- 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>
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>
This is a preparation patch for adding a number of WARN_CONSOLE_UNLOCKED()
calls to the fbcon code, which may be built as a module (event though
usually it is not).
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
This patch make sure printing of log on console if loglevel
at time of storing log is less than current console loglevel.
@why
In SMP printk can work asynchronously, logs can be missed on console
because it checks current log level at time of console_unlock,
not at time of storing logs.
func()
{
....
....
console_verbose(); // user wants to have all the logs on console.
pr_alert();
dump_backtrace(); //prints with default loglevel.
...
console_silent(); // stop all logs from printing on console.
}
Now if console_lock was owned by another process, the messages might
be handled after the consoles were silenced.
Reused flag LOG_NOCONS as its usage is gone long back by the commit
5c2992ee7f ("printk: remove console flushing special cases
for partial buffered lines").
Note that there are still some corner cases where this patch is not enough.
For example, when the messages are flushed later from printk_safe buffers
or when there are races between console_verbose() and console_silent()
callers.
Link: http://lkml.kernel.org/r/20180601090029epcas5p3cc93d4bfbebb3199f0a2684058da7e26~z-a_jkmrI2993329933epcas5p3q@epcas5p3.samsung.com
Cc: linux-kernel@vger.kernel.org
Cc: a.sahrawat@samsung.com
Cc: pankaj.m@samsung.com
Cc: v.narang@samsung.com
Cc: <maninder1.s@samsung.com>
Signed-off-by: Vaneet Narang <v.narang@samsung.com>
Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
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Merge tag 'printk-for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk
Pull printk updates from Petr Mladek:
- Help userspace log daemons to catch up with a flood of messages. They
will get woken after each message even if the console is far behind
and handled by another process.
- Flush printk safe buffers safely even when panic() happens in the
normal context.
- Fix possible va_list reuse when race happened in printk_safe().
- Remove %pCr printf format to prevent sleeping in the atomic context.
- Misc vsprintf code cleanup.
* tag 'printk-for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
printk: drop in_nmi check from printk_safe_flush_on_panic()
lib/vsprintf: Remove atomic-unsafe support for %pCr
serial: sh-sci: Stop using printk format %pCr
thermal: bcm2835: Stop using printk format %pCr
clk: renesas: cpg-mssr: Stop using printk format %pCr
printk: fix possible reuse of va_list variable
printk: wake up klogd in vprintk_emit
vsprintf: Tweak pF/pf comment
lib/vsprintf: Mark expected switch fall-through
lib/vsprintf: Replace space with '_' before crng is ready
lib/vsprintf: Deduplicate pointer_string()
lib/vsprintf: Move pointer_string() upper
lib/vsprintf: Make flag_spec global
lib/vsprintf: Make strspec global
lib/vsprintf: Make dec_spec global
lib/test_printf: Mark big constant with UL
We wake up klogd very late - only when current console_sem owner
is done pushing pending kernel messages to the serial/net consoles.
In some cases this results in lost syslog messages, because kernel
log buffer is a circular buffer and if we don't wakeup syslog long
enough there are chances that logbuf simply will wrap around.
The patch moves the klogd wake up call to vprintk_emit(), which is
the only legit way for a kernel message to appear in the logbuf,
right after the attempt to handle consoles. As a result, klogd
will get waken either after flushing the new message to consoles
or immediately when consoles are still busy with older messages.
Link: http://lkml.kernel.org/r/20180419014250.5692-1-sergey.senozhatsky@gmail.com
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
- Tom Zanussi's extended histogram work
This adds the synthetic events to have histograms from multiple event data
Adds triggers "onmatch" and "onmax" to call the synthetic events
Several updates to the histogram code from this
- Allow way to nest ring buffer calls in the same context
- Allow absolute time stamps in ring buffer
- Rewrite of filter code parsing based on Al Viro's suggestions
- Setting of trace_clock to global if TSC is unstable (on boot)
- Better OOM handling when allocating large ring buffers
- Added initcall tracepoints (consolidated initcall_debug code with them)
And other various fixes and clean ups
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Merge tag 'trace-v4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"New features:
- Tom Zanussi's extended histogram work.
