linux-toradex.git/lib, branch v5.14-rc2

lib/test_hmm: remove set but unused page variable

2021-07-15T17:13:49+00:00

The HMM selftests use atomic_check_access() to check atomic access to a
page has been revoked.  It doesn't matter if the page mapping has been
removed from the mirrored page tables as that also implies atomic access
has been revoked.  Therefore remove the unused page variable to fix this
compiler warning:

  lib/test_hmm.c:631:16: warning: variable `page' set but not used [-Wunused-but-set-variable]

Link: https://lkml.kernel.org/r/20210706025603.4059-1-apopple@nvidia.com
Fixes: b659baea7546 ("mm: selftests for exclusive device memory")
Signed-off-by: Alistair Popple 
Reported-by: Hulk Robot 
Reported-by: kernel test robot 
Reported-by: Yang Yingliang 
Acked-by: Souptick Joarder 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/page_alloc: Revert pahole zero-sized workaround

2021-07-10T23:09:39+00:00

Commit dbbee9d5cd83 ("mm/page_alloc: convert per-cpu list protection to
local_lock") folded in a workaround patch for pahole that was unable to
deal with zero-sized percpu structures.

A superior workaround is achieved with commit a0b8200d06ad ("kbuild:
skip per-CPU BTF generation for pahole v1.18-v1.21").

This patch reverts the dummy field and the pahole version check.

Fixes: dbbee9d5cd83 ("mm/page_alloc: convert per-cpu list protection to local_lock")
Signed-off-by: Mel Gorman 
Signed-off-by: Linus Torvalds

Merge tag 'kbuild-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2021-07-10T18:01:38+00:00

Pull Kbuild updates from Masahiro Yamada:

 - Increase the -falign-functions alignment for the debug option.

 - Remove ugly libelf checks from the top Makefile.

 - Make the silent build (-s) more silent.

 - Re-compile the kernel if KBUILD_BUILD_TIMESTAMP is specified.

 - Various script cleanups

* tag 'kbuild-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (27 commits)
  scripts: add generic syscallnr.sh
  scripts: check duplicated syscall number in syscall table
  sparc: syscalls: use pattern rules to generate syscall headers
  parisc: syscalls: use pattern rules to generate syscall headers
  nds32: add arch/nds32/boot/.gitignore
  kbuild: mkcompile_h: consider timestamp if KBUILD_BUILD_TIMESTAMP is set
  kbuild: modpost: Explicitly warn about unprototyped symbols
  kbuild: remove trailing slashes from $(KBUILD_EXTMOD)
  kconfig.h: explain IS_MODULE(), IS_ENABLED()
  kconfig: constify long_opts
  scripts/setlocalversion: simplify the short version part
  scripts/setlocalversion: factor out 12-chars hash construction
  scripts/setlocalversion: add more comments to -dirty flag detection
  scripts/setlocalversion: remove workaround for old make-kpkg
  scripts/setlocalversion: remove mercurial, svn and git-svn supports
  kbuild: clean up ${quiet} checks in shell scripts
  kbuild: sink stdout from cmd for silent build
  init: use $(call cmd,) for generating include/generated/compile.h
  kbuild: merge scripts/mkmakefile to top Makefile
  sh: move core-y in arch/sh/Makefile to arch/sh/Kbuild
  ...

Merge tag 'for-linus-5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml

2021-07-09T17:19:13+00:00

Pull UML updates from Richard Weinberger:

 - Support for optimized routines based on the host CPU

 - Support for PCI via virtio

 - Various fixes

* tag 'for-linus-5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
  um: remove unneeded semicolon in um_arch.c
  um: Remove the repeated declaration
  um: fix error return code in winch_tramp()
  um: fix error return code in slip_open()
  um: Fix stack pointer alignment
  um: implement flush_cache_vmap/flush_cache_vunmap
  um: add a UML specific futex implementation
  um: enable the use of optimized xor routines in UML
  um: Add support for host CPU flags and alignment
  um: allow not setting extra rpaths in the linux binary
  um: virtio/pci: enable suspend/resume
  um: add PCI over virtio emulation driver
  um: irqs: allow invoking time-travel handler multiple times
  um: time-travel/signals: fix ndelay() in interrupt
  um: expose time-travel mode to userspace side
  um: export signals_enabled directly
  um: remove unused smp_sigio_handler() declaration
  lib: add iomem emulation (logic_iomem)
  um: allow disabling NO_IOMEM

kdump: use vmlinux_build_id to simplify

2021-07-08T18:48:22+00:00

We can use the vmlinux_build_id array here now instead of open coding it.
This mostly consolidates code.

