Commit Graph

42 Commits

Author SHA1 Message Date
Petr Mladek 6a7ca80f40 vsprintf: Update %pGp documentation about that it prints hex value
The commit 23efd0804c ("vsprintf: Make %pGp print
the hex value") changed the behavior of %pGp printk format.
Update the documentation accordingly.

Fixes: 23efd0804c ("vsprintf: Make %pGp print the hex value")
Reviewed-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/YXlKqCPY9suM4mfT@alley
2021-11-01 15:55:06 +01:00
Ioana Ciornei 5b42d0bfb7 docs: printk-formats: fix build warning
Add an empty line after the '::' starting the code block so that the
following lines are properly interpreted.

Without this, the following build warnings are visible.

Documentation/core-api/printk-formats.rst:136: WARNING: Unexpected indentation.
Documentation/core-api/printk-formats.rst:137: WARNING: Block quote ends without a blank line; unexpected unindent.

Fixes: 9294523e37 ("module: add printk formats to add module build ID to stacktraces")
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Acked-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210722100356.635078-2-ciorneiioana@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-07-25 14:34:32 -06:00
Stephen Boyd 9294523e37 module: add printk formats to add module build ID to stacktraces
Let's make kernel stacktraces easier to identify by including the build
ID[1] of a module if the stacktrace is printing a symbol from a module.
This makes it simpler for developers to locate a kernel module's full
debuginfo for a particular stacktrace.  Combined with
scripts/decode_stracktrace.sh, a developer can download the matching
debuginfo from a debuginfod[2] server and find the exact file and line
number for the functions plus offsets in a stacktrace that match the
module.  This is especially useful for pstore crash debugging where the
kernel crashes are recorded in something like console-ramoops and the
recovery kernel/modules are different or the debuginfo doesn't exist on
the device due to space concerns (the debuginfo can be too large for space
limited devices).

Originally, I put this on the %pS format, but that was quickly rejected
given that %pS is used in other places such as ftrace where build IDs
aren't meaningful.  There was some discussions on the list to put every
module build ID into the "Modules linked in:" section of the stacktrace
message but that quickly becomes very hard to read once you have more than
three or four modules linked in.  It also provides too much information
when we don't expect each module to be traversed in a stacktrace.  Having
the build ID for modules that aren't important just makes things messy.
Splitting it to multiple lines for each module quickly explodes the number
of lines printed in an oops too, possibly wrapping the warning off the
console.  And finally, trying to stash away each module used in a
callstack to provide the ID of each symbol printed is cumbersome and would
require changes to each architecture to stash away modules and return
their build IDs once unwinding has completed.

Instead, we opt for the simpler approach of introducing new printk formats
'%pS[R]b' for "pointer symbolic backtrace with module build ID" and '%pBb'
for "pointer backtrace with module build ID" and then updating the few
places in the architecture layer where the stacktrace is printed to use
this new format.

Before:

 Call trace:
  lkdtm_WARNING+0x28/0x30 [lkdtm]
  direct_entry+0x16c/0x1b4 [lkdtm]
  full_proxy_write+0x74/0xa4
  vfs_write+0xec/0x2e8

After:

 Call trace:
  lkdtm_WARNING+0x28/0x30 [lkdtm 6c2215028606bda50de823490723dc4bc5bf46f9]
  direct_entry+0x16c/0x1b4 [lkdtm 6c2215028606bda50de823490723dc4bc5bf46f9]
  full_proxy_write+0x74/0xa4
  vfs_write+0xec/0x2e8

[akpm@linux-foundation.org: fix build with CONFIG_MODULES=n, tweak code layout]
[rdunlap@infradead.org: fix build when CONFIG_MODULES is not set]
  Link: https://lkml.kernel.org/r/20210513171510.20328-1-rdunlap@infradead.org
[akpm@linux-foundation.org: make kallsyms_lookup_buildid() static]
[cuibixuan@huawei.com: fix build error when CONFIG_SYSFS is disabled]
  Link: https://lkml.kernel.org/r/20210525105049.34804-1-cuibixuan@huawei.com

Link: https://lkml.kernel.org/r/20210511003845.2429846-6-swboyd@chromium.org
Link: https://fedoraproject.org/wiki/Releases/FeatureBuildId [1]
Link: https://sourceware.org/elfutils/Debuginfod.html [2]
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Bixuan Cui <cuibixuan@huawei.com>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Evan Green <evgreen@chromium.org>
Cc: Hsin-Yi Wang <hsinyi@chromium.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-08 11:48:22 -07:00
Linus Torvalds e563592c3e printk changes for 5.14
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 =Oa1c
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Merge tag 'printk-for-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux

Pull printk updates from Petr Mladek:

 - Add %pt[RT]s modifier to vsprintf(). It overrides ISO 8601 separator
   by using ' ' (space). It produces "YYYY-mm-dd HH:MM:SS" instead of
   "YYYY-mm-ddTHH:MM:SS".

 - Correctly parse long row of numbers by sscanf() when using the field
   width. Add extensive sscanf() selftest.

 - Generalize re-entrant CPU lock that has already been used to
   serialize dump_stack() output. It is part of the ongoing printk
   rework. It will allow to remove the obsoleted printk_safe buffers and
   introduce atomic consoles.

 - Some code clean up and sparse warning fixes.

* tag 'printk-for-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
  printk: fix cpu lock ordering
  lib/dump_stack: move cpu lock to printk.c
  printk: Remove trailing semicolon in macros
  random32: Fix implicit truncation warning in prandom_seed_state()
  lib: test_scanf: Remove pointless use of type_min() with unsigned types
  selftests: lib: Add wrapper script for test_scanf
  lib: test_scanf: Add tests for sscanf number conversion
  lib: vsprintf: Fix handling of number field widths in vsscanf
  lib: vsprintf: scanf: Negative number must have field width > 1
  usb: host: xhci-tegra: Switch to use %ptTs
  nilfs2: Switch to use %ptTs
  kdb: Switch to use %ptTs
  lib/vsprintf: Allow to override ISO 8601 date and time separator
2021-06-29 12:07:18 -07:00
Carlos Llamas d7c176e9b5 docs: printk-formats: update size-casting examples
Since commit 72deb455b5 ("block: remove CONFIG_LBDAF") sector_t and
blkcnt_t types are no longer variable in size, making them unsuitable
examples for casting to the largest possible type. This patch replaces
such examples with cycles_t and blk_status_t types, whose sizes depend
on architecture and config options respectively.