This adds the synthetic events to have histograms from multiple
event data Adds triggers "onmatch" and "onmax" to call the
synthetic events Several updates to the histogram code from this
- Allow way to nest ring buffer calls in the same context
- Allow absolute time stamps in ring buffer
- Rewrite of filter code parsing based on Al Viro's suggestions
- Setting of trace_clock to global if TSC is unstable (on boot)
- Better OOM handling when allocating large ring buffers
- Added initcall tracepoints (consolidated initcall_debug code with
them)
And other various fixes and clean ups"
* tag 'trace-v4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (68 commits)
init: Have initcall_debug still work without CONFIG_TRACEPOINTS
init, tracing: Have printk come through the trace events for initcall_debug
init, tracing: instrument security and console initcall trace events
init, tracing: Add initcall trace events
tracing: Add rcu dereference annotation for test func that touches filter->prog
tracing: Add rcu dereference annotation for filter->prog
tracing: Fixup logic inversion on setting trace_global_clock defaults
tracing: Hide global trace clock from lockdep
ring-buffer: Add set/clear_current_oom_origin() during allocations
ring-buffer: Check if memory is available before allocation
lockdep: Add print_irqtrace_events() to __warn
vsprintf: Do not preprocess non-dereferenced pointers for bprintf (%px and %pK)
tracing: Uninitialized variable in create_tracing_map_fields()
tracing: Make sure variable string fields are NULL-terminated
tracing: Add action comparisons when testing matching hist triggers
tracing: Don't add flag strings when displaying variable references
tracing: Fix display of hist trigger expressions containing timestamps
ftrace: Drop a VLA in module_exists()
tracing: Mention trace_clock=global when warning about unstable clocks
tracing: Default to using trace_global_clock if sched_clock is unstable
...
Trace events have been added around the initcall functions defined in
init/main.c. But console and security have their own initcalls. This adds
the trace events associated for those initcall functions.
Link: http://lkml.kernel.org/r/1521765208.19745.2.camel@polymtl.ca
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Abderrahmane Benbachir <abderrahmane.benbachir@polymtl.ca>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Pull printk updates from Petr Mladek:
- Add info about loaded kdump kernel into the dump stack header
- Move dump-stack related code from printk.c to lib/dump_stack.c
- Write message about suspending consoles in KERN_INFO log level
* 'for-4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
printk: change message to pr_info
printk: move dump stack related code to lib/dump_stack.c
print kdump kernel loaded status in stack dump
To allow userspace to prevent this message from appearing in the
console by changing the log priority.
This matches other informative messages that the power subsystem emits
when the system changes power states.
Link: http://lkml.kernel.org/r/20180322135833.16602-1-tomeu.vizoso@collabora.com
To: linux-kernel@vger.kernel.org
Cc: kernel@collabora.com
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
dump_stack related stuff should belong to lib/dump_stack.c thus move them
there. Also conditionally compile lib/dump_stack.c since dump_stack code
does not make sense if printk is disabled.
Link: http://lkml.kernel.org/r/20180213072834.GA24784@dhcp-128-65.nay.redhat.com
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org
Cc: akpm@linux-foundation.org
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Dave Young <dyoung@redhat.com>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Suggested-by: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Pull printk fix from Petr Mladek:
"Make sure that we wake up userspace loggers. This fixes a race
introduced by the console waiter logic during this merge window"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
printk: Wake klogd when passing console_lock owner
wake_klogd is a local variable in console_unlock(). The information
is lost when the console_lock owner using the busy wait added by
the commit dbdda842fe ("printk: Add console owner and waiter
logic to load balance console writes"). The following race is
possible:
CPU0 CPU1
console_unlock()
for (;;)
/* calling console for last message */
printk()
log_store()
log_next_seq++;
/* see new message */
if (seen_seq != log_next_seq) {
wake_klogd = true;
seen_seq = log_next_seq;
}
console_lock_spinning_enable();
if (console_trylock_spinning())
/* spinning */
if (console_lock_spinning_disable_and_check()) {
printk_safe_exit_irqrestore(flags);
return;
console_unlock()
if (seen_seq != log_next_seq) {
/* already seen */
/* nothing to do */
Result: Nobody would wakeup klogd.
One solution would be to make a global variable from wake_klogd.
But then we would need to manipulate it under a lock or so.
This patch wakes klogd also when console_lock is passed to the
spinning waiter. It looks like the right way to go. Also userspace
should have a chance to see and store any "flood" of messages.
Note that the very late klogd wake up was a historic solution.
It made sense on single CPU systems or when sys_syslog() operations
were synchronized using the big kernel lock like in v2.1.113.
But it is questionable these days.
Fixes: dbdda842fe ("printk: Add console owner and waiter logic to load balance console writes")
Link: http://lkml.kernel.org/r/20180226155734.dzwg3aovqnwtvkoy@pathway.suse.cz
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org
Cc: Tejun Heo <tj@kernel.org>
Suggested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:
for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
done
with de-mangling cleanups yet to come.
NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do. But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.
The next patch from Al will sort out the final differences, and we
should be all done.
Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull printk updates from Petr Mladek:
- Add a console_msg_format command line option:
The value "default" keeps the old "[time stamp] text\n" format. The
value "syslog" allows to see the syslog-like "<log
level>[timestamp] text" format.
This feature was requested by people doing regression tests, for
example, 0day robot. They want to have both filtered and full logs
at hands.
