commit 8a8109f303e25a27f92c1d8edd67d7cbbc60a4eb upstream.
printk_safe_flush_on_panic() caused the following deadlock on our
server:
CPU0: CPU1:
panic rcu_dump_cpu_stacks
kdump_nmi_shootdown_cpus nmi_trigger_cpumask_backtrace
register_nmi_handler(crash_nmi_callback) printk_safe_flush
__printk_safe_flush
raw_spin_lock_irqsave(&read_lock)
// send NMI to other processors
apic_send_IPI_allbutself(NMI_VECTOR)
// NMI interrupt, dead loop
crash_nmi_callback
printk_safe_flush_on_panic
printk_safe_flush
__printk_safe_flush
// deadlock
raw_spin_lock_irqsave(&read_lock)
DEADLOCK: read_lock is taken on CPU1 and will never get released.
It happens when panic() stops a CPU by NMI while it has been in
the middle of printk_safe_flush().
Handle the lock the same way as logbuf_lock. The printk_safe buffers
are flushed only when both locks can be safely taken. It can avoid
the deadlock _in this particular case_ at expense of losing contents
of printk_safe buffers.
Note: It would actually be safe to re-init the locks when all CPUs were
stopped by NMI. But it would require passing this information
from arch-specific code. It is not worth the complexity.
Especially because logbuf_lock and printk_safe buffers have been
obsoleted by the lockless ring buffer.
Fixes: cf9b1106c8 ("printk/nmi: flush NMI messages on the system panic")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: <stable@vger.kernel.org>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210210034823.64867-1-songmuchun@bytedance.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 48021f98130880dd74286459a1ef48b5e9bc374f ]
If uboot passes a blank string to console_setup then it results in
a trashed memory. Ultimately, the kernel crashes during freeing up
the memory.
This fix checks if there is a blank parameter being
passed to console_setup from uboot. In case it detects that
the console parameter is blank then it doesn't setup the serial
device and it gracefully exits.
Link: https://lore.kernel.org/r/20200522065306.83-1-shreyas.joshi@biamp.com
Signed-off-by: Shreyas Joshi <shreyas.joshi@biamp.com>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
[pmladek@suse.com: Better format the commit message and code, remove unnecessary brackets.]
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit ab6f762f0f53162d41497708b33c9a3236d3609e upstream.
printk_deferred(), similarly to printk_safe/printk_nmi, does not
immediately attempt to print a new message on the consoles, avoiding
calls into non-reentrant kernel paths, e.g. scheduler or timekeeping,
which potentially can deadlock the system.
Those printk() flavors, instead, rely on per-CPU flush irq_work to print
messages from safer contexts. For same reasons (recursive scheduler or
timekeeping calls) printk() uses per-CPU irq_work in order to wake up
user space syslog/kmsg readers.
However, only printk_safe/printk_nmi do make sure that per-CPU areas
have been initialised and that it's safe to modify per-CPU irq_work.
This means that, for instance, should printk_deferred() be invoked "too
early", that is before per-CPU areas are initialised, printk_deferred()
will perform illegal per-CPU access.
Lech Perczak [0] reports that after commit 1b710b1b10ef ("char/random:
silence a lockdep splat with printk()") user-space syslog/kmsg readers
are not able to read new kernel messages.
The reason is printk_deferred() being called too early (as was pointed
out by Petr and John).
Fix printk_deferred() and do not queue per-CPU irq_work before per-CPU
areas are initialized.
Link: https://lore.kernel.org/lkml/aa0732c6-5c4e-8a8b-a1c1-75ebe3dca05b@camlintechnologies.com/
Reported-by: Lech Perczak <l.perczak@camlintechnologies.com>
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Tested-by: Jann Horn <jannh@google.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit def97da136515cb289a14729292c193e0a93bc64 ]
Commit f92b070f2d ("printk: Do not miss new messages when replaying
the log") introduced a new variable @exclusive_console_stop_seq to
store when an exclusive console should stop printing. It should be
set to the @console_seq value at registration. However, @console_seq
is previously set to @syslog_seq so that the exclusive console knows
where to begin. This results in the exclusive console immediately
reactivating all the other consoles and thus repeating the messages
for those consoles.
Set @console_seq after @exclusive_console_stop_seq has stored the
current @console_seq value.
Fixes: f92b070f2d ("printk: Do not miss new messages when replaying the log")
Link: http://lkml.kernel.org/r/20191219115322.31160-1-john.ogness@linutronix.de
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
strncmp(str, const, len) is error-prone because len is easy to have typo.
An example is the hard-coded len has counting error or sizeof(const)
forgets - 1.
So we prefer using newly introduced str_has_prefix() to substitute
such strncmp() to make code better.
Link: http://lkml.kernel.org/r/20190809071034.17279-1-hslester96@gmail.com
Cc: "Steven Rostedt" <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Chuhong Yuan <hslester96@gmail.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
[pmladek@suse.com: Slightly updated and reformatted the commit message.]
