commit 3cffa06aee upstream.
The commit 48021f9813 ("printk: handle blank console arguments
passed in.") prevented crash caused by empty console= parameter value.
Unfortunately, this value is widely used on Chromebooks to disable
the console output. The above commit caused performance regression
because the messages were pushed on slow console even though nobody
was watching it.
Use ttynull driver explicitly for console="" and console=null
parameters. It has been created for exactly this purpose.
It causes that preferred_console is set. As a result, ttySX and ttyX
are not used as a fallback. And only ttynull console gets registered by
default.
It still allows to register other consoles either by additional console=
parameters or SPCR. It prevents regression because it worked this way even
before. Also it is a sane semantic. Preventing output on all consoles
should be done another way, for example, by introducing mute_console
parameter.
Link: https://lore.kernel.org/r/20201006025935.GA597@jagdpanzerIV.localdomain
Suggested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20201111135450.11214-3-pmladek@suse.com
Cc: Yi Fan <yfa@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8a8109f303 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 48021f9813 ]
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>
[ Upstream commit d2130e82e9 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit b46eff55ad5bd98e746c0a7022fe7ee071de5fee ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 5aa068ea40 ]
The record logging code looks at the previous record flags in various
ways, and they are all wrong.
You can't use the previous record flags to determine anything about the
next record, because they may simply not be related. In particular, the
reason the previous record was a continuation record may well be exactly
_because_ the new record was printed by a different process, which is
why the previous record was flushed.
So all those games are simply wrong, and make the code hard to
understand (because the code fundamentally cdoes not make sense).
So remove it.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit d1c392c9e2 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
PD#SWPL-4900
Problem:
printk_prefix() passes NULL buf to print_time() to get the length of
the time prefix; when printk times are enable, the current code just
return "snprint(NULL, 0, "[%5lu.000000]", (unsigned long)ts)"
but in the SMP case, we add cpu core id at the end of time prefix, the
format is "[%5lu, %06lu@%d]", this gives a wrong size(shorter).
this will make buf get out of boundary, when run dmesg.
Solution:
replace [%5lu.000000] with [%5lu.000000@0]
Verify:
g12a-u200
Change-Id: Ic74b9f466b5af5aac7e6569a1afc7a46d9594050
Signed-off-by: Jianxiong Pan <jianxiong.pan@amlogic.com>
Signed-off-by: Victor Wan <victor.wan@amlogic.com>
Conflicts:
drivers/md/dm-bufio.c
drivers/media/dvb-core/dvb_frontend.c
drivers/usb/dwc3/core.c
drivers/usb/gadget/function/f_fs.c
Changes in 4.9.111
x86/spectre_v1: Disable compiler optimizations over array_index_mask_nospec()
x86/mce: Improve error message when kernel cannot recover
x86/mce: Check for alternate indication of machine check recovery on Skylake
x86/mce: Fix incorrect "Machine check from unknown source" message
x86/mce: Do not overwrite MCi_STATUS in mce_no_way_out()
x86: Call fixup_exception() before notify_die() in math_error()
m68k/mm: Adjust VM area to be unmapped by gap size for __iounmap()
serial: sh-sci: Use spin_{try}lock_irqsave instead of open coding version
signal/xtensa: Consistenly use SIGBUS in do_unaligned_user
usb: do not reset if a low-speed or full-speed device timed out
1wire: family module autoload fails because of upper/lower case mismatch.
ASoC: dapm: delete dapm_kcontrol_data paths list before freeing it
ASoC: cirrus: i2s: Fix LRCLK configuration
ASoC: cirrus: i2s: Fix {TX|RX}LinCtrlData setup
clk: renesas: cpg-mssr: Stop using printk format %pCr
lib/vsprintf: Remove atomic-unsafe support for %pCr
mips: ftrace: fix static function graph tracing
branch-check: fix long->int truncation when profiling branches
ipmi:bt: Set the timeout before doing a capabilities check
Bluetooth: hci_qca: Avoid missing rampatch failure with userspace fw loader
fuse: atomic_o_trunc should truncate pagecache
fuse: don't keep dead fuse_conn at fuse_fill_super().
fuse: fix control dir setup and teardown
powerpc/mm/hash: Add missing isync prior to kernel stack SLB switch
powerpc/ptrace: Fix setting 512B aligned breakpoints with PTRACE_SET_DEBUGREG
powerpc/ptrace: Fix enforcement of DAWR constraints
powerpc/powernv/ioda2: Remove redundant free of TCE pages
cpuidle: powernv: Fix promotion from snooze if next state disabled
powerpc/fadump: Unregister fadump on kexec down path.
ARM: 8764/1: kgdb: fix NUMREGBYTES so that gdb_regs[] is the correct size
arm64: kpti: Use early_param for kpti= command-line option
arm64: mm: Ensure writes to swapper are ordered wrt subsequent cache maintenance
of: unittest: for strings, account for trailing \0 in property length field
IB/qib: Fix DMA api warning with debug kernel
IB/{hfi1, qib}: Add handling of kernel restart
IB/mlx5: Fetch soft WQE's on fatal error state
IB/isert: Fix for lib/dma_debug check_sync warning
IB/isert: fix T10-pi check mask setting
RDMA/mlx4: Discard unknown SQP work requests
mtd: cfi_cmdset_0002: Change write buffer to check correct value
mtd: cfi_cmdset_0002: Use right chip in do_ppb_xxlock()
mtd: cfi_cmdset_0002: fix SEGV unlocking multiple chips
mtd: cfi_cmdset_0002: Fix unlocking requests crossing a chip boudary
mtd: cfi_cmdset_0002: Avoid walking all chips when unlocking.