Signed-off-by: Carlos Llamas <cmllamas@google.com>
Link: https://lore.kernel.org/r/20210609195058.3518943-1-cmllamas@google.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-06-14 08:12:01 -06:00
Andy Shevchenko 20bc8c1e97 lib/vsprintf: Allow to override ISO 8601 date and time separator
ISO 8601 defines 'T' as a separator between date and time. Though,
some ABIs use time and date with ' ' (space) separator instead.

Add a flavour to the %pt specifier to override default separator.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210511153958.34527-1-andriy.shevchenko@linux.intel.com
2021-05-17 12:01:26 +02:00
Linus Torvalds 68a32ba141 drm for 5.13-rc1
- printk fourcc modifier support added %p4cc
 
 core:
 - drm_crtc_commit_wait
 - atomic plane state helpers reworked for full state
 - dma-buf heaps API rework
 - edid: rework and improvements for displayid
 
 dp-mst:
  - better topology logging
 
 bridge:
 - Chipone ICN6211
 - Lontium LT8912B
 - anx7625 regulator support
 
 panel:
 - fix lt9611 4k panels handling
 
 simple-kms:
 - add plane state helpers
 
 ttm:
 - debugfs support
 - removal of unused sysfs
 - ignore signaled moved fences
 - ioremap buffer according to mem caching
 
 i915:
 - Alderlake S enablement
 - Conversion to dma_resv_locking
 - Bring back watchdog timeout support
 - legacy ioctl cleanups
 - add GEM TDDO and RFC process
 - DG1 LMEM preparation work
 - intel_display.c refactoring
 - Gen9/TGL PCH combination support
 - eDP MSO Support
 - multiple PSR instance support
 - Link training debug updates
 - Disable PSR2 support on JSL/EHL
 - DDR5/LPDDR5 support for bw calcs
 - LSPCON limited to gen9/10 platforms
 - HSW/BDW async flip/VTd corruption workaround
 = SAGV watermakr fixes
 - SNB hard hang on ring resume fix
 - Limit imported dma-buf size
 - move to use new tasklet API
 - refactor KBL/TGL/ADL-S display/gt steppings
 - refactoring legacy DP/HDMI, FB plane code out
 
 amdgpu:
 - uapi: add ioctl to query video capabilities
 - Iniital AMD Freesync HDMI support
 - Initial Adebaran support
 - 10bpc dithering improvements
 - DCN secure display support
 - Drop legacy IO BAR requirements
 - PCIE/S0ix/RAS/Prime/Reset fixes
 - Display ASSR support
 - SMU gfx busy queues for RV/PCO
 - Initial LTTPR display work
 
 amdkfd:
 - MMU notifier fixes
 - APU fixes
 
 radeon:
 - debugfs cleanps
 - fw error handling ifix
 - Flexible array cleanups
 
 msm:
 - big DSI phy/pll cleanup
 - sc7280 initial support
 - commong bandwidth scaling path
 - shrinker locking contention fixes
 - unpin/swap support for GEM objcets
 
 ast:
 - cursor plane handling reworked
 
 tegra:
 - don't register DP AUX channels before connectors
 
 zynqmp:
 - fix OOB struct padding memset
 
 gma500:
 - drop ttm and medfield support
 
 exynos:
 - request_irq cleanup function
 
 mediatek:
 - fine tune line time for EOTp
 - MT8192 dpi support
 - atomic crtc config updates
 - don't support HDMI connector creation
 
 mxsdb:
 - imx8mm support
 
 panfrost:
 -= MMU IRQ handling rework
 
 qxl:
 - locking fixes
 - resource deallocation changes
 
 sun4i:
 - add alpha properties to UI/VI layers
 
 vc4:
 - RPi4 CEC support
 
 vmwgfx:
 - doc cleanups
 
 arc:
 - moved to drm/tiny
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Merge tag 'drm-next-2021-04-28' of git://anongit.freedesktop.org/drm/drm

Pull drm updates from Dave Airlie:
 "The usual lots of work all over the place.

  i915 has gotten some Alderlake work and prelim DG1 code, along with a
  major locking rework over the GEM code, and brings back the property
  of timing out long running jobs using a watchdog. amdgpu has some
  Alderbran support (new GPU), freesync HDMI support along with a lot
  other fixes.

  Outside of the drm, there is a new printf specifier added which should
  have all the correct acks/sobs:

   - printk fourcc modifier support added %p4cc

  Summary:

  core:
   - drm_crtc_commit_wait
   - atomic plane state helpers reworked for full state
   - dma-buf heaps API rework
   - edid: rework and improvements for displayid

  dp-mst:
   - better topology logging

  bridge:
   - Chipone ICN6211
   - Lontium LT8912B
   - anx7625 regulator support

  panel:
   - fix lt9611 4k panels handling

  simple-kms:
   - add plane state helpers

  ttm:
   - debugfs support
   - removal of unused sysfs
   - ignore signaled moved fences
   - ioremap buffer according to mem caching

  i915:
   - Alderlake S enablement
   - Conversion to dma_resv_locking
   - Bring back watchdog timeout support
   - legacy ioctl cleanups
   - add GEM TDDO and RFC process
   - DG1 LMEM preparation work
   - intel_display.c refactoring
   - Gen9/TGL PCH combination support
   - eDP MSO Support
   - multiple PSR instance support
   - Link training debug updates
   - Disable PSR2 support on JSL/EHL
   - DDR5/LPDDR5 support for bw calcs
   - LSPCON limited to gen9/10 platforms
   - HSW/BDW async flip/VTd corruption workaround
   - SAGV watermark fixes
   - SNB hard hang on ring resume fix
   - Limit imported dma-buf size
   - move to use new tasklet API
   - refactor KBL/TGL/ADL-S display/gt steppings
   - refactoring legacy DP/HDMI, FB plane code out

