08 Apr, 2020
40 commits
-
There are several places where code is indented incorrectly. Fix these.
Signed-off-by: Colin Ian King
Signed-off-by: Andrew Morton
Link: http://lkml.kernel.org/r/20200325135018.113431-1-colin.king@canonical.com
Signed-off-by: Linus Torvalds -
kallsyms_lookup_name() and kallsyms_on_each_symbol() are exported to
modules despite having no in-tree users and being wide open to abuse by
out-of-tree modules that can use them as a method to invoke arbitrary
non-exported kernel functions.Unexport kallsyms_lookup_name() and kallsyms_on_each_symbol().
Signed-off-by: Will Deacon
Signed-off-by: Andrew Morton
Reviewed-by: Greg Kroah-Hartman
Reviewed-by: Christoph Hellwig
Reviewed-by: Masami Hiramatsu
Reviewed-by: Quentin Perret
Acked-by: Alexei Starovoitov
Cc: Thomas Gleixner
Cc: Frederic Weisbecker
Cc: K.Prasad
Cc: Miroslav Benes
Cc: Petr Mladek
Cc: Joe Lawrence
Cc: Mathieu Desnoyers
Link: http://lkml.kernel.org/r/20200221114404.14641-4-will@kernel.org
Signed-off-by: Linus Torvalds -
The 'data_breakpoint' test code is the only modular user of
kallsyms_lookup_name(), which was exported as part of fixing the test in
f60d24d2ad04 ("hw-breakpoints: Fix broken hw-breakpoint sample module").In preparation for un-exporting this symbol, switch the test over to using
__symbol_get(), which can be used to place breakpoints on exported
symbols.Signed-off-by: Will Deacon
Signed-off-by: Andrew Morton
Reviewed-by: Christoph Hellwig
Reviewed-by: Masami Hiramatsu
Reviewed-by: Quentin Perret
Cc: K.Prasad
Cc: Thomas Gleixner
Cc: Greg Kroah-Hartman
Cc: Frederic Weisbecker
Cc: Alexei Starovoitov
Cc: Miroslav Benes
Cc: Petr Mladek
Cc: Joe Lawrence
Link: http://lkml.kernel.org/r/20200221114404.14641-3-will@kernel.org
Signed-off-by: Linus Torvalds -
Patch series "Unexport kallsyms_lookup_name() and kallsyms_on_each_symbol()".
Despite having just a single modular in-tree user that I could spot,
kallsyms_lookup_name() is exported to modules and provides a mechanism
for out-of-tree modules to access and invoke arbitrary, non-exported
kernel symbols when kallsyms is enabled.This patch series fixes up that one user and unexports the symbol along
with kallsyms_on_each_symbol(), since that could also be abused in a
similar manner.I would like to avoid out-of-tree modules being easily able to call
functions that are not exported. kallsyms_lookup_name() makes this
trivial to the point that there is very little incentive to rework these
modules to either use upstream interfaces correctly or propose
functionality which may be otherwise missing upstream. Both of these
latter solutions would be pre-requisites to upstreaming these modules, and
the current state of things actively discourages that approach.The background here is that we are aiming for Android devices to be able
to use a generic binary kernel image closely following upstream, with any
vendor extensions coming in as kernel modules. In this case, we (Google)
end up maintaining the binary module ABI within the scope of a single LTS
kernel. Monitoring and managing the ABI surface is not feasible if it
effectively includes all data and functions via kallsyms_lookup_name().
Of course, we could just carry this patch in the Android kernel tree, but
we're aiming to carry as little as possible (ideally nothing) and I think
it's a sensible change in its own right. I'm surprised you object to it,
in all honesty.Now, you could turn around and say "that's not upstream's problem", but it
still seems highly undesirable to me to have an upstream bypass for
exported symbols that isn't even used by upstream modules. It's ripe for
abuse and encourages people to work outside of the upstream tree. The
usual rule is that we don't export symbols without a user in the tree and
that seems especially relevant in this case.Joe Lawrence said:
: FWIW, kallsyms was historically used by the out-of-tree kpatch support
: module to resolve external symbols as well as call set_memory_r{w,o}()
: API. All of that support code has been merged upstream, so modern kpatch
: modules* no longer leverage kallsyms by default.
:
: That said, there are still some users who still use the deprecated support
: module with newer kernels, but that is not officially supported by the
: project.This patch (of 3):
Given the name of a kernel symbol, the 'data_breakpoint' test claims to
"report any write operations on the kernel symbol". However, it creates
the breakpoint using both HW_BREAKPOINT_W and HW_BREAKPOINT_R, which menas
it also fires for read access.Drop HW_BREAKPOINT_R from the breakpoint attributes.