MIPS: BCM47XX: Enable 74K Core ExternalSync for PCIe erratum
PCI: Add ACS quirk for Intel 7th & 8th Gen mobile
PCI: Add ACS quirk for Intel 300 series
PCI: pciehp: Clear Presence Detect and Data Link Layer Status Changed on resume
printk: fix possible reuse of va_list variable
MIPS: io: Add barrier after register read in inX()
time: Make sure jiffies_to_msecs() preserves non-zero time periods
X.509: unpack RSA signatureValue field from BIT STRING
Btrfs: fix return value on rename exchange failure
Btrfs: fix unexpected cow in run_delalloc_nocow
iio:buffer: make length types match kfifo types
scsi: qla2xxx: Fix setting lower transfer speed if GPSC fails
scsi: zfcp: fix missing SCSI trace for result of eh_host_reset_handler
scsi: zfcp: fix missing SCSI trace for retry of abort / scsi_eh TMF
scsi: zfcp: fix misleading REC trigger trace where erp_action setup failed
scsi: zfcp: fix missing REC trigger trace on terminate_rport_io early return
scsi: zfcp: fix missing REC trigger trace on terminate_rport_io for ERP_FAILED
scsi: zfcp: fix missing REC trigger trace for all objects in ERP_FAILED
scsi: zfcp: fix missing REC trigger trace on enqueue without ERP thread
linvdimm, pmem: Preserve read-only setting for pmem devices
clk: at91: PLL recalc_rate() now using cached MUL and DIV values
md: fix two problems with setting the "re-add" device state.
rpmsg: smd: do not use mananged resources for endpoints and channels
ubi: fastmap: Cancel work upon detach
ubi: fastmap: Correctly handle interrupted erasures in EBA
UBIFS: Fix potential integer overflow in allocation
backlight: as3711_bl: Fix Device Tree node lookup
backlight: max8925_bl: Fix Device Tree node lookup
backlight: tps65217_bl: Fix Device Tree node lookup
mfd: intel-lpss: Program REMAP register in PIO mode
perf tools: Fix symbol and object code resolution for vdso32 and vdsox32
perf intel-pt: Fix sync_switch INTEL_PT_SS_NOT_TRACING
perf intel-pt: Fix decoding to accept CBR between FUP and corresponding TIP
perf intel-pt: Fix MTC timing after overflow
perf intel-pt: Fix "Unexpected indirect branch" error
perf intel-pt: Fix packet decoding of CYC packets
media: v4l2-compat-ioctl32: prevent go past max size
media: cx231xx: Add support for AverMedia DVD EZMaker 7
media: dvb_frontend: fix locking issues at dvb_frontend_get_event()
nfsd: restrict rd_maxcount to svc_max_payload in nfsd_encode_readdir
NFSv4: Fix possible 1-byte stack overflow in nfs_idmap_read_and_verify_message
NFSv4: Revert commit 5f83d86cf5 ("NFSv4.x: Fix wraparound issues..")
video: uvesafb: Fix integer overflow in allocation
Input: elan_i2c - add ELAN0618 (Lenovo v330 15IKB) ACPI ID
pwm: lpss: platform: Save/restore the ctrl register over a suspend/resume
rbd: flush rbd_dev->watch_dwork after watch is unregistered
mm: fix devmem_is_allowed() for sub-page System RAM intersections
xen: Remove unnecessary BUG_ON from __unbind_from_irq()
udf: Detect incorrect directory size
Input: elan_i2c_smbus - fix more potential stack buffer overflows
Input: elantech - enable middle button of touchpads on ThinkPad P52
Input: elantech - fix V4 report decoding for module with middle key
ALSA: hda/realtek - Fix pop noise on Lenovo P50 & co
ALSA: hda/realtek - Add a quirk for FSC ESPRIMO U9210
block: Fix transfer when chunk sectors exceeds max
dm thin: handle running out of data space vs concurrent discard
cdc_ncm: avoid padding beyond end of skb
Linux 4.9.111
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Signed-off-by: Victor Wan <victor.wan@amlogic.com>
Conflicts:
arch/arm/configs/bcm2835_defconfig
arch/arm/configs/sunxi_defconfig
include/linux/cpufreq.h
init/main.c
Changes in 4.9.89
blkcg: fix double free of new_blkg in blkcg_init_queue
Input: tsc2007 - check for presence and power down tsc2007 during probe
perf stat: Issue a HW watchdog disable hint
staging: speakup: Replace BUG_ON() with WARN_ON().
staging: wilc1000: add check for kmalloc allocation failure.
HID: reject input outside logical range only if null state is set
drm: qxl: Don't alloc fbdev if emulation is not supported
ARM: dts: r8a7791: Remove unit-address and reg from integrated cache
ARM: dts: r8a7792: Remove unit-address and reg from integrated cache
ARM: dts: r8a7793: Remove unit-address and reg from integrated cache
ARM: dts: r8a7794: Remove unit-address and reg from integrated cache
arm64: dts: r8a7796: Remove unit-address and reg from integrated cache
drm/sun4i: Fix up error path cleanup for master bind function
drm/sun4i: Set drm_crtc.port to the underlying TCON's output port node
ath10k: fix a warning during channel switch with multiple vaps
drm/sun4i: Fix TCON clock and regmap initialization sequence
PCI/MSI: Stop disabling MSI/MSI-X in pci_device_shutdown()
selinux: check for address length in selinux_socket_bind()
x86/mm: Make mmap(MAP_32BIT) work correctly
perf sort: Fix segfault with basic block 'cycles' sort dimension
x86/mce: Handle broadcasted MCE gracefully with kexec
eventpoll.h: fix epoll event masks
i40e: Acquire NVM lock before reads on all devices
i40e: fix ethtool to get EEPROM data from X722 interface
perf tools: Make perf_event__synthesize_mmap_events() scale
ARM: brcmstb: Enable ZONE_DMA for non 64-bit capable peripherals
drivers: net: xgene: Fix hardware checksum setting
drivers: net: phy: xgene: Fix mdio write
drivers: net: xgene: Fix wrong logical operation
drivers: net: xgene: Fix Rx checksum validation logic
drm: Defer disabling the vblank IRQ until the next interrupt (for instant-off)
ath10k: disallow DFS simulation if DFS channel is not enabled
