linux-stable.git/include/linux/kallsyms.h, branch v6.0.2

kallsyms: Make kallsyms_on_each_symbol generally available

2022-05-10T21:42:06+00:00

Making kallsyms_on_each_symbol generally available, so it can be
used outside CONFIG_LIVEPATCH option in following changes.

Rather than adding another ifdef option let's make the function
generally available (when CONFIG_KALLSYMS option is defined).

Cc: Christoph Hellwig 
Reviewed-by: Masami Hiramatsu 
Signed-off-by: Jiri Olsa 
Link: https://lore.kernel.org/r/20220510122616.2652285-2-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov

asm-generic: Define CONFIG_HAVE_FUNCTION_DESCRIPTORS

2022-02-16T12:25:11+00:00

Replace HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR by a config option
named CONFIG_HAVE_FUNCTION_DESCRIPTORS and use it instead of
'dereference_function_descriptor' macro to know whether an
arch has function descriptors.

To limit churn in one of the following patches, use
an #ifdef/#else construct with empty first part
instead of an #ifndef in asm-generic/sections.h

On powerpc, make sure the config option matches the ABI used
by the compiler with a BUILD_BUG_ON() and add missing _CALL_ELF=2
when calling 'sparse' so that sparse sees the same piece of
code as GCC.

And include a helper to check whether an arch has function
descriptors or not : have_function_descriptors()

Signed-off-by: Christophe Leroy 
Reviewed-by: Kees Cook 
Reviewed-by: Nicholas Piggin 
Acked-by: Helge Deller 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/4a0f11fb0ea74a3197bc44dd7ba25e53a24fd03d.1644928018.git.christophe.leroy@csgroup.eu

sections: provide internal __is_kernel() and __is_kernel_text() helper

2021-11-09T18:02:51+00:00

An internal __is_kernel() helper which only check the kernel address
ranges, and an internal __is_kernel_text() helper which only check text
section ranges.

Link: https://lkml.kernel.org/r/20210930071143.63410-7-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang 
Reviewed-by: Sergey Senozhatsky 
Cc: Alexander Potapenko 
Cc: Alexei Starovoitov 
Cc: Andrey Konovalov 
Cc: Andrey Ryabinin 
Cc: Arnd Bergmann 
Cc: Benjamin Herrenschmidt 
Cc: Borislav Petkov 
Cc: Christophe Leroy 
Cc: "David S. Miller" 
Cc: Dmitry Vyukov 
Cc: Ingo Molnar 
Cc: Ivan Kokshaysky 
Cc: Matt Turner 
Cc: Michael Ellerman 
Cc: Michal Simek 
Cc: Paul Mackerras 
Cc: Petr Mladek 
Cc: Richard Henderson 
Cc: Steven Rostedt 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

sections: move is_kernel_inittext() into sections.h

2021-11-09T18:02:50+00:00

The is_kernel_inittext() and init_kernel_text() are with same
functionality, let's just keep is_kernel_inittext() and move it into
sections.h, then update all the callers.

Link: https://lkml.kernel.org/r/20210930071143.63410-5-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang 
Reviewed-by: Sergey Senozhatsky 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: Arnd Bergmann 
Cc: Alexander Potapenko 
Cc: Alexei Starovoitov 
Cc: Andrey Konovalov 
Cc: Andrey Ryabinin 
Cc: Benjamin Herrenschmidt 
Cc: Borislav Petkov 
Cc: Christophe Leroy 
Cc: "David S. Miller" 
Cc: Dmitry Vyukov 
Cc: Ivan Kokshaysky 
Cc: Matt Turner 
Cc: Michael Ellerman 
Cc: Michal Simek 
Cc: Paul Mackerras 
Cc: Petr Mladek 
Cc: Richard Henderson 
Cc: Steven Rostedt 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kallsyms: fix address-checks for kernel related range

2021-11-09T18:02:50+00:00

The is_kernel_inittext/is_kernel_text/is_kernel function should not
include the end address(the labels _einittext, _etext and _end) when check
the address range, the issue exists since Linux v2.6.12.