Signed-off-by: Petr Mladek <pmladek@suse.com>
kmsg_dump_get_buffer() is supposed to select all the youngest log
messages which fit into the provided buffer. It determines the correct
start index by using msg_print_text() with a NULL buffer to calculate
the size of each entry. However, when performing the actual writes,
msg_print_text() only writes the entry to the buffer if the written len
is lesser than the size of the buffer. So if the lengths of the
selected youngest log messages happen to precisely fill up the provided
buffer, the last log message is not included.
We don't want to modify msg_print_text() to fill up the buffer and start
returning a length which is equal to the size of the buffer, since
callers of its other users, such as kmsg_dump_get_line(), depend upon
the current behaviour.
Instead, fix kmsg_dump_get_buffer() to compensate for this.
For example, with the following two final prints:
[ 6.427502] AAAAAAAAAAAAA
[ 6.427769] BBBBBBBB12345
A dump of a 64-byte buffer filled by kmsg_dump_get_buffer(), before this
patch:
00000000: 3c 30 3e 5b 20 20 20 20 36 2e 35 32 32 31 39 37 <0>[ 6.522197
00000010: 5d 20 41 41 41 41 41 41 41 41 41 41 41 41 41 0a ] AAAAAAAAAAAAA.
00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
After this patch:
00000000: 3c 30 3e 5b 20 20 20 20 36 2e 34 35 36 36 37 38 <0>[ 6.456678
00000010: 5d 20 42 42 42 42 42 42 42 42 31 32 33 34 35 0a ] BBBBBBBB12345.
00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
Link: http://lkml.kernel.org/r/20190711142937.4083-1-vincent.whitchurch@axis.com
Fixes: e2ae715d66 ("kmsg - kmsg_dump() use iterator to receive log buffer content")
To: rostedt@goodmis.org
Cc: linux-kernel@vger.kernel.org
Cc: <stable@vger.kernel.org> # v3.5+
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Based on 2 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details you
should have received a copy of the gnu general public license along
with this program if not see http www gnu org licenses
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details [based]
[from] [clk] [highbank] [c] you should have received a copy of the
gnu general public license along with this program if not see http
www gnu org licenses
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 355 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Jilayne Lovejoy <opensource@jilayne.com>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190519154041.837383322@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add SPDX license identifiers to all Make/Kconfig files which:
- Have no license information of any form
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 <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 <feng.tang@intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Aaro Koskinen <aaro.koskinen@nokia.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Borislav Petkov <bp@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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:
<IRQ>
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 <feng.tang@intel.com>
Suggested-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Sasha Levin <sashal@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- 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)
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Merge tag 'fbdev-v5.1' of git://github.com/bzolnier/linux
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"
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 <rppt@linux.ibm.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Petr Mladek <pmladek@suse.com> [printk]
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Guo Ren <ren_guo@c-sky.com> [c-sky]
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Juergen Gross <jgross@suse.com> [Xen]
Cc: Mark Salter <msalter@redhat.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Merge tag 'printk-for-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk
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.
When commit 5becfb1df5 ("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 4bcc595ccd ("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
5aa068ea40 ("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 <rostedt@goodmis.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
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 <dvyukov@google.com>
To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
[pmladek: broke 80-column rule where it made more harm than good]
Signed-off-by: Petr Mladek <pmladek@suse.com>
The fbcon can be built as a module and requires console_printk.
Export console_printk.
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
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 <torvalds@linux-foundation.org>
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Merge tag 'printk-for-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk
Pull printk updates from Petr Mladek:
- Keep spinlocks busted until the end of panic()
- Fix races between calculating number of messages that would fit into
user space buffers, filling the buffers, and switching printk.time
parameter
- Some code clean up
* tag 'printk-for-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
printk: Remove print_prefix() calls with NULL buffer.
printk: fix printk_time race.
printk: Make printk_emit() local function.
panic: avoid deadlocks in re-entrant console drivers
Sometimes we want to print a series of printk() messages to consoles
without being disturbed by concurrent printk() from interrupts and/or
other threads. But we can't enforce printk() callers to use their local
buffers because we need to ask them to make too much changes. Also, even
buffering up to one line inside printk() might cause failing to emit
an important clue under critical situation.
Therefore, instead of trying to help buffering, let's try to help
reconstructing messages by saving caller information as of calling
log_store() and adding it as "[T$thread_id]" or "[C$processor_id]"
upon printing to consoles.