ath10k: fix fetching channel during potential radar detection
usb: misc: lvs: fix race condition in disconnect handling
ARM: bcm2835: Enable missing CMA settings for VC4 driver
net: ethernet: bgmac: Allow MAC address to be specified in DTB
netem: apply correct delay when rate throttling
x86/mce: Init some CPU features early
omapfb: dss: Handle return errors in dss_init_ports()
perf probe: Fix concat_probe_trace_events
perf probe: Return errno when not hitting any event
HID: clamp input to logical range if no null state
net/8021q: create device with all possible features in wanted_features
ARM: dts: Adjust moxart IRQ controller and flags
qed: Always publish VF link from leading hwfn
s390/topology: fix typo in early topology code
zd1211rw: fix NULL-deref at probe
batman-adv: handle race condition for claims between gateways
of: fix of_device_get_modalias returned length when truncating buffers
solo6x10: release vb2 buffers in solo_stop_streaming()
x86/boot/32: Defer resyncing initial_page_table until per-cpu is set up
scsi: fnic: Fix for "Number of Active IOs" in fnicstats becoming negative
scsi: ipr: Fix missed EH wakeup
media: i2c/soc_camera: fix ov6650 sensor getting wrong clock
timers, sched_clock: Update timeout for clock wrap
sysrq: Reset the watchdog timers while displaying high-resolution timers
Input: qt1070 - add OF device ID table
sched: act_csum: don't mangle TCP and UDP GSO packets
PCI: hv: Properly handle PCI bus remove
PCI: hv: Lock PCI bus on device eject
ASoC: rcar: ssi: don't set SSICR.CKDV = 000 with SSIWSR.CONT
spi: omap2-mcspi: poll OMAP2_MCSPI_CHSTAT_RXS for PIO transfer
tcp: sysctl: Fix a race to avoid unexpected 0 window from space
dmaengine: imx-sdma: add 1ms delay to ensure SDMA channel is stopped
usb: dwc3: make sure UX_EXIT_PX is cleared
ARM: dts: bcm2835: add index to the ethernet alias
perf annotate: Fix a bug following symbolic link of a build-id file
perf buildid: Do not assume that readlink() returns a null terminated string
i40e/i40evf: Fix use after free in Rx cleanup path
scsi: be2iscsi: Check tag in beiscsi_mccq_compl_wait
driver: (adm1275) set the m,b and R coefficients correctly for power
bonding: make speed, duplex setting consistent with link state
mm: Fix false-positive VM_BUG_ON() in page_cache_{get,add}_speculative()
ALSA: firewire-lib: add a quirk of packet without valid EOH in CIP format
ARM: dts: r8a7794: Add DU1 clock to device tree
ARM: dts: r8a7794: Correct clock of DU1
ARM: dts: silk: Correct clock of DU1
blk-throttle: make sure expire time isn't too big
regulator: core: Limit propagation of parent voltage count and list
perf trace: Handle unpaired raw_syscalls:sys_exit event
f2fs: relax node version check for victim data in gc
drm/ttm: never add BO that failed to validate to the LRU list
bonding: refine bond_fold_stats() wrap detection
PCI: Apply Cavium ACS quirk only to CN81xx/CN83xx/CN88xx devices
powerpc/mm/hugetlb: Filter out hugepage size not supported by page table layout
braille-console: Fix value returned by _braille_console_setup
drm/vmwgfx: Fixes to vmwgfx_fb
vxlan: vxlan dev should inherit lowerdev's gso_max_size
NFC: nfcmrvl: Include unaligned.h instead of access_ok.h
NFC: nfcmrvl: double free on error path
NFC: pn533: change order of free_irq and dev unregistration
ARM: dts: r7s72100: fix ethernet clock parent
ARM: dts: r8a7790: Correct parent of SSI[0-9] clocks
ARM: dts: r8a7791: Correct parent of SSI[0-9] clocks
ARM: dts: r8a7793: Correct parent of SSI[0-9] clocks
powerpc: Avoid taking a data miss on every userspace instruction miss
net: hns: Correct HNS RSS key set function
net/faraday: Add missing include of of.h
qed: Fix TM block ILT allocation
rtmutex: Fix PI chain order integrity
printk: Correctly handle preemption in console_unlock()
drm: rcar-du: Handle event when disabling CRTCs
ARM: dts: koelsch: Correct clock frequency of X2 DU clock input
reiserfs: Make cancel_old_flush() reliable
ASoC: rt5677: Add OF device ID table
IB/hfi1: Check for QSFP presence before attempting reads
ALSA: firewire-digi00x: add support for console models of Digi00x series
ALSA: firewire-digi00x: handle all MIDI messages on streaming packets
fm10k: correctly check if interface is removed
EDAC, altera: Fix peripheral warnings for Cyclone5
scsi: ses: don't get power status of SES device slot on probe
qed: Correct MSI-x for storage
apparmor: Make path_max parameter readonly
iommu/iova: Fix underflow bug in __alloc_and_insert_iova_range
kvm/svm: Setup MCG_CAP on AMD properly
kvm: nVMX: Disallow userspace-injected exceptions in guest mode
video: ARM CLCD: fix dma allocation size
drm/radeon: Fail fb creation from imported dma-bufs.
drm/amdgpu: Fail fb creation from imported dma-bufs. (v2)
drm/rockchip: vop: Enable pm domain before vop_initial
i40e: only register client on iWarp-capable devices
coresight: Fixes coresight DT parse to get correct output port ID.
lkdtm: turn off kcov for lkdtm_rodata_do_nothing:
tty: amba-pl011: Fix spurious TX interrupts
serial: imx: setup DCEDTE early and ensure DCD and RI irqs to be off
MIPS: BPF: Quit clobbering callee saved registers in JIT code.
MIPS: BPF: Fix multiple problems in JIT skb access helpers.
MIPS: r2-on-r6-emu: Fix BLEZL and BGTZL identification
MIPS: r2-on-r6-emu: Clear BLTZALL and BGEZALL debugfs counters
v4l: vsp1: Prevent multiple streamon race commencing pipeline early
v4l: vsp1: Register pipe with output WPF
regulator: isl9305: fix array size
md/raid6: Fix anomily when recovering a single device in RAID6.
