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This isn't a reliable mechanism to tell if we have task_work pending, we
really should be looking at whether we have any items queued. This is
problematic if forward progress is gated on running said task_work. One
such example is reading from a pipe, where the write side has been closed
right before the read is started. The fput() of the file queues TWA_RESUME
task_work, and we need that task_work to be run before ->release() is
called for the pipe. If ->release() isn't called, then the read will sit
forever waiting on data that will never arise.
Fix this by io_run_task_work() so it checks if we have task_work pending
rather than rely on TIF_NOTIFY_SIGNAL for that. The latter obviously
doesn't work for task_work that is queued without TWA_SIGNAL.
Reported-by: Christiano Haesbaert <haesbaert@haesbaert.org>
Cc: stable@vger.kernel.org
Link: https://github.com/axboe/liburing/issues/665
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Pull coredump fix from Al Viro:
"Fix for breakage in dump_user_range()"
* tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
[coredump] don't use __kernel_write() on kmap_local_page()
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No conflicts.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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In the probe path, dev_err() can be replaced with dev_err_probe()
which will check if error code is -EPROBE_DEFER and prints the
error name. It also sets the defer probe reason which can be
checked later through debugfs.
Signed-off-by: Yuan Can <yuancan@huawei.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220929015503.17301-3-yuancan@huawei.com
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In the probe path, dev_err() can be replaced with dev_err_probe()
which will check if error code is -EPROBE_DEFER and prints the
error name. It also sets the defer probe reason which can be
checked later through debugfs.
Signed-off-by: Yuan Can <yuancan@huawei.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220929015503.17301-2-yuancan@huawei.com
Link: https://patchwork.freedesktop.org/patch/msgid/20220929015503.17301-2-yuancan@huawei.com
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This uses l2cap_chan_hold_unless_zero() after calling
__l2cap_get_chan_blah() to prevent the following trace:
Bluetooth: l2cap_core.c:static void l2cap_chan_destroy(struct kref
*kref)
Bluetooth: chan 0000000023c4974d
Bluetooth: parent 00000000ae861c08
==================================================================
BUG: KASAN: use-after-free in __mutex_waiter_is_first
kernel/locking/mutex.c:191 [inline]
BUG: KASAN: use-after-free in __mutex_lock_common
kernel/locking/mutex.c:671 [inline]
BUG: KASAN: use-after-free in __mutex_lock+0x278/0x400
kernel/locking/mutex.c:729
Read of size 8 at addr ffff888006a49b08 by task kworker/u3:2/389
Link: https://lore.kernel.org/lkml/20220622082716.478486-1-lee.jones@linaro.org
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sungwoo Kim <iam@sung-woo.kim>
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checkpatch does not point out that VM_BUG_ON() and friends should be
avoided, however, Linus notes:
VM_BUG_ON() has the exact same semantics as BUG_ON. It is literally
no different, the only difference is "we can make the code smaller
because these are less important". [1]
So let's warn on VM_BUG_ON() and other BUG variants as well. While at it,
make it clearer that the kernel really shouldn't be crashed.
As there are some subsystem BUG macros that actually don't end up crashing
the kernel -- for example, KVM_BUG_ON() -- exclude these manually.