- Reduce the risk of softlockup:
Pass the console owner in a busy loop.
This is a new approach to the old problem. It was first proposed by
Steven Rostedt on Kernel Summit 2017. It marks a context in which
the console_lock owner calls console drivers and could not sleep.
On the other side, printk() callers could detect this state and use
a busy wait instead of a simple console_trylock(). Finally, the
console_lock owner checks if there is a busy waiter at the end of
the special context and eventually passes the console_lock to the
waiter.
The hand-off works surprisingly well and helps in many situations.
Well, there is still a possibility of the softlockup, for example,
when the flood of messages stops and the last owner still has too
much to flush.
There is increasing number of people having problems with
printk-related softlockups. We might eventually need to get better
solution. Anyway, this looks like a good start and promising
direction.
- Do not allow to schedule in console_unlock() called from printk():
This reverts an older controversial commit. The reschedule helped
to avoid softlockups. But it also slowed down the console output.
This patch is obsoleted by the new console waiter logic described
above. In fact, the reschedule made the hand-off less effective.
- Deprecate "%pf" and "%pF" format specifier:
It was needed on ia64, ppc64 and parisc64 to dereference function
descriptors and show the real function address. It is done
transparently by "%ps" and "pS" format specifier now.
Sergey Senozhatsky found that all the function descriptors were in
a special elf section and could be easily detected.
- Remove printk_symbol() API:
It has been obsoleted by "%pS" format specifier, and this change
helped to remove few continuous lines and a less intuitive old API.
- Remove redundant memsets:
Sergey removed unnecessary memset when processing printk.devkmsg
command line option.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk: (27 commits)
printk: drop redundant devkmsg_log_str memsets
printk: Never set console_may_schedule in console_trylock()
printk: Hide console waiter logic into helpers
printk: Add console owner and waiter logic to load balance console writes
kallsyms: remove print_symbol() function
checkpatch: add pF/pf deprecation warning
symbol lookup: introduce dereference_symbol_descriptor()
parisc64: Add .opd based function descriptor dereference
powerpc64: Add .opd based function descriptor dereference
ia64: Add .opd based function descriptor dereference
sections: split dereference_function_descriptor()
openrisc: Fix conflicting types for _exext and _stext
lib: do not use print_symbol()
irq debug: do not use print_symbol()
sysfs: do not use print_symbol()
drivers: do not use print_symbol()
x86: do not use print_symbol()
unicore32: do not use print_symbol()
sh: do not use print_symbol()
mn10300: do not use print_symbol()
...
Pull poll annotations from Al Viro:
"This introduces a __bitwise type for POLL### bitmap, and propagates
the annotations through the tree. Most of that stuff is as simple as
'make ->poll() instances return __poll_t and do the same to local
variables used to hold the future return value'.
Some of the obvious brainos found in process are fixed (e.g. POLLIN
misspelled as POLL_IN). At that point the amount of sparse warnings is
low and most of them are for genuine bugs - e.g. ->poll() instance
deciding to return -EINVAL instead of a bitmap. I hadn't touched those
in this series - it's large enough as it is.
Another problem it has caught was eventpoll() ABI mess; select.c and
eventpoll.c assumed that corresponding POLL### and EPOLL### were
equal. That's true for some, but not all of them - EPOLL### are
arch-independent, but POLL### are not.
The last commit in this series separates userland POLL### values from
the (now arch-independent) kernel-side ones, converting between them
in the few places where they are copied to/from userland. AFAICS, this
is the least disruptive fix preserving poll(2) ABI and making epoll()
work on all architectures.
As it is, it's simply broken on sparc - try to give it EPOLLWRNORM and
it will trigger only on what would've triggered EPOLLWRBAND on other
architectures. EPOLLWRBAND and EPOLLRDHUP, OTOH, are never triggered
at all on sparc. With this patch they should work consistently on all
architectures"
* 'misc.poll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (37 commits)
make kernel-side POLL... arch-independent
eventpoll: no need to mask the result of epi_item_poll() again
eventpoll: constify struct epoll_event pointers
debugging printk in sg_poll() uses %x to print POLL... bitmap
annotate poll(2) guts
9p: untangle ->poll() mess
->si_band gets POLL... bitmap stored into a user-visible long field
ring_buffer_poll_wait() return value used as return value of ->poll()
the rest of drivers/*: annotate ->poll() instances
media: annotate ->poll() instances
fs: annotate ->poll() instances
ipc, kernel, mm: annotate ->poll() instances
net: annotate ->poll() instances
apparmor: annotate ->poll() instances
tomoyo: annotate ->poll() instances
sound: annotate ->poll() instances
acpi: annotate ->poll() instances
crypto: annotate ->poll() instances
block: annotate ->poll() instances
x86: annotate ->poll() instances
...
