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2014-06-04kernel/printk: use symbolic defines for console loglevelsBorislav Petkov
... 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>
2014-06-04printk: report dropping of messages from logbufWill Deacon
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>
2014-06-04printk: rename printk_sched to printk_deferredJohn Stultz
After learning we'll need some sort of deferred printk functionality in the timekeeping core, Peter suggested we rename the printk_sched function so it can be reused by needed subsystems. This only changes the function name. No logic changes. Signed-off-by: John Stultz <john.stultz@linaro.org> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Cc: Jan Kara <jack@suse.cz> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Jiri Bohac <jbohac@suse.cz> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04printk: disable preemption for printk_schedJohn Stultz
An earlier change in -mm (printk: remove separate printk_sched buffers...), removed the printk_sched irqsave/restore lines since it was safe for current users. Since we may be expanding usage of printk_sched(), disable preepmtion for this function to make it more generally safe to call. Signed-off-by: John Stultz <john.stultz@linaro.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Jiri Bohac <jbohac@suse.cz> 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>
2014-06-04printk: remove separate printk_sched buffers and use printk buf insteadSteven Rostedt
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>
2014-06-04printk: enable interrupts before calling console_trylock_for_printk()Jan Kara
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>
2014-06-04printk: fix lockdep instrumentation of console_semJan Kara
Printk calls mutex_acquire() / mutex_release() by hand to instrument lockdep about console_sem. However in some corner cases the instrumentation is missing. Fix the problem by creating helper functions for locking / unlocking console_sem which take care of lockdep instrumentation as well. Signed-off-by: Jan Kara <jack@suse.cz> Reported-by: Fabio Estevam <festevam@gmail.com> Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Tested-by: Fabio Estevam <fabio.estevam@freescale.com> Tested-By: Valdis Kletnieks <valdis.kletnieks@vt.edu> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04printk: release lockbuf_lock before calling console_trylock_for_printk()Jan Kara
There's no reason to hold lockbuf_lock when entering console_trylock_for_printk(). The first thing this function does is to call down_trylock(console_sem) and if that fails it immediately unlocks lockbuf_lock. So lockbuf_lock isn't needed for that branch. When down_trylock() succeeds, the rest of console_trylock() is OK without lockbuf_lock (it is called without it from other places), and the only remaining thing in console_trylock_for_printk() is can_use_console() call. For that call console_sem is enough (it iterates all consoles and checks CON_ANYTIME flag). So we drop logbuf_lock before entering console_trylock_for_printk() which simplifies the code. [akpm@linux-foundation.org: fix have_callable_console() comment] 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>
2014-06-04printk: remove outdated commentJan Kara
Comment about interesting interlocking between lockbuf_lock and console_sem is outdated. It was added in 2002 by commit a880f45a48be during conversion of console_lock to console_sem + lockbuf_lock. At that time release_console_sem() (today's equivalent is console_unlock()) was indeed using lockbuf_lock to avoid races between trylock on console_sem in printk() and unlock of console_sem. However these days the interlocking is gone and the races are avoided by rechecking logbuf state after releasing console_sem. 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>
2014-06-04printk: return really stored message lengthPetr Mladek
I wonder if anyone uses printk return value but it is there and should be counted correctly. This patch modifies log_store() to return the number of really stored bytes from the 'text' part. Also it handles the return value in vprintk_emit(). Note that log_store() is used also in cont_flush() but we could ignore the return value there. The function works with characters that were already counted earlier. In addition, the store could newer fail here because the length of the printed text is limited by the "cont" buffer and "dict" is NULL. Signed-off-by: Petr Mladek <pmladek@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04printk: shrink too long messagesPetr Mladek
We might want to print at least part of too long messages and add some warning for debugging purpose. The question is how long the shrunken message should be. If we use the whole buffer, it might get rotated too soon. Let's try to use only 1/4 of the buffer for now. Also shrink the whole dictionary. We do not want to parse it or break it in the middle of some pair of values. It would not cause any real harm but still. Signed-off-by: Petr Mladek <pmladek@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04printk: split message size computationPetr Mladek