Signed-off-by: Will Deacon
Signed-off-by: Andrew Morton
Reviewed-by: Christoph Hellwig
Reviewed-by: Masami Hiramatsu
Reviewed-by: Quentin Perret
Cc: K.Prasad
Cc: Thomas Gleixner
Cc: Greg Kroah-Hartman
Cc: Frederic Weisbecker
Cc: Alexei Starovoitov
Cc: Miroslav Benes
Cc: Petr Mladek
Cc: Joe Lawrence
Link: http://lkml.kernel.org/r/20200221114404.14641-2-will@kernel.org
Signed-off-by: Linus Torvalds -
Static executables don't need to free NULL pointer.
It doesn't matter really because static executable is not common scenario
but do it anyway out of pedantry.Signed-off-by: Alexey Dobriyan
Signed-off-by: Andrew Morton
Link: http://lkml.kernel.org/r/20200219185330.GA4933@avx2
Signed-off-by: Linus Torvalds -
PT_INTERP ELF header can be spared if executable is static.
Signed-off-by: Alexey Dobriyan
Signed-off-by: Andrew Morton
Link: http://lkml.kernel.org/r/20200219185012.GB4871@avx2
Signed-off-by: Linus Torvalds -
"loc" variable became just a wrapper for PT_INTERP ELF header after main
ELF header was moved to "bprm->buf". Delete it.Signed-off-by: Alexey Dobriyan
Signed-off-by: Andrew Morton
Link: http://lkml.kernel.org/r/20200219184847.GA4871@avx2
Signed-off-by: Linus Torvalds -
Davidlohr Bueso pointed out that when CONFIG_DEBUG_LOCK_ALLOC is set
ep_poll_safewake() can take several non-raw spinlocks after disabling
interrupts. Since a spinlock can block in the -rt kernel, we can't take a
spinlock after disabling interrupts. So let's re-work how we determine
the nesting level such that it plays nicely with the -rt kernel.Let's introduce a 'nests' field in struct eventpoll that records the
current nesting level during ep_poll_callback(). Then, if we nest again
we can find the previous struct eventpoll that we were called from and
increase our count by 1. The 'nests' field is protected by
ep->poll_wait.lock.I've also moved the visited field to reduce the size of struct eventpoll
from 184 bytes to 176 bytes on x86_64 for !CONFIG_DEBUG_LOCK_ALLOC, which
is typical for a production config.Reported-by: Davidlohr Bueso
Signed-off-by: Jason Baron
Signed-off-by: Andrew Morton
Reviewed-by: Davidlohr Bueso
Cc: Roman Penyaev
Cc: Eric Wong
Cc: Al Viro
Link: http://lkml.kernel.org/r/1582739816-13167-1-git-send-email-jbaron@akamai.com
Signed-off-by: Linus Torvalds -
This testcase repeats epollbug.c from the bug:
https://bugzilla.kernel.org/show_bug.cgi?id=205933
What it tests? It tests the race between epoll_ctl() and epoll_wait().
New event mask passed to epoll_ctl() triggers wake up, which can be missed
because of the bug described in the link. Reproduction is 100%, so easy
to fix. Kudos, Max, for wonderful test case.Signed-off-by: Roman Penyaev
Signed-off-by: Andrew Morton
Cc: Max Neunhoeffer
Cc: Jakub Kicinski
Cc: Christopher Kohlhoff
Cc: Davidlohr Bueso
Cc: Jason Baron
Cc: Jes Sorensen
Link: http://lkml.kernel.org/r/20200214170211.561524-2-rpenyaev@suse.de
Signed-off-by: Linus Torvalds -
WARNING: function definition argument 'flags' should also have an identifier name
#26: FILE: drivers/tty/serial/sh-sci.c:1348:
+ unsigned long uninitialized_var(flags);Special-case uninitialized_var() to prevent this.