Link: https://lkml.kernel.org/r/20210930071143.63410-3-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang 
Reviewed-by: Petr Mladek 
Reviewed-by: Steven Rostedt (VMware) 
Acked-by: Sergey Senozhatsky 
Cc: Arnd Bergmann 
Cc: Alexander Potapenko 
Cc: Alexei Starovoitov 
Cc: Andrey Konovalov 
Cc: Andrey Ryabinin 
Cc: Benjamin Herrenschmidt 
Cc: Borislav Petkov 
Cc: Christophe Leroy 
Cc: "David S. Miller" 
Cc: Dmitry Vyukov 
Cc: Ingo Molnar 
Cc: Ivan Kokshaysky 
Cc: Matt Turner 
Cc: Michael Ellerman 
Cc: Michal Simek 
Cc: Paul Mackerras 
Cc: Richard Henderson 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kallsyms: remove arch specific text and data check

2021-11-09T18:02:50+00:00

Patch series "sections: Unify kernel sections range check and use", v4.

There are three head files(kallsyms.h, kernel.h and sections.h) which
include the kernel sections range check, let's make some cleanup and unify
them.

1. cleanup arch specific text/data check and fix address boundary check
   in kallsyms.h

2. make all the basic/core kernel range check function into sections.h

3. update all the callers, and use the helper in sections.h to simplify
   the code

After this series, we have 5 APIs about kernel sections range check in
sections.h

 * is_kernel_rodata()		--- already in sections.h
 * is_kernel_core_data()	--- come from core_kernel_data() in kernel.h
 * is_kernel_inittext()		--- come from kernel.h and kallsyms.h
 * __is_kernel_text()		--- add new internal helper
 * __is_kernel()		--- add new internal helper

Note: For the last two helpers, people should not use directly, consider to
      use corresponding function in kallsyms.h.

This patch (of 11):

Remove arch specific text and data check after commit 4ba66a976072 ("arch:
remove blackfin port"), no need arch-specific text/data check.

Link: https://lkml.kernel.org/r/20210930071143.63410-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20210930071143.63410-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang 
Reviewed-by: Sergey Senozhatsky 
Cc: Arnd Bergmann 
Cc: Steven Rostedt 
Cc: Ingo Molnar 
Cc: David S. Miller 
Cc: Alexei Starovoitov 
Cc: Andrey Ryabinin 
Cc: Michael Ellerman 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Christophe Leroy 
Cc: Kefeng Wang 
Cc: Alexander Potapenko 
Cc: Andrey Konovalov 
Cc: Borislav Petkov 
Cc: Dmitry Vyukov 
Cc: Ivan Kokshaysky 
Cc: Matt Turner 
Cc: Michal Simek 
Cc: Petr Mladek 
Cc: Richard Henderson 
Cc: Thomas Gleixner 
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

kallsyms: only build {,module_}kallsyms_on_each_symbol when required

2021-02-08T11:24:04+00:00

kallsyms_on_each_symbol and module_kallsyms_on_each_symbol are only used
by the livepatching code, so don't build them if livepatching is not
enabled.

Reviewed-by: Miroslav Benes 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Jessica Yu

kallsyms: Refactor kallsyms_show_value() to take cred

2020-07-08T22:59:57+00:00

In order to perform future tests against the cred saved during open(),
switch kallsyms_show_value() to operate on a cred, and have all current
callers pass current_cred(). This makes it very obvious where callers
are checking the wrong credential in their "read" contexts. These will
be fixed in the coming patches.

Additionally switch return value to bool, since it is always used as a
direct permission check, not a 0-on-success, negative-on-error style
function return.

Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook

kallsyms/printk: add loglvl to print_ip_sym()

2020-06-09T16:39:10+00:00

Patch series "Add log level to show_stack()", v3.

Add log level argument to show_stack().

Done in three stages:
1. Introducing show_stack_loglvl() for every architecture
2. Migrating old users with an explicit log level
3. Renaming show_stack_loglvl() into show_stack()

Justification:

- It's a design mistake to move a business-logic decision into platform
  realization detail.