[1] https://lore.kernel.org/r/CAHk-=wg40EAZofO16Eviaj7mfqDhZ2gVEbvfsMf6gYzspRjYvw@mail.gmail.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20220923113426.52871-3-david@redhat.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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Linus notes [1] that the introduction of new code that uses VM_BUG_ON()
is just as bad as BUG_ON(), because it will crash the kernel on
distributions that enable CONFIG_DEBUG_VM (like Fedora):
VM_BUG_ON() has the exact same semantics as BUG_ON. It is literally
no different, the only difference is "we can make the code smaller
because these are less important". [2]
This resulted in a more generic discussion about usage of BUG() and
friends. While there might be corner cases that still deserve a BUG_ON(),
most BUG_ON() cases should simply use WARN_ON_ONCE() and implement a
recovery path if reasonable:
The only possible case where BUG_ON can validly be used is "I have
some fundamental data corruption and cannot possibly return an
error". [2]
As a very good approximation is the general rule:
"absolutely no new BUG_ON() calls _ever_" [2]
... not even if something really shouldn't ever happen and is merely for
documenting that an invariant always has to hold. However, there are sill
exceptions where BUG_ON() may be used:
If you have a "this is major internal corruption, there's no way we can
continue", then BUG_ON() is appropriate. [3]
There is only one good BUG_ON():
Now, that said, there is one very valid sub-form of BUG_ON():
BUILD_BUG_ON() is absolutely 100% fine. [2]
While WARN will also crash the machine with panic_on_warn set, that's
exactly to be expected:
So we have two very different cases: the "virtual machine with good
logging where a dead machine is fine" - use 'panic_on_warn'. And
the actual real hardware with real drivers, running real loads by
users. [4]
The basic idea is that warnings will similarly get reported by users
and be found during testing. However, in contrast to a BUG(), there is a
way to actually influence the expected behavior (e.g., panic_on_warn)
and to eventually keep the machine alive to extract some debug info.
Ingo notes that not all WARN_ON_ONCE cases need recovery. If we don't ever
expect this code to trigger in any case, recovery code is not really
helpful.
I'd prefer to keep all these warnings 'simple' - i.e. no attempted
recovery & control flow, unless we ever expect these to trigger.
[5]
There have been different rules floating around that were never properly
documented. Let's try to clarify.
[1] https://lkml.kernel.org/r/CAHk-=wiEAH+ojSpAgx_Ep=NKPWHU8AdO3V56BXcCsU97oYJ1EA@mail.gmail.com
[2] https://lore.kernel.org/r/CAHk-=wg40EAZofO16Eviaj7mfqDhZ2gVEbvfsMf6gYzspRjYvw@mail.gmail.com
[3] https://lkml.kernel.org/r/CAHk-=wit-DmhMfQErY29JSPjFgebx_Ld+pnerc4J2Ag990WwAA@mail.gmail.com
[4] https://lore.kernel.org/r/CAHk-=wgF7K2gSSpy=m_=K3Nov4zaceUX9puQf1TjkTJLA2XC_g@mail.gmail.com
[5] https://lore.kernel.org/r/YwIW+mVeZoTOxn%2F4@gmail.com
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20220923113426.52871-2-david@redhat.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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Add missing devm_request_free_mem_region() to devres.rst.
It's introduced by commit 0092908d16c6 ("mm: factor out a
devm_request_free_mem_region helper").
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20220927080215.1359979-1-yangyingliang@huawei.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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devm_irq_sim_init() has been changed to devm_irq_domain_create_sim()
in commit 337cbeb2c13e ("genirq/irq_sim: Simplify the API").
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20220927083819.12484-1-yangyingliang@huawei.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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Since commit b3ac04132c4b ("mm/rmap: Turn page_referenced() into
folio_referenced()") the page_referenced function name was modified,
so fix it up to use the correct one.
Signed-off-by: Vernon Yang <vernon2gm@gmail.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Link: https://lore.kernel.org/r/20220926152032.74621-1-vernon2gm@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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The Code of Conduct interpretation does not reflect the current
practices of the CoC committee or the TAB. Update the documentation
to remove references to initial committees and boot strap periods
since it is past that time, and note that the this document
does serve as the documentation for the CoC committee processes.
Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220926211149.2278214-1-kristen@linux.intel.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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Now that building html docs with math expressions does not need texlive
packages, remove the note on the requirement in the "Sphinx Install"
section.
Instead, add sections of "Math Expressions in HTML" and "Choice of Math
Renderer".
Describe the effect of setting SPHINX_IMGMATH in the latter section.
Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/a67e3279-6bc7-ee2c-2b49-9275252460b0@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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Bring the description on when to use the Reported-by: tag found in
Documentation/process/5.Posting.rst more in line with the description in
Documentation/process/submitting-patches.rst: before this change the two
were contradicting each other, as the latter is way more permissive and
only states '[...] if the bug was reported in private, then ask for
permission first before using the Reported-by tag.'