We will want to recompute the message size when shrinking too long messages. Let's put the code into separate function. The side effect of setting "pad_len" is not nice but it is worth removing the code duplication. Note that I will probably have one more usage for this function when handling messages safe way in NMI context. This patch does not change the existing behavior. Signed-off-by: Petr Mladek <pmladek@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04printk: ignore too long messagesPetr Mladek
There was no check for too long messages. The check for free space always passed when first_seq and next_seq were equal. Enough free space was not guaranteed, though. log_store() might be called to store messages up to 64kB + 64kB + 16B. This is sum of maximal text_len, dict_len values, and the size of the structure printk_log. On the other hand, the minimal size for the main log buffer currently is 4kB and it is enforced only by Kconfig. The good news is that the usage looks safe right now. log_store() is called only from vprintk_emit() and cont_flush(). Here the "text" part is always passed via a static buffer and the length is limited to LOG_LINE_MAX which is 1024. The "dict" part is NULL in most cases. The only exceptions is when vprintk_emit() is called from printk_emit() and dev_vprintk_emit(). But printk_emit() is currently used only in devkmsg_writev() and here "dict" is NULL as well. In dev_vprintk_emit(), "dict" is limited by the static buffer "hdr" of the size 128 bytes. It meas that the current maximal printed text is 1024B + 128B + 16B and it always fit the log buffer. But it is only matter of time when someone calls printk_emit() with unsafe parameters, especially the "dict" one. This patch adds a check for the free space when the buffer is empty. It reuses the already existing log_has_space() function but it has to add an extra parameter. It defines whether the buffer is empty. Note that the same values of "first_idx" and "next_idx" might also mean that the buffer is full. If the buffer is empty, we must respect the current position of the indexes. We cannot reset them to the beginning of the buffer. Otherwise, the functions reading the buffer would get crazy. The question is what to do when the message is too long. This patch uses the easiest solution and just ignores the problematic message. Let's do something better in a followup patch. Signed-off-by: Petr Mladek <pmladek@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04printk: split code for making free space in the log bufferPetr Mladek
The check for free space in the log buffer always passes when "first_seq" and "next_seq" are equal. In theory, it might cause writing outside of the log buffer. Fortunately, the current usage looks safe because the used "text" and "dict" buffers are quite limited. See the second patch for more details. Anyway, it is better to be on the safe side and add a check. An easy solution is done in the 2nd patch and it is improved in the 4th patch. 5th patch fixes the computation of the printed message length. 1st and 3rd patches just do some code refactoring to make the other patches easier. This patch (of 5): There will be needed some fixes in the check for free space. They will be easier if the code is moved outside of the quite long log_store() function. This patch does not change the existing behavior. Signed-off-by: Petr Mladek <pmladek@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-03Merge tag 'tty-3.16-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty into next Pull tty/serial driver updates from Greg KH: "Here is the big tty / serial driver pull request for 3.16-rc1. A variety of different serial driver fixes and updates and additions, nothing huge, and no real major core tty changes at all. All have been in linux-next for a while" * tag 'tty-3.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (84 commits) Revert "serial: imx: remove the DMA wait queue" serial: kgdb_nmi: Improve console integration with KDB I/O serial: kgdb_nmi: Switch from tasklets to real timers serial: kgdb_nmi: Use container_of() to locate private data serial: cpm_uart: No LF conversion in put_poll_char() serial: sirf: Fix compilation failure console: Remove superfluous readonly check console: Use explicit pointer type for vc_uni_pagedir* fields vgacon: Fix & cleanup refcounting ARM: tty: Move HVC DCC assembly to arch/arm tty/hvc/hvc_console: Fix wakeup of HVC thread on hvc_kick() drivers/tty/n_hdlc.c: replace kmalloc/memset by kzalloc vt: emulate 8- and 24-bit colour codes. printk/of_serial: fix serial console cessation part way through boot. serial: 8250_dma: check the result of TX buffer mapping serial: uart: add hw flow control support configuration tty/serial: at91: add interrupts for modem control lines tty/serial: at91: use mctrl_gpio helpers tty/serial: Add GPIOLIB helpers for controlling modem lines ARM: at91: gpio: implement get_direction ...