This patch, basically, reverts commit 6b97a20d3a ("printk:
set may_schedule for some of console_trylock() callers").
That commit was a mistake, it introduced a big dependency
on the scheduler, by enabling preemption under console_sem
in printk()->console_unlock() path, which is rather too
critical. The patch did not significantly reduce the
possibilities of printk() lockups, but made it possible to
stall printk(), as has been reported by Tetsuo Handa [1].
Another issues is that preemption under console_sem also
messes up with Steven Rostedt's hand off scheme, by making
it possible to sleep with console_sem both in console_unlock()
and in vprintk_emit(), after acquiring the console_sem
ownership (anywhere between printk_safe_exit_irqrestore() in
console_trylock_spinning() and printk_safe_enter_irqsave()
in console_unlock()). This makes hand off less likely and,
at the same time, may result in a significant amount of
pending logbuf messages. Preempted console_sem owner makes
it impossible for other CPUs to emit logbuf messages, but
does not make it impossible for other CPUs to append new
messages to the logbuf.
Reinstate the old behavior and make printk() non-preemptible.
Should any printk() lockup reports arrive they must be handled
in a different way.
[1] http://lkml.kernel.org/r/201603022101.CAH73907.OVOOMFHFFtQJSL%20()%20I-love%20!%20SAKURA%20!%20ne%20!%20jp
Fixes: 6b97a20d3a ("printk: set may_schedule for some of console_trylock() callers")
Link: http://lkml.kernel.org/r/20180116044716.GE6607@jagdpanzerIV
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: akpm@linux-foundation.org
Cc: linux-mm@kvack.org
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
The commit ("printk: Add console owner and waiter logic to load balance
console writes") made vprintk_emit() and console_unlock() even more
complicated.
This patch extracts the new code into 3 helper functions. They should
help to keep it rather self-contained. It will be easier to use and
maintain.
This patch just shuffles the existing code. It does not change
the functionality.
Link: http://lkml.kernel.org/r/20180112160837.GD24497@linux.suse
Cc: akpm@linux-foundation.org
Cc: linux-mm@kvack.org
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: rostedt@home.goodmis.org
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
This patch implements what I discussed in Kernel Summit. I added
lockdep annotation (hopefully correctly), and it hasn't had any splats
(since I fixed some bugs in the first iterations). It did catch
problems when I had the owner covering too much. But now that the owner
is only set when actively calling the consoles, lockdep has stayed
quiet.
Here's the design again:
I added a "console_owner" which is set to a task that is actively
writing to the consoles. It is *not* the same as the owner of the
console_lock. It is only set when doing the calls to the console
functions. It is protected by a console_owner_lock which is a raw spin
lock.
There is a console_waiter. This is set when there is an active console
owner that is not current, and waiter is not set. This too is protected
by console_owner_lock.
In printk() when it tries to write to the consoles, we have:
if (console_trylock())
console_unlock();
Now I added an else, which will check if there is an active owner, and
no current waiter. If that is the case, then console_waiter is set, and
the task goes into a spin until it is no longer set.
When the active console owner finishes writing the current message to
the consoles, it grabs the console_owner_lock and sees if there is a
waiter, and clears console_owner.
If there is a waiter, then it breaks out of the loop, clears the waiter
flag (because that will release the waiter from its spin), and exits.
Note, it does *not* release the console semaphore. Because it is a
semaphore, there is no owner. Another task may release it. This means
that the waiter is guaranteed to be the new console owner! Which it
becomes.
Then the waiter calls console_unlock() and continues to write to the
consoles.
If another task comes along and does a printk() it too can become the
new waiter, and we wash rinse and repeat!
By Petr Mladek about possible new deadlocks:
The thing is that we move console_sem only to printk() call
that normally calls console_unlock() as well. It means that
the transferred owner should not bring new type of dependencies.
As Steven said somewhere: "If there is a deadlock, it was
there even before."
We could look at it from this side. The possible deadlock would
look like:
CPU0 CPU1
console_unlock()
console_owner = current;
spin_lockA()
printk()
spin = true;
while (...)
call_console_drivers()
spin_lockA()
This would be a deadlock. CPU0 would wait for the lock A.
While CPU1 would own the lockA and would wait for CPU0
to finish calling the console drivers and pass the console_sem
owner.
But if the above is true than the following scenario was
already possible before:
CPU0
spin_lockA()
printk()
console_unlock()
call_console_drivers()
spin_lockA()
By other words, this deadlock was there even before. Such
deadlocks are prevented by using printk_deferred() in
the sections guarded by the lock A.