Some examples for console output:
[ 1.222773][ T1] x86: Booting SMP configuration:
[ 2.779635][ T1] pci 0000:00:01.0: PCI bridge to [bus 01]
[ 5.069193][ T268] Fusion MPT base driver 3.04.20
[ 9.316504][ C2] random: fast init done
[ 13.413336][ T3355] Initialized host personality
Some examples for /dev/kmsg output:
6,496,1222773,-,caller=T1;x86: Booting SMP configuration:
6,968,2779635,-,caller=T1;pci 0000:00:01.0: PCI bridge to [bus 01]
SUBSYSTEM=pci
DEVICE=+pci:0000:00:01.0
6,1353,5069193,-,caller=T268;Fusion MPT base driver 3.04.20
5,1526,9316504,-,caller=C2;random: fast init done
6,1575,13413336,-,caller=T3355;Initialized host personality
Note that this patch changes max length of messages which can be printed
by printk() or written to /dev/kmsg interface from 992 bytes to 976 bytes,
based on an assumption that userspace won't try to write messages hitting
that border line to /dev/kmsg interface.
Link: http://lkml.kernel.org/r/93f19e57-5051-c67d-9af4-b17624062d44@i-love.sakura.ne.jp
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: syzkaller <syzkaller@googlegroups.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Since printk_time can be toggled via /sys/module/printk/parameters/time ,
it is not safe to assume that output length does not change across
multiple msg_print_text() calls. If we hit this race, we can observe
failures such as SYSLOG_ACTION_READ_ALL writes more bytes than userspace
has supplied, SYSLOG_ACTION_SIZE_UNREAD returns -EFAULT when succeeded,
SYSLOG_ACTION_READ reads garbage memory or even triggers an kernel oops
at _copy_to_user() due to integer overflow.
To close this race, get a snapshot value of printk_time and pass it to
SYSLOG_ACTION_READ, SYSLOG_ACTION_READ_ALL, SYSLOG_ACTION_SIZE_UNREAD and
kmsg_dump_get_buffer().
Link: http://lkml.kernel.org/r/555af37c-b9e0-f940-cb73-a78eba2d4944@i-love.sakura.ne.jp
To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
printk_emit() is called from only devkmsg_write() in the same file.
Save object size by making it a local function.
Link: http://lkml.kernel.org/r/5cc99d2c-c408-34f7-d1fc-e1cd2a9e31da@i-love.sakura.ne.jp
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Move remaining definitions and declarations from include/linux/bootmem.h
into include/linux/memblock.h and remove the redundant header.
The includes were replaced with the semantic patch below and then
semi-automated removal of duplicated '#include <linux/memblock.h>
@@
@@
- #include <linux/bootmem.h>
+ #include <linux/memblock.h>
[sfr@canb.auug.org.au: dma-direct: fix up for the removal of linux/bootmem.h]
Link: http://lkml.kernel.org/r/20181002185342.133d1680@canb.auug.org.au
[sfr@canb.auug.org.au: powerpc: fix up for removal of linux/bootmem.h]
Link: http://lkml.kernel.org/r/20181005161406.73ef8727@canb.auug.org.au
[sfr@canb.auug.org.au: x86/kaslr, ACPI/NUMA: fix for linux/bootmem.h removal]
Link: http://lkml.kernel.org/r/20181008190341.5e396491@canb.auug.org.au
Link: http://lkml.kernel.org/r/1536927045-23536-30-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Serge Semin <fancer.lancer@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The way we calculate logbuf free space percentage overflows signed
integer:
int free;
free = __LOG_BUF_LEN - log_next_idx;
pr_info("early log buf free: %u(%u%%)\n",
free, (free * 100) / __LOG_BUF_LEN);
We support LOG_BUF_LEN of up to 1<<25 bytes. Since setup_log_buf() is
called during early init, logbuf is mostly empty, so
__LOG_BUF_LEN - log_next_idx
is close to 1<<25. Thus when we multiply it by 100, we overflow signed
integer value range: 100 is 2^6 + 2^5 + 2^2.
Example, booting with LOG_BUF_LEN 1<<25 and log_buf_len=2G
boot param:
[ 0.075317] log_buf_len: -2147483648 bytes
[ 0.075319] early log buf free: 33549896(-28%)
Make "free" unsigned integer and use appropriate printk() specifier.
Link: http://lkml.kernel.org/r/20181010113308.9337-1-sergey.senozhatsky@gmail.com
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
We have a proper 'overflow' check which tells us that we need to
split up existing cont buffer in separate records:
if (cont.len + len > sizeof(cont.buf))
cont_flush();
At the same time we also have one extra flush: "if cont buffer is
80% full then split it up" in cont_add():
if (cont.len > (sizeof(cont.buf) * 80) / 100)
cont_flush();
This looks to be redundant, since the existing "overflow" check
should work just fine, so remove this 80% check and wait for either
a normal cont termination \n, for preliminary flush due to
possible buffer overflow or for preliminary flush due to cont race.