Signed-off-by: Joe Perches
Signed-off-by: Andrew Morton
Tested-by: Andrew Morton
Link: http://lkml.kernel.org/r/7db7944761b0bd88c70eb17d4b7f40fe589e14ed.camel@perches.com
Signed-off-by: Linus Torvalds -
According to Devicetree maintainers (see Link: below), the Devicetree
binding documents are preferrably licensed (GPL-2.0-only OR BSD-2-Clause).Let's check that. The actual check is a bit more relaxed, to allow more
liberal but compatible licensing (e.g. GPL-2.0-or-later OR BSD-2-Clause).Signed-off-by: Lubomir Rintel
Signed-off-by: Andrew Morton
Acked-by: Joe Perches
Acked-by: Laurent Pinchart
Cc: Rob Herring
Cc: Neil Armstrong
Cc: Laurent Pinchart ,
Cc: Jonas Karlman ,
Cc: Jernej Skrabec ,
Cc: Mark Rutland ,
Cc: David Airlie
Cc: Daniel Vetter ,
Link: https://lore.kernel.org/lkml/20200108142132.GA4830@bogus/
Link: http://lkml.kernel.org/r/20200309215153.38824-1-lkundrak@v3.sk
Signed-off-by: Linus Torvalds -
The Gerrit Change-Id: entry is sometimes placed after a Signed-off-by:
line. When this occurs, the Gerrit warning is not currently emitted as
the first Signed-off-by: signature sets a flag to stop looking.Change the test to add a test for the --- patch separator and emit the
warning before any before the --- and also before any diff file name.Signed-off-by: Joe Perches
Signed-off-by: Andrew Morton
Tested-by: John Stultz
Link: http://lkml.kernel.org/r/2f6d5f8766fe7439a116c77ea8cc721a3f2d77a2.camel@perches.com
Signed-off-by: Linus Torvalds -
Linux kernel coding style requires a size of 8 characters for both TAB and
indentation, and such value is embedded as magic value allover the
checkpatch script.This makes hard to reuse the script by other projects with different
requirements in their coding style (e.g. OpenOCD [1] requires TAB size of
4 characters [2]).Replace the magic value 8 with a variable.
Add a command-line option "--tab-size" to let the user select a
TAB size value other than 8.[1] http://openocd.org/
[2] http://openocd.org/doc/doxygen/html/stylec.html#styleformatSigned-off-by: Antonio Borneo
Signed-off-by: Erik Ahlén
Signed-off-by: Spencer Oliver
Signed-off-by: Andrew Morton
Cc: Joe Perches
Link: http://lkml.kernel.org/r/20200122163852.124417-3-borneo.antonio@gmail.com
Signed-off-by: Linus Torvalds -
Commit 1574a29f8e76 ("checkpatch: allow multiple const * types") claims to
support repetition of pattern "const *", but it actually allows only one
extra instance.Check the following lines
int a(char const * const x[]);
int b(char const * const *x);
int c(char const * const * const x[]);
int d(char const * const * const *x);with command
./scripts/checkpatch.pl --show-types -f filename
to find that only the first line passes the test, while a warning
is triggered by the other 3 lines:WARNING:FUNCTION_ARGUMENTS: function definition argument
'char const * const' should also have an identifier nameThe reason is that the pattern match halts at the second asterisk in the
line, thus the remaining text starting with asterisk fails to match a
valid name for a variable.Fixed by replacing "?" (Match 1 or 0 times) with "{0,4}" (Match no more
than 4 times) in the regular expression. Fix also the similar test for
types in unusual order.Fixes: 1574a29f8e76 ("checkpatch: allow multiple const * types")
Signed-off-by: Antonio Borneo
Signed-off-by: Andrew Morton
Cc: Joe Perches
Link: http://lkml.kernel.org/r/20200122163852.124417-1-borneo.antonio@gmail.com
Signed-off-by: Linus Torvalds -
Fix spelling of "concatenation".
Don't use tab after space in indentation.Signed-off-by: Antonio Borneo
Signed-off-by: Andrew Morton
Cc: Joe Perches
Link: http://lkml.kernel.org/r/20200122163852.124417-2-borneo.antonio@gmail.com
Signed-off-by: Linus Torvalds -
commit 294f69e662d1 ("compiler_attributes.h: Add 'fallthrough' pseudo
keyword for switch/case use") added the pseudo keyword so add a test for
it to checkpatch.Warn on a patch or use --strict for files.
Signed-off-by: Joe Perches
Signed-off-by: Andrew Morton
Link: http://lkml.kernel.org/r/8b6c1b9031ab9f3cdebada06b8d46467f1492d68.camel@perches.com
Signed-off-by: Linus Torvalds -
In order to support the get-lore-mbox.py tool described in [1], I ran:
git format-patch --base= --cover-letter
... which generated a "base-commit: " tag at the end of the
cover letter. However, checkpatch.pl generated an error upon encounting
"base-commit:" in the cover letter:"ERROR: Please use git commit description style..."