By Steven Rostedt:
To demonstrate the issue, this module has been shown to lock up a
system with 4 CPUs and a slow console (like a serial console). It is
also able to lock up a 8 CPU system with only a fast (VGA) console, by
passing in "loops=100". The changes in this commit prevent this module
from locking up the system.
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/mutex.h>
#include <linux/workqueue.h>
#include <linux/hrtimer.h>
static bool stop_testing;
static unsigned int loops = 1;
static void preempt_printk_workfn(struct work_struct *work)
{
int i;
while (!READ_ONCE(stop_testing)) {
for (i = 0; i < loops && !READ_ONCE(stop_testing); i++) {
preempt_disable();
pr_emerg("%5d%-75s\n", smp_processor_id(),
" XXX NOPREEMPT");
preempt_enable();
}
msleep(1);
}
}
static struct work_struct __percpu *works;
static void finish(void)
{
int cpu;
WRITE_ONCE(stop_testing, true);
for_each_online_cpu(cpu)
flush_work(per_cpu_ptr(works, cpu));
free_percpu(works);
}
static int __init test_init(void)
{
int cpu;
works = alloc_percpu(struct work_struct);
if (!works)
return -ENOMEM;
/*
* This is just a test module. This will break if you
* do any CPU hot plugging between loading and
* unloading the module.
*/
for_each_online_cpu(cpu) {
struct work_struct *work = per_cpu_ptr(works, cpu);
INIT_WORK(work, &preempt_printk_workfn);
schedule_work_on(cpu, work);
}
return 0;
}
static void __exit test_exit(void)
{
finish();
}
module_param(loops, uint, 0);
module_init(test_init);
module_exit(test_exit);
MODULE_LICENSE("GPL");
Link: http://lkml.kernel.org/r/20180110132418.7080-2-pmladek@suse.com
Cc: akpm@linux-foundation.org
Cc: linux-mm@kvack.org
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
[pmladek@suse.com: Commit message about possible deadlocks]
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
0day and kernelCI automatically parse kernel log - basically some sort
of grepping using the pre-defined text patterns - in order to detect
and report regressions/errors. There are several sources they get the
kernel logs from:
a) dmesg or /proc/ksmg
This is the preferred way. Because `dmesg --raw' (see later Note)
and /proc/kmsg output contains facility and log level, which greatly
simplifies grepping for EMERG/ALERT/CRIT/ERR messages.
b) serial consoles
This option is harder to maintain, because serial console messages
don't contain facility and log level.
This patch introduces a `console_msg_format=' command line option,
to switch between different message formatting on serial consoles.
For the time being we have just two options - default and syslog.
The "default" option just keeps the existing format. While the
"syslog" option makes serial console messages to appear in syslog
format [syslog() syscall], matching the `dmesg -S --raw' and
`cat /proc/kmsg' output formats:
- facility and log level
- time stamp (depends on printk_time/PRINTK_TIME)
- message
<%u>[time stamp] text\n
NOTE: while Kevin and Fengguang talk about "dmesg --raw", it's actually
"dmesg -S --raw" that always prints messages in syslog format [per
Petr Mladek]. Running "dmesg --raw" may produce output in non-syslog
format sometimes. console_msg_format=syslog enables syslog format,
thus in documentation we mention "dmesg -S --raw", not "dmesg --raw".
Per Kevin Hilman:
: Right now we can get this info from a "dmesg --raw" after bootup,
: but it would be really nice in certain automation frameworks to
: have a kernel command-line option to enable printing of loglevels
: in default boot log.
:
: This is especially useful when ingesting kernel logs into advanced
: search/analytics frameworks (I'm playing with and ELK stack: Elastic
: Search, Logstash, Kibana).
:
: The other important reason for having this on the command line is that
: for testing linux-next (and other bleeding edge developer branches),
: it's common that we never make it to userspace, so can't even run
: "dmesg --raw" (or equivalent.) So we really want this on the primary
: boot (serial) console.
Per Fengguang Wu, 0day scripts should quickly benefit from that
feature, because they will be able to switch to a more reliable
parsing, based on messages' facility and log levels [1]:
`#{grep} -a -E -e '^<[0123]>' -e '^kern :(err |crit |alert |emerg )'
instead of doing text pattern matching
`#{grep} -a -F -f /lkp/printk-error-messages #{kmsg_file} |
grep -a -v -E -f #{LKP_SRC}/etc/oops-pattern |
grep -a -v -F -f #{LKP_SRC}/etc/kmsg-blacklist`
[1] https://github.com/fengguang/lkp-tests/blob/master/lib/dmesg.rb
Link: http://lkml.kernel.org/r/20171221054149.4398-1-sergey.senozhatsky@gmail.com
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Fengguang Wu <fengguang.wu@intel.com>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Tested-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Geert Uytterhoeven reported a NFS oops, and pointed out that some of the
numbers were hashed and useless.