Link: http://lkml.kernel.org/r/20181002023836.4487-4-sergey.senozhatsky@gmail.com
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Tejun Heo <tj@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Prior to commit 5c2992ee7f ("printk: remove console flushing special
cases for partial buffered lines") we would do console_cont_flush()
for each pr_cont() to print cont fragments, so console_unlock() would
actually print data:
pr_cont();
console_lock();
console_unlock()
console_cont_flush(); // print cont fragment
...
pr_cont();
console_lock();
console_unlock()
console_cont_flush(); // print cont fragment
We don't do console_cont_flush() anymore, so when we do pr_cont()
console_unlock() does nothing (unless we flushed the cont buffer):
pr_cont();
console_lock();
console_unlock(); // noop
...
pr_cont();
console_lock();
console_unlock(); // noop
...
pr_cont();
cont_flush();
console_lock();
console_unlock(); // print data
We also wakeup klogd purposelessly for pr_cont() output - un-flushed
cont buffer is not stored in log_buf; there is nothing to pull.
Thus we can console_lock()/console_unlock()/wake_up_klogd() only when
we know that we log_store()-ed a message and there is something to
print to the consoles/syslog.
Link: http://lkml.kernel.org/r/20181002023836.4487-3-sergey.senozhatsky@gmail.com
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Tejun Heo <tj@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Since commit 5c2992ee7f ("printk: remove console flushing special
cases for partial buffered lines") we don't print cont fragments
to the consoles; cont lines are now proper log_buf entries and
there is no "consecutive continuation flag" anymore: we either
have 'c' entries that mark continuation lines without fragments;
or '-' entries that mark normal logbuf entries. There are no '+'
entries anymore.
However, we still have a small leftover - presence of ext_console
drivers disables kernel cont support and we flush each pr_cont()
and store it as a separate log_buf entry. Previously, it worked
because msg_print_ext_header() had that "an optional external merge
of the records" functionality:
if (msg->flags & LOG_CONT)
cont = (prev_flags & LOG_CONT) ? '+' : 'c';
We don't do this as of now, so keep kernel cont always enabled.
Note from pmladek:
The original purpose was to get full information including
the metadata and dictionary via extended console drivers,
see commit 6fe29354be ("printk: implement support
for extended console drivers").
The dictionary probably was the most important part but
it was actually lost:
static void cont_flush(void)
{
[...]
log_store(cont.facility, cont.level, cont.flags, cont.ts_nsec,
NULL, 0, cont.buf, cont.len);
Nobody noticed because the only dictionary user is dev_printk()
and dev_cont() is _not_ defined.
Link: http://lkml.kernel.org/r/20181002023836.4487-2-sergey.senozhatsky@gmail.com
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Tejun Heo <tj@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
[pmladek@suse.com: Updated commit message]
Signed-off-by: Petr Mladek <pmladek@suse.com>
The current printk() is ready to handle log buffer size up to 2G.
Give an explicit error for users who want to use larger log buffer.
Also fix printk formatting to show the 2G as a positive number.
Link: http://lkml.kernel.org/r/20181008135916.gg4kkmoki5bgtco5@pathway.suse.cz
Cc: rostedt@goodmis.org
Cc: linux-kernel@vger.kernel.org
Suggested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: He Zhe <zhe.he@windriver.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
[pmladek: Fixed to the really safe limit 2GB.]
Signed-off-by: Petr Mladek <pmladek@suse.com>
log_buf_len_setup does not check input argument before passing it to
simple_strtoull. The argument would be a NULL pointer if "log_buf_len",
without its value, is set in command line and thus causes the following
panic.
PANIC: early exception 0xe3 IP 10:ffffffffaaeacd0d error 0 cr2 0x0
[ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.19.0-rc4-yocto-standard+ #1
[ 0.000000] RIP: 0010:_parse_integer_fixup_radix+0xd/0x70
...
[ 0.000000] Call Trace:
[ 0.000000] simple_strtoull+0x29/0x70
[ 0.000000] memparse+0x26/0x90
[ 0.000000] log_buf_len_setup+0x17/0x22
[ 0.000000] do_early_param+0x57/0x8e
[ 0.000000] parse_args+0x208/0x320
[ 0.000000] ? rdinit_setup+0x30/0x30
[ 0.000000] parse_early_options+0x29/0x2d
[ 0.000000] ? rdinit_setup+0x30/0x30
[ 0.000000] parse_early_param+0x36/0x4d
[ 0.000000] setup_arch+0x336/0x99e
[ 0.000000] start_kernel+0x6f/0x4ee
[ 0.000000] x86_64_start_reservations+0x24/0x26
[ 0.000000] x86_64_start_kernel+0x6f/0x72
[ 0.000000] secondary_startup_64+0xa4/0xb0
This patch adds a check to prevent the panic.