Link: https://lkml.kernel.org/r/20210511003845.2429846-14-swboyd@chromium.org
Signed-off-by: Stephen Boyd 
Cc: Jiri Olsa 
Cc: Alexei Starovoitov 
Cc: Jessica Yu 
Cc: Evan Green 
Cc: Hsin-Yi Wang 
Cc: Dave Young 
Cc: Baoquan He 
Cc: Vivek Goyal 
Cc: Andy Shevchenko 
Cc: Borislav Petkov 
Cc: Catalin Marinas 
Cc: Ingo Molnar 
Cc: Konstantin Khlebnikov 
Cc: Matthew Wilcox 
Cc: Petr Mladek 
Cc: Rasmus Villemoes 
Cc: Sasha Levin 
Cc: Sergey Senozhatsky 
Cc: Steven Rostedt 
Cc: Thomas Gleixner 
Cc: Will Deacon 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

buildid: fix kernel-doc notation

2021-07-08T18:48:22+00:00

Kernel doc should use "Return:" instead of "Returns" to properly reflect
the return values.

Link: https://lkml.kernel.org/r/20210511003845.2429846-13-swboyd@chromium.org
Signed-off-by: Stephen Boyd 
Cc: Jiri Olsa 
Cc: Alexei Starovoitov 
Cc: Jessica Yu 
Cc: Evan Green 
Cc: Hsin-Yi Wang 
Cc: Andy Shevchenko 
Cc: Baoquan He 
Cc: Borislav Petkov 
Cc: Catalin Marinas 
Cc: Dave Young 
Cc: Ingo Molnar 
Cc: Konstantin Khlebnikov 
Cc: Matthew Wilcox 
Cc: Petr Mladek 
Cc: Rasmus Villemoes 
Cc: Sasha Levin 
Cc: Sergey Senozhatsky 
Cc: Steven Rostedt 
Cc: Thomas Gleixner 
Cc: Vivek Goyal 
Cc: Will Deacon 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

buildid: mark some arguments const

2021-07-08T18:48:22+00:00

These arguments are never modified so they can be marked const to indicate
as such.

Link: https://lkml.kernel.org/r/20210511003845.2429846-12-swboyd@chromium.org
Signed-off-by: Stephen Boyd 
Cc: Jiri Olsa 
Cc: Alexei Starovoitov 
Cc: Jessica Yu 
Cc: Evan Green 
Cc: Hsin-Yi Wang 
Cc: Andy Shevchenko 
Cc: Baoquan He 
Cc: Borislav Petkov 
Cc: Catalin Marinas 
Cc: Dave Young 
Cc: Ingo Molnar 
Cc: Konstantin Khlebnikov 
Cc: Matthew Wilcox 
Cc: Petr Mladek 
Cc: Rasmus Villemoes 
Cc: Sasha Levin 
Cc: Sergey Senozhatsky 
Cc: Steven Rostedt 
Cc: Thomas Gleixner 
Cc: Vivek Goyal 
Cc: Will Deacon 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

module: add printk formats to add module build ID to stacktraces

2021-07-08T18:48:22+00:00

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 
Signed-off-by: Bixuan Cui 
Signed-off-by: Randy Dunlap 
Cc: Jiri Olsa 
Cc: Alexei Starovoitov 
Cc: Jessica Yu 
Cc: Evan Green 
Cc: Hsin-Yi Wang 
Cc: Petr Mladek 
Cc: Steven Rostedt 
Cc: Sergey Senozhatsky 
Cc: Andy Shevchenko 
Cc: Rasmus Villemoes 
Cc: Matthew Wilcox 
Cc: Baoquan He 
Cc: Borislav Petkov 
Cc: Catalin Marinas 
Cc: Dave Young 
Cc: Ingo Molnar 
Cc: Konstantin Khlebnikov 
Cc: Sasha Levin 
Cc: Thomas Gleixner 
Cc: Vivek Goyal 
Cc: Will Deacon 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

dump_stack: add vmlinux build ID to stack traces

2021-07-08T18:48:22+00:00

Add the running kernel's build ID[1] to the stacktrace information header.
This makes it simpler for developers to locate the vmlinux with full
debuginfo for a particular kernel stacktrace.  Combined with
scripts/decode_stracktrace.sh, a developer can download the correct
vmlinux from a debuginfod[2] server and find the exact file and line
number for the functions plus offsets in a stacktrace.