We could just turn them from '%p' into '%px', but those numbers are
really just legacy, and useless even when not hashed.
So just remove them entirely.
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
so this message will not mess with the next one
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Maxim Akristiniy <maksim.akristiniy@yotadevices.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Pull printk updates from Petr Mladek:
- Do not allow use of freed init data and code even when boot consoles
are forced to stay. Also check for the init memory more precisely.
- Some code clean up by starting contributors.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
printk: Clean up do_syslog() error handling
printk/console: Enhance the check for consoles using init memory
printk/console: Always disable boot consoles that use init memory before it is freed
printk: Modify operators of printed_len and text_len
This reverts commit 68c4a4f8ab, with
various conflict clean-ups.
The capability check required too much privilege compared to simple DAC
controls. A system builder was forced to have crash handler processes
run with CAP_SYSLOG which would give it the ability to read (and wipe)
the _current_ dmesg, which is much more access than being given access
only to the historical log stored in pstorefs.
With the prior commit to make the root directory 0750, the files are
protected by default but a system builder can now opt to give access
to a specific group (via chgrp on the pstorefs root directory) without
being forced to also give away CAP_SYSLOG.
Suggested-by: Nick Kralevich <nnk@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
The error variable in do_syslog() is preemptively set to the error code
before the error condition is checked, and then set to 0 if the error
condition is not encountered. This is not necessary, as it is likely
simpler to return immediately upon encountering the error condition. A
redundant set of the error variable to 0 is also removed.
This patch has been build-tested on x86_64, but not tested for
functionality.
Link: http://lkml.kernel.org/r/20170730033636.GA935@vostro
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Nikitas Angelinas <nikitas.angelinas@gmail.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
printk_late_init() is responsible for disabling boot consoles that
use init memory. It checks the address of struct console for this.
But this is not enough. For example, there are several early
consoles that have write() method in the init section and
struct console in the normal section. They are not disabled
and could cause fancy and hard to debug system states.
It is even more complicated by the macros EARLYCON_DECLARE() and
OF_EARLYCON_DECLARE() where various struct members are set at
runtime by the provided setup() function.
I have tried to reproduce this problem and forced the classic uart
early console to stay using keep_bootcon parameter. In particular
I used earlycon=uart,io,0x3f8 keep_bootcon console=ttyS0,115200.
The system did not boot:
[ 1.570496] PM: Image not found (code -22)
[ 1.570496] PM: Image not found (code -22)
[ 1.571886] PM: Hibernation image not present or could not be loaded.
[ 1.571886] PM: Hibernation image not present or could not be loaded.
[ 1.576407] Freeing unused kernel memory: 2528K
[ 1.577244] kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
The double lines are caused by having both early uart console and
ttyS0 console enabled at the same time. The early console stopped
working when the init memory was freed. Fortunately, the invalid
call was caught by the NX-protexted page check and did not cause
any silent fancy problems.
This patch adds a check for many other addresses stored in
struct console. It omits setup() and match() that are used
only when the console is registered. Therefore they have
already been used at this point and there is no reason
to use them again.
Link: http://lkml.kernel.org/r/1500036673-7122-3-git-send-email-pmladek@suse.com
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Cc: "Fabio M. Di Nitto" <fdinitto@redhat.com>
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Commit 4c30c6f566 ("kernel/printk: do not turn off bootconsole in
printk_late_init() if keep_bootcon") added a check on keep_bootcon to
ensure that boot consoles were kept around until the real console is
registered.
This can lead to problems if the boot console data and code are in the
init section, since it can be freed before the boot console is
unregistered.
Commit 81cc26f2bd ("printk: only unregister boot consoles when
necessary") fixed this a better way. It allowed to keep boot consoles
that did not use init data. Unfortunately it did not remove the check
of keep_bootcon.
This can lead to crashes and weird panics when the bootconsole is
accessed after free, especially if page poisoning is in use and the
code / data have been overwritten with a poison value.
To prevent this, always free the boot console if it is within the init
section. In addition, print a warning about that the console is removed
prematurely.
Finally there is a new comment how to avoid the warning. It replaced
an explanation that duplicated a more comprehensive function
description few lines above.
Fixes: 4c30c6f566 ("kernel/printk: do not turn off bootconsole in printk_late_init() if keep_bootcon")
Link: http://lkml.kernel.org/r/1500036673-7122-2-git-send-email-pmladek@suse.com
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Cc: "Fabio M. Di Nitto" <fdinitto@redhat.com>
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
[pmladek@suse.com: print the warning, code and comments clean up]
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
With commit <ddb9baa82226> ("printk: report lost messages in printk
safe/nmi contexts") and commit <8b1742c9c207> ("printk: remove zap_locks()
function"), it seems we can remove initialization, "=0", of text_len and
directly assign result of log_output to printed_len.