md.c:didn't unlock the mddev before return EINVAL in array_size_store
powerpc/nohash: Fix use of mmu_has_feature() in setup_initial_memory_limit()
usb: dwc2: Make sure we disconnect the gadget state
usb: gadget: dummy_hcd: Fix wrong power status bit clear/reset in dummy_hub_control()
perf evsel: Return exact sub event which failed with EPERM for wildcards
iwlwifi: mvm: fix RX SKB header size and align it properly
drivers/perf: arm_pmu: handle no platform_device
perf inject: Copy events when reordering events in pipe mode
net: fec: add phy-reset-gpios PROBE_DEFER check
perf session: Don't rely on evlist in pipe mode
vfio/powerpc/spapr_tce: Enforce IOMMU type compatibility check
vfio/spapr_tce: Check kzalloc() return when preregistering memory
scsi: sg: check for valid direction before starting the request
scsi: sg: close race condition in sg_remove_sfp_usercontext()
ALSA: hda: Add Geminilake id to SKL_PLUS
kprobes/x86: Fix kprobe-booster not to boost far call instructions
kprobes/x86: Set kprobes pages read-only
pwm: tegra: Increase precision in PWM rate calculation
clk: qcom: msm8996: Fix the vfe1 powerdomain name
Bluetooth: Avoid bt_accept_unlink() double unlinking
Bluetooth: 6lowpan: fix delay work init in add_peer_chan()
mac80211_hwsim: use per-interface power level
ath10k: fix compile time sanity check for CE4 buffer size
wil6210: fix protection against connections during reset
wil6210: fix memory access violation in wil_memcpy_from/toio_32
perf stat: Fix bug in handling events in error state
mwifiex: Fix invalid port issue
drm/edid: set ELD connector type in drm_edid_to_eld()
video/hdmi: Allow "empty" HDMI infoframes
HID: elo: clear BTN_LEFT mapping
iwlwifi: mvm: rs: don't override the rate history in the search cycle
clk: meson: gxbb: fix wrong clock for SARADC/SANA
ARM: dts: exynos: Correct Trats2 panel reset line
sched: Stop switched_to_rt() from sending IPIs to offline CPUs
sched: Stop resched_cpu() from sending IPIs to offline CPUs
test_firmware: fix setting old custom fw path back on exit
net: ieee802154: adf7242: Fix bug if defined DEBUG
net: xfrm: allow clearing socket xfrm policies.
mtd: nand: fix interpretation of NAND_CMD_NONE in nand_command[_lp]()
net: thunderx: Set max queue count taking XDP_TX into account
ARM: dts: am335x-pepper: Fix the audio CODEC's reset pin
ARM: dts: omap3-n900: Fix the audio CODEC's reset pin
mtd: nand: ifc: update bufnum mask for ver >= 2.0.0
userns: Don't fail follow_automount based on s_user_ns
leds: pm8058: Silence pointer to integer size warning
power: supply: ab8500_charger: Fix an error handling path
power: supply: ab8500_charger: Bail out in case of error in 'ab8500_charger_init_hw_registers()'
ath10k: update tdls teardown state to target
scsi: ses: don't ask for diagnostic pages repeatedly during probe
pwm: stmpe: Fix wrong register offset for hwpwm=2 case
clk: qcom: msm8916: fix mnd_width for codec_digcodec
mwifiex: cfg80211: do not change virtual interface during scan processing
ath10k: fix invalid STS_CAP_OFFSET_MASK
tools/usbip: fixes build with musl libc toolchain
spi: sun6i: disable/unprepare clocks on remove
bnxt_en: Don't print "Link speed -1 no longer supported" messages.
scsi: core: scsi_get_device_flags_keyed(): Always return device flags
scsi: devinfo: apply to HP XP the same flags as Hitachi VSP
scsi: dh: add new rdac devices
media: vsp1: Prevent suspending and resuming DRM pipelines
media: cpia2: Fix a couple off by one bugs
veth: set peer GSO values
drm/amdkfd: Fix memory leaks in kfd topology
powerpc/modules: Don't try to restore r2 after a sibling call
agp/intel: Flush all chipset writes after updating the GGTT
mac80211_hwsim: enforce PS_MANUAL_POLL to be set after PS_ENABLED
mac80211: remove BUG() when interface type is invalid
ASoC: nuc900: Fix a loop timeout test
ipvlan: add L2 check for packets arriving via virtual devices
rcutorture/configinit: Fix build directory error message
locking/locktorture: Fix num reader/writer corner cases
ima: relax requiring a file signature for new files with zero length
net: hns: Some checkpatch.pl script & warning fixes
x86/boot/32: Fix UP boot on Quark and possibly other platforms
x86/cpufeatures: Add Intel PCONFIG cpufeature
selftests/x86/entry_from_vm86: Exit with 1 if we fail
selftests/x86: Add tests for User-Mode Instruction Prevention
selftests/x86: Add tests for the STR and SLDT instructions
selftests/x86/entry_from_vm86: Add test cases for POPF
x86/vm86/32: Fix POPF emulation
x86/speculation, objtool: Annotate indirect calls/jumps for objtool on 32-bit kernels
x86/speculation: Remove Skylake C2 from Speculation Control microcode blacklist
x86/mm: Fix vmalloc_fault to use pXd_large
parisc: Handle case where flush_cache_range is called with no context
ALSA: pcm: Fix UAF in snd_pcm_oss_get_formats()
ALSA: hda - Revert power_save option default value
ALSA: seq: Fix possible UAF in snd_seq_check_queue()
ALSA: seq: Clear client entry before deleting else at closing
drm/amdgpu: fix prime teardown order
drm/amdgpu/dce: Don't turn off DP sink when disconnected
fs: Teach path_connected to handle nfs filesystems with multiple roots.
lock_parent() needs to recheck if dentry got __dentry_kill'ed under it
fs/aio: Add explicit RCU grace period when freeing kioctx
fs/aio: Use RCU accessors for kioctx_table->table[]
irqchip/gic-v3-its: Ensure nr_ites >= nr_lpis
scsi: sg: fix SG_DXFER_FROM_DEV transfers
scsi: sg: fix static checker warning in sg_is_valid_dxfer
scsi: sg: only check for dxfer_len greater than 256M
btrfs: alloc_chunk: fix DUP stripe size handling
btrfs: Fix use-after-free when cleaning up fs_devs with a single stale device
scsi: qla2xxx: Fix extraneous ref on sp's after adapter break
USB: gadget: udc: Add missing platform_device_put() on error in bdc_pci_probe()
usb: dwc3: Fix GDBGFIFOSPACE_TYPE values
usb: gadget: bdc: 64-bit pointer capability check
Linux 4.9.89
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
[ Upstream commit 257ab44311 ]
Some console drivers code calls console_conditional_schedule()
that looks at @console_may_schedule. The value must be cleared
when the drivers are called from console_unlock() with
interrupts disabled. But rescheduling is fine when the same
code is called, for example, from tty operations where the
console semaphore is taken via console_lock().
This is why @console_may_schedule is cleared before calling console
drivers. The original value is stored to decide if we could sleep
between lines.
Now, @console_may_schedule is not cleared when we call
console_trylock() and jump back to the "again" goto label.
This has become a problem, since the commit 6b97a20d3a
("printk: set may_schedule for some of console_trylock() callers").