  amdgpu:
   - uapi: add ioctl to query video capabilities
   - Iniital AMD Freesync HDMI support
   - Initial Adebaran support
   - 10bpc dithering improvements
   - DCN secure display support
   - Drop legacy IO BAR requirements
   - PCIE/S0ix/RAS/Prime/Reset fixes
   - Display ASSR support
   - SMU gfx busy queues for RV/PCO
   - Initial LTTPR display work

  amdkfd:
   - MMU notifier fixes
   - APU fixes

  radeon:
   - debugfs cleanps
   - fw error handling ifix
   - Flexible array cleanups

  msm:
   - big DSI phy/pll cleanup
   - sc7280 initial support
   - commong bandwidth scaling path
   - shrinker locking contention fixes
   - unpin/swap support for GEM objcets

  ast:
   - cursor plane handling reworked

  tegra:
   - don't register DP AUX channels before connectors

  zynqmp:
   - fix OOB struct padding memset

  gma500:
   - drop ttm and medfield support

  exynos:
   - request_irq cleanup function

  mediatek:
   - fine tune line time for EOTp
   - MT8192 dpi support
   - atomic crtc config updates
   - don't support HDMI connector creation

  mxsdb:
   - imx8mm support

  panfrost:
   - MMU IRQ handling rework

  qxl:
   - locking fixes
   - resource deallocation changes

  sun4i:
   - add alpha properties to UI/VI layers

  vc4:
   - RPi4 CEC support

  vmwgfx:
   - doc cleanups

  arc:
   - moved to drm/tiny"

* tag 'drm-next-2021-04-28' of git://anongit.freedesktop.org/drm/drm: (1390 commits)
  drm/ttm: Don't count pages in SG BOs against pages_limit
  drm/ttm: fix return value check
  drm/bridge: lt8912b: fix incorrect handling of of_* return values
  drm: bridge: fix LONTIUM use of mipi_dsi_() functions
  drm: bridge: fix ANX7625 use of mipi_dsi_() functions
  drm/amdgpu: page retire over debugfs mechanism
  drm/radeon: Fix a missing check bug in radeon_dp_mst_detect()
  drm/amd/display: Fix the Wunused-function warning
  drm/radeon/r600: Fix variables that are not used after assignment
  drm/amdgpu/smu7: fix CAC setting on TOPAZ
  drm/amd/display: Update DCN302 SR Exit Latency
  drm/amdgpu: enable ras eeprom on aldebaran
  drm/amdgpu: RAS harvest on driver load
  drm/amdgpu: add ras aldebaran ras eeprom driver
  drm/amd/pm: increase time out value when sending msg to SMU
  drm/amdgpu: add DMUB outbox event IRQ source define/complete/debug flag
  drm/amd/pm: add the callback to get vbios bootup values for vangogh
  drm/radeon: Fix size overflow
  drm/amdgpu: Fix size overflow
  drm/amdgpu: move mmhub ras_func init to ip specific file
  ...
2021-04-28 10:01:40 -07:00
Petr Mladek da34b03fbd Merge branch 'for-5.13-vsprintf-pgp' into for-linus 2021-04-27 14:31:38 +02:00
Vlastimil Babka a48849e235 printk: clarify the documentation for plain pointer printing
We have several modifiers for plain pointers (%p, %px and %pK) and now
also the no_hash_pointers boot parameter. The documentation should help
to choose which variant to use. Importantly, we should discourage %px
in favor of %p (with the new boot parameter when debugging), and stress
that %pK should be only used for procfs and similar files, not dmesg
buffer. This patch clarifies the documentation in that regard.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210225164639.27212-1-vbabka@suse.cz
2021-04-07 13:20:59 +02:00
Yafang Shao c244297acb vsprintf: dump full information of page flags in pGp
Currently the pGp only shows the names of page flags, rather than
the full information including section, node, zone, last cpupid and
kasan tag. While it is not easy to parse these information manually
because there're so many flavors. Let's interpret them in pGp as well.

To be compitable with the existed format of pGp, the new introduced ones
also use '|' as the separator, then the user tools parsing pGp won't
need to make change, suggested by Matthew. The new information is
tracked onto the end of the existed one.

On example of the output in mm/slub.c as follows,
- Before the patch,
[ 6343.396602] Slab 0x000000004382e02b objects=33 used=3 fp=0x000000009ae06ffc flags=0x17ffffc0010200(slab|head)

- After the patch,
[ 8448.272530] Slab 0x0000000090797883 objects=33 used=3 fp=0x00000000790f1c26 flags=0x17ffffc0010200(slab|head|node=0|zone=2|lastcpupid=0x1fffff)

The documentation and test cases are also updated. The output of the
test cases as follows,
[68599.816764] test_printf: loaded.
[68599.819068] test_printf: all 388 tests passed
[68599.830367] test_printf: unloaded.

[lkp@intel.com: reported issues in the prev version in test_printf.c]

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: kernel test robot <lkp@intel.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210319101246.73513-4-laoar.shao@gmail.com
2021-03-19 16:38:49 +01:00
Sakari Ailus af612e43de lib/vsprintf: Add support for printing V4L2 and DRM fourccs
Add a printk modifier %p4cc (for pixel format) for printing V4L2 and DRM
pixel formats denoted by fourccs. The fourcc encoding is the same for both
so the same implementation can be used.