Link: http://lkml.kernel.org/r/1499755255-6258-1-git-send-email-vichy.kuo@gmail.com
Cc: rostedt@goodmis.org
Cc: linux-kernel@vger.kernel.org
Cc: joe@perches.com
Signed-off-by: Pierre Kuo <vichy.kuo@gmail.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Pull printk updates from Petr Mladek:
- Store printk() messages into the main log buffer directly even in NMI
when the lock is available. It is the best effort to print even large
chunk of text. It is handy, for example, when all ftrace messages are
printed during the system panic in NMI.
- Add missing annotations to calm down compiler warnings
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
printk: add __printf attributes to internal functions
printk: Use the main logbuf in NMI when logbuf_lock is available
Conflicts:
kernel/sched/Makefile
Pick up the waitqueue related renames - it didn't get much feedback,
so it appears to be uncontroversial. Famous last words? ;-)
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull printk fix from Petr Mladek:
"This reverts a fix added into 4.12-rc1. It caused the kernel log to be
printed on another console when two consoles of the same type were
defined, e.g. console=ttyS0 console=ttyS1.
This configuration was never supported by kernel itself, but it
started to make sense with systemd. In other words, the commit broke
userspace"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
Revert "printk: fix double printing with earlycon"
This reverts commit cf39bf58af.
The commit regression to users that define both console=ttyS1
and console=ttyS0 on the command line, see
https://lkml.kernel.org/r/20170509082915.GA13236@bistromath.localdomain
The kernel log messages always appeared only on one serial port. It is
even documented in Documentation/admin-guide/serial-console.rst:
"Note that you can only define one console per device type (serial,
video)."
The above mentioned commit changed the order in which the command line
parameters are searched. As a result, the kernel log messages go to
the last mentioned ttyS* instead of the first one.
We long thought that using two console=ttyS* on the command line
did not make sense. But then we realized that console= parameters
were handled also by systemd, see
http://0pointer.de/blog/projects/serial-console.html
"By default systemd will instantiate one serial-getty@.service on
the main kernel console, if it is not a virtual terminal."
where
"[4] If multiple kernel consoles are used simultaneously, the main
console is the one listed first in /sys/class/tty/console/active,
which is the last one listed on the kernel command line."
This puts the original report into another light. The system is running
in qemu. The first serial port is used to store the messages into a file.
The second one is used to login to the system via a socket. It depends
on systemd and the historic kernel behavior.
By other words, systemd causes that it makes sense to define both
console=ttyS1 console=ttyS0 on the command line. The kernel fix
caused regression related to userspace (systemd) and need to be
reverted.
In addition, it went out that the fix helped only partially.
The messages still were duplicated when the boot console was
removed early by late_initcall(printk_late_init). Then the entire
log was replayed when the same console was registered as a normal one.
Link: 20170606160339.GC7604@pathway.suse.cz
Cc: Aleksey Makarov <aleksey.makarov@linaro.org>
Cc: Sabrina Dubroca <sd@queasysnail.net>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Robin Murphy <robin.murphy@arm.com>,
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Nair, Jayachandran" <Jayachandran.Nair@cavium.com>
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reported-by: Sabrina Dubroca <sd@queasysnail.net>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
To enable smp_processor_id() and might_sleep() debug checks earlier, it's
required to add system states between SYSTEM_BOOTING and SYSTEM_RUNNING.
Adjust the system_state check in boot_delay_msec() to handle the extra
states.
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170516184736.027534895@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The commit 42a0bb3f71 ("printk/nmi: generic solution for safe
printk in NMI") caused that printk stores messages into a temporary
buffer in NMI context.
The buffer is per-CPU and therefore the size is rather limited.
It works quite well for NMI backtraces. But there are longer logs
that might get printed in NMI context, for example, lockdep
warnings, ftrace_dump_on_oops.
The temporary buffer is used to avoid deadlocks caused by
logbuf_lock. Also it is needed to avoid races with the other
temporary buffer that is used when PRINTK_SAFE_CONTEXT is entered.
But the main buffer can be used in NMI if the lock is available
and we did not interrupt PRINTK_SAFE_CONTEXT.
The lock is checked using raw_spin_is_locked(). It might cause
false negatives when the lock is taken on another CPU and
this CPU is in the safe context from other reasons. Note that
the safe context is used also to get console semaphore or when
calling console drivers. For this reason, we do the check in
printk_nmi_enter(). It makes the handling consistent for
the entire NMI handler and avoids reshuffling of the messages.
The patch also defines special printk context that allows
to use printk_deferred() in NMI. Note that we could not flush
the messages to the consoles because console drivers might use
many other internal locks.