@console_may_schedule might get enabled now.
There is also the opposite problem. console_lock() can be called
only from preemptive context. It can always enable scheduling in
the console code. But console_trylock() is not able to detect it
when CONFIG_PREEMPT_COUNT is disabled. Therefore we should use the
original @console_may_schedule value after re-acquiring
the console semaphore in console_unlock().
This patch solves both problems by moving the "again" goto label.
Alternative solution was to clear and restore the value around
call_console_drivers(). Then console_conditional_schedule() could
be used also inside console_unlock(). But there was a potential race
with console_flush_on_panic() as reported by Sergey Senozhatsky.
That function should be called only where there is only one CPU
and with interrupts disabled. But better be on the safe side
because stopping CPUs might fail.
Fixes: 6b97a20d3a ("printk: set may_schedule for some of console_trylock() callers")
Link: http://lkml.kernel.org/r/1490372045-22288-1-git-send-email-pmladek@suse.com
Suggested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: linux-fbdev@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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 2ed2b8621b ]
commit bbeddf52ad ("printk: move braille console support into
separate braille.[ch] files") introduced _braille_console_setup()
to outline the braille initialization code. There was however some
confusion over the value it was supposed to return. commit 2cfe6c4ac7
("printk: Fix return of braille_register_console()") tried to fix it
but failed to.
This fixes and documents the returned value according to the use
in printk.c: non-zero return means a parsing error, and thus this
console configuration should be ignored.
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: Aleksey Makarov <aleksey.makarov@linaro.org>
Cc: Joe Perches <joe@perches.com>
Cc: Ming Lei <ming.lei@canonical.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
PD#154008: the log output is in disorder
The defination for a continues line in printk is much more strict
from 3.14 to 4.9:
in kernel 3.14, if the first fragment does not end with CR, and the
next fragment does not start with LOG_PREFIX(KERN_ALERT, KERN_ERR and
so on), then they are in a continues line
eg. pr_err("foo "); printk("bar\n")
or pr_err("foo "); pr_cont("bar\n"); both are printing a continues
line
in kernel 4.9, if only the first fragment does not end with CR, and the
next fragment start with LOG_CONT, then they are in a continues line
eg. pr_err("foo "); printk("bar\n"); are not printing a continues line
and pr_err("foo "); pr_cont("bar\n"); are printing a continues line
but in the code path of crash info dumping in kernel 4.9.y, not all of
the continues line printing has been switched to the 4.9 way(aka.
calling pr_cont). Only in kernel 4.13.y all of that has been updated.
so in this commit, we lose the definition of continues line back to
3.14 way to sovle current issue, and need to revert it when we sync
with upstream kernel 4.13.y
Change-Id: I64403d3a18531ceb832b41d96dff4b79a6d7fb5a
Signed-off-by: Jiamin Ma <jiamin.ma@amlogic.com>
commit fc98c3c8c9 upstream.
Use rcuidle console tracepoint because, apparently, it may be issued
from an idle CPU:
hw-breakpoint: Failed to enable monitor mode on CPU 0.
hw-breakpoint: CPU 0 failed to disable vector catch
===============================
[ ERR: suspicious RCU usage. ]
4.10.0-rc8-next-20170215+ #119 Not tainted
-------------------------------
./include/trace/events/printk.h:32 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
RCU used illegally from idle CPU!
rcu_scheduler_active = 2, debug_locks = 0
RCU used illegally from extended quiescent state!
2 locks held by swapper/0/0:
#0: (cpu_pm_notifier_lock){......}, at: [<c0237e2c>] cpu_pm_exit+0x10/0x54
#1: (console_lock){+.+.+.}, at: [<c01ab350>] vprintk_emit+0x264/0x474
stack backtrace:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.10.0-rc8-next-20170215+ #119
Hardware name: Generic OMAP4 (Flattened Device Tree)
console_unlock
vprintk_emit
vprintk_default
printk
reset_ctrl_regs
dbg_cpu_pm_notify
notifier_call_chain
cpu_pm_exit
omap_enter_idle_coupled
cpuidle_enter_state
cpuidle_enter_state_coupled
do_idle
cpu_startup_entry
start_kernel
This RCU warning, however, is suppressed by lockdep_off() in printk().
lockdep_off() increments the ->lockdep_recursion counter and thus
disables RCU_LOCKDEP_WARN() and debug_lockdep_rcu_enabled(), which want
lockdep to be enabled "current->lockdep_recursion == 0".
Link: http://lkml.kernel.org/r/20170217015932.11898-1-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: Tony Lindgren <tony@atomide.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Russell King <rmk@armlinux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit bfd8d3f23b.
It turns out that this flushes things much too aggressiverly, and causes
lines to break up when the system logger races with new continuation
lines being printed.
There's a pending patch to make printk() flushing much more
straightforward, but it's too invasive for 4.9, so in the meantime let's
just not make the system message logging flush continuation lines.
They'll be flushed by the final newline anyway.
Suggested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This reverts commit 05fd007e46 ("console: don't prefer first
registered if DT specifies stdout-path").
The reverted commit changes existing behavior on which many ARM boards
rely. Many ARM small-board-computers, like e.g. the Raspberry Pi have
both a video output and a serial console. Depending on whether the user
is using the device as a more regular computer; or as a headless device
we need to have the console on either one or the other.
Many users rely on the kernel behavior of the console being present on
both outputs, before the reverted commit the console setup with no
console= kernel arguments on an ARM board which sets stdout-path in dt
would look like this:
[root@localhost ~]# cat /proc/consoles
ttyS0 -W- (EC p a) 4:64
tty0 -WU (E p ) 4:1
Where as after the reverted commit, it looks like this:
[root@localhost ~]# cat /proc/consoles
ttyS0 -W- (EC p a) 4:64
This commit reverts commit 05fd007e46 ("console: don't prefer first
registered if DT specifies stdout-path") restoring the original
behavior.
Fixes: 05fd007e46 ("console: don't prefer first registered if DT specifies stdout-path")
Link: http://lkml.kernel.org/r/20161104121135.4780-2-hdegoede@redhat.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We have a fairly common pattern where you print several things as
continuations on one single line in a loop, and then at the end you do
printk(KERN_CONT "\n");
to flush the buffered output.
But if the output was flushed by something else (concurrent printk
activity, or just system logging), we don't want that final flushing to
just print an empty line.