Link: http://lkml.kernel.org/r/1538239553-81805-1-git-send-email-zhe.he@windriver.com
Cc: stable@vger.kernel.org
Cc: rostedt@goodmis.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: He Zhe <zhe.he@windriver.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
CON_PRINTBUFFER console registration requires us to do several
preparation steps:
- Rollback console_seq to replay logbuf messages which were already
seen on other consoles;
- Set exclusive_console flag so console_unlock() will ->write() logbuf
messages only to the exclusive_console driver.
The way we do it, however, is a bit racy
logbuf_lock_irqsave(flags);
console_seq = syslog_seq;
console_idx = syslog_idx;
logbuf_unlock_irqrestore(flags);
<< preemption enabled
<< irqs enabled
exclusive_console = newcon;
console_unlock();
We rollback console_seq under logbuf_lock with IRQs disabled, but
we set exclusive_console with local IRQs enabled and logbuf unlocked.
If the system oops-es or panic-s before we set exclusive_console - and
given that we have IRQs and preemption enabled there is such a
possibility - we will re-play all logbuf messages to every registered
console, which may be a bit annoying and time consuming.
Move exclusive_console assignment to the same IRQs-disabled and
logbuf_lock-protected section where we rollback console_seq.
Link: http://lkml.kernel.org/r/20180928095304.9972-1-sergey.senozhatsky@gmail.com
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
The variable "exclusive_console" is used to reply all existing messages
on a newly registered console. It is cleared when all messages are out.
The problem is that new messages might appear in the meantime. These
are then visible only on the exclusive console.
The obvious solution is to clear "exclusive_console" after we replay
all messages that were already proceed before we started the reply.
Reported-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Link: http://lkml.kernel.org/r/20180913123406.14378-1-pmladek@suse.com
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: linux-kernel@vger.kernel.org
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
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Merge tag 'printk-for-4.19-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk
Pull printk fix from Petr Mladek:
"Revert a commit that caused "quiet", "debug", and "loglevel" early
parameters to be ignored for early boot messages"
* tag 'printk-for-4.19-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
Revert "printk: make sure to print log on console."
This reverts commit 375899cddc.
The visibility of early messages did not longer take into account
"quiet", "debug", and "loglevel" early parameters.
It would be possible to invalidate and recompute LOG_NOCONS flag
for the affected messages. But it would be hairy.
Instead this patch just reverts the problematic commit. We could
come up with a better solution for the original problem. For example,
we could simplify the logic and just mark messages that should always
be visible or always invisible on the console.
Also this patch reverts the related build fix commit ffaa619af1
("printk: Fix warning about unused suppress_message_printing").
Finally, this patch does not put back the unused LOG_NOCONS flag.
Link: http://lkml.kernel.org/r/20180910145747.emvfzv4mzlk5dfqk@pathway.suse.cz
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Maninder Singh <maninder1.s@samsung.com>
Reported-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
I hit the following splat in my tests:
------------[ cut here ]------------
IRQs not enabled as expected
WARNING: CPU: 3 PID: 0 at kernel/time/tick-sched.c:982 tick_nohz_idle_enter+0x44/0x8c
Modules linked in: ip6t_REJECT nf_reject_ipv6 ip6table_filter ip6_tables ipv6
CPU: 3 PID: 0 Comm: swapper/3 Not tainted 4.19.0-rc2-test+ #2
Hardware name: MSI MS-7823/CSM-H87M-G43 (MS-7823), BIOS V1.6 02/22/2014
EIP: tick_nohz_idle_enter+0x44/0x8c
Code: ec 05 00 00 00 75 26 83 b8 c0 05 00 00 00 75 1d 80 3d d0 36 3e c1 00
75 14 68 94 63 12 c1 c6 05 d0 36 3e c1 01 e8 04 ee f8 ff <0f> 0b 58 fa bb a0
e5 66 c1 e8 25 0f 04 00 64 03 1d 28 31 52 c1 8b
EAX: 0000001c EBX: f26e7f8c ECX: 00000006 EDX: 00000007
ESI: f26dd1c0 EDI: 00000000 EBP: f26e7f40 ESP: f26e7f38
DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010296
CR0: 80050033 CR2: 0813c6b0 CR3: 2f342000 CR4: 001406f0
Call Trace:
do_idle+0x33/0x202
cpu_startup_entry+0x61/0x63
start_secondary+0x18e/0x1ed
startup_32_smp+0x164/0x168
irq event stamp: 18773830
hardirqs last enabled at (18773829): [<c040150c>] trace_hardirqs_on_thunk+0xc/0x10
hardirqs last disabled at (18773830): [<c040151c>] trace_hardirqs_off_thunk+0xc/0x10
softirqs last enabled at (18773824): [<c0ddaa6f>] __do_softirq+0x25f/0x2bf
softirqs last disabled at (18773767): [<c0416bbe>] call_on_stack+0x45/0x4b
---[ end trace b7c64aa79e17954a ]---
After a bit of debugging, I found what was happening. This would trigger
when performing "perf" with a high NMI interrupt rate, while enabling and
disabling function tracer. Ftrace uses breakpoints to convert the nops at
the start of functions to calls to the function trampolines. The breakpoint
traps disable interrupts and this makes calls into lockdep via the
trace_hardirqs_off_thunk in the entry.S code. What happens is the following:
do_idle {
[interrupts enabled]
<interrupt> [interrupts disabled]
TRACE_IRQS_OFF [lockdep says irqs off]
[...]