The newly created vprintk_deferred() disables the preemption
only around the irq work handling. It is needed there to keep
the consistency between the two per-CPU variables. But there
is no reason to disable preemption around vprintk_emit().
Finally, the patch puts back explicit serialization of the NMI
backtraces from different CPUs. It was removed by the
commit a9edc88093 ("x86/nmi: Perform a safe
NMI stack trace on all CPUs"). It was not needed because
the flushing of the temporary per-CPU buffers was serialized.
Link: http://lkml.kernel.org/r/1493912763-24873-1-git-send-email-pmladek@suse.com
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <rack+kernel@arm.linux.org.uk>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: x86@kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Suggested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Here is the "big" TTY/Serial patch updates for 4.12-rc1
Not a lot of new things here, the normal number of serial driver updates
and additions, tiny bugs fixed, and some core files split up to make
future changes a bit easier for Nicolas's "tiny-tty" work.
All of these have been in linux-next for a while. There will be a merge
conflict with include/linux/serdev.h coming from the bluetooth tree
merge, which we knew about, as we wanted some of the serdev changes to
go in through that tree. I'll send the expected merge result as a
follow-on message.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty/serial updates from Greg KH:
"Here is the "big" TTY/Serial patch updates for 4.12-rc1
Not a lot of new things here, the normal number of serial driver
updates and additions, tiny bugs fixed, and some core files split up
to make future changes a bit easier for Nicolas's "tiny-tty" work.
All of these have been in linux-next for a while"
* tag 'tty-4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (62 commits)
serial: small Makefile reordering
tty: split job control support into a file of its own
tty: move baudrate handling code to a file of its own
console: move console_init() out of tty_io.c
serial: 8250_early: Add earlycon support for Palmchip UART
tty: pl011: use "qdf2400_e44" as the earlycon name for QDF2400 E44
vt: make mouse selection of non-ASCII consistent
vt: set mouse selection word-chars to gpm's default
imx-serial: Reduce RX DMA startup latency when opening for reading
serial: omap: suspend device on probe errors
serial: omap: fix runtime-pm handling on unbind
tty: serial: omap: add UPF_BOOT_AUTOCONF flag for DT init
serial: samsung: Remove useless spinlock
serial: samsung: Add missing checks for dma_map_single failure
serial: samsung: Use right device for DMA-mapping calls
serial: imx: setup DCEDTE early and ensure DCD and RI irqs to be off
tty: fix comment typo s/repsonsible/responsible/
tty: amba-pl011: Fix spurious TX interrupts
serial: xuartps: Enable clocks in the pm disable case also
serial: core: Re-use struct uart_port {name} field
...
Patch series "kexec/fadump: remove dependency with CONFIG_KEXEC and
reuse crashkernel parameter for fadump", v4.
Traditionally, kdump is used to save vmcore in case of a crash. Some
architectures like powerpc can save vmcore using architecture specific
support instead of kexec/kdump mechanism. Such architecture specific
support also needs to reserve memory, to be used by dump capture kernel.
crashkernel parameter can be a reused, for memory reservation, by such
architecture specific infrastructure.
This patchset removes dependency with CONFIG_KEXEC for crashkernel
parameter and vmcoreinfo related code as it can be reused without kexec
support. Also, crashkernel parameter is reused instead of
fadump_reserve_mem to reserve memory for fadump.
The first patch moves crashkernel parameter parsing and vmcoreinfo
related code under CONFIG_CRASH_CORE instead of CONFIG_KEXEC_CORE. The
second patch reuses the definitions of append_elf_note() & final_note()
functions under CONFIG_CRASH_CORE in IA64 arch code. The third patch
removes dependency on CONFIG_KEXEC for firmware-assisted dump (fadump)
in powerpc. The next patch reuses crashkernel parameter for reserving
memory for fadump, instead of the fadump_reserve_mem parameter. This
has the advantage of using all syntaxes crashkernel parameter supports,
for fadump as well. The last patch updates fadump kernel documentation
about use of crashkernel parameter.
This patch (of 5):
Traditionally, kdump is used to save vmcore in case of a crash. Some
architectures like powerpc can save vmcore using architecture specific
support instead of kexec/kdump mechanism. Such architecture specific
support also needs to reserve memory, to be used by dump capture kernel.
crashkernel parameter can be a reused, for memory reservation, by such
architecture specific infrastructure.
But currently, code related to vmcoreinfo and parsing of crashkernel
parameter is built under CONFIG_KEXEC_CORE. This patch introduces
CONFIG_CRASH_CORE and moves the above mentioned code under this config,
allowing code reuse without dependency on CONFIG_KEXEC. There is no
functional change with this patch.
Link: http://lkml.kernel.org/r/149035338104.6881.4550894432615189948.stgit@hbathini.in.ibm.com
Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com>
Acked-by: Dave Young <dyoung@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>