- I have currently two patches sets that would benefit from this work:
  Removing console_loglevel jumps in sysrq driver [1] Hung task warning
  before panic [2] - suggested by Tetsuo (but he probably didn't realise
  what it would involve).

- While doing (1), (2) the backtraces were adjusted to headers and other
  messages for each situation - so there won't be a situation when the
  backtrace is printed, but the headers are missing because they have
  lesser log level (or the reverse).

- As the result in (2) plays with console_loglevel for kdb are removed.

The least important for upstream, but maybe still worth to note that every
company I've worked in so far had an off-list patch to print backtrace
with the needed log level (but only for the architecture they cared
about).  If you have other ideas how you will benefit from show_stack()
with a log level - please, reply to this cover letter.

See also discussion on v1:
https://lore.kernel.org/linux-riscv/20191106083538.z5nlpuf64cigxigh@pathway.suse.cz/

This patch (of 50):

print_ip_sym() needs to have a log level parameter to comply with other
parts being printed.  Otherwise, half of the expected backtrace would be
printed and other may be missing with some logging level.

The following callee(s) are using now the adjusted log level:
- microblaze/unwind: the same level as headers & userspace unwind.
  Note that pr_debug()'s there are for debugging the unwinder itself.
- nds32/traps: symbol addresses are printed with the same log level
  as backtrace headers.
- lockdep: ip for locking issues is printed with the same log level
  as other part of the warning.
- sched: ip where preemption was disabled is printed as error like
  the rest part of the message.
- ftrace: bug reports are now consistent in the log level being used.

Signed-off-by: Dmitry Safonov 
Signed-off-by: Andrew Morton 
Acked-by: Steven Rostedt (VMware) 
Cc: Albert Ou 
Cc: Ben Segall 
Cc: Dietmar Eggemann 
Cc: Greentime Hu 
Cc: Greg Kroah-Hartman 
Cc: Ingo Molnar 
Cc: James Hogan 
Cc: Juri Lelli 
Cc: Mel Gorman 
Cc: Michal Simek 
Cc: Palmer Dabbelt 
Cc: Paul Burton 
Cc: Paul Walmsley 
Cc: Peter Zijlstra 
Cc: Ralf Baechle 
Cc: Thomas Gleixner 
Cc: Vincent Chen 
Cc: Vincent Guittot 
Cc: Will Deacon 
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Dmitry Safonov 
Cc: Jiri Slaby 
Cc: Petr Mladek 
Cc: Sergey Senozhatsky 
Cc: Ivan Kokshaysky 
Cc: Matt Turner 
Cc: Richard Henderson 
Cc: Vineet Gupta 
Cc: Russell King 
Cc: Catalin Marinas 
Cc: Aurelien Jacquiot 
Cc: Mark Salter 
Cc: Guo Ren 
Cc: Yoshinori Sato 
Cc: Brian Cain 
Cc: Fenghua Yu 
Cc: Tony Luck 
Cc: Geert Uytterhoeven 
Cc: Ley Foon Tan 
Cc: Jonas Bonn 
Cc: Stafford Horne 
Cc: Stefan Kristiansson 
Cc: Helge Deller 
Cc: "James E.J. Bottomley" 
Cc: Benjamin Herrenschmidt 
Cc: Michael Ellerman 
Cc: Paul Mackerras 
Cc: Christian Borntraeger 
Cc: Heiko Carstens 
Cc: Vasily Gorbik 
Cc: Rich Felker 
Cc: "David S. Miller" 
Cc: Anton Ivanov 
Cc: Jeff Dike 
Cc: Richard Weinberger 
Cc: Guan Xuetao 
Cc: Borislav Petkov 
Cc: "H. Peter Anvin" 
Cc: Chris Zankel 
Cc: Max Filippov 
Cc: Len Brown 
Cc: Pavel Machek 
Cc: "Rafael J. Wysocki" 
Cc: "Rafael J. Wysocki" 
Cc: Daniel Thompson 
Cc: Douglas Anderson 
Cc: Jason Wessel 
Link: http://lkml.kernel.org/r/20200418201944.482088-2-dima@arista.com
Signed-off-by: Linus Torvalds