2014-05-28printk/of_serial: fix serial console cessation part way through boot.Stephen Chivers
Commit 5f5c9ae56c38942623f69c3e6dc6ec78e4da2076 "serial_core: Unregister console in uart_remove_one_port()" fixed a crash where a serial port was removed but not deregistered as a console. There is a side effect of that commit for platforms having serial consoles and of_serial configured (CONFIG_SERIAL_OF_PLATFORM). The serial console is disabled midway through the boot process. This cessation of the serial console affects PowerPC computers such as the MVME5100 and SAM440EP. The sequence is: bootconsole [udbg0] enabled .... serial8250/16550 driver initialises and registers its UARTS, one of these is the serial console. console [ttyS0] enabled .... of_serial probes "platform" devices, registering them as it goes. One of these is the serial console. console [ttyS0] disabled. The disabling of the serial console is due to: a. unregister_console in printk not clearing the CONS_ENABLED bit in the console flags, even though it has announced that the console is disabled; and b. of_platform_serial_probe in of_serial not setting the port type before it registers with serial8250_register_8250_port. This patch ensures that the serial console is re-enabled when of_serial registers a serial port that corresponds to the designated console. Signed-off-by: Stephen Chivers <schivers@csc.com> Tested-by: Stephen Chivers <schivers@csc.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [unregister_console] Cc: stable <stable@vger.kernel.org> # 3.15 === The above failure was identified in Linux-3.15-rc2. Tested using MVME5100 and SAM440EP PowerPC computers with kernels built from Linux-3.15-rc5 and tty-next. The continued operation of the serial console is vital for computers such as the MVME5100 as that Single Board Computer does not have any grapical/display hardware. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-05-05asmlinkage: Add explicit __visible to drivers/*, lib/*, kernel/*Andi Kleen
As requested by Linus add explicit __visible to the asmlinkage users. This marks functions visible to assembler. Tree sweep for rest of tree. Signed-off-by: Andi Kleen <ak@linux.intel.com> Link: http://lkml.kernel.org/r/1398984278-29319-4-git-send-email-andi@firstfloor.org Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-04-03printk: fix one circular lockdep warning about console_lockJane Li
Fix a warning about possible circular locking dependency. If do in following sequence: enter suspend -> resume -> plug-out CPUx (echo 0 > cpux/online) lockdep will show warning as following: ====================================================== [ INFO: possible circular locking dependency detected ] 3.10.0 #2 Tainted: G O ------------------------------------------------------- sh/1271 is trying to acquire lock: (console_lock){+.+.+.}, at: console_cpu_notify+0x20/0x2c but task is already holding lock: (cpu_hotplug.lock){+.+.+.}, at: cpu_hotplug_begin+0x2c/0x58 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (cpu_hotplug.lock){+.+.+.}: lock_acquire+0x98/0x12c mutex_lock_nested+0x50/0x3d8 cpu_hotplug_begin+0x2c/0x58 _cpu_up+0x24/0x154 cpu_up+0x64/0x84 smp_init+0x9c/0xd4 kernel_init_freeable+0x78/0x1c8 kernel_init+0x8/0xe4 ret_from_fork+0x14/0x2c -> #1 (cpu_add_remove_lock){+.+.+.}: lock_acquire+0x98/0x12c mutex_lock_nested+0x50/0x3d8 disable_nonboot_cpus+0x8/0xe8 suspend_devices_and_enter+0x214/0x448 pm_suspend+0x1e4/0x284 try_to_suspend+0xa4/0xbc process_one_work+0x1c4/0x4fc worker_thread+0x138/0x37c kthread+0xa4/0xb0 ret_from_fork+0x14/0x2c -> #0 (console_lock){+.+.+.}: __lock_acquire+0x1b38/0x1b80 lock_acquire+0x98/0x12c console_lock+0x54/0x68 console_cpu_notify+0x20/0x2c notifier_call_chain+0x44/0x84 __cpu_notify+0x2c/0x48 cpu_notify_nofail+0x8/0x14 _cpu_down+0xf4/0x258 cpu_down+0x24/0x40 store_online+0x30/0x74 dev_attr_store+0x18/0x24 sysfs_write_file+0x16c/0x19c vfs_write+0xb4/0x190 SyS_write+0x3c/0x70 ret_fast_syscall+0x0/0x48 Chain exists of: console_lock --> cpu_add_remove_lock --> cpu_hotplug.lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(cpu_hotplug.lock); lock(cpu_add_remove_lock); lock(cpu_hotplug.lock); lock(console_lock); *** DEADLOCK *** There are three locks involved in two sequence: a) pm suspend: console_lock (@suspend_console()) cpu_add_remove_lock (@disable_nonboot_cpus()) cpu_hotplug.lock (@_cpu_down()) b) Plug-out CPUx: cpu_add_remove_lock (@(cpu_down()) cpu_hotplug.lock (@_cpu_down()) console_lock (@console_cpu_notify()) => Lockdeps prints warning log. There should be not real deadlock, as flag of console_suspended can protect this. Although console_suspend() releases console_sem, it doesn't tell lockdep about it. That results in the lockdep warning about circular locking when doing the following: enter suspend -> resume -> plug-out CPUx (echo 0 > cpux/online) Fix the problem by telling lockdep we actually released the semaphore in console_suspend() and acquired it again in console_resume(). Signed-off-by: Jane Li <jiel@marvell.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03printk: do not compute the size of the message twicePetr Mladek
This is just a tiny optimization. It removes duplicate computation of the message size. Signed-off-by: Petr Mladek <pmladek@suse.cz> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03printk: use also the last bytes in the ring bufferPetr Mladek
It seems that we have newer used the last byte in the ring buffer. In fact, we have newer used the last 4 bytes because of padding. First problem is in the check for free space. The exact number of free bytes is enough to store the length of data. Second problem is in the check where the ring buffer is rotated. The left side counts the first unused index. It is unused, so it might be the same as the size of the buffer. Note that the first problem has to be fixed together with the second one. Otherwise, the buffer is rotated even when there is enough space on the end of the buffer. Then the beginning of the buffer is rewritten and valid entries get corrupted. Signed-off-by: Petr Mladek <pmladek@suse.cz> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03printk: add comment about tricky check for text buffer sizePetr Mladek
There is no check for potential "text_len" overflow. It is not needed because only valid level is detected. It took me some time to understand why. It would deserve a comment ;-) Signed-off-by: Petr Mladek <pmladek@suse.cz> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03printk: remove obsolete check for log level "c"Petr Mladek
The kernel log level "c" was removed in commit 61e99ab8e35a ("printk: remove the now unnecessary "C" annotation for KERN_CONT"). It is no longer detected in printk_get_level(). Hence we do not need to check it in vprintk_emit. Signed-off-by: Petr Mladek <pmladek@suse.cz> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-02-17printk: fix syslog() overflowing user bufferLinus Torvalds
This is not a buffer overflow in the traditional sense: we don't overflow any *kernel* buffers, but we do mis-count the amount of data we copy back to user space for the SYSLOG_ACTION_READ_ALL case. In particular, if the user buffer is too small to hold everything, and *if* there is a continuation line at just the right place, we can end up giving the user more data than he asked for. The reason is that we first count up the number of bytes all the log records contains, then we walk the records again until we've skipped the records at the beginning that won't fit, and then we walk the rest of the records and copy them to the user space buffer. And in between that "skip the initial records that won't fit" and the "copy the records that *will* fit to user space", we reset the 'prev' variable that contained the record information for the last record not copied. That meant that when we started copying to user space, we now had a different character count than what we had originally calculated in the first record walk-through. The fix is to simply not clear the 'prev' flags value (in both cases where we had the same logic: syslog_print_all and kmsg_dump_get_buffer: the latter is used for pstore-like dumping) Reported-and-tested-by: Debabrata Banerjee <dbanerje@akamai.com> Acked-by: Kay Sievers <kay@vrfy.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-23printk: flush conflicting continuation lineArun KS