Suggested-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20210216155723.17109-2-sakari.ailus@linux.intel.com
2021-02-17 12:52:20 +01:00
Geert Uytterhoeven 04d0608b44 docs: core-api/printk-formats.rst: Clarify formatting {cpu,node}mask
Clarify how to pass the field width for bitmaps, and mention the helper
macros that are available to ease printing cpumask and nodemask.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20201110144121.3278667-1-geert+renesas@glider.be
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-11-13 15:03:20 -07:00
Linus Torvalds 2324d50d05 It's been a busy cycle for documentation - hopefully the busiest for a
while to come.  Changes include:
 
  - Some new Chinese translations
 
  - Progress on the battle against double words words and non-HTTPS URLs
 
  - Some block-mq documentation
 
  - More RST conversions from Mauro.  At this point, that task is
    essentially complete, so we shouldn't see this kind of churn again for a
    while.  Unless we decide to switch to asciidoc or something...:)
 
  - Lots of typo fixes, warning fixes, and more.
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Merge tag 'docs-5.9' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "It's been a busy cycle for documentation - hopefully the busiest for a
  while to come. Changes include:

   - Some new Chinese translations

   - Progress on the battle against double words words and non-HTTPS
     URLs

   - Some block-mq documentation

   - More RST conversions from Mauro. At this point, that task is
     essentially complete, so we shouldn't see this kind of churn again
     for a while. Unless we decide to switch to asciidoc or
     something...:)

   - Lots of typo fixes, warning fixes, and more"

* tag 'docs-5.9' of git://git.lwn.net/linux: (195 commits)
  scripts/kernel-doc: optionally treat warnings as errors
  docs: ia64: correct typo
  mailmap: add entry for <alobakin@marvell.com>
  doc/zh_CN: add cpu-load Chinese version
  Documentation/admin-guide: tainted-kernels: fix spelling mistake
  MAINTAINERS: adjust kprobes.rst entry to new location
  devices.txt: document rfkill allocation
  PCI: correct flag name
  docs: filesystems: vfs: correct flag name
  docs: filesystems: vfs: correct sync_mode flag names
  docs: path-lookup: markup fixes for emphasis
  docs: path-lookup: more markup fixes
  docs: path-lookup: fix HTML entity mojibake
  CREDITS: Replace HTTP links with HTTPS ones
  docs: process: Add an example for creating a fixes tag
  doc/zh_CN: add Chinese translation prefer section
  doc/zh_CN: add clearing-warn-once Chinese version
  doc/zh_CN: add admin-guide index
  doc:it_IT: process: coding-style.rst: Correct __maybe_unused compiler label
  futex: MAINTAINERS: Re-add selftests directory
  ...
2020-08-04 22:47:54 -07:00
Daniel W. S. Almeida b7f419950c docs: core-api/printk-formats.rst: use literal block syntax
Fix the following warning:

WARNING: Definition list ends without a blank line;
unexpected unindent.

By switching to the literal block syntax.

Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com>
Link: https://lore.kernel.org/r/20200718165107.625847-8-dwlsalmeida@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-07-23 14:29:25 -06:00
Alexander A. Klimov 8eda94bde4 Replace HTTP links with HTTPS ones: vsprintf
Rationale:
Reduces attack surface on kernel devs opening the links for MITM
as HTTPS traffic is much harder to manipulate.

Deterministic algorithm:
For each file:
  If not .svg:
    For each line:
      If doesn't contain `\bxmlns\b`:
        For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`:
          If both the HTTP and HTTPS versions
          return 200 OK and serve the same content:
            Replace HTTP with HTTPS.

Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20200702200536.13389-1-grandmaster@al2klimov.de
2020-07-03 14:07:00 +02:00
Linus Torvalds b23c4771ff A fair amount of stuff this time around, dominated by yet another massive
set from Mauro toward the completion of the RST conversion.  I *really*
 hope we are getting close to the end of this.  Meanwhile, those patches
 reach pretty far afield to update document references around the tree;
 there should be no actual code changes there.  There will be, alas, more of
 the usual trivial merge conflicts.
 
 Beyond that we have more translations, improvements to the sphinx
 scripting, a number of additions to the sysctl documentation, and lots of
 fixes.
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Merge tag 'docs-5.8' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "A fair amount of stuff this time around, dominated by yet another
  massive set from Mauro toward the completion of the RST conversion. I
  *really* hope we are getting close to the end of this. Meanwhile,
  those patches reach pretty far afield to update document references
  around the tree; there should be no actual code changes there. There
  will be, alas, more of the usual trivial merge conflicts.

  Beyond that we have more translations, improvements to the sphinx
  scripting, a number of additions to the sysctl documentation, and lots
  of fixes"

* tag 'docs-5.8' of git://git.lwn.net/linux: (130 commits)
  Documentation: fixes to the maintainer-entry-profile template
  zswap: docs/vm: Fix typo accept_threshold_percent in zswap.rst
  tracing: Fix events.rst section numbering
  docs: acpi: fix old http link and improve document format
  docs: filesystems: add info about efivars content
  Documentation: LSM: Correct the basic LSM description
  mailmap: change email for Ricardo Ribalda
  docs: sysctl/kernel: document unaligned controls
  Documentation: admin-guide: update bug-hunting.rst
  docs: sysctl/kernel: document ngroups_max
  nvdimm: fixes to maintainter-entry-profile
  Documentation/features: Correct RISC-V kprobes support entry
  Documentation/features: Refresh the arch support status files
  Revert "docs: sysctl/kernel: document ngroups_max"
  docs: move locking-specific documents to locking/
  docs: move digsig docs to the security book
  docs: move the kref doc into the core-api book
  docs: add IRQ documentation at the core-api book
  docs: debugging-via-ohci1394.txt: add it to the core-api book
  docs: fix references for ipmi.rst file
  ...
2020-06-01 15:45:27 -07:00
Linus Torvalds ca1f5df23f Printk changes for 5.8
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Merge tag 'printk-for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux

Pull printk updates from Petr Mladek:

 - Benjamin Herrenschmidt solved a problem with non-matched console
   aliases by first checking consoles defined on the command line. It is
   a more conservative approach than the previous attempts.

 - Benjamin also made sure that the console accessible via /dev/console
   always has CON_CONSDEV flag.

 - Andy Shevchenko added the %ptT modifier for printing struct time64_t.
   It extends the existing %ptR handling for struct rtc_time.

 - Bruno Meneguele fixed /dev/kmsg error value returned by unsupported
   SEEK_CUR.

 - Tetsuo Handa removed unused pr_cont_once().

... and a few small fixes.