TRACE_IRQS_IRET
test if pt_regs say return to interrupts enabled [yes]
TRACE_IRQS_ON [lockdep says irqs are on]
<nmi>
nmi_enter() {
printk_nmi_enter() [traced by ftrace]
[ hit ftrace breakpoint ]
<breakpoint exception>
TRACE_IRQS_OFF [lockdep says irqs off]
[...]
TRACE_IRQS_IRET [return from breakpoint]
test if pt_regs say interrupts enabled [no]
[iret back to interrupt]
[iret back to code]
tick_nohz_idle_enter() {
lockdep_assert_irqs_enabled() [lockdep say no!]
Although interrupts are indeed enabled, lockdep thinks it is not, and since
we now do asserts via lockdep, it gives a false warning. The issue here is
that printk_nmi_enter() is called before lockdep_off(), which disables
lockdep (for this reason) in NMIs. By simply not allowing ftrace to see
printk_nmi_enter() (via notrace annotation) we keep lockdep from getting
confused.
Cc: stable@vger.kernel.org
Fixes: 42a0bb3f71 ("printk/nmi: generic solution for safe printk in NMI")
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
- add support for deferred console takeover, when enabled defers
fbcon taking over the console from the dummy console until the
first text is displayed on the console - together with the "quiet"
kernel commandline option this allows fbcon to still be used
together with a smooth graphical bootup (Hans de Goede)
- improve console locking debugging code (Thomas Zimmermann)
- copy the ACPI BGRT boot graphics to the framebuffer when deferred
console takeover support is used in efifb driver (Hans de Goede)
- update udlfb driver - fix lost console when the user unplugs a USB
adapter, fix the screen corruption issue, fix locking and add some
performance optimizations (Mikulas Patocka)
- update pxafb driver - fix using uninitialized memory, switch to
devm_* API, handle initialization errors and add support for
lcd-supply regulator (Daniel Mack)
- add support for boards booted with a DeviceTree in pxa3xx_gcu
driver (Daniel Mack)
- rename omap2 module to omap2fb.ko to avoid conflicts with omap1
driver (Arnd Bergmann)
- enable ACPI-based enumeration for goldfishfb driver (Yu Ning)
- fix goldfishfb driver to make user space Android code use 60 fps
(Christoffer Dall)
- print big fat warning when nomodeset kernel parameter is used in
vgacon driver (Lyude Paul)
- remove VLA usage from fsl-diu-fb driver (Kees Cook)
- misc fixes (Julia Lawall, Geert Uytterhoeven, Fredrik Noring,
Yisheng Xie, Dan Carpenter, Daniel Vetter, Anton Vasilyev, Randy
Dunlap, Gustavo A. R. Silva, Colin Ian King, Fengguang Wu)
- misc cleanups (Roman Kiryanov, Yisheng Xie, Colin Ian King)
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Merge tag 'fbdev-v4.19' of https://github.com/bzolnier/linux
Pull fbdev updates from Bartlomiej Zolnierkiewicz:
"Mostly small fixes and cleanups for fb drivers (the biggest updates
are for udlfb and pxafb drivers). This also adds deferred console
takeover support to the console code and efifb driver.