... because it found the "commit" keyword, and failed to recognize that
it was part of the "base-commit" phrase, and as such, should not be
subjected to the same commit description style rules.Update checkpatch.pl to include a special case for "base-commit:" (at the
start of the line, possibly with some leading whitespace) so that that tag
no longer generates a checkpatch error.[1] https://lwn.net/Articles/811528/ "Better tools for kernel
developers"Suggested-by: Joe Perches
Signed-off-by: John Hubbard
Signed-off-by: Andrew Morton
Acked-by: Joe Perches
Cc: Andy Whitcroft
Cc: Konstantin Ryabitsev
Cc: Jonathan Corbet
Link: http://lkml.kernel.org/r/20200213055004.69235-2-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds -
This adds a warning when a YAML file is lacking a SPDX header on first
line, or it uses incorrect commenting style.Currently the only YAML files in the tree are Devicetree binding
documents.Signed-off-by: Lubomir Rintel
Signed-off-by: Andrew Morton
Acked-by: Joe Perches
Cc: Rob Herring
Link: http://lkml.kernel.org/r/20200129123356.388669-1-lkundrak@v3.sk
Signed-off-by: Linus Torvalds -
About 2% of the last 100K commits have email addresses that include an
RFC2822 compliant comment like:Peter Zijlstra (Intel)
checkpatch currently does a comparison of the complete name and address to
the submitted author to determine if the author has signed-off and emits a
warning if the exact email names and addresses do not match.Unfortunately, the author email address can be written without the comment
like:Peter Zijlstra
Add logic to compare the comment stripped email addresses to avoid this
warning.Reported-by: Peter Zijlstra
Signed-off-by: Joe Perches
Signed-off-by: Andrew Morton
Acked-by: Peter Zijlstra (Intel)
Link: http://lkml.kernel.org/r/ebaa2f7c8f94e25520981945cddcc1982e70e072.camel@perches.com
Signed-off-by: Linus Torvalds -
Clang warns:
../lib/dynamic_debug.c:1034:24: warning: array comparison always
evaluates to false [-Wtautological-compare]
if (__start___verbose == __stop___verbose) {
^
1 warning generated.These are not true arrays, they are linker defined symbols, which are just
addresses. Using the address of operator silences the warning and does
not change the resulting assembly with either clang/ld.lld or gcc/ld
(tested with diff + objdump -Dr).Suggested-by: Nick Desaulniers
Signed-off-by: Nathan Chancellor
Signed-off-by: Andrew Morton
Acked-by: Jason Baron
Link: https://github.com/ClangBuiltLinux/linux/issues/894
Link: http://lkml.kernel.org/r/20200220051320.10739-1-natechancellor@gmail.com
Signed-off-by: Linus Torvalds -
GENMASK() and GENMASK_ULL() are supposed to be called with the high bit as
the first argument and the low bit as the second argument. Mixing them
will return a mask with zero bits set.Recent commits show getting this wrong is not uncommon, see e.g. commit
aa4c0c9091b0 ("net: stmmac: Fix misuses of GENMASK macro") and commit
9bdd7bb3a844 ("clocksource/drivers/npcm: Fix misuse of GENMASK macro").To prevent such mistakes from appearing again, add compile time sanity
checking to the arguments of GENMASK() and GENMASK_ULL(). If both
arguments are known at compile time, and the low bit is higher than the
high bit, break the build to detect the mistake immediately.Since GENMASK() is used in declarations, BUILD_BUG_ON_ZERO() must be used
instead of BUILD_BUG_ON().__builtin_constant_p does not evaluate is argument, it only checks if it
is a constant or not at compile time, and __builtin_choose_expr does not
evaluate the expression that is not chosen. Therefore, GENMASK(x++, 0)
does only evaluate x++ once.Commit 95b980d62d52 ("linux/bits.h: make BIT(), GENMASK(), and friends
available in assembly") made the macros in linux/bits.h available in
assembly. Since BUILD_BUG_OR_ZERO() is not asm compatible, disable the
checks if the file is included in an asm file.Due to bugs in GCC versions before 4.9 [0], disable the check if building
with a too old GCC compiler.[0]: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=19449
Signed-off-by: Rikard Falkeborn
Signed-off-by: Andrew Morton
Reviewed-by: Masahiro Yamada
Reviewed-by: Kees Cook
Cc: Borislav Petkov
Cc: Geert Uytterhoeven
Cc: Haren Myneni
Cc: Joe Perches
Cc: Johannes Berg
Cc: lkml
Cc: Ingo Molnar
Cc: Thomas Gleixner