* tag 'printk-for-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
  printk: Remove pr_cont_once()
  printk: handle blank console arguments passed in.
  kernel/printk: add kmsg SEEK_CUR handling
  printk: Fix a typo in comment "interator"->"iterator"
  usb: pulse8-cec: Switch to use %ptT
  ARM: bcm2835: Switch to use %ptT
  lib/vsprintf: Print time64_t in human readable format
  lib/vsprintf: update comment about simple_strto<foo>() functions
  printk: Correctly set CON_CONSDEV even when preferred console was not registered
  printk: Fix preferred console selection with multiple matches
  printk: Move console matching logic into a separate function
  printk: Convert a use of sprintf to snprintf in console_unlock
2020-06-01 12:13:30 -07:00
Andy Shevchenko 7daac5b2fd lib/vsprintf: Print time64_t in human readable format
There are users which print time and date represented by content of
time64_t type in human readable format.

Instead of open coding that each time introduce %ptT[dt][r] specifier.

Few test cases for %ptT specifier has been added as well.

Link: https://lore.kernel.org/r/20200415170046.33374-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Rewieved-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2020-05-20 14:54:18 +02:00
Daniel Borkmann b2a5212fb6 bpf: Restrict bpf_trace_printk()'s %s usage and add %pks, %pus specifier
Usage of plain %s conversion specifier in bpf_trace_printk() suffers from the
very same issue as bpf_probe_read{,str}() helpers, that is, it is broken on
archs with overlapping address ranges.

While the helpers have been addressed through work in 6ae08ae3de ("bpf: Add
probe_read_{user, kernel} and probe_read_{user, kernel}_str helpers"), we need
an option for bpf_trace_printk() as well to fix it.

Similarly as with the helpers, force users to make an explicit choice by adding
%pks and %pus specifier to bpf_trace_printk() which will then pick the corresponding
strncpy_from_unsafe*() variant to perform the access under KERNEL_DS or USER_DS.
The %pk* (kernel specifier) and %pu* (user specifier) can later also be extended
for other objects aside strings that are probed and printed under tracing, and
reused out of other facilities like bpf_seq_printf() or BTF based type printing.

Existing behavior of %s for current users is still kept working for archs where it
is not broken and therefore gated through CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE.
For archs not having this property we fall-back to pick probing under KERNEL_DS as
a sensible default.

Fixes: 8d3b7dce86 ("bpf: add support for %s specifier to bpf_trace_printk()")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Link: https://lore.kernel.org/bpf/20200515101118.6508-4-daniel@iogearbox.net
2020-05-15 08:10:36 -07:00
Ricardo Cañuelo 90c165f0de docs: pr_*() kerneldocs and basic printk docs
Add kerneldocs comments to the pr_*() macros in printk.h.

Add a new rst node in the core-api manual describing the basic usage of
printk and the related macro aliases.

Signed-off-by: Ricardo Cañuelo <ricardo.canuelo@collabora.com>
Link: https://lore.kernel.org/r/20200403093617.18003-1-ricardo.canuelo@collabora.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-20 17:15:32 -06:00
Linus Torvalds 937d6eefc7 Here's the main documentation changes for 5.5:
- Various kerneldoc script enhancements.
 
  - More RST conversions; those are slowing down as we run out of things to
    convert, but we're a ways from done still.
 
  - Dan's "maintainer profile entry" work landed at last.  Now we just need
    to get maintainers to fill in the profiles...
 
  - A reworking of the parallel build setup to work better with a variety of
    systems (and to not take over huge systems entirely in particular).
 
  - The MAINTAINERS file is now converted to RST during the build.
    Hopefully nobody ever tries to print this thing, or they will need to
    load a lot of paper.
 
  - A script and documentation making it easy for maintainers to add Link:
    tags at commit time.
 
 Also included is the removal of a bunch of spurious CR characters.
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Merge tag 'docs-5.5a' of git://git.lwn.net/linux

Pull Documentation updates from Jonathan Corbet:
 "Here are the main documentation changes for 5.5:

   - Various kerneldoc script enhancements.

   - More RST conversions; those are slowing down as we run out of
     things to convert, but we're a ways from done still.

   - Dan's "maintainer profile entry" work landed at last. Now we just
     need to get maintainers to fill in the profiles...

   - A reworking of the parallel build setup to work better with a
     variety of systems (and to not take over huge systems entirely in
     particular).

   - The MAINTAINERS file is now converted to RST during the build.
     Hopefully nobody ever tries to print this thing, or they will need
     to load a lot of paper.

   - A script and documentation making it easy for maintainers to add
     Link: tags at commit time.

  Also included is the removal of a bunch of spurious CR characters"

* tag 'docs-5.5a' of git://git.lwn.net/linux: (91 commits)
  docs: remove a bunch of stray CRs
  docs: fix up the maintainer profile document
  libnvdimm, MAINTAINERS: Maintainer Entry Profile
  Maintainer Handbook: Maintainer Entry Profile
  MAINTAINERS: Reclaim the P: tag for Maintainer Entry Profile
  docs, parallelism: Rearrange how jobserver reservations are made
  docs, parallelism: Do not leak blocking mode to other readers
  docs, parallelism: Fix failure path and add comment
  Documentation: Remove bootmem_debug from kernel-parameters.txt
  Documentation: security: core.rst: fix warnings
  Documentation/process/howto/kokr: Update for 4.x -> 5.x versioning
  Documentation/translation: Use Korean for Korean translation title
  docs/memory-barriers.txt: Remove remaining references to mmiowb()
  docs/memory-barriers.txt/kokr: Update I/O section to be clearer about CPU vs thread
  docs/memory-barriers.txt/kokr: Fix style, spacing and grammar in I/O section
  Documentation/kokr: Kill all references to mmiowb()
  docs/memory-barriers.txt/kokr: Rewrite "KERNEL I/O BARRIER EFFECTS" section
  docs: Add initial documentation for devfreq
  Documentation: Document how to get links with git am
  docs: Add request_irq() documentation
  ...
2019-12-02 11:51:02 -08:00
Linus Torvalds 361b0d286a Device properties framework updates for 5.5-rc1
Add support for printing fwnode names using a new conversion
 specifier "%pfw" (Sakari Ailus), clean up the software node and
 efi/apple-properties code in preparation for improved software node
 reference properties handling (Dmitry Torokhov) and fix the struct
 fwnode_operations description (Heikki Krogerus).
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Merge tag 'devprop-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull device properties framework updates from Rafael Wysocki:
 "Add support for printing fwnode names using a new conversion specifier
  "%pfw" (Sakari Ailus), clean up the software node and
  efi/apple-properties code in preparation for improved software node
  reference properties handling (Dmitry Torokhov) and fix the struct
  fwnode_operations description (Heikki Krogerus)"