So just suppress empty continuation lines when they couldn't be merged
into the line they are a continuation of.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge my system logging cleanups, triggered by the broken '\n' patches.
The line continuation handling has been broken basically forever, and
the code to handle the system log records was both confusing and
dubious. And it would do entirely the wrong thing unless you always had
a terminating newline, partly because it couldn't actually see whether a
message was marked KERN_CONT or not (but partly because the LOG_CONT
handling in the recording code was rather confusing too).
This re-introduces a real semantically meaningful KERN_CONT, and fixes
the few places I noticed where it was missing. There are probably more
missing cases, since KERN_CONT hasn't actually had any semantic meaning
for at least four years (other than the checkpatch meaning of "no log
level necessary, this is a continuation line").
This also allows the combination of KERN_CONT and a log level. In that
case the log level will be ignored if the merging with a previous line
is successful, but if a new record is needed, that new record will now
get the right log level.
That also means that you can at least in theory combine KERN_CONT with
the "pr_info()" style helpers, although any use of pr_fmt() prefixing
would make that just result in a mess, of course (the prefix would end
up in the middle of a continuing line).
* printk-cleanups:
printk: make reading the kernel log flush pending lines
printk: re-organize log_output() to be more legible
printk: split out core logging code into helper function
printk: reinstate KERN_CONT for printing continuation lines
That will mean that any possible subsequent continuation will now be
broken up onto a line of its own (since reading the log has finalized
the beginning og the line), but if user space has activated system
logging (or if there's a kernel message dump going on) that is the right
thing to do.
And now that we actually get the continuation flags _right_ for this
all, the user space logger that is reading the kernel messages can
actually see the continuation marker. Not that anybody seems to really
bother with it (or care), but in theory user space can do its own
message stitching.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Avoid some duplicate logic now that we can return early, and update the
comments for the new LOG_CONT world order.
This also stops the continuation flushing from just using random record
flags for the flushing action, instead taking the flags from the proper
original line and updating them as we add continuations to it.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The code that actually decides how to log the message (whether to put it
directly into the record log, whether to append it to an existing
buffered log, or whether to start a new buffered log) is fairly
non-obvious code in the middle of the vprintk_emit() function.
Splitting that code up into a helper function makes it easier to
understand, but perhaps more importantly also allows for the code to
just return early out of the helper function once it has made the
decision about where the new log content goes.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Long long ago the kernel log buffer was a buffered stream of bytes, very
much like stdio in user space. It supported log levels by scanning the
stream and noticing the log level markers at the beginning of each line,
but if you wanted to print a partial line in multiple chunks, you just
did multiple printk() calls, and it just automatically worked.
Except when it didn't, and you had very confusing output when different
lines got all mixed up with each other. Then you got fragment lines
mixing with each other, or with non-fragment lines, because it was
traditionally impossible to tell whether a printk() call was a
continuation or not.
To at least help clarify the issue of continuation lines, we added a
KERN_CONT marker back in 2007 to mark continuation lines:
4749252776 ("printk: add KERN_CONT annotation").
That continuation marker was initially an empty string, and didn't
actuall make any semantic difference. But it at least made it possible
to annotate the source code, and have check-patch notice that a printk()
didn't need or want a log level marker, because it was a continuation of
a previous line.
To avoid the ambiguity between a continuation line that had that
KERN_CONT marker, and a printk with no level information at all, we then
in 2009 made KERN_CONT be a real log level marker which meant that we
could now reliably tell the difference between the two cases.
5fd29d6ccb ("printk: clean up handling of log-levels and newlines")
and we could take advantage of that to make sure we didn't mix up
continuation lines with lines that just didn't have any loglevel at all.
Then, in 2012, the kernel log buffer was changed to be a "record" based
log, where each line was a record that has a loglevel and a timestamp.
You can see the beginning of that conversion in commits
e11fea92e1 ("kmsg: export printk records to the /dev/kmsg interface")
7ff9554bb5 ("printk: convert byte-buffer to variable-length record buffer")
with a number of follow-up commits to fix some painful fallout from that
conversion. Over all, it took a couple of months to sort out most of
it. But the upside was that you could have concurrent readers (and
writers) of the kernel log and not have lines with mixed output in them.
And one particular pain-point for the record-based kernel logging was
exactly the fragmentary lines that are generated in smaller chunks. In
order to still log them as one recrod, the continuation lines need to be
attached to the previous record properly.
However the explicit continuation record marker that is actually useful
for this exact case was actually removed in aroundm the same time by commit
61e99ab8e3 ("printk: remove the now unnecessary "C" annotation for KERN_CONT")
due to the incorrect belief that KERN_CONT wasn't meaningful. The
ambiguity between "is this a continuation line" or "is this a plain
printk with no log level information" was reintroduced, and in fact
became an even bigger pain point because there was now the whole
record-level merging of kernel messages going on.
This patch reinstates the KERN_CONT as a real non-empty string marker,
so that the ambiguity is fixed once again.
But it's not a plain revert of that original removal: in the four years
since we made KERN_CONT an empty string again, not only has the format
of the log level markers changed, we've also had some usage changes in
this area.
For example, some ACPI code seems to use KERN_CONT _together_ with a log
level, and now uses both the KERN_CONT marker and (for example) a
KERN_INFO marker to show that it's an informational continuation of a
line.
Which is actually not a bad idea - if the continuation line cannot be
attached to its predecessor, without the log level information we don't
know what log level to assign to it (and we traditionally just assigned
it the default loglevel). So having both a log level and the KERN_CONT
marker is not necessarily a bad idea, but it does mean that we need to
actually iterate over potentially multiple markers, rather than just a
single one.
Also, since KERN_CONT was still conceptually needed, and encouraged, but
didn't actually _do_ anything, we've also had the reverse problem:
rather than having too many annotations it has too few, and there is bit
rot with code that no longer marks the continuation lines with the
KERN_CONT marker.
So this patch not only re-instates the non-empty KERN_CONT marker, it
also fixes up the cases of bit-rot I noticed in my own logs.
There are probably other cases where KERN_CONT will be needed to be
added, either because it is new code that never dealt with the need for
KERN_CONT, or old code that has bitrotted without anybody noticing.
That said, we should strive to avoid the need for KERN_CONT. It does
result in real problems for logging, and should generally not be seen as
a good feature. If we some day can get rid of the feature entirely,
because nobody does any fragmented printk calls, that would be lovely.