Link: http://lkml.kernel.org/r/20200308193954.2372399-1-rikard.falkeborn@gmail.com
Signed-off-by: Linus Torvalds -
The "info" pointer has already been dereferenced so checking here is too
late. Fortunately, we never pass NULL pointers to the
test_kmod_put_module() function so the test can simply be removed.Signed-off-by: Dan Carpenter
Signed-off-by: Andrew Morton
Acked-by: Luis Chamberlain
Link: http://lkml.kernel.org/r/20200228092452.vwkhthsn77nrxdy6@kili.mountain
Signed-off-by: Linus Torvalds -
Leave blank space between the right-hand and left-hand side of the
assignment to meet the kernel coding style better.Signed-off-by: chenqiwu
Signed-off-by: Andrew Morton
Reviewed-by: Michel Lespinasse
Link: http://lkml.kernel.org/r/1582621140-25850-1-git-send-email-qiwuchen55@gmail.com
Signed-off-by: Linus Torvalds -
Commit 30544ed5de43 ("lib/bitmap: introduce bitmap_replace() helper")
introduced some new test cases to the test_bitmap.c module. Among these
it also introduced an (unused) definition. Let's make use of
EXP2_IN_BITS.Reported-by: Alex Shi
Signed-off-by: Andy Shevchenko
Signed-off-by: Andrew Morton
Reviewed-by: Alex Shi
Link: http://lkml.kernel.org/r/20200121151847.75223-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Linus Torvalds -
"vm_committed_as.count" could be accessed concurrently as reported by
KCSAN,BUG: KCSAN: data-race in __vm_enough_memory / percpu_counter_add_batch
write to 0xffffffff9451c538 of 8 bytes by task 65879 on cpu 35:
percpu_counter_add_batch+0x83/0xd0
percpu_counter_add_batch at lib/percpu_counter.c:91
__vm_enough_memory+0xb9/0x260
dup_mm+0x3a4/0x8f0
copy_process+0x2458/0x3240
_do_fork+0xaa/0x9f0
__do_sys_clone+0x125/0x160
__x64_sys_clone+0x70/0x90
do_syscall_64+0x91/0xb05
entry_SYSCALL_64_after_hwframe+0x49/0xberead to 0xffffffff9451c538 of 8 bytes by task 66773 on cpu 19:
__vm_enough_memory+0x199/0x260
percpu_counter_read_positive at include/linux/percpu_counter.h:81
(inlined by) __vm_enough_memory at mm/util.c:839
mmap_region+0x1b2/0xa10
do_mmap+0x45c/0x700
vm_mmap_pgoff+0xc0/0x130
ksys_mmap_pgoff+0x6e/0x300
__x64_sys_mmap+0x33/0x40
do_syscall_64+0x91/0xb05
entry_SYSCALL_64_after_hwframe+0x49/0xbeThe read is outside percpu_counter::lock critical section which results in
a data race. Fix it by adding a READ_ONCE() in
percpu_counter_read_positive() which could also service as the existing
compiler memory barrier.Signed-off-by: Qian Cai
Signed-off-by: Andrew Morton
Acked-by: Marco Elver
Link: http://lkml.kernel.org/r/1582302724-2804-1-git-send-email-cai@lca.pw
Signed-off-by: Linus Torvalds -
filter_irq_stacks() can be used by other tools (e.g. KMSAN), so it needs
to be moved to a common location. lib/stackdepot.c seems a good place, as
filter_irq_stacks() is usually applied to the output of
stack_trace_save().This patch has been previously mailed as part of KMSAN RFC patch series.
[glider@google.co: nds32: linker script: add SOFTIRQENTRY_TEXT\
Link: http://lkml.kernel.org/r/20200311121002.241430-1-glider@google.com
[glider@google.com: add IRQENTRY_TEXT and SOFTIRQENTRY_TEXT to linker script]
Link: http://lkml.kernel.org/r/20200311121124.243352-1-glider@google.com
Signed-off-by: Alexander Potapenko
Signed-off-by: Andrew Morton
Cc: Vegard Nossum
Cc: Dmitry Vyukov
Cc: Marco Elver
Cc: Andrey Konovalov
Cc: Andrey Ryabinin
Cc: Arnd Bergmann
Cc: Sergey Senozhatsky
Link: http://lkml.kernel.org/r/20200220141916.55455-3-glider@google.com
Signed-off-by: Linus Torvalds -
Clang may replace stackdepot_memcmp() with a call to instrumented bcmp(),
which is exactly what we wanted to avoid creating stackdepot_memcmp().
Building the file with -fno-builtin prevents such optimizations.This patch has been previously mailed as part of KMSAN RFC patch series.
Signed-off-by: Alexander Potapenko
Signed-off-by: Andrew Morton
Cc: Vegard Nossum
Cc: Dmitry Vyukov
Cc: Marco Elver
Cc: Andrey Konovalov
Cc: Sergey Senozhatsky
Cc: Arnd Bergmann
Cc: Andrey Ryabinin
Link: http://lkml.kernel.org/r/20200220141916.55455-2-glider@google.com
Signed-off-by: Linus Torvalds -
Avoid crashes on corrupted stack ids. Despite stack ID corruption may
indicate other bugs in the program, we'd better fail gracefully on such
IDs instead of crashing the kernel.This patch has been previously mailed as part of KMSAN RFC patch series.