Summary:
- add support for deferred console takeover, when enabled defers
fbcon taking over the console from the dummy console until the
first text is displayed on the console - together with the "quiet"
kernel commandline option this allows fbcon to still be used
together with a smooth graphical bootup (Hans de Goede)
- improve console locking debugging code (Thomas Zimmermann)
- copy the ACPI BGRT boot graphics to the framebuffer when deferred
console takeover support is used in efifb driver (Hans de Goede)
- update udlfb driver - fix lost console when the user unplugs a USB
adapter, fix the screen corruption issue, fix locking and add some
performance optimizations (Mikulas Patocka)
- update pxafb driver - fix using uninitialized memory, switch to
devm_* API, handle initialization errors and add support for
lcd-supply regulator (Daniel Mack)
- add support for boards booted with a DeviceTree in pxa3xx_gcu
driver (Daniel Mack)
- rename omap2 module to omap2fb.ko to avoid conflicts with omap1
driver (Arnd Bergmann)
- enable ACPI-based enumeration for goldfishfb driver (Yu Ning)
- fix goldfishfb driver to make user space Android code use 60 fps
(Christoffer Dall)
- print big fat warning when nomodeset kernel parameter is used in
vgacon driver (Lyude Paul)
- remove VLA usage from fsl-diu-fb driver (Kees Cook)
- misc fixes (Julia Lawall, Geert Uytterhoeven, Fredrik Noring,
Yisheng Xie, Dan Carpenter, Daniel Vetter, Anton Vasilyev, Randy
Dunlap, Gustavo A. R. Silva, Colin Ian King, Fengguang Wu)
- misc cleanups (Roman Kiryanov, Yisheng Xie, Colin Ian King)"
* tag 'fbdev-v4.19' of https://github.com/bzolnier/linux: (54 commits)
Documentation/fb: corrections for fbcon.txt
fbcon: Do not takeover the console from atomic context
dummycon: Stop exporting dummycon_[un]register_output_notifier
fbcon: Only defer console takeover if the current console driver is the dummycon
fbcon: Only allow FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER if fbdev is builtin
fbdev: omap2: omapfb: fix ifnullfree.cocci warnings
fbdev: omap2: omapfb: fix bugon.cocci warnings
fbdev: omap2: omapfb: fix boolreturn.cocci warnings
fb: amifb: fix build warnings when not builtin
fbdev/core: Disable console-lock warnings when fb.lockless_register_fb is set
console: Replace #if 0 with atomic var 'ignore_console_lock_warning'
udlfb: use spin_lock_irq instead of spin_lock_irqsave
udlfb: avoid prefetch
udlfb: optimization - test the backing buffer
udlfb: allow reallocating the framebuffer
udlfb: set line_length in dlfb_ops_set_par
udlfb: handle allocation failure
udlfb: set optimal write delay
udlfb: make a local copy of fb_ops
udlfb: don't switch if we are switching to the same videomode
...
Allow the initcall tables to be emitted using relative references that
are only half the size on 64-bit architectures and don't require fixups
at runtime on relocatable kernels.
Link: http://lkml.kernel.org/r/20180704083651.24360-5-ard.biesheuvel@linaro.org
Acked-by: James Morris <james.morris@microsoft.com>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Petr Mladek <pmladek@suse.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morris <jmorris@namei.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Merge tag 'drm-next-2018-08-15' of git://anongit.freedesktop.org/drm/drm
Pull drm updates from Dave Airlie:
"This is the main drm pull request for 4.19.
Rob has some new hardware support for new qualcomm hw that I'll send
along separately. This has the display part of it, the remaining pull
is for the acceleration engine.
This also contains a wound-wait/wait-die mutex rework, Peter has acked
it for merging via my tree.
Otherwise mostly the usual level of activity. Summary:
core:
- Wound-wait/wait-die mutex rework
- Add writeback connector type
- Add "content type" property for HDMI
- Move GEM bo to drm_framebuffer
- Initial gpu scheduler documentation
- GPU scheduler fixes for dying processes
- Console deferred fbcon takeover support
- Displayport support for CEC tunneling over AUX
panel:
- otm8009a panel driver fixes
- Innolux TV123WAM and G070Y2-L01 panel driver
- Ilitek ILI9881c panel driver
- Rocktech RK070ER9427 LCD
- EDT ETM0700G0EDH6 and EDT ETM0700G0BDH6
- DLC DLC0700YZG-1
- BOE HV070WSA-100
- newhaven, nhd-4.3-480272ef-atxl LCD
- DataImage SCF0700C48GGU18
- Sharp LQ035Q7DB03
- p079zca: Refactor to support multiple panels
tinydrm:
- ILI9341 display panel
New driver:
- vkms - virtual kms driver to testing.
i915:
- Icelake:
Display enablement
DSI support
IRQ support
Powerwell support
- GPU reset fixes and improvements
- Full ppgtt support refactoring
- PSR fixes and improvements
- Execlist improvments
- GuC related fixes
amdgpu:
- Initial amdgpu documentation
- JPEG engine support on VCN
- CIK uses powerplay by default
- Move to using core PCIE functionality for gens/lanes
- DC/Powerplay interface rework
- Stutter mode support for RV
- Vega12 Powerplay updates
- GFXOFF fixes
- GPUVM fault debugging
- Vega12 GFXOFF
- DC improvements
- DC i2c/aux changes
- UVD 7.2 fixes
- Powerplay fixes for Polaris12, CZ/ST
- command submission bo_list fixes
amdkfd:
- Raven support
- Power management fixes
udl:
- Cleanups and fixes
nouveau:
- misc fixes and cleanups.
msm:
- DPU1 support display controller in sdm845
- GPU coredump support.
vmwgfx:
- Atomic modesetting validation fixes
- Support for multisample surfaces
armada:
- Atomic modesetting support completed.