An earlier newline was missing and current print is from different task. In this scenario flush the continuation line and store this line seperatly. This patch fix the below scenario of timestamp interleaving, [ 28.154370 ] read_word_reg : reg[0x 3], reg[0x 4] data [0x 642] [ 28.155428 ] uart disconnect [ 31.947341 ] dvfs[cpufreq.c<275>]:plug-in cpu<1> done [ 28.155445 ] UART detached : send switch state 201 [ 32.014112 ] read_reg : reg[0x 3] data[0x21] [akpm@linux-foundation.org: simplify and condense the code] Signed-off-by: Arun KS <getarunks@gmail.com> Signed-off-by: Arun KS <arun.ks@broadcom.com> Cc: Joe Perches <joe@perches.com> Cc: Tejun Heo <tj@kernel.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21kernel/printk/printk.c: use memblock apis for early memory allocationsSantosh Shilimkar
Switch to memblock interfaces for early memory allocator instead of bootmem allocator. No functional change in beahvior than what it is in current code from bootmem users points of view. Archs already converted to NO_BOOTMEM now directly use memblock interfaces instead of bootmem wrappers build on top of memblock. And the archs which still uses bootmem, these new apis just fallback to exiting bootmem APIs. Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Paul Walmsley <paul@pwsan.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Russell King <linux@arm.linux.org.uk> Cc: Tony Lindgren <tony@atomide.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13printk.c: comments should refer to /proc/vmcore instead of /proc/vmcoreinfoDirk Gouders
In one of those comments a typo was fixed, too. Signed-off-by: Dirk Gouders <dirk@gouders.net> Cc: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13kernel/printk/printk.c: enable boot delay for earlyprintkDave Young
boot_delay does not work for earlyprintk because the kernel cmdline parsing is late. Change to use early_param so early kernel messages can also be delayed. Signed-off-by: Dave Young <dyoung@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13kernel/printk/printk.c: convert to pr_foo()Andrew Morton
It was half-and-half. Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Joe Perches <joe@perches.com> Cc: Kees Cook <keescook@chromium.org> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13printk: report console names during cut-overKees Cook
This reports the names of consoles as they're being disabled to help identify which is which during cut-over. Helps answer the question "which boot console actually got activated?" once the regular console is running, mostly when debugging boot console failures. Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Joe Perches <joe@perches.com> Cc: Tejun Heo <tj@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-03Merge tag 'tty-3.12-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty Pull tty/serial driver patches from Greg KH: "Here's the big tty/serial driver pull request for 3.12-rc1. Lots of n_tty reworks to resolve some very long-standing issues, removing the 3-4 different locks that were taken for every character. This code has been beaten on for a long time in linux-next with no reported regressions. Other than that, a range of serial and tty driver updates and revisions. Full details in the shortlog" * tag 'tty-3.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (226 commits) hvc_xen: Remove unnecessary __GFP_ZERO from kzalloc serial: imx: initialize the local variable tty: ar933x_uart: add device tree support and binding documentation tty: ar933x_uart: allow to build the driver as a module ARM: dts: msm: Update uartdm compatible strings devicetree: serial: Document msm_serial bindings serial: unify serial bindings into a single dir serial: fsl-imx-uart: Cleanup duplicate device tree binding tty: ar933x_uart: use config_enabled() macro to clean up ifdefs tty: ar933x_uart: remove superfluous assignment of ar933x_uart_driver.nr tty: ar933x_uart: use the clk API to get the uart clock tty: serial: cpm_uart: Adding proper request of GPIO used by cpm_uart driver serial: sirf: fix the amount of serial ports serial: sirf: define macro for some magic numbers of USP serial: icom: move array overflow checks earlier TTY: amiserial, remove unnecessary platform_set_drvdata() serial: st-asc: remove unnecessary platform_set_drvdata() msm_serial: Send more than 1 character on the console w/ UARTDM msm_serial: Add support for non-GSBI UARTDM devices msm_serial: Switch clock consumer strings and simplify code ...