Link: http://lkml.kernel.org/r/20200220141916.55455-1-glider@google.com
Signed-off-by: Alexander Potapenko
Cc: Vegard Nossum
Cc: Dmitry Vyukov
Cc: Marco Elver
Cc: Andrey Konovalov
Cc: Andrey Ryabinin
Cc: Arnd Bergmann
Cc: Sergey Senozhatsky
From: Dan Carpenter
Subject: lib/stackdepot.c: fix a condition in stack_depot_fetch()We should check for a NULL pointer first before adding the offset.
Otherwise if the pointer is NULL and the offset is non-zero, it will lead
to an Oops.Fixes: d45048e65a59 ("lib/stackdepot.c: check depot_index before accessing the stack slab")
Signed-off-by: Dan Carpenter
Signed-off-by: Andrew Morton
Acked-by: Alexander Potapenko
Link: http://lkml.kernel.org/r/20200312113006.GA20562@mwanda
Signed-off-by: Linus Torvalds -
The tests for initializing a variable defined between a switch statement's
test and its first "case" statement are currently not initialized in
Clang[1] nor the proposed auto-initialization feature in GCC.We should retain the test (so that we can evaluate compiler fixes), but
mark it as an "expected fail". The rest of the kernel source will be
adjusted to avoid this corner case.Also disable -Wswitch-unreachable for the test so that the intentionally
broken code won't trigger warnings for GCC (nor future Clang) when
initialization happens this unhandled place.[1] https://bugs.llvm.org/show_bug.cgi?id=44916
Suggested-by: Alexander Potapenko
Signed-off-by: Kees Cook
Signed-off-by: Andrew Morton
Cc: Jann Horn
Cc: Ard Biesheuvel
Link: http://lkml.kernel.org/r/202002191358.2897A07C6@keescook
Signed-off-by: Linus Torvalds -
Add the missing closing parenthesis to the description for the to_buffer
parameter of sg_copy_buffer().Signed-off-by: Geert Uytterhoeven
Signed-off-by: Andrew Morton
Cc: Akinobu Mita -
The current codebase makes use of the zero-length array language extension
to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:struct foo {
int stuff;
struct boo array[];
};By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertenly introduced[3] to the codebase from now on.This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")Signed-off-by: Gustavo A. R. Silva
Signed-off-by: Andrew Morton
Link: http://lkml.kernel.org/r/20200211205948.GA26459@embeddedor
Signed-off-by: Linus Torvalds -
The current codebase makes use of the zero-length array language extension
to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:struct foo {
int stuff;
struct boo array[];
};By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertenly introduced[3] to the codebase from now on.This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")Signed-off-by: Gustavo A. R. Silva
Signed-off-by: Andrew Morton
Link: http://lkml.kernel.org/r/20200211205813.GA25602@embeddedor
Signed-off-by: Linus Torvalds -
The current codebase makes use of the zero-length array language extension
to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:struct foo {
int stuff;
struct boo array[];
};By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertenly introduced[3] to the codebase from now on.This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")Signed-off-by: Gustavo A. R. Silva
Signed-off-by: Andrew Morton
Link: http://lkml.kernel.org/r/20200211205620.GA24694@embeddedor
Signed-off-by: Linus Torvalds -
The current codebase makes use of the zero-length array language extension
to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:struct foo {
int stuff;
struct boo array[];
};By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertenly introduced[3] to the codebase from now on.This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")Signed-off-by: Gustavo A. R. Silva
Signed-off-by: Andrew Morton
Link: http://lkml.kernel.org/r/20200211205119.GA21234@embeddedor
Signed-off-by: Linus Torvalds -
file_path= defines file or directory to open
lock_inode=Y set lock_rwsem_ptr to inode->i_rwsem
lock_mapping=Y set lock_rwsem_ptr to mapping->i_mmap_rwsem
lock_sb_umount=Y set lock_rwsem_ptr to sb->s_umountThis gives safe and simple way to see how system reacts to contention of
common vfs locks and how syscalls depend on them directly or indirectly.For example to block s_umount for 60 seconds:
# modprobe test_lockup file_path=. lock_sb_umount time_secs=60 state=SThis is useful for checking/testing scalability issues like this:
https://lore.kernel.org/lkml/158497590858.7371.9311902565121473436.stgit@buzz/Signed-off-by: Konstantin Khlebnikov
Signed-off-by: Andrew Morton
Cc: Colin Ian King
Cc: Greg Kroah-Hartman
Cc: Guenter Roeck
Cc: Kees Cook
Cc: Peter Zijlstra
Cc: Petr Mladek
Cc: Sasha Levin
Cc: Sergey Senozhatsky
Cc: Steven Rostedt
Link: http://lkml.kernel.org/r/158498153964.5621.83061779039255681.stgit@buzz
Signed-off-by: Linus Torvalds -
There is a spelling mistake in a pr_notice message. Fix it.