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Link: https://lore.kernel.org/r/2fc7162dfb76e04da5ea903c9c170d913e735dad.1664372256.git.linux@leemhuis.info
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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After commit 22471e1313f2 ("kconfig: use a menu in arch/Kconfig to reduce
clutter"), the location of Kprobes is under "General architecture-dependent
options" rather than "General setup".
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Fixes: 22471e1313f2 ("kconfig: use a menu in arch/Kconfig to reduce clutter")
Link: https://lore.kernel.org/r/1663322106-12178-1-git-send-email-yangtiezhu@loongson.cn
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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Enable sram on vcn_4_0_2
Signed-off-by: Sonny Jiang <sonny.jiang@amd.com>
Reviewed-by: James Zhu <James.Zhu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
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Enable VCN DPG on GC11_0_1
Signed-off-by: Sonny Jiang <sonny.jiang@amd.com>
Reviewed-by: James Zhu <James.Zhu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
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scripting engine
A brown paper bag where -Wno-error=deprecated-declarations was added
from compiler output when the right thing is to add
-Wno-deprecated-declarations, fix it.
Fixes: 4ee3c4da8b1b9c22 ("perf scripting python: Do not build fail on deprecation warnings")
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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The top-level index.rst file is the entry point for the kernel's
documentation, especially for readers of the HTML output. It is currently
a mess containing everything we thought to throw in there. Firefox says it
would require 26 pages of paper to print it. That is not a user-friendly
introduction.
This series aims to improve our documentation entry point with a focus on
rewriting index.rst. The result is, IMO, simpler and more approachable.
For anybody who wants to see the rendered results without building the
docs, have a look at:
https://static.lwn.net/kerneldoc/
This time around I've rendered the pages using the "Read The Docs" theme,
since that's what everybody will get by default. That theme ignores the
directives regarding the left column, so the results are not as good there.
I have a series proposing a default-theme change in the works, but that's a
separate topic.
This is only a beginning; I think this kind of organizational effort has to
be pushed down into the lower layers of the docs tree itself. But one has
to start somewhere.
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Readers looking for user-oriented information may benefit from it.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Reviewed-by: David Vernet <void@manifault.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20220927160559.97154-8-corbet@lwn.net
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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These files describe part of the core API, but have never been converted to
RST due to ... let's say local oppposition. So, create a set of
special-purpose wrappers to ..include these files into a separate page so
that they can be a part of the htmldocs build. Then link them into the
core-api manual and remove them from the "staging" dumping ground.
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Reviewed-by: David Vernet <void@manifault.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20220927160559.97154-7-corbet@lwn.net
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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This one file should not really be in the top-level documentation
directory. core-api/ may not be a perfect fit but seems to be best, so
move it there. Adjust a couple of internal document references to make
them location-independent, and point checkpatch.pl at the new location.
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Joe Perches <joe@perches.com>
Reviewed-by: David Vernet <void@manifault.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20220927160559.97154-6-corbet@lwn.net
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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There is some useless boilerplate text that was added by sphinx when this
file was first created; take it out.
Reviewed-by: David Vernet <void@manifault.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20220927160559.97154-5-corbet@lwn.net
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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Use the html_sidebars directive to get a more useful set of links in the
left column.
Unfortunately, this is a no-op with the default RTD theme, but others
observe it.
Reviewed-by: David Vernet <void@manifault.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20220927160559.97154-4-corbet@lwn.net
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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The front page is the entry point to the documentation, especially for
people who read it online. It's a big mess of everything we could think to
toss into it. Rewrite the page with an eye toward simplicity and making it
easy for readers to get going toward what they really want to find.
This is only a beginning, but it makes our docs more approachable than
before.
Acked-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: David Vernet <void@manifault.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20220927160559.97154-3-corbet@lwn.net
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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...otherwise Sphinx won't cooperate when trying to list it explicitly in
the top-level index.rst file
Reviewed-by: David Vernet <void@manifault.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20220927160559.97154-2-corbet@lwn.net
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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A clang 15 build reveal several unused-but-set variables, removing the
'foo' variable in tests/mmap-basic.o object to address one of those
cases.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20220929140514.226807-2-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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bison produced code
clang 15 now warns:
46 65.20 fedora:rawhide : FAIL clang version 15.0.0 (Fedora 15.0.0-3.fc38)
util/parse-events-bison.c:1401:9: error: variable 'parse_events_nerrs' set but not used [-Werror,-Wunused-but-set-variable]
int yynerrs = 0;
^
#define yynerrs parse_events_nerrs
^
1 error generated.
make[3]: *** [/git/perf-6.0.0-rc7/tools/build/Makefile.build:139: util] Error 2
Just ignore one more compiler warning for the bison generated C code.
Committer notes:
Older clangs don't know about -Wunused-but-set-variable, so we need to
add -Wno-unknown-warning-option to avoid this:
37 44.92 fedora:32 : FAIL clang version 10.0.1 (Fedora 10.0.1-3.fc32)
error: unknown warning option '-Wno-unused-but-set-variable'; did you mean '-Wno-unused-const-variable'? [-Werror,-Wunknown-warning-option]
make[3]: *** [/git/perf-6.0.0-rc7/tools/build/Makefile.build:139: util] Error 2
Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/lkml/20220929140514.226807-1-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Add Coresight to defconfig so that build errors are caught.
CONFIG_CORESIGHT_SOURCE_ETM4X is excluded because it depends on
CONFIG_PID_IN_CONTEXTIDR which has a performance cost.
Signed-off-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20220922142400.478815-2-james.clark@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Currently we treat any error when reading from the child as a failure and
don't read any more output from that child as a result. This ignores the
fact that it is valid for read() to return EINTR as the error code if there
is a signal pending so we could stop handling the output of children,
especially during exit when we will get some SIGCHLD signals delivered to
us. Fix this by pulling the read handling out into a separate function
which returns a flag if reads should be continued and wrapping it in a
loop.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220921181345.618085-4-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Once we have started exiting the termination handler will have the same
effect as what we're already running so set the termination flag at that
point.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220921181345.618085-3-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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When fp-stress gets a termination signal it sets a flag telling itself to
exit and sends a termination signal to all the children. If the flag is set
then don't bother repeating this process, it isn't going to accomplish
anything other than consume CPU time which can be an issue when running in
emulation.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220921181345.618085-2-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Add missing __init/__exit annotations to module init/exit funcs.
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Link: https://lore.kernel.org/r/20220911034747.132098-1-xiujianfeng@huawei.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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We can't call these off the kiocb completion as that might be off
soft/hard irq context. Defer the calls to when we process the
task_work for this request. That avoids valid complaints like:
stack backtrace:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.0.0-rc6-syzkaller-00321-g105a36f3694e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_usage_bug kernel/locking/lockdep.c:3961 [inline]
valid_state kernel/locking/lockdep.c:3973 [inline]
mark_lock_irq kernel/locking/lockdep.c:4176 [inline]
mark_lock.part.0.cold+0x18/0xd8 kernel/locking/lockdep.c:4632
mark_lock kernel/locking/lockdep.c:4596 [inline]
mark_usage kernel/locking/lockdep.c:4527 [inline]
__lock_acquire+0x11d9/0x56d0 kernel/locking/lockdep.c:5007
lock_acquire kernel/locking/lockdep.c:5666 [inline]
lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631
__fs_reclaim_acquire mm/page_alloc.c:4674 [inline]
fs_reclaim_acquire+0x115/0x160 mm/page_alloc.c:4688
might_alloc include/linux/sched/mm.h:271 [inline]
slab_pre_alloc_hook mm/slab.h:700 [inline]
slab_alloc mm/slab.c:3278 [inline]
__kmem_cache_alloc_lru mm/slab.c:3471 [inline]
kmem_cache_alloc+0x39/0x520 mm/slab.c:3491
fanotify_alloc_fid_event fs/notify/fanotify/fanotify.c:580 [inline]
fanotify_alloc_event fs/notify/fanotify/fanotify.c:813 [inline]
fanotify_handle_event+0x1130/0x3f40 fs/notify/fanotify/fanotify.c:948
send_to_group fs/notify/fsnotify.c:360 [inline]
fsnotify+0xafb/0x1680 fs/notify/fsnotify.c:570
__fsnotify_parent+0x62f/0xa60 fs/notify/fsnotify.c:230
fsnotify_parent include/linux/fsnotify.h:77 [inline]
fsnotify_file include/linux/fsnotify.h:99 [inline]
fsnotify_access include/linux/fsnotify.h:309 [inline]
__io_complete_rw_common+0x485/0x720 io_uring/rw.c:195
io_complete_rw+0x1a/0x1f0 io_uring/rw.c:228
iomap_dio_complete_work fs/iomap/direct-io.c:144 [inline]
iomap_dio_bio_end_io+0x438/0x5e0 fs/iomap/direct-io.c:178
bio_endio+0x5f9/0x780 block/bio.c:1564
req_bio_endio block/blk-mq.c:695 [inline]
blk_update_request+0x3fc/0x1300 block/blk-mq.c:825
scsi_end_request+0x7a/0x9a0 drivers/scsi/scsi_lib.c:541
scsi_io_completion+0x173/0x1f70 drivers/scsi/scsi_lib.c:971
scsi_complete+0x122/0x3b0 drivers/scsi/scsi_lib.c:1438
blk_complete_reqs+0xad/0xe0 block/blk-mq.c:1022
__do_softirq+0x1d3/0x9c6 kernel/softirq.c:571
invoke_softirq kernel/softirq.c:445 [inline]
__irq_exit_rcu+0x123/0x180 kernel/softirq.c:650
irq_exit_rcu+0x5/0x20 kernel/softirq.c:662
common_interrupt+0xa9/0xc0 arch/x86/kernel/irq.c:240
Fixes: f63cf5192fe3 ("io_uring: ensure that fsnotify is always called")
Link: https://lore.kernel.org/all/20220929135627.ykivmdks2w5vzrwg@quack3/
Reported-by: syzbot+dfcc5f4da15868df7d4d@syzkaller.appspotmail.com
Reported-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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KFENCE requires linear map to be mapped at page granularity, so that it
is possible to protect/unprotect single pages, just like with
rodata_full and DEBUG_PAGEALLOC.
Instead of repating
can_set_direct_map() || IS_ENABLED(CONFIG_KFENCE)
make can_set_direct_map() handle the KFENCE case.
This also prevents potential false positives in kernel_page_present()
that may return true for non-present page if CONFIG_KFENCE is enabled.
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/20220921074841.382615-1-rppt@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Li Huafei reports that mcount-based ftrace with module PLTs was broken
by commit:
a6253579977e4c6f ("arm64: ftrace: consistently handle PLTs.")
When a module PLTs are used and a module is loaded sufficiently far away
from the kernel, we'll create PLTs for any branches which are
out-of-range. These are separate from the special ftrace trampoline
PLTs, which the module PLT code doesn't directly manipulate.
When mcount is in use this is a problem, as each mcount callsite in a
module will be initialized to point to a module PLT, but since commit
a6253579977e4c6f ftrace_make_nop() will assume that the callsite has
been initialized to point to the special ftrace trampoline PLT, and
ftrace_find_callable_addr() rejects other cases.
This means that when ftrace tries to initialize a callsite via
ftrace_make_nop(), the call to ftrace_find_callable_addr() will find
that the `_mcount` stub is out-of-range and is not handled by the ftrace
PLT, resulting in a splat:
| ftrace_test: loading out-of-tree module taints kernel.