But until that point, let's at mark the code that relies on the hacky
multi-fragment kernel printk's. Not only does it avoid the ambiguity,
it also annotates code as "maybe this would be good to fix some day".
(That said, particularly during single-threaded bootup, the downsides of
KERN_CONT are very limited. Things get much hairier when you have
multiple threads going on and user level reading and writing logs too).
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If a device tree specifies a preferred device for kernel console output
via the stdout-path or linux,stdout-path chosen node properties or the
stdout alias then the kernel ought to honor it & output the kernel
console to that device. As it stands, this isn't the case. Whilst we
parse the stdout-path properties & set an of_stdout variable from
of_alias_scan(), and use that from of_console_check() to determine
whether to add a console device as a preferred console whilst
registering it, we also prefer the first registered console if no other
has been selected at the time of its registration.
This means that if a console other than the one the device tree selects
via stdout-path is registered first, we will switch to using it & when
the stdout-path console is later registered the call to
add_preferred_console() via of_console_check() is too late to do
anything useful. In practice this seems to mean that we switch to the
dummy console device fairly early & see no further console output:
Console: colour dummy device 80x25
console [tty0] enabled
bootconsole [ns16550a0] disabled
Fix this by not automatically preferring the first registered console if
one is specified by the device tree. This allows consoles to be
registered but not enabled, and once the driver for the console selected
by stdout-path calls of_console_check() the driver will be added to the
list of preferred consoles before any other console has been enabled.
When that console is then registered via register_console() it will be
enabled as expected.
Link: http://lkml.kernel.org/r/20160809151937.26118-1-paul.burton@imgtec.com
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Ivan Delalande <colona@arista.com>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Jan Kara <jack@suse.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Joe Perches <joe@perches.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
__printk_nmi_flush() can be called from nmi_panic(), therefore it has to
test whether it's executed in NMI context and thus must route the
messages through deferred printk() or via direct printk().
This is to avoid potential deadlocks, as described in commit
cf9b1106c8 ("printk/nmi: flush NMI messages on the system panic").
However there remain two places where __printk_nmi_flush() does
unconditional direct printk() calls:
- pr_err("printk_nmi_flush: internal error ...")
- pr_cont("\n")
Factor out print_nmi_seq_line() parts into a new printk_nmi_flush_line()
function, which takes care of in_nmi(), and use it in
__printk_nmi_flush() for printing and error-reporting.
Link: http://lkml.kernel.org/r/20160830161354.581-1-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit bbeddf52ad ("printk: move braille console support into separate
braille.[ch] files") moved the parsing of braille-related options into
_braille_console_setup(), changing the type of variable str from char*
to char**. In this commit, memcmp(str, "brl,", 4) was correctly updated
to memcmp(*str, "brl,", 4) but not memcmp(str, "brl=", 4).
Update the code to make "brl=" option work again and replace memcmp()
with strncmp() to make the compiler able to detect such an issue.
Fixes: bbeddf52ad ("printk: move braille console support into separate braille.[ch] files")
Link: http://lkml.kernel.org/r/20160823165700.28952-1-nicolas.iooss_linux@m4x.org
Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This reverts commit 874f9c7da9.
Geert Uytterhoeven reports:
"This change seems to have an (unintendent?) side-effect.
Before, pr_*() calls without a trailing newline characters would be
printed with a newline character appended, both on the console and in
the output of the dmesg command.
After this commit, no new line character is appended, and the output
of the next pr_*() call of the same type may be appended, like in:
- Truncating RAM at 0x0000000040000000-0x00000000c0000000 to -0x0000000070000000
- Ignoring RAM at 0x0000000200000000-0x0000000240000000 (!CONFIG_HIGHMEM)
+ Truncating RAM at 0x0000000040000000-0x00000000c0000000 to -0x0000000070000000Ignoring RAM at 0x0000000200000000-0x0000000240000000 (!CONFIG_HIGHMEM)"
Joe Perches says:
"No, that is not intentional.
The newline handling code inside vprintk_emit is a bit involved and
for now I suggest a revert until this has all the same behavior as
earlier"
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Requested-by: Joe Perches <joe@perches.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In commit 874f9c7da9 ("printk: create pr_<level> functions"), new
pr_level defines were added to printk.c.
These new defines are guarded by an #ifdef CONFIG_PRINTK - however,
there is already a surrounding #ifdef CONFIG_PRINTK starting a lot
earlier in line 249 which means the newly introduced #ifdef is
unnecessary.
Let's remove it to avoid confusion.
Signed-off-by: Andreas Ziegler <andreas.ziegler@fau.de>
Cc: Joe Perches <joe@perches.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a "printk.devkmsg" kernel command line parameter which controls how
userspace writes into /dev/kmsg. It has three options:
* ratelimit - ratelimit logging from userspace.
* on - unlimited logging from userspace
* off - logging from userspace gets ignored
The default setting is to ratelimit the messages written to it.
This changes the kernel default setting of "on" to "ratelimit" and we do
that because we want to keep userspace spamming /dev/kmsg to sane
levels. This is especially moot when a small kernel log buffer wraps
around and messages get lost. So the ratelimiting setting should be a
sane setting where kernel messages should have a bit higher chance of
survival from all the spamming.
It additionally does not limit logging to /dev/kmsg while the system is
booting if we haven't disabled it on the command line.
Furthermore, we can control the logging from a lower priority sysctl
interface - kernel.printk_devkmsg.
That interface will succeed only if printk.devkmsg *hasn't* been
supplied on the command line. If it has, then printk.devkmsg is a
one-time setting which remains for the duration of the system lifetime.
This "locking" of the setting is to prevent userspace from changing the
logging on us through sysctl(2).
This patch is based on previous patches from Linus and Steven.
[bp@suse.de: fixes]
Link: http://lkml.kernel.org/r/20160719072344.GC25563@nazgul.tnic
Link: http://lkml.kernel.org/r/20160716061745.15795-3-bp@alien8.de
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Dave Young <dyoung@redhat.com>
Cc: Franck Bui <fbui@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Messages' levels and console log level are inspected when the actual
printing occurs, which may provoke console_unlock() and
console_cont_flush() to waste CPU cycles on every message that has
loglevel above the current console_loglevel.