Signed-off-by: Colin Ian King
Signed-off-by: Andrew Morton
Cc: Greg Kroah-Hartman
Cc: Guenter Roeck
Cc: Kees Cook
Cc: Konstantin Khlebnikov
Cc: Peter Zijlstra
Cc: Petr Mladek
Cc: Sasha Levin
Cc: Sergey Senozhatsky
Cc: Steven Rostedt
Link: http://lkml.kernel.org/r/20200221155145.79522-1-colin.king@canonical.com
Signed-off-by: Linus Torvalds -
CONFIG_TEST_LOCKUP=m adds module "test_lockup" that helps to make sure
that watchdogs and lockup detectors are working properly.Depending on module parameters test_lockup could emulate soft or hard
lockup, "hung task", hold arbitrary lock, allocate bunch of pages.Also it could generate series of lockups with cooling-down periods, in
this way it could be used as "ping" for locks or page allocator. Loop
checks signals between iteration thus could be stopped by ^C.# modinfo test_lockup
...
parm: time_secs:lockup time in seconds, default 0 (uint)
parm: time_nsecs:nanoseconds part of lockup time, default 0 (uint)
parm: cooldown_secs:cooldown time between iterations in seconds, default 0 (uint)
parm: cooldown_nsecs:nanoseconds part of cooldown, default 0 (uint)
parm: iterations:lockup iterations, default 1 (uint)
parm: all_cpus:trigger lockup at all cpus at once (bool)
parm: state:wait in 'R' running (default), 'D' uninterruptible, 'K' killable, 'S' interruptible state (charp)
parm: use_hrtimer:use high-resolution timer for sleeping (bool)
parm: iowait:account sleep time as iowait (bool)
parm: lock_read:lock read-write locks for read (bool)
parm: lock_single:acquire locks only at one cpu (bool)
parm: reacquire_locks:release and reacquire locks/irq/preempt between iterations (bool)
parm: touch_softlockup:touch soft-lockup watchdog between iterations (bool)
parm: touch_hardlockup:touch hard-lockup watchdog between iterations (bool)
parm: call_cond_resched:call cond_resched() between iterations (bool)
parm: measure_lock_wait:measure lock wait time (bool)
parm: lock_wait_threshold:print lock wait time longer than this in nanoseconds, default off (ulong)
parm: disable_irq:disable interrupts: generate hard-lockups (bool)
parm: disable_softirq:disable bottom-half irq handlers (bool)
parm: disable_preempt:disable preemption: generate soft-lockups (bool)
parm: lock_rcu:grab rcu_read_lock: generate rcu stalls (bool)
parm: lock_mmap_sem:lock mm->mmap_sem: block procfs interfaces (bool)
parm: lock_rwsem_ptr:lock rw_semaphore at address (ulong)
parm: lock_mutex_ptr:lock mutex at address (ulong)
parm: lock_spinlock_ptr:lock spinlock at address (ulong)
parm: lock_rwlock_ptr:lock rwlock at address (ulong)
parm: alloc_pages_nr:allocate and free pages under locks (uint)
parm: alloc_pages_order:page order to allocate (uint)
parm: alloc_pages_gfp:allocate pages with this gfp_mask, default GFP_KERNEL (uint)
parm: alloc_pages_atomic:allocate pages with GFP_ATOMIC (bool)
parm: reallocate_pages:free and allocate pages between iterations (bool)Parameters for locking by address are unsafe and taints kernel. With
CONFIG_DEBUG_SPINLOCK=y they at least check magics for embedded spinlocks.Examples:
task hang in D-state:
modprobe test_lockup time_secs=1 iterations=60 state=Dtask hang in io-wait D-state:
modprobe test_lockup time_secs=1 iterations=60 state=D iowaitsoftlockup:
modprobe test_lockup time_secs=1 iterations=60 state=Rhardlockup:
modprobe test_lockup time_secs=1 iterations=60 state=R disable_irqsystem-wide hardlockup:
modprobe test_lockup time_secs=1 iterations=60 state=R \
disable_irq all_cpusrcu stall:
modprobe test_lockup time_secs=1 iterations=60 state=R \
lock_rcu touch_softlockuplock mmap_sem / block procfs interfaces:
modprobe test_lockup time_secs=1 iterations=60 state=S lock_mmap_semlock tasklist_lock for read / block forks:
TASKLIST_LOCK=$(awk '$3 == "tasklist_lock" {print "0x"$1}' /proc/kallsyms)
modprobe test_lockup time_secs=1 iterations=60 state=R \
disable_irq lock_read lock_rwlock_ptr=$TASKLIST_LOCKlock namespace_sem / block vfs mount operations:
NAMESPACE_SEM=$(awk '$3 == "namespace_sem" {print "0x"$1}' /proc/kallsyms)
modprobe test_lockup time_secs=1 iterations=60 state=S \