exynos:
- IPPv2 fixes
- Move g2d to component framework
- Suspend/resume support cleanups
- Driver cleanups
imx:
- CSI configuration improvements
- Driver cleanups
- Use atomic suspend/resume helpers
- ipu-v3 V4L2 XRGB32/XBGR32 support
pl111:
- Add Nomadik LCDC variant
v3d:
- GPU scheduler jobs management
sun4i:
- R40 display engine support
- TCON TOP driver
mediatek:
- MT2712 SoC support
rockchip:
- vop fixes
omapdrm:
- Workaround for DRA7 errata i932
- Fix mm_list locking
mali-dp:
- Writeback implementation
PM improvements
- Internal error reporting debugfs
tilcdc:
- Single fix for deferred probing
hdlcd:
- Teardown fixes
tda998x:
- Converted to a bridge driver.
etnaviv:
- Misc fixes"
* tag 'drm-next-2018-08-15' of git://anongit.freedesktop.org/drm/drm: (1506 commits)
drm/amdgpu/sriov: give 8s for recover vram under RUNTIME
drm/scheduler: fix param documentation
drm/i2c: tda998x: correct PLL divider calculation
drm/i2c: tda998x: get rid of private fill_modes function
drm/i2c: tda998x: move mode_valid() to bridge
drm/i2c: tda998x: register bridge outside of component helper
drm/i2c: tda998x: cleanup from previous changes
drm/i2c: tda998x: allocate tda998x_priv inside tda998x_create()
drm/i2c: tda998x: convert to bridge driver
drm/scheduler: fix timeout worker setup for out of order job completions
drm/amd/display: display connected to dp-1 does not light up
drm/amd/display: update clk for various HDMI color depths
drm/amd/display: program display clock on cache match
drm/amd/display: Add NULL check for enabling dp ss
drm/amd/display: add vbios table check for enabling dp ss
drm/amd/display: Don't share clk source between DP and HDMI
drm/amd/display: Fix DP HBR2 Eye Diagram Pattern on Carrizo
drm/amd/display: Use calculated disp_clk_khz value for dce110
drm/amd/display: Implement custom degamma lut on dcn
drm/amd/display: Destroy aux_engines only once
...
The macro WARN_CONSOLE_UNLOCKED prints a warning when a thread enters
the console's critical section without having acquired the console
lock. The console lock can be ignored when debugging the console using
printk, but this makes WARN_CONSOLE_UNLOCKED generate unnecessary
warnings.
The variable ignore_console_lock_warning temporarily disables
WARN_CONSOLE_UNLOCKED. Developers interested in debugging the console's
critical sections should increment it before entering the CS and
decrement it after leaving the CS. Setting ignore_console_lock_warning
is only for debugging. Regular operation should not manipulate it.
Acknoledgements: This patch is based on an earlier version by Steven
Rostedt. The use of atomic increment/decrement was suggested by Petr
Mladek.
Link: http://lkml.kernel.org/r/717e6337-e7a6-7a92-1c1b-8929a25696b5@suse.de
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
[b.zolnierkie: use <linux/atomic.h>]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
suppress_message_printing() is not longer called in console_unlock().
Therefore it is not longer needed with disabled CONFIG_PRINTK.
This fixes the warning:
kernel/printk/printk.c:2033:13: warning: ‘suppress_message_printing’ defined but not used [-Wunused-function]
static bool suppress_message_printing(int level) { return false; }
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Maninder Singh <maninder1.s@samsung.com>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
The commit 719f6a7040 ("printk: Use the main logbuf in NMI
when logbuf_lock is available") brought back the possible deadlocks
in printk() and NMI.
The check of logbuf_lock is done only in printk_nmi_enter() to prevent
mixed output. But another CPU might take the lock later, enter NMI, and:
+ Both NMIs might be serialized by yet another lock, for example,
the one in nmi_cpu_backtrace().
+ The other CPU might get stopped in NMI, see smp_send_stop()
in panic().
The only safe solution is to use trylock when storing the message
into the main log-buffer. It might cause reordering when some lines
go to the main lock buffer directly and others are delayed via
the per-CPU buffer. It means that it is not useful in general.
This patch replaces the problematic NMI deferred context with NMI
direct context. It can be used to mark a code that might produce
many messages in NMI and the risk of losing them is more critical
than problems with eventual reordering.
The context is then used when dumping trace buffers on oops. It was
the primary motivation for the original fix. Also the reordering is
even smaller issue there because some traces have their own time stamps.
Finally, nmi_cpu_backtrace() need not longer be serialized because
it will always us the per-CPU buffers again.
Fixes: 719f6a7040 ("printk: Use the main logbuf in NMI when logbuf_lock is available")
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20180627142028.11259-1-pmladek@suse.com
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
It is just a preparation step. The patch does not change
the existing behavior.
Link: http://lkml.kernel.org/r/20180627140817.27764-3-pmladek@suse.com
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
It is just a preparation step. The patch does not change
the existing behavior.
Link: http://lkml.kernel.org/r/20180627140817.27764-2-pmladek@suse.com
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Muchun Song