* tag 'devprop-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (22 commits)
  software node: simplify property_entry_read_string_array()
  software node: unify PROPERTY_ENTRY_XXX macros
  software node: remove property_entry_read_uNN_array functions
  software node: get rid of property_set_pointer()
  software node: clean up property_copy_string_array()
  software node: mark internal macros with double underscores
  efi/apple-properties: use PROPERTY_ENTRY_U8_ARRAY_LEN
  software node: introduce PROPERTY_ENTRY_XXX_ARRAY_LEN()
  software node: remove DEV_PROP_MAX
  device property: Fix the description of struct fwnode_operations
  lib/test_printf: Add tests for %pfw printk modifier
  lib/vsprintf: Add %pfw conversion specifier for printing fwnode names
  lib/vsprintf: OF nodes are first and foremost, struct device_nodes
  lib/vsprintf: Make use of fwnode API to obtain node names and separators
  lib/vsprintf: Add a note on re-using %pf or %pF
  lib/vsprintf: Remove support for %pF and %pf in favour of %pS and %ps
  device property: Add a function to obtain a node's prefix
  device property: Add fwnode_get_name for returning the name of a node
  device property: Add functions for accessing node's parents
  device property: Move fwnode_get_parent() up
  ...
2019-11-26 19:45:12 -08:00
Linus Torvalds 436b2a8039 Printk changes for 5.5
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Merge tag 'printk-for-5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk

Pull printk updates from Petr Mladek:

 - Allow to print symbolic error names via new %pe modifier.

 - Use pr_warn() instead of the remaining pr_warning() calls. Fix
   formatting of the related lines.

 - Add VSPRINTF entry to MAINTAINERS.

* tag 'printk-for-5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk: (32 commits)
  checkpatch: don't warn about new vsprintf pointer extension '%pe'
  MAINTAINERS: Add VSPRINTF
  tools lib api: Renaming pr_warning to pr_warn
  ASoC: samsung: Use pr_warn instead of pr_warning
  lib: cpu_rmap: Use pr_warn instead of pr_warning
  trace: Use pr_warn instead of pr_warning
  dma-debug: Use pr_warn instead of pr_warning
  vgacon: Use pr_warn instead of pr_warning
  fs: afs: Use pr_warn instead of pr_warning
  sh/intc: Use pr_warn instead of pr_warning
  scsi: Use pr_warn instead of pr_warning
  platform/x86: intel_oaktrail: Use pr_warn instead of pr_warning
  platform/x86: asus-laptop: Use pr_warn instead of pr_warning
  platform/x86: eeepc-laptop: Use pr_warn instead of pr_warning
  oprofile: Use pr_warn instead of pr_warning
  of: Use pr_warn instead of pr_warning
  macintosh: Use pr_warn instead of pr_warning
  idsn: Use pr_warn instead of pr_warning
  ide: Use pr_warn instead of pr_warning
  crypto: n2: Use pr_warn instead of pr_warning
  ...
2019-11-25 19:40:40 -08:00
Miles Chen 88288ed050 docs: printk-formats: add ptrdiff_t type to printk-formats
When print the difference between two pointers, we should use
the ptrdiff_t modifier %t.

Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-11-07 13:17:26 -07:00
Rasmus Villemoes 57f5677e53 printf: add support for printing symbolic error names
It has been suggested several times to extend vsnprintf() to be able
to convert the numeric value of ENOSPC to print "ENOSPC". This
implements that as a %p extension: With %pe, one can do

  if (IS_ERR(foo)) {
    pr_err("Sorry, can't do that: %pe\n", foo);
    return PTR_ERR(foo);
  }

instead of what is seen in quite a few places in the kernel:

  if (IS_ERR(foo)) {
    pr_err("Sorry, can't do that: %ld\n", PTR_ERR(foo));
    return PTR_ERR(foo);
  }

If the value passed to %pe is an ERR_PTR, but the library function
errname() added here doesn't know about the value, the value is simply
printed in decimal. If the value passed to %pe is not an ERR_PTR, we
treat it as an ordinary %p and thus print the hashed value (passing
non-ERR_PTR values to %pe indicates a bug in the caller, but we can't
do much about that).

With my embedded hat on, and because it's not very invasive to do,
I've made it possible to remove this. The errname() function and
associated lookup tables take up about 3K. For most, that's probably
quite acceptable and a price worth paying for more readable
dmesg (once this starts getting used), while for those that disable
printk() it's of very little use - I don't see a
procfs/sysfs/seq_printf() file reasonably making use of this - and
they clearly want to squeeze vmlinux as much as possible. Hence the
default y if PRINTK.

The symbols to include have been found by massaging the output of

  find arch include -iname 'errno*.h' | xargs grep -E 'define\s*E'

In the cases where some common aliasing exists
(e.g. EAGAIN=EWOULDBLOCK on all platforms, EDEADLOCK=EDEADLK on most),
I've moved the more popular one (in terms of 'git grep -w Efoo | wc)
to the bottom so that one takes precedence.

Link: http://lkml.kernel.org/r/20191015190706.15989-1-linux@rasmusvillemoes.dk
To: "Jonathan Corbet" <corbet@lwn.net>
To: linux-kernel@vger.kernel.org
Cc: "Andy Shevchenko" <andy.shevchenko@gmail.com>
Cc: "Andrew Morton" <akpm@linux-foundation.org>
Cc: "Joe Perches" <joe@perches.com>
Cc: linux-doc@vger.kernel.org
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
[andy.shevchenko@gmail.com: use abs()]
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2019-10-17 16:23:25 +02:00
Sakari Ailus 3bd32d6a2e lib/vsprintf: Add %pfw conversion specifier for printing fwnode names
Add support for %pfw conversion specifier (with "f" and "P" modifiers) to
support printing full path of the node, including its name ("f") and only
the node's name ("P") in the printk family of functions. The two flags
have equivalent functionality to existing %pOF with the same two modifiers
("f" and "P") on OF based systems. The ability to do the same on ACPI
based systems is added by this patch.