lock_rwsem_ptr=$NAMESPACE_SEMlock cgroup mutex / block cgroup operations:
CGROUP_MUTEX=$(awk '$3 == "cgroup_mutex" {print "0x"$1}' /proc/kallsyms)
modprobe test_lockup time_secs=1 iterations=60 state=S \
lock_mutex_ptr=$CGROUP_MUTEXping cgroup_mutex every second and measure maximum lock wait time:
modprobe test_lockup cooldown_secs=1 iterations=60 state=S \
lock_mutex_ptr=$CGROUP_MUTEX reacquire_locks measure_lock_wait[linux@roeck-us.net: rename disable_irq to fix build error]
Link: http://lkml.kernel.org/r/20200317133614.23152-1-linux@roeck-us.net
Signed-off-by: Konstantin Khlebnikov
Signed-off-by: Guenter Roeck
Signed-off-by: Andrew Morton
Cc: Sasha Levin
Cc: Petr Mladek
Cc: Kees Cook
Cc: Peter Zijlstra
Cc: Greg Kroah-Hartman
Cc: Steven Rostedt
Cc: Sergey Senozhatsky
Cc: Dmitry Monakhov
Cc: Guenter Roeck
Link: http://lkml.kernel.org/r/158132859146.2797.525923171323227836.stgit@buzz
Signed-off-by: Linus Torvalds -
With CONFIG_CC_OPTIMIZE_FOR_SIZE, objtool reports:
drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: i915_gem_execbuffer2_ioctl()+0x5b7: call to gen8_canonical_addr() with UACCESS enabled
This means i915_gem_execbuffer2_ioctl() is calling gen8_canonical_addr()
from the user_access_begin/end critical region (i.e, with SMAP disabled).While it's probably harmless in this case, in general we like to avoid
extra function calls in SMAP-disabled regions because it can open up
inadvertent security holes.Fix the warning by changing the sign extension helpers to __always_inline.
This convinces GCC to inline gen8_canonical_addr().The sign extension functions are trivial anyway, so it makes sense to
always inline them. With my test optimize-for-size-based config, this
actually shrinks the text size of i915_gem_execbuffer.o by 45 bytes -- and
no change for vmlinux.Reported-by: Randy Dunlap
Signed-off-by: Josh Poimboeuf
Signed-off-by: Andrew Morton
Cc: Peter Zijlstra
Cc: Al Viro
Cc: Chris Wilson
Link: http://lkml.kernel.org/r/740179324b2b18b750b16295c48357f00b5fa9ed.1582982020.git.jpoimboe@redhat.com
Signed-off-by: Linus Torvalds -
The MAINTAINERS file header has never shown a preferred order for the
section entries but scripts/parse-maintainers.pl added a preferred order
with commit 61f741645a35 ("parse-maintainers: Add section pattern
sorting")Commit 5cdbec108fd2 ("parse-maintainers: Do not sort section content by
default") changed the preferred order to be a bit more sensible.Update the MAINTAINERS section description block to use this preferred
section entry ordering.Add a slightly better description for the N: entry too.
Signed-off-by: Joe Perches
Signed-off-by: Andrew Morton
Reviewed-by: Andy Shevchenko
Link: http://lkml.kernel.org/r/5aa5aad6fb1678230c260337dc066cd449a2bf32.camel@perches.com
Signed-off-by: Linus Torvalds -
compiletime_assert() uses __LINE__ to create a unique function name. This
means that if you have more than one BUILD_BUG_ON() in the same source
line (which can happen if they appear e.g. in a macro), then the error
message from the compiler might output the wrong condition.For this source file:
#include
#define macro() \
BUILD_BUG_ON(1); \
BUILD_BUG_ON(0);void foo()
{
macro();
}gcc would output:
./include/linux/compiler.h:350:38: error: call to `__compiletime_assert_9' declared with attribute error: BUILD_BUG_ON failed: 0
_compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)However, it was not the BUILD_BUG_ON(0) that failed, so it should say 1
instead of 0. With this patch, we use __COUNTER__ instead of __LINE__, so
each BUILD_BUG_ON() gets a different function name and the correct
condition is printed:./include/linux/compiler.h:350:38: error: call to `__compiletime_assert_0' declared with attribute error: BUILD_BUG_ON failed: 1
_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)Signed-off-by: Vegard Nossum
Signed-off-by: Andrew Morton
Reviewed-by: Masahiro Yamada
Reviewed-by: Daniel Santos
Cc: Rasmus Villemoes
Cc: Ian Abbott
Cc: Joe Perches
Link: http://lkml.kernel.org/r/20200331112637.25047-1-vegard.nossum@oracle.com
Signed-off-by: Linus Torvalds
