed-off-by: Petr Mladek

printk: Pass caller information to log_store().

2019-02-21T09:41:15+00:00

When thread1 called printk() which did not end with '\n', and then thread2
called printk() which ends with '\n' before thread1 calls pr_cont(), the
partial content saved into "struct cont" is flushed by thread2 despite the
partial content was generated by thread1. This leads to confusing output
as if the partial content was generated by thread2. Fix this problem by
passing correct caller information to log_store().

Before:

  [ T8533] abcdefghijklm
  [ T8533] ABCDEFGHIJKLMNOPQRSTUVWXYZ
  [ T8532] nopqrstuvwxyz
  [ T8532] abcdefghijklmnopqrstuvwxyz
  [ T8533] abcdefghijklm
  [ T8533] ABCDEFGHIJKLMNOPQRSTUVWXYZ
  [ T8532] nopqrstuvwxyz

After:

  [ T8507] abcdefghijklm
  [ T8508] ABCDEFGHIJKLMNOPQRSTUVWXYZ
  [ T8507] nopqrstuvwxyz
  [ T8507] abcdefghijklmnopqrstuvwxyz
  [ T8507] abcdefghijklm
  [ T8508] ABCDEFGHIJKLMNOPQRSTUVWXYZ
  [ T8507] nopqrstuvwxyz

Link: http://lkml.kernel.org/r/1550314773-8607-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp
To: Dmitry Vyukov 
To: Sergey Senozhatsky 
To: Steven Rostedt 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Tetsuo Handa 
Reviewed-by: Sergey Senozhatsky 
[pmladek: broke 80-column rule where it made more harm than good]
Signed-off-by: Petr Mladek

printk: Export console_printk

2019-02-08T18:24:49+00:00

The fbcon can be built as a module and requires console_printk.

Export console_printk.

Signed-off-by: Prarit Bhargava 
Reviewed-by: Sergey Senozhatsky 
Acked-by: Petr Mladek 
Signed-off-by: Bartlomiej Zolnierkiewicz

Remove 'type' argument from access_ok() function

2019-01-04T02:57:57+00:00

Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.

It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access.  But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.

A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model.  And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.

This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.

There were a couple of notable cases:

 - csky still had the old "verify_area()" name as an alias.

 - the iter_iov code had magical hardcoded knowledge of the actual
   values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
   really used it)

 - microblaze used the type argument for a debug printout

but other than those oddities this should be a total no-op patch.

I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something.  Any missed conversion should be trivially fixable, though.

Signed-off-by: Linus Torvalds