Convert printk to current pr_foo() logging functions.
Also add pr_fmt based on KBUILD_MODNAME to avoid repeating prefix. Prefix
is now "atomic64_test: "
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Luca Barbieri <luca@luca-barbieri.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Coalesce formats
- "WARNING:" prefix unchanged to keep bug format.
- printk(KERN_DEFAULT not converted.
- define pr_fmt without prefix to avoid any default prefix update
(suggested by Joe Perches).
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change CONFIG_DEBUG_PI_LIST to be user-selectable, and add a title and
description. Remove the dependency on DEBUG_RT_MUTEXES since they were
changed to use rbtrees, and there are other users of plists now.
Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I use btree from 3.14-rc2 in my own module. When the btree module is
removed, a warning arises:
kmem_cache_destroy btree_node: Slab cache still has objects
CPU: 13 PID: 9150 Comm: rmmod Tainted: GF O 3.14.0-rc2 #1
Hardware name: Inspur NF5270M3/NF5270M3, BIOS CHEETAH_2.1.3 09/10/2013
Call Trace:
dump_stack+0x49/0x5d
kmem_cache_destroy+0xcf/0xe0
btree_module_exit+0x10/0x12 [btree]
SyS_delete_module+0x198/0x1f0
system_call_fastpath+0x16/0x1b
The cause is that it doesn't release the last btree node, when height = 1
and fill = 1.
[akpm@linux-foundation.org: remove unneeded test of NULL]
Signed-off-by: Minfei Huang <huangminfei@ucloud.cn>
Cc: Joern Engel <joern@logfs.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fixing 2 coccinelle warnings:
lib/vsprintf.c:2350:2-9: WARNING: Assignment of bool to 0/1
lib/vsprintf.c:2389:3-10: WARNING: Assignment of bool to 0/1
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Replace pr_debug() in lib/plist.c test function plist_test() with
printk(KERN_DEBUG ...).
Without DEBUG defined, pr_debug() is complied out, but the entire
plist_test() function is already inside CONFIG_DEBUG_PI_LIST, so printk
should just be used directly.
Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For strncpy() and friends the source string may or may not have an actual
NUL character at the end. The documentation is confusing in this because
it specifically mentions that you are passing a "NUL-terminated" string.
Wikipedia says that "C-string" is an alternative name we can use instead.
http://en.wikipedia.org/wiki/Null-terminated_string
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
... instead of naked numbers.
Stuff in sysrq.c used to set it to 8 which is supposed to mean above
default level so set it to DEBUG instead as we're terminating/killing all
tasks and we want to be verbose there.
Also, correct the check in x86_64_start_kernel which should be >= as
we're clearly issuing the string there for all debug levels, not only
the magical 10.
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Joe Perches <joe@perches.com>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If the log ring buffer becomes full, we silently overwrite old messages
with new data. console_unlock will detect this case and fast-forward the
console_* pointers to skip over the corrupted data, but nothing will be
reported to the user.
This patch hijacks the first valid log message after detecting that we
dropped messages and prefixes it with a note detailing how many messages
were dropped. For long (~1000 char) messages, this will result in some
truncation of the real message, but given that we're dropping things
anyway, that doesn't seem to be the end of the world.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The pr_debug() and related debug print macros all differ from the normal
pr_XXX() macros, in that the normal ones print unconditionally, while
the debug macros are compiled out unless DEBUG is defined or
CONFIG_DYNAMIC_DEBUG is set. This isn't obvious, and the only way to
find this out is either to review the actual printk.h code or to read
CodingStyle, and the message there doesn't highlight the fact.
Change Documentation/CodingStyle to clearly indicate that pr_debug() and
related debug printing macros behave differently than all other pr_XXX()
macros, and attempt to clarify when and where the different debug
printing methods might be used.
Add short comment to printk.h above the pr_XXX() macros indicating that
while these macros print unconditionally, pr_debug() does not.
Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Cc: Joe Perches <joe@perches.com>
Cc: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Jiri Bohac pointed out that there are rare but potential deadlock
possibilities when calling printk while holding the timekeeping
seqlock.
This is due to printk() triggering console sem wakeup, which can
cause scheduling code to trigger hrtimers which may try to read
the time.
Specifically, as Jiri pointed out, that path is:
printk
vprintk_emit
console_unlock
up(&console_sem)
__up
wake_up_process
try_to_wake_up
ttwu_do_activate
ttwu_activate
activate_task
enqueue_task
enqueue_task_fair
hrtick_update
hrtick_start_fair
hrtick_start_fair
get_time
ktime_get
--> endless loop on
read_seqcount_retry(&timekeeper_seq, ...)
This patch tries to avoid this issue by using printk_deferred (previously
named printk_sched) which should defer printing via a irq_work_queue.
Signed-off-by: John Stultz <john.stultz@linaro.org>
Reported-by: Jiri Bohac <jbohac@suse.cz>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To prevent deadlocks with doing a printk inside the scheduler,
printk_sched() was created. The issue is that printk has a console_sem
that it can grab and release. The release does a wake up if there's a
task pending on the sem, and this wake up grabs the rq locks that is
held in the scheduler. This leads to a possible deadlock if the wake up
uses the same rq as the one with the rq lock held already.
What printk_sched() does is to save the printk write in a per cpu buffer
and sets the PRINTK_PENDING_SCHED flag. On a timer tick, if this flag is
set, the printk() is done against the buffer.
There's a couple of issues with this approach.
1) If two printk_sched()s are called before the tick, the second one
will overwrite the first one.
2) The temporary buffer is 512 bytes and is per cpu. This is a quite a
bit of space wasted for something that is seldom used.
In order to remove this, the printk_sched() can use the printk buffer
instead, and delay the console_trylock()/console_unlock() to the queued
work.
Because printk_sched() would then be taking the logbuf_lock, the
logbuf_lock must not be held while doing anything that may call into the
scheduler functions, which includes wake ups. Unfortunately, printk()
also has a console_sem that it uses, and on release, the up(&console_sem)
may do a wake up of any pending waiters. This must be avoided while
holding the logbuf_lock.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We need interrupts disabled when calling console_trylock_for_printk()
only so that cpu id we pass to can_use_console() remains valid (for
other things console_sem provides all the exclusion we need and
deadlocks on console_sem due to interrupts are impossible because we use
down_trylock()). However if we are rescheduled, we are guaranteed to
run on an online cpu so we can easily just get the cpu id in
can_use_console().
We can lose a bit of performance when we enable interrupts in
vprintk_emit() and then disable them again in console_unlock() but OTOH
it can somewhat reduce interrupt latency caused by console_unlock()
especially since later in the patch series we will want to spin on
console_sem in console_trylock_for_printk().
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fabian Frederick
Dan Streetman
Minfei Huang
Lasse Collin
Dan Carpenter
Borislav Petkov
Will Deacon
John Stultz
Steven Rostedt
Jan Kara