2013-08-06printk: Fix return of braille_register_console()Steven Rostedt
Some of my configs I test with have CONFIG_A11Y_BRAILLE_CONSOLE set. When I started testing against v3.11-rc4 my console went bonkers. Using ktest to bisect the issue, it came down to: commit bbeddf52a "printk: move braille console support into separate braille.[ch] files" Looking into the patch I found the problem. It's with the return of braille_register_console(). As anything other than NULL is considered a failure. But for those of us that have CONFIG_A11Y_BRAILLE_CONSOLE set but do not define a "brl" or "brl=" on the command line, we still may want a console that those with sight can still use. Return NULL (success) if "brl" or "brl=" is not on the console line. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Acked-by: Joe Perches <joe@perches.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-08-05register_console: prevent adding the same console twiceAndreas Bießmann
This patch guards the console_drivers list to be corrupted. The for_each_console() macro insist on a strictly forward list ended by NULL: con0->next->con1->next->NULL Without this patch it may happen easily to destroy this list for example by adding 'earlyprintk' twice, especially on embedded devices where the early console is often a single static instance. This will result in the following list: con0->next->con0 This in turn will result in an endless loop in console_unlock() later on by printing the first __log_buf line endlessly. Signed-off-by: Andreas Bießmann <andreas@biessmann.de> Cc: Kay Sievers <kay@vrfy.org> Cc: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-07-31printk: rename struct log to struct printk_logJoe Perches
Rename the struct to enable moving portions of printk.c to separate files. The rename changes output of /proc/vmcoreinfo. Signed-off-by: Joe Perches <joe@perches.com> Cc: Samuel Thibault <samuel.thibault@ens-lyon.org> Cc: Ming Lei <ming.lei@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-31printk: use pointer for console_cmdline indexingJoe Perches
Make the code a bit more compact by always using a pointer for the active console_cmdline. Move overly indented code to correct indent level. Signed-off-by: Joe Perches <joe@perches.com> Cc: Samuel Thibault <samuel.thibault@ens-lyon.org> Cc: Ming Lei <ming.lei@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-31printk: move braille console support into separate braille.[ch] filesJoe Perches
Create files with prototypes and static inlines for braille support. Make braille_console functions return 1 on success. Corrected CONFIG_A11Y_BRAILLE_CONSOLE=n _braille_console_setup return value to NULL. Signed-off-by: Joe Perches <joe@perches.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Cc: Ming Lei <ming.lei@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-31printk: add console_cmdline.hJoe Perches
Add an include file for the console_cmdline struct so that the braille console driver can be separated. Signed-off-by: Joe Perches <joe@perches.com> Cc: Samuel Thibault <samuel.thibault@ens-lyon.org> Cc: Ming Lei <ming.lei@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-31printk: move to separate directory for easier modificationJoe Perches
Make it easier to break up printk into bite-sized chunks. Remove printk path/filename from comment. Signed-off-by: Joe Perches <joe@perches.com> Cc: Samuel Thibault <samuel.thibault@ens-lyon.org> Cc: Ming Lei <ming.lei@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>