On ACPI based systems the resulting strings look like

	\_SB.PCI0.CIO2.port@1.endpoint@0

where the nodes are separated by a dot (".") and the first three are
ACPI device nodes and the latter two ACPI data nodes.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-10-11 11:26:55 +02:00
Sakari Ailus 9af7706492 lib/vsprintf: Remove support for %pF and %pf in favour of %pS and %ps
%pS and %ps are now the preferred conversion specifiers to print function
names. The functionality is equivalent; remove the old, deprecated %pF
and %pf support.

Depends-on: commit 2d44d165e9 ("scsi: lpfc: Convert existing %pf users to %ps")
Depends-on: commit b295c3e39c ("tools lib traceevent: Convert remaining %p[fF] users to %p[sS]")
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-10-11 11:26:55 +02:00
Joe Perches cbacb5ab0a docs: printk-formats: Stop encouraging use of unnecessary %h[xudi] and %hh[xudi]
Standard integer promotion is already done and %hx and %hhx is useless
so do not encourage the use of %hh[xudi] or %h[xudi].

As Linus said in:
https://lore.kernel.org/lkml/CAHk-=wgoxnmsj8GEVFJSvTwdnWm8wVJthefNk2n6+4TC=20e0Q@mail.gmail.com/

It's a pointless warning, making for more complex code, and
making people remember esoteric printf format details that have no
reason for existing.

The "h" and "hh" things should never be used. The only reason for them
being used if if you have an "int", but you want to print it out as a
"char" (and honestly, that is a really bad reason, you'd be better off
just using a proper cast to make the code more obvious).

So if what you have a "char" (or unsigned char) you should always just
print it out as an "int", knowing that the compiler already did the
proper type conversion.

Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-by: Louis Taylor <louis@kragniz.eu>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-09-14 01:57:43 -06:00
Mauro Carvalho Chehab 5704324702 docs: admin-guide: move sysctl directory to it
The stuff under sysctl describes /sys interface from userspace
point of view. So, add it to the admin-guide and remove the
:orphan: from its index file.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
2019-07-15 11:03:01 -03:00
Mauro Carvalho Chehab 53b9537509 docs: sysctl: convert to ReST
Rename the /proc/sys/ documentation files to ReST, using the
README file as a template for an index.rst, adding the other
files there via TOC markup.

Despite being written on different times with different
styles, try to make them somewhat coherent with a similar
look and feel, ensuring that they'll look nice as both
raw text file and as via the html output produced by the
Sphinx build system.

At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
2019-07-15 09:20:26 -03:00
Petr Mladek 635720ac75 vsprintf: Avoid confusion between invalid address and value
We are able to detect invalid values handled by %p[iI] printk specifier.
The current error message is "invalid address". It might cause confusion
against "(efault)" reported by the generic valid_pointer_address() check.

Let's unify the style and use the more appropriate error code description
"(einval)".

Link: http://lkml.kernel.org/r/20190417115350.20479-10-pmladek@suse.com
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Tobin C . Harding" <me@tobin.cc>
Cc: Joe Perches <joe@perches.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2019-04-26 16:21:03 +02:00
Petr Mladek 3e5903eb9c vsprintf: Prevent crash when dereferencing invalid pointers
We already prevent crash when dereferencing some obviously broken
pointers. But the handling is not consistent. Sometimes we print "(null)"
only for pure NULL pointer, sometimes for pointers in the first
page and sometimes also for pointers in the last page (error codes).

Note that printk() call this code under logbuf_lock. Any recursive
printks are redirected to the printk_safe implementation and the messages
are stored into per-CPU buffers. These buffers might be eventually flushed
in printk_safe_flush_on_panic() but it is not guaranteed.

This patch adds a check using probe_kernel_read(). It is not a full-proof
test. But it should help to see the error message in 99% situations where
the kernel would silently crash otherwise.

Also it makes the error handling unified for "%s" and the many %p*
specifiers that need to read the data from a given address. We print:

   + (null)   when accessing data on pure pure NULL address
   + (efault) when accessing data on an invalid address

It does not affect the %p* specifiers that just print the given address
in some form, namely %pF, %pf, %pS, %ps, %pB, %pK, %px, and plain %p.

Note that we print (efault) from security reasons. In fact, the real
address can be seen only by %px or eventually %pK.

Link: http://lkml.kernel.org/r/20190417115350.20479-9-pmladek@suse.com
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Tobin C . Harding" <me@tobin.cc>
Cc: Joe Perches <joe@perches.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2019-04-26 16:20:43 +02:00
Linus Torvalds c4703acd6d Printk changes for 5.1
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Merge tag 'printk-for-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk

Pull printk updates from Petr Mladek:

 - Allow to sort mixed lines by an extra information about the caller

 - Remove no longer used LOG_PREFIX.

 - Some clean up and documentation update.

* tag 'printk-for-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
  printk/docs: Add extra integer types to printk-formats
  printk: Remove no longer used LOG_PREFIX.
  lib/vsprintf: Remove %pCr remnant in comment
  printk: Pass caller information to log_store().
  printk: Add caller information to printk() output.
2019-03-09 09:22:42 -08:00
Louis Taylor 943ca6ad81 printk/docs: Add extra integer types to printk-formats
A few commonly used integer types were absent from this table, so add
them.