| ftrace: no module PLT for _mcount
| ------------[ ftrace bug ]------------
| ftrace failed to modify
| [<ffff800029180014>] 0xffff800029180014
| actual: 44:00:00:94
| Initializing ftrace call sites
| ftrace record flags: 2000000
| (0)
| expected tramp: ffff80000802eb3c
| ------------[ cut here ]------------
| WARNING: CPU: 3 PID: 157 at kernel/trace/ftrace.c:2120 ftrace_bug+0x94/0x270
| Modules linked in:
| CPU: 3 PID: 157 Comm: insmod Tainted: G O 6.0.0-rc6-00151-gcd722513a189-dirty #22
| Hardware name: linux,dummy-virt (DT)
| pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
| pc : ftrace_bug+0x94/0x270
| lr : ftrace_bug+0x21c/0x270
| sp : ffff80000b2bbaf0
| x29: ffff80000b2bbaf0 x28: 0000000000000000 x27: ffff0000c4d38000
| x26: 0000000000000001 x25: ffff800009d7e000 x24: ffff0000c4d86e00
| x23: 0000000002000000 x22: ffff80000a62b000 x21: ffff8000098ebea8
| x20: ffff0000c4d38000 x19: ffff80000aa24158 x18: ffffffffffffffff
| x17: 0000000000000000 x16: 0a0d2d2d2d2d2d2d x15: ffff800009aa9118
| x14: 0000000000000000 x13: 6333626532303830 x12: 3030303866666666
| x11: 203a706d61727420 x10: 6465746365707865 x9 : 3362653230383030
| x8 : c0000000ffffefff x7 : 0000000000017fe8 x6 : 000000000000bff4
| x5 : 0000000000057fa8 x4 : 0000000000000000 x3 : 0000000000000001
| x2 : ad2cb14bb5438900 x1 : 0000000000000000 x0 : 0000000000000022
| Call trace:
| ftrace_bug+0x94/0x270
| ftrace_process_locs+0x308/0x430
| ftrace_module_init+0x44/0x60
| load_module+0x15b4/0x1ce8
| __do_sys_init_module+0x1ec/0x238
| __arm64_sys_init_module+0x24/0x30
| invoke_syscall+0x54/0x118
| el0_svc_common.constprop.4+0x84/0x100
| do_el0_svc+0x3c/0xd0
| el0_svc+0x1c/0x50
| el0t_64_sync_handler+0x90/0xb8
| el0t_64_sync+0x15c/0x160
| ---[ end trace 0000000000000000 ]---
| ---------test_init-----------
Fix this by reverting to the old behaviour of ignoring the old
instruction when initialising an mcount callsite in a module, which was
the behaviour prior to commit a6253579977e4c6f.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Fixes: a6253579977e ("arm64: ftrace: consistently handle PLTs.")
Reported-by: Li Huafei <lihuafei1@huawei.com>
Link: https://lore.kernel.org/linux-arm-kernel/20220929094134.99512-1-lihuafei1@huawei.com
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20220929134525.798593-1-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Since commit f1a54ae9af0d ("arm64: module/ftrace: intialize PLT at load
time"), plt_entry_is_initialized() is unused anymore , so remove it.
Signed-off-by: Li Huafei <lihuafei1@huawei.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220929094134.99512-3-lihuafei1@huawei.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Since commit 4e69ecf4da1e ("arm64/module: ftrace: deal with place
relative nature of PLTs"), plt_equals_entry() is not used outside of
module-plts.c, so make it static.
Signed-off-by: Li Huafei <lihuafei1@huawei.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220929094134.99512-2-lihuafei1@huawei.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Jon Hunter reports that for some toolchains the build has been broken
since commit:
4c0bd995d73ed889 ("arm64: alternatives: have callbacks take a cap")
... with a stream of build-time splats of the form:
| CC arch/arm64/kvm/hyp/vhe/debug-sr.o
| /tmp/ccY3kbki.s: Assembler messages:
| /tmp/ccY3kbki.s:1600: Error: found 'L', expected: ')'
| /tmp/ccY3kbki.s:1600: Error: found 'L', expected: ')'
| /tmp/ccY3kbki.s:1600: Error: found 'L', expected: ')'
| /tmp/ccY3kbki.s:1600: Error: found 'L', expected: ')'
| /tmp/ccY3kbki.s:1600: Error: junk at end of line, first unrecognized character
| is `L'
| /tmp/ccY3kbki.s:1723: Error: found 'L', expected: ')'
| /tmp/ccY3kbki.s:1723: Error: found 'L', expected: ')'
| /tmp/ccY3kbki.s:1723: Error: found 'L', expected: ')'
| /tmp/ccY3kbki.s:1723: Error: found 'L', expected: ')'
| /tmp/ccY3kbki.s:1723: Error: junk at end of line, first unrecognized character
| is `L'
| scripts/Makefile.build:249: recipe for target
| 'arch/arm64/kvm/hyp/vhe/debug-sr.o' failed
The issue here is that older versions of binutils (up to and including
2.27.0) don't like an 'L' suffix on constants. For plain assembly files,
UL() avoids this suffix, but in C files this gets added, and so for
inline assembly we can't directly use a constant defined with `UL()`.
We could avoid this by passing the constant as an input parameter, but
this isn't practical given the way we use the alternative macros.
Instead, just open code the constant without the `UL` suffix, and for
consistency do this for both the inline assembly macro and the regular
assembly macro.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Fixes: 4c0bd995d73e ("arm64: alternatives: have callbacks take a cap")
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Link: https://lore.kernel.org/linux-arm-kernel/3cecc3a5-30b0-f0bd-c3de-9e09bd21909b@nvidia.com/
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20220929150227.1028556-1-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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It seems that all code should use double backquotes, which is also used
to convert "%" defines. Let's use an homogeneous style and remove all
use of simple backquotes (which should only be used for emphasis).
Cc: Günther Noack <gnoack3000@gmail.com>
Cc: Paul Moore <paul@paul-moore.com>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Link: https://lore.kernel.org/r/20220923154207.3311629-4-mic@digikod.net
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Now that we have more than one ABI version, make limitation explanation
more consistent by replacing "ABI 1" with "ABI < 2". This also
indicates which ABIs support such past limitation.
Improve documentation consistency by not using contractions.
Fix spelling in fs.c .
Cc: Paul Moore <paul@paul-moore.com>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Reviewed-by: Günther Noack <gnoack3000@gmail.com>
Link: https://lore.kernel.org/r/20220923154207.3311629-3-mic@digikod.net
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Extend the help with the latest Landlock ABI version supported by the
sandboxer.
Inform users about the sandboxer or the kernel not being up-to-date.
Make the version check code easier to update and harder to misuse.
Cc: Paul Moore <paul@paul-moore.com>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Reviewed-by: Günther Noack <gnoack3000@gmail.com>
Link: https://lore.kernel.org/r/20220923154207.3311629-2-mic@digikod.net
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Currently we set -march=armv8.5+memtag when building the MTE selftests,
allowing the compiler to emit v8.5 and MTE instructions for anything it
generates. This means that we may get code that will generate SIGILLs when
run on older systems rather than skipping on non-MTE systems as should be
the case. Most toolchains don't select any incompatible instructions but
I have seen some reports which suggest that some may be appearing which do
so. This is also potentially problematic in that if the compiler chooses to
emit any MTE instructions for the C code it may interfere with the MTE
usage we are trying to test.
Since the only reason we are specifying this option is to allow us to
assemble MTE instructions in mte_helper.S we can avoid these issues by
moving to using a .arch directive there and adding the -march explicitly to
the toolchain support check instead of the generic CFLAGS.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220928154517.173108-1-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Martin KaFai Lau says:
====================
From: Martin KaFai Lau <martin.lau@kernel.org>
The struct_ops is sharing the tracing-trampoline's enter/exit
function which tracks prog->active to avoid recursion. It turns
out the struct_ops bpf prog will hit this prog->active and
unnecessarily skipped running the struct_ops prog. eg. The
'.ssthresh' may run in_task() and then interrupted by softirq
that runs the same '.ssthresh'.
The kernel does not call the tcp-cc's ops in a recursive way,
so this set is to remove the recursion check for struct_ops prog.
v3:
- Clear the bpf_chg_cc_inprogress from the newly cloned tcp_sock
in tcp_create_openreq_child() because the listen sk can
be cloned without lock being held. (Eric Dumazet)
v2:
- v1 [0] turned into a long discussion on a few cases and also
whether it needs to follow the bpf_run_ctx chain if there is
tracing bpf_run_ctx (kprobe/trace/trampoline) running in between.
It is a good signal that it is not obvious enough to reason
about it and needs a tradeoff for a more straight forward approach.
This revision uses one bit out of an existing 1 byte hole
in the tcp_sock. It is in Patch 4.
[0]: https://lore.kernel.org/bpf/20220922225616.3054840-1-kafai@fb.com/T/#md98d40ac5ec295fdadef476c227a3401b2b6b911
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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This patch changes the bpf_dctcp test to ensure the recurred
bpf_setsockopt(TCP_CONGESTION) returns -EBUSY.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220929070407.965581-6-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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When a bad bpf prog '.init' calls
bpf_setsockopt(TCP_CONGESTION, "itself"), it will trigger this loop:
.init => bpf_setsockopt(tcp_cc) => .init => bpf_setsockopt(tcp_cc) ...
... => .init => bpf_setsockopt(tcp_cc).
It was prevented by the prog->active counter before but the prog->active
detection cannot be used in struct_ops as explained in the earlier
patch of the set.
In this patch, the second bpf_setsockopt(tcp_cc) is not allowed
in order to break the loop. This is done by using a bit of
an existing 1 byte hole in tcp_sock to check if there is
on-going bpf_setsockopt(TCP_CONGESTION) in this tcp_sock.
Note that this essentially limits only the first '.init' can
call bpf_setsockopt(TCP_CONGESTION) to pick a fallback cc (eg. peer
does not support ECN) and the second '.init' cannot fallback to
another cc. This applies even the second
bpf_setsockopt(TCP_CONGESTION) will not cause a loop.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20220929070407.965581-5-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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This patch moves the bpf_setsockopt(TCP_CONGESTION) logic into
another function. The next patch will add extra logic to avoid
recursion and this will make the latter patch easier to follow.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220929070407.965581-4-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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The check on the tcp-cc, "cdg", is done in the bpf_sk_setsockopt which is
used by the bpf_tcp_ca, bpf_lsm, cg_sockopt, and tcp_iter hooks.
However, it is not done for cg sock_ddr, cg sockops, and some of
the bpf_lsm_cgroup hooks.
The tcp-cc "cdg" should have very limited usage. This patch is to
move the "cdg" check to the common sol_tcp_sockopt() so that all
hooks have a consistent behavior. The motivation to make
this check consistent now is because the latter patch will
refactor the bpf_setsockopt(TCP_CONGESTION) into another function,
so it is better to take this chance to refactor this piece
also.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220929070407.965581-3-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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The struct_ops prog is to allow using bpf to implement the functions in
a struct (eg. kernel module). The current usage is to implement the
tcp_congestion. The kernel does not call the tcp-cc's ops (ie.
the bpf prog) in a recursive way.
The struct_ops is sharing the tracing-trampoline's enter/exit
function which tracks prog->active to avoid recursion. It is
needed for tracing prog. However, it turns out the struct_ops
bpf prog will hit this prog->active and unnecessarily skipped
running the struct_ops prog. eg. The '.ssthresh' may run in_task()
and then interrupted by softirq that runs the same '.ssthresh'.
Skip running the '.ssthresh' will end up returning random value
to the caller.
The patch adds __bpf_prog_{enter,exit}_struct_ops for the
struct_ops trampoline. They do not track the prog->active
to detect recursion.
One exception is when the tcp_congestion's '.init' ops is doing
bpf_setsockopt(TCP_CONGESTION) and then recurs to the same
'.init' ops. This will be addressed in the following patches.
Fixes: ca06f55b9002 ("bpf: Add per-program recursion prevention mechanism")
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220929070407.965581-2-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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The driver field in the struct snd_ctl_card_info is a valid
user space identifier. Actually, many ASoC drivers do not care
and let to initialize this field using a standard wrapping method.
Unfortunately, in this way, this field becomes unusable and
unreadable for the drivers with longer card names. Also,
there is a possibility to have clashes (driver field has
only limit of 15 characters).
This change will print an error when the wrapping is used.
The developers of the affected drivers should fix the problem.
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
|