Schematically, console_unlock() does the following:
console_unlock()
{
...
for (;;) {
...
raw_spin_lock_irqsave(&logbuf_lock, flags);
skip:
msg = log_from_idx(console_idx);
if (msg->flags & LOG_NOCONS) {
...
goto skip;
}
level = msg->level;
len += msg_print_text(); >> sprintfs
memcpy,
etc.
if (nr_ext_console_drivers) {
ext_len = msg_print_ext_header(); >> scnprintf
ext_len += msg_print_ext_body(); >> scnprintfs
etc.
}
...
raw_spin_unlock(&logbuf_lock);
call_console_drivers(level, ext_text, ext_len, text, len)
{
if (level >= console_loglevel && >> drop the message
!ignore_loglevel)
return;
console->write(...);
}
local_irq_restore(flags);
}
...
}
The thing here is this deferred `level >= console_loglevel' check. We
are wasting CPU cycles on sprintfs/memcpy/etc. preparing the messages
that we will eventually drop.
This can be huge when we register a new CON_PRINTBUFFER console, for
instance. For every such a console register_console() resets the
console_seq, console_idx, console_prev
and sets a `exclusive console' pointer to replay the log buffer to that
just-registered console. And there can be a lot of messages to replay,
in the worst case most of which can be dropped after console_loglevel
test.
We know messages' levels long before we call msg_print_text() and
friends, so we can just move console_loglevel check out of
call_console_drivers() and format a new message only if we are sure that
it won't be dropped.
The patch factors out loglevel check into suppress_message_printing()
function and tests message->level and console_loglevel before formatting
functions in console_unlock() and console_cont_flush() are getting
executed. This improves things not only for exclusive CON_PRINTBUFFER
consoles, but for every console_unlock() that attempts to print a
message of level above the console_loglevel.
Link: http://lkml.kernel.org/r/20160627135012.8229-1-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Calvin Owens <calvinowens@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Using functions instead of macros can reduce overall code size by
eliminating unnecessary "KERN_SOH<digit>" prefixes from format strings.
defconfig x86-64:
$ size vmlinux*
text data bss dec hex filename
10193570 4331464 1105920 15630954 ee826a vmlinux.new
10192623 4335560 1105920 15634103 ee8eb7 vmlinux.old
As the return value are unimportant and unused in the kernel tree, these
new functions return void.
Miscellanea:
- change pr_<level> macros to call new __pr_<level> functions
- change vprintk_nmi and vprintk_default to add LOGLEVEL_<level> argument
[akpm@linux-foundation.org: fix LOGLEVEL_INFO, per Joe]
Link: http://lkml.kernel.org/r/e16cc34479dfefcae37c98b481e6646f0f69efc3.1466718827.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In NMI context, printk() messages are stored into per-CPU buffers to
avoid a possible deadlock. They are normally flushed to the main ring
buffer via an IRQ work. But the work is never called when the system
calls panic() in the very same NMI handler.
This patch tries to flush NMI buffers before the crash dump is
generated. In this case it does not risk a double release and bails out
when the logbuf_lock is already taken. The aim is to get the messages
into the main ring buffer when possible. It makes them better
accessible in the vmcore.
Then the patch tries to flush the buffers second time when other CPUs
are down. It might be more aggressive and reset logbuf_lock. The aim
is to get the messages available for the consequent kmsg_dump() and
console_flush_on_panic() calls.
The patch causes vprintk_emit() to be called even in NMI context again.
But it is done via printk_deferred() so that the console handling is
skipped. Consoles use internal locks and we could not prevent a
deadlock easily. They are explicitly called later when the crash dump
is not generated, see console_flush_on_panic().
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: David Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jiri Kosina <jkosina@suse.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We could not resize the temporary buffer in NMI context. Let's warn if
a message is lost.
This is rather theoretical. printk() should not be used in NMI. The
only sensible use is when we want to print backtrace from all CPUs. The
current buffer should be enough for this purpose.
[akpm@linux-foundation.org: whitespace fixlet]
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jiri Kosina <jkosina@suse.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: David Miller <davem@davemloft.net>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
printk() takes some locks and could not be used a safe way in NMI
context.
The chance of a deadlock is real especially when printing stacks from
all CPUs. This particular problem has been addressed on x86 by the
commit a9edc88093 ("x86/nmi: Perform a safe NMI stack trace on all
CPUs").
The patchset brings two big advantages. First, it makes the NMI
backtraces safe on all architectures for free. Second, it makes all NMI
messages almost safe on all architectures (the temporary buffer is
limited. We still should keep the number of messages in NMI context at
minimum).
Note that there already are several messages printed in NMI context:
WARN_ON(in_nmi()), BUG_ON(in_nmi()), anything being printed out from MCE
handlers. These are not easy to avoid.
This patch reuses most of the code and makes it generic. It is useful
for all messages and architectures that support NMI.
The alternative printk_func is set when entering and is reseted when
leaving NMI context. It queues IRQ work to copy the messages into the
main ring buffer in a safe context.
__printk_nmi_flush() copies all available messages and reset the buffer.
Then we could use a simple cmpxchg operations to get synchronized with
writers. There is also used a spinlock to get synchronized with other
flushers.
We do not longer use seq_buf because it depends on external lock. It
would be hard to make all supported operations safe for a lockless use.
It would be confusing and error prone to make only some operations safe.
The code is put into separate printk/nmi.c as suggested by Steven
Rostedt. It needs a per-CPU buffer and is compiled only on
architectures that call nmi_enter(). This is achieved by the new
HAVE_NMI Kconfig flag.
The are MN10300 and Xtensa architectures. We need to clean up NMI
handling there first. Let's do it separately.
The patch is heavily based on the draft from Peter Zijlstra, see
https://lkml.org/lkml/2015/6/10/327
[arnd@arndb.de: printk-nmi: use %zu format string for size_t]
[akpm@linux-foundation.org: min_t->min - all types are size_t here]
Signed-off-by: Petr Mladek <pmladek@suse.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Jan Kara <jack@suse.cz>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> [arm part]
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jiri Kosina <jkosina@suse.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: David Miller <davem@davemloft.net>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This allows us to extract from the vmcore only the messages emitted
since the last time the ring buffer was cleared. We just have to make
sure its value is always up-to-date, when old messages are discarded to
free space in log_make_free_space() for example.
Signed-off-by: Zeyu Zhao <zzy8200@gmail.com>
Signed-off-by: Ivan Delalande <colona@arista.com>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