Link: https://github.com/ClangBuiltLinux/linux/issues/378
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Link: http://lkml.kernel.org/r/20190303123647.22020-1-louis@kragniz.eu
Cc: pmladek@suse.com
Cc: geert+renesas@glider.be
Cc: andriy.shevchenko@linux.intel.com
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: clang-built-linux@googlegroups.com
Cc: ndesaulniers@google.com
Cc: jflat@chromium.org
Cc: Louis Taylor <louis@kragniz.eu>
Signed-off-by: Louis Taylor <louis@kragniz.eu>
[pmladek@suse.com: sorted both variants the same way by size]
Signed-off-by: Petr Mladek <pmladek@suse.com>
2019-03-04 16:39:08 +01:00
Andy Shevchenko 4d42c44727 lib/vsprintf: Print time and date in human readable format via %pt
There are users which print time and date represented by content of
struct rtc_time in human readable format.

Instead of open coding that each time introduce %ptR[dt][r] specifier.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
2018-12-10 22:39:34 +01:00
Linus Torvalds a67eefad99 Printk changes for 4.20
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Merge tag 'printk-for-4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk

Pull printk updates from Petr Mladek:

 - Fix two more locations where printf formatting leaked pointers

 - Better log_buf_len parameter handling

 - Add prefix to messages from printk code

 - Do not miss messages on other consoles when the log is replayed on a
   new one

 - Reduce race between console registration and panic() when the log
   might get replayed on all consoles

 - Some cont buffer code clean up

 - Call console only when there is something to do (log vs cont buffer)

* tag 'printk-for-4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
  lib/vsprintf: Hash printed address for netdev bits fallback
  lib/vsprintf: Hash legacy clock addresses
  lib/vsprintf: Prepare for more general use of ptr_to_id()
  lib/vsprintf: Make ptr argument conts in ptr_to_id()
  printk: fix integer overflow in setup_log_buf()
  printk: do not preliminary split up cont buffer
  printk: lock/unlock console only for new logbuf entries
  printk: keep kernel cont support always enabled
  printk: Give error on attempt to set log buffer length to over 2G
  printk: Add KBUILD_MODNAME and remove a redundant print prefix
  printk: Correct wrong casting
  printk: Fix panic caused by passing log_buf_len to command line
  printk: CON_PRINTBUFFER console registration is a bit racy
  printk: Do not miss new messages when replaying the log
2018-10-25 17:11:52 -07:00
Geert Uytterhoeven 94ac8f2074 doc: printk-formats: Remove bogus kobject references for device nodes
When converting from text to rst, the kobjects section and its sole
subsection about device tree nodes were coalesced into a single section,
yielding an inconsistent result.

Remove all references to kobjects, as
  1. Device tree object pointers are not compatible to kobject pointers
     (the former may embed the latter, though), and
  2. there are no printk formats defined for kobject types.

Update the vsprintf() source code comments to match the above.

Fixes: b3ed23213e ("doc: convert printk-formats.txt to rst")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2018-10-12 11:38:18 -06:00
Geert Uytterhoeven ec12bc2909 lib/vsprintf: Hash legacy clock addresses
On platforms using the Common Clock Framework, "%pC" prints the clock's
name. On legacy platforms, it prints the unhashed clock's address,
potentially leaking sensitive information regarding the kernel layout in
memory.

Avoid this leak by printing the hashed address instead.  To distinguish
between clocks, a 32-bit unique identifier is as good as an actual
pointer value.

Fixes: ad67b74d24 ("printk: hash addresses printed with %p")
Link: http://lkml.kernel.org/r/20181011084249.4520-3-geert+renesas@glider.be
To: "Tobin C . Harding" <me@tobin.cc>
To: Andrew Morton <akpm@linux-foundation.org>
To: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2018-10-12 11:24:41 +02:00
Geert Uytterhoeven 666902e42f lib/vsprintf: Remove atomic-unsafe support for %pCr
"%pCr" formats the current rate of a clock, and calls clk_get_rate().
The latter obtains a mutex, hence it must not be called from atomic
context.

Remove support for this rarely-used format, as vsprintf() (and e.g.
printk()) must be callable from any context.

Any remaining out-of-tree users will start seeing the clock's name
printed instead of its rate.

Reported-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Fixes: 900cca2944 ("lib/vsprintf: add %pC{,n,r} format specifiers for clocks")
Link: http://lkml.kernel.org/r/1527845302-12159-5-git-send-email-geert+renesas@glider.be
To: Jia-Ju Bai <baijiaju1990@gmail.com>
To: Jonathan Corbet <corbet@lwn.net>
To: Michael Turquette <mturquette@baylibre.com>
To: Stephen Boyd <sboyd@kernel.org>
To: Zhang Rui <rui.zhang@intel.com>
To: Eduardo Valentin <edubezval@gmail.com>
To: Eric Anholt <eric@anholt.net>
To: Stefan Wahren <stefan.wahren@i2se.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-doc@vger.kernel.org
Cc: linux-clk@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: linux-serial@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-renesas-soc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: stable@vger.kernel.org # 4.1+
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2018-06-05 09:43:39 +02:00
Joel Stanley 156383b190 Documentation: Mention why %p prints ptrval
When debugging recent kernels, people will see '(ptrval)' but there
isn't much information as to what that means. Briefly describe why it's
there.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Acked-by: Tobin C. Harding <me@tobin.cc>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2018-03-23 12:42:18 -06:00
Linus Torvalds ab486bc9a5 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk
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()
  ...
2018-02-01 13:36:15 -08:00
Tobin C. Harding b3ed23213e doc: convert printk-formats.txt to rst
Documentation/printk-formats.txt is a candidate for conversion to
ReStructuredText format. Some effort has already been made to do this
conversion even thought the suffix is currently .txt

Changes required to complete conversion

 - Move printk-formats.txt to core-api/printk-formats.rst
 - Add entry to Documentation/core-api/index.rst
 - Remove entry from Documentation/00-INDEX
 - Fix minor grammatical errors.
 - Order heading adornments as suggested by rst docs.
 - Use 'Passed by reference' uniformly.
 - Update pointer documentation around %px specifier.
 - Fix erroneous double backticks (to commas).
 - Remove extraneous double backticks (suggested by Jonathan Corbet).
 - Simplify documentation for kobject.

Signed-off-by: Tobin C. Harding <me@tobin.cc>
[jc: downcased "kernel"]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2017-12-21 13:39:07 -07:00