This is especially useful for pstore crash debugging where the kernel
crashes are recorded in the pstore logs and the recovery kernel is
different or the debuginfo doesn't exist on the device due to space
concerns (the data can be large and a security concern).  The stacktrace
can be analyzed after the crash by using the build ID to find the matching
vmlinux and understand where in the function something went wrong.

Example stacktrace from lkdtm:

 WARNING: CPU: 4 PID: 3255 at drivers/misc/lkdtm/bugs.c:83 lkdtm_WARNING+0x28/0x30 [lkdtm]
 Modules linked in: lkdtm rfcomm algif_hash algif_skcipher af_alg xt_cgroup uinput xt_MASQUERADE
 CPU: 4 PID: 3255 Comm: bash Not tainted 5.11 #3 aa23f7a1231c229de205662d5a9e0d4c580f19a1
 Hardware name: Google Lazor (rev3+) with KB Backlight (DT)
 pstate: 00400009 (nzcv daif +PAN -UAO -TCO BTYPE=--)
 pc : lkdtm_WARNING+0x28/0x30 [lkdtm]

The hex string aa23f7a1231c229de205662d5a9e0d4c580f19a1 is the build ID,
following the kernel version number. Put it all behind a config option,
STACKTRACE_BUILD_ID, so that kernel developers can remove this
information if they decide it is too much.

Link: https://lkml.kernel.org/r/20210511003845.2429846-5-swboyd@chromium.org
Link: https://fedoraproject.org/wiki/Releases/FeatureBuildId [1]
Link: https://sourceware.org/elfutils/Debuginfod.html [2]
Signed-off-by: Stephen Boyd 
Cc: Jiri Olsa 
Cc: Alexei Starovoitov 
Cc: Jessica Yu 
Cc: Evan Green 
Cc: Hsin-Yi Wang 
Cc: Petr Mladek 
Cc: Steven Rostedt 
Cc: Andy Shevchenko 
Cc: Matthew Wilcox 
Cc: Baoquan He 
Cc: Borislav Petkov 
Cc: Catalin Marinas 
Cc: Dave Young 
Cc: Ingo Molnar 
Cc: Konstantin Khlebnikov 
Cc: Rasmus Villemoes 
Cc: Sasha Levin 
Cc: Sergey Senozhatsky 
Cc: Thomas Gleixner 
Cc: Vivek Goyal 
Cc: Will Deacon 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

buildid: stash away kernels build ID on init

2021-07-08T18:48:22+00:00

Parse the kernel's build ID at initialization so that other code can print
a hex format string representation of the running kernel's build ID.  This
will be used in the kdump and dump_stack code so that developers can
easily locate the vmlinux debug symbols for a crash/stacktrace.

[swboyd@chromium.org: fix implicit declaration of init_vmlinux_build_id()]
  Link: https://lkml.kernel.org/r/CAE-0n51UjTbay8N9FXAyE7_aR2+ePrQnKSRJ0gbmRsXtcLBVaw@mail.gmail.com

Link: https://lkml.kernel.org/r/20210511003845.2429846-4-swboyd@chromium.org
Signed-off-by: Stephen Boyd 
Acked-by: Baoquan He 
Cc: Jiri Olsa 
Cc: Alexei Starovoitov 
Cc: Jessica Yu 
Cc: Evan Green 
Cc: Hsin-Yi Wang 
Cc: Dave Young 
Cc: Vivek Goyal 
Cc: Andy Shevchenko 
Cc: Borislav Petkov 
Cc: Catalin Marinas 
Cc: Ingo Molnar 
Cc: Konstantin Khlebnikov 
Cc: Matthew Wilcox 
Cc: Petr Mladek 
Cc: Rasmus Villemoes 
Cc: Sasha Levin 
Cc: Sergey Senozhatsky 
Cc: Steven Rostedt 
Cc: Thomas Gleixner 
Cc: Will Deacon 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds