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Some KUnit functions use variable arguments to implement a printf-like
format string. Use the __printf() attribute to let the compiler warn if
invalid format strings are passed in.
If the kernel is build with W=1, it complained about the lack of these
specifiers, e.g.:
../lib/kunit/test.c:72:2: warning: function ‘kunit_log_append’ might be a candidate for ‘gnu_printf’ format attribute [-Wsuggest-attribute=format]
Signed-off-by: David Gow <davidgow@google.com>
Reviewed-by: Daniel Latypov <dlatypov@google.com>
Acked-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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With some of the stricter type checking in KUnit's EXPECT macros
removed, a cast in cmdline_kunit is no longer required.
Remove the unnecessary cast, using NULL instead of (int *) to make it
clearer.
Signed-off-by: David Gow <davidgow@google.com>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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With some of the stricter type checking in KUnit's EXPECT macros
removed, several casts in sysctl-test are no longer required.
Remove the unnecessary casts, making the conditions clearer.
Signed-off-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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With some of the stricter type checking in KUnit's EXPECT macros
removed, several casts in the thunderbolt KUnit tests are no longer
required.
Remove the unnecessary casts, making the conditions clearer.
Signed-off-by: David Gow <davidgow@google.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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With KUnit's EXPECT macros no longer typechecking arguments as strictly,
get rid of a number of now unnecessary casts.
Signed-off-by: David Gow <davidgow@google.com>
Acked-by: Andrew Jeffery <andrew@aj.id.au>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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KUnit's EXPECT macros no longer typecheck as stringently, so casting the
result of strcmp() is now unnecessary.
Signed-off-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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With some of the stricter type checking in KUnit's EXPECT macros
removed, several casts in property-entry-test are no longer required.
Remove the unnecessary casts, making the conditions clearer.
Signed-off-by: David Gow <davidgow@google.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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As the type checking is no longer excessively strict, get rid of the
unsightly (char*) casts -- and comment discussing them -- from the KUnit
usage page.
Signed-off-by: David Gow <davidgow@google.com>
Reviewed-by: Daniel Latypov <dlatypov@google.com>
Acked-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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Currently, the KUNIT_EXPECT_STREQ() and related macros assign both
string arguments to variables of their own type (via typeof()). This
seems to be to prevent the macro argument from being evaluated multiple
times.
However, this doesn't work if one of these is a fixed-length character
array, rather than a character pointer, as (for example) char[16] will
always allocate a new string.
By always using 'const char*' (the type strcmp expects), we're always
just taking a pointer to the string, which works even with character
arrays.
Signed-off-by: David Gow <davidgow@google.com>
Reviewed-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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The use of typecheck() in KUNIT_EXPECT_EQ() and friends is causing more
problems than I think it's worth. Things like enums need to have their
values explicitly cast, and literals all need to be very precisely
typed, else a large warning will be printed.
While typechecking does have its uses, the additional overhead of having
lots of needless casts -- combined with the awkward error messages which
don't mention which types are involved -- makes tests less readable and
more difficult to write.
By removing the typecheck() call, the two arguments still need to be of
compatible types, but don't need to be of exactly the same time, which
seems a less confusing and more useful compromise.
Signed-off-by: David Gow <davidgow@google.com>
Reviewed-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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We'll be replacing :doc:`foo` references to
Documentation/foo.rst. Yet, here it happens inside a table.
Doing a search-and-replace would break it.
Yet, as there's no good reason to use a table there,
let's just convert it into a list.
Reviewed-by: David Gow <davidgow@google.com>
Acked-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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Add basic support to run QEMU via kunit_tool. Add support for i386,
x86_64, arm, arm64, and a bunch more.
Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Tested-by: David Gow <davidgow@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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Document QEMU support, what it does, and how to use it in kunit_tool.
Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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Add a new kernel command-line option, 'kunit_shutdown', which allows the
user to specify that the kernel poweroff, halt, or reboot after
completing all KUnit tests; this is very handy for running KUnit tests
on UML or a VM so that the UML/VM process exits cleanly immediately
after running all tests without needing a special initramfs.
Signed-off-by: David Gow <davidgow@google.com>
Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Tested-By: Daniel Latypov <dlatypov@google.com>
Reviewed-by: Daniel Latypov <dlatypov@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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When one parameter of a parameterised test failed, its failure would be
propagated to the overall test, but not to the suite result (unless it
was the last parameter).
This is because test_case->success was being reset to the test->success
result after each parameter was used, so a failing test's result would
be overwritten by a non-failing result. The overall test result was
handled in a third variable, test_result, but this was discarded after
the status line was printed.
Instead, just propagate the result after each parameter run.
Signed-off-by: David Gow <davidgow@google.com>
Fixes: fadb08e7c750 ("kunit: Support for Parameterized Testing")
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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The kunit_tool documentation page was pretty minimal, and a bit
outdated. Update it and flesh it out a bit.
In particular,
- Mention that .kunitconfig is now in the build directory
- Describe the use of --kunitconfig to specify a different config
framgent
- Mention the split functionality (i.e., commands other than 'run')
- Describe --raw_output and kunit.py parse
- Mention the globbing support
- Provide a quick overview of other options, including --build_dir and
--alltests
Note that this does overlap a little with the new running_tips page. I
don't think it's a problem having both: this page is supposed to be a
bit more of a reference, rather than a list of useful tips, so the fact
that they both describe the same features isn't a problem.
Signed-off-by: David Gow <davidgow@google.com>
Reviewed-by: Daniel Latypov <dlatypov@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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This is long overdue.
There are several things that aren't nailed down (in-tree
.kunitconfig's), or partially broken (GCOV on UML), but having them
documented, warts and all, is better than having nothing.
This covers a bunch of the more recent features
* kunit_filter_glob
* kunit.py run --kunitconfig
* slightly more detail on building tests as modules
* CONFIG_KUNIT_DEBUGFS
By my count, the only headline features now not mentioned are the KASAN
integration and KernelCI json output support (kunit.py run --json).
And then it also discusses how to get code coverage reports under UML
and non-UML since this is a question people have repeatedly asked.
Non-UML coverage collection is no different from normal, but we should
probably explicitly call this out.
As for UML, I was able to get it working again with two small hacks.*
E.g. with CONFIG_KUNIT=y && CONFIG_KUNIT_ALL_TESTS=y
Overall coverage rate:
lines......: 15.1% (18294 of 120776 lines)
functions..: 16.8% (1860 of 11050 functions)
Note: this doesn't document --alltests since this is not stable yet.
Hopefully being run more frequently as part of KernelCI will help...
*Using gcc/gcov-6 and not using uml_abort() in os_dump_core().
I've documented these hacks in "Notes" but left TODOs for
brendanhiggins@google.com who tracked down the runtime issue in GCC.
To be clear: these are not issues specific to KUnit, but rather to UML.
Signed-off-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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syzbot is reporting OOB write at vga16fb_imageblit() [1], for
resize_screen() from ioctl(VT_RESIZE) returns 0 without checking whether
requested rows/columns fit the amount of memory reserved for the graphical
screen if current mode is KD_GRAPHICS.
----------
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/kd.h>
#include <linux/vt.h>
int main(int argc, char *argv[])
{
const int fd = open("/dev/char/4:1", O_RDWR);
struct vt_sizes vt = { 0x4100, 2 };
ioctl(fd, KDSETMODE, KD_GRAPHICS);
ioctl(fd, VT_RESIZE, &vt);
ioctl(fd, KDSETMODE, KD_TEXT);
return 0;
}
----------
Allow framebuffer drivers to return -EINVAL, by moving vc->vc_mode !=
KD_GRAPHICS check from resize_screen() to fbcon_resize().
Link: https://syzkaller.appspot.com/bug?extid=1f29e126cf461c4de3b3 [1]
Reported-by: syzbot <syzbot+1f29e126cf461c4de3b3@syzkaller.appspotmail.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Tested-by: syzbot <syzbot+1f29e126cf461c4de3b3@syzkaller.appspotmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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iomap_max_page_shift is expected to contain a page shift, so it can't be a
'bool', has to be an 'unsigned int'
And fix the default values: P4D_SHIFT is when huge iomap is allowed.
However, on some architectures (eg: powerpc book3s/64), P4D_SHIFT is not a
constant so it can't be used to initialise a static variable. So,
initialise iomap_max_page_shift with a maximum shift supported by the
architecture, it is gated by P4D_SHIFT in vmap_try_huge_p4d() anyway.
Link: https://lkml.kernel.org/r/ad2d366015794a9f21320dcbdd0a8eb98979e9df.1620898113.git.christophe.leroy@csgroup.eu
Fixes: bbc180a5adb0 ("mm: HUGE_VMAP arch support cleanup")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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When I added CONFIG_MODPROBE_PATH, I neglected to update Documentation/.
It's still true that this defaults to /sbin/modprobe, but now via a level
of indirection. So document that the kernel might have been built with
something other than /sbin/modprobe as the initial value.
Link: https://lkml.kernel.org/r/20210420125324.1246826-1-linux@rasmusvillemoes.dk
Fixes: 17652f4240f7a ("modules: add CONFIG_MODPROBE_PATH")
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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I believe there are some issues introduced by commit 31651c607151
("hfsplus: avoid deadlock on file truncation")
HFS+ has extent records which always contains 8 extents. In case the
first extent record in catalog file gets full, new ones are allocated from
extents overflow file.
In case shrinking truncate happens to middle of an extent record which
locates in extents overflow file, the logic in hfsplus_file_truncate() was
changed so that call to hfs_brec_remove() is not guarded any more.
Right action would be just freeing the extents that exceed the new size
inside extent record by calling hfsplus_free_extents(), and then check if
the whole extent record should be removed. However since the guard
(blk_cnt > start) is now after the call to hfs_brec_remove(), this has
unfortunate effect that the last matching extent record is removed
unconditionally.
To reproduce this issue, create a file which has at least 10 extents, and
then perform shrinking truncate into middle of the last extent record, so
that the number of remaining extents is not under or divisible by 8. This
causes the last extent record (8 extents) to be removed totally instead of
truncating into middle of it. Thus this causes corruption, and lost data.
Fix for this is simply checking if the new truncated end is below the
start of this extent record, making it safe to remove the full extent
record. However call to hfs_brec_remove() can't be moved to it's previous
place since we're dropping ->tree_lock and it can cause a race condition
and the cached info being invalidated possibly corrupting the node data.
Another issue is related to this one. When entering into the block
(blk_cnt > start) we are not holding the ->tree_lock. We break out from
the loop not holding the lock, but hfs_find_exit() does unlock it. Not
sure if it's possible for someone else to take the lock under our feet,
but it can cause hard to debug errors and premature unlocking. Even if
there's no real risk of it, the locking should still always be kept in
balance. Thus taking the lock now just before the check.
Link: https://lkml.kernel.org/r/20210429165139.3082828-1-jouni.roivas@tuxera.com
Fixes: 31651c607151f ("hfsplus: avoid deadlock on file truncation")
Signed-off-by: Jouni Roivas <jouni.roivas@tuxera.com>
Reviewed-by: Anton Altaparmakov <anton@tuxera.com>
Cc: Anatoly Trosinenko <anatoly.trosinenko@gmail.com>
Cc: Viacheslav Dubeyko <slava@dubeyko.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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A readahead request will not allocate more memory than can be represented
by a size_t, even on systems that have HIGHMEM available. Change the
length functions from returning an loff_t to a size_t.
Link: https://lkml.kernel.org/r/20210510201201.1558972-1-willy@infradead.org
Fixes: 32c0a6bcaa1f57 ("btrfs: add and use readahead_batch_length")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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These tests deliberately access these arrays out of bounds, which will
cause the dynamic local bounds checks inserted by
CONFIG_UBSAN_LOCAL_BOUNDS to fail and panic the kernel. To avoid this
problem, access the arrays via volatile pointers, which will prevent the
compiler from being able to determine the array bounds.
These accesses use volatile pointers to char (char *volatile) rather than
the more conventional pointers to volatile char (volatile char *) because
we want to prevent the compiler from making inferences about the pointer
itself (i.e. its array bounds), not the data that it refers to.
Link: https://lkml.kernel.org/r/20210507025915.1464056-1-pcc@google.com
Link: https://linux-review.googlesource.com/id/I90b1713fbfa1bf68ff895aef099ea77b98a7c3b9
Signed-off-by: Peter Collingbourne <pcc@google.com>
Tested-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: George Popescu <georgepope@android.com>
Cc: Elena Petrova <lenaptr@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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32-bit architectures which expect 8-byte alignment for 8-byte integers and
need 64-bit DMA addresses (arm, mips, ppc) had their struct page
inadvertently expanded in 2019. When the dma_addr_t was added, it forced
the alignment of the union to 8 bytes, which inserted a 4 byte gap between
'flags' and the union.
Fix this by storing the dma_addr_t in one or two adjacent unsigned longs.
This restores the alignment to that of an unsigned long. We always
store the low bits in the first word to prevent the PageTail bit from
being inadvertently set on a big endian platform. If that happened,
get_user_pages_fast() racing against a page which was freed and
reallocated to the page_pool could dereference a bogus compound_head(),
which would be hard to trace back to this cause.
Link: https://lkml.kernel.org/r/20210510153211.1504886-1-willy@infradead.org
Fixes: c25fff7171be ("mm: add dma_addr_t to struct page")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Matteo Croce <mcroce@linux.microsoft.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This reverts commit 3e96b6a2e9ad929a3230a22f4d64a74671a0720b. General
Protection Fault in rmap_walk_ksm() under memory pressure:
remove_rmap_item_from_tree() needs to take page lock, of course.
Link: https://lkml.kernel.org/r/alpine.LSU.2.11.2105092253500.1127@eggly.anvils
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Consider the following sequence of events:
1. Userspace issues a UFFD ioctl, which ends up calling into
shmem_mfill_atomic_pte(). We successfully account the blocks, we
shmem_alloc_page(), but then the copy_from_user() fails. We return
-ENOENT. We don't release the page we allocated.
2. Our caller detects this error code, tries the copy_from_user() after
dropping the mmap_lock, and retries, calling back into
shmem_mfill_atomic_pte().
3. Meanwhile, let's say another process filled up the tmpfs being used.
4. So shmem_mfill_atomic_pte() fails to account blocks this time, and
immediately returns - without releasing the page.
This triggers a BUG_ON in our caller, which asserts that the page
should always be consumed, unless -ENOENT is returned.
To fix this, detect if we have such a "dangling" page when accounting
fails, and if so, release it before returning.
Link: https://lkml.kernel.org/r/20210428230858.348400-1-axelrasmussen@google.com
Fixes: cb658a453b93 ("userfaultfd: shmem: avoid leaking blocks and used blocks in UFFDIO_COPY")
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
Reported-by: Hugh Dickins <hughd@google.com>
Acked-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Sysbot has reported a "divide error" which has been identified as being
caused by a corrupted file_size value within the file inode. This value
has been corrupted to a much larger value than expected.
Calculate_skip() is passed i_size_read(inode) >> msblk->block_log. Due to
the file_size value corruption this overflows the int argument/variable in
that function, leading to the divide error.
This patch changes the function to use u64. This will accommodate any
unexpectedly large values due to corruption.
The value returned from calculate_skip() is clamped to be never more than
SQUASHFS_CACHED_BLKS - 1, or 7. So file_size corruption does not lead to
an unexpectedly large return result here.
Link: https://lkml.kernel.org/r/20210507152618.9447-1-phillip@squashfs.org.uk
Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
Reported-by: <syzbot+e8f781243ce16ac2f962@syzkaller.appspotmail.com>
Reported-by: <syzbot+7b98870d4fec9447b951@syzkaller.appspotmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Splitting an earlier version of a patch that allowed calling
__request_region() while holding the resource lock into a series of
patches required changing the return code for the newly introduced
__request_region_locked().
Unfortunately this change was not carried through to a subsequent commit
56fd94919b8b ("kernel/resource: fix locking in request_free_mem_region")
in the series. This resulted in a use-after-free due to freeing the
struct resource without properly releasing it. Fix this by correcting the
return code check so that the struct is not freed if the request to add it
was successful.
Link: https://lkml.kernel.org/r/20210512073528.22334-1-apopple@nvidia.com
Fixes: 56fd94919b8b ("kernel/resource: fix locking in request_free_mem_region")
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Muchun Song <smuchun@gmail.com>
Cc: Oliver Sang <oliver.sang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Paul E. McKenney reported [1] that commit 1f0723a4c0df ("mm, slub: enable
slub_debug static key when creating cache with explicit debug flags")
results in the lockdep complaint:
======================================================
WARNING: possible circular locking dependency detected
5.12.0+ #15 Not tainted
------------------------------------------------------
rcu_torture_sta/109 is trying to acquire lock:
ffffffff96063cd0 (cpu_hotplug_lock){++++}-{0:0}, at: static_key_enable+0x9/0x20
but task is already holding lock:
ffffffff96173c28 (slab_mutex){+.+.}-{3:3}, at: kmem_cache_create_usercopy+0x2d/0x250
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (slab_mutex){+.+.}-{3:3}:
lock_acquire+0xb9/0x3a0
__mutex_lock+0x8d/0x920
slub_cpu_dead+0x15/0xf0
cpuhp_invoke_callback+0x17a/0x7c0
cpuhp_invoke_callback_range+0x3b/0x80
_cpu_down+0xdf/0x2a0
cpu_down+0x2c/0x50
device_offline+0x82/0xb0
remove_cpu+0x1a/0x30
torture_offline+0x80/0x140
torture_onoff+0x147/0x260
kthread+0x10a/0x140
ret_from_fork+0x22/0x30
-> #0 (cpu_hotplug_lock){++++}-{0:0}:
check_prev_add+0x8f/0xbf0
__lock_acquire+0x13f0/0x1d80
lock_acquire+0xb9/0x3a0
cpus_read_lock+0x21/0xa0
static_key_enable+0x9/0x20
__kmem_cache_create+0x38d/0x430
kmem_cache_create_usercopy+0x146/0x250
kmem_cache_create+0xd/0x10
rcu_torture_stats+0x79/0x280
kthread+0x10a/0x140
ret_from_fork+0x22/0x30
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(slab_mutex);
lock(cpu_hotplug_lock);
lock(slab_mutex);
lock(cpu_hotplug_lock);
*** DEADLOCK ***
1 lock held by rcu_torture_sta/109:
#0: ffffffff96173c28 (slab_mutex){+.+.}-{3:3}, at: kmem_cache_create_usercopy+0x2d/0x250
stack backtrace:
CPU: 3 PID: 109 Comm: rcu_torture_sta Not tainted 5.12.0+ #15
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014
Call Trace:
dump_stack+0x6d/0x89
check_noncircular+0xfe/0x110
? lock_is_held_type+0x98/0x110
check_prev_add+0x8f/0xbf0
__lock_acquire+0x13f0/0x1d80
lock_acquire+0xb9/0x3a0
? static_key_enable+0x9/0x20
? mark_held_locks+0x49/0x70
cpus_read_lock+0x21/0xa0
? static_key_enable+0x9/0x20
static_key_enable+0x9/0x20
__kmem_cache_create+0x38d/0x430
kmem_cache_create_usercopy+0x146/0x250
? rcu_torture_stats_print+0xd0/0xd0
kmem_cache_create+0xd/0x10
rcu_torture_stats+0x79/0x280
? rcu_torture_stats_print+0xd0/0xd0
kthread+0x10a/0x140
? kthread_park+0x80/0x80
ret_from_fork+0x22/0x30
This is because there's one order of locking from the hotplug callbacks:
lock(cpu_hotplug_lock); // from hotplug machinery itself
lock(slab_mutex); // in e.g. slab_mem_going_offline_callback()
And commit 1f0723a4c0df made the reverse sequence possible:
lock(slab_mutex); // in kmem_cache_create_usercopy()
lock(cpu_hotplug_lock); // kmem_cache_open() -> static_key_enable()
The simplest fix is to move static_key_enable() to a place before slab_mutex is
taken. That means kmem_cache_create_usercopy() in mm/slab_common.c which is not
ideal for SLUB-specific code, but the #ifdef CONFIG_SLUB_DEBUG makes it
at least self-contained and obvious.
[1] https://lore.kernel.org/lkml/20210502171827.GA3670492@paulmck-ThinkPad-P17-Gen-1/
Link: https://lkml.kernel.org/r/20210504120019.26791-1-vbabka@suse.cz
Fixes: 1f0723a4c0df ("mm, slub: enable slub_debug static key when creating cache with explicit debug flags")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
When rework early cow of pinned hugetlb pages, we moved huge_ptep_get()
upper but overlooked a side effect that the huge_ptep_get() will fetch the
pte after wr-protection. After moving it upwards, we need explicit
wr-protect of child pte or we will keep the write bit set in the child
process, which could cause data corrution where the child can write to the
original page directly.
This issue can also be exposed by "memfd_test hugetlbfs" kselftest.
Link: https://lkml.kernel.org/r/20210503234356.9097-3-peterx@redhat.com
Fixes: 4eae4efa2c299 ("hugetlb: do early cow when page pinned on src mm")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Patch series "mm/hugetlb: Fix issues on file sealing and fork", v2.
Hugh reported issue with F_SEAL_FUTURE_WRITE not applied correctly to
hugetlbfs, which I can easily verify using the memfd_test program, which
seems that the program is hardly run with hugetlbfs pages (as by default
shmem).
Meanwhile I found another probably even more severe issue on that hugetlb
fork won't wr-protect child cow pages, so child can potentially write to
parent private pages. Patch 2 addresses that.
After this series applied, "memfd_test hugetlbfs" should start to pass.
This patch (of 2):
F_SEAL_FUTURE_WRITE is missing for hugetlb starting from the first day.
There is a test program for that and it fails constantly.
$ ./memfd_test hugetlbfs
memfd-hugetlb: CREATE
memfd-hugetlb: BASIC
memfd-hugetlb: SEAL-WRITE
memfd-hugetlb: SEAL-FUTURE-WRITE
mmap() didn't fail as expected
Aborted (core dumped)
I think it's probably because no one is really running the hugetlbfs test.
Fix it by checking FUTURE_WRITE also in hugetlbfs_file_mmap() as what we
do in shmem_mmap(). Generalize a helper for that.
Link: https://lkml.kernel.org/r/20210503234356.9097-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20210503234356.9097-2-peterx@redhat.com
Fixes: ab3948f58ff84 ("mm/memfd: add an F_SEAL_FUTURE_WRITE seal to memfd")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reported-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
To ensure that instructions are observable in a new mapping, the arm64
set_pte_at() implementation cleans the D-cache and invalidates the
I-cache to the PoU. As an optimisation, this is only done on executable
mappings and the PG_dcache_clean page flag is set to avoid future cache
maintenance on the same page.
When two different processes map the same page (e.g. private executable
file or shared mapping) there's a potential race on checking and setting
PG_dcache_clean via set_pte_at() -> __sync_icache_dcache(). While on the
fault paths the page is locked (PG_locked), mprotect() does not take the
page lock. The result is that one process may see the PG_dcache_clean
flag set but the I/D cache maintenance not yet performed.
Avoid test_and_set_bit(PG_dcache_clean) in favour of separate test_bit()
and set_bit(). In the rare event of a race, the cache maintenance is
done twice.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: <stable@vger.kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210514095001.13236-1-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
|
|
Fix the following kernel-doc warning:
block/partitions/efi.c:685: warning: wrong kernel-doc identifier on line:
* efi_partition(struct parsed_partitions *state)
Cc: Alexander Viro <viro@math.psu.edu>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20210513171708.8391-1-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
|
If a tag set is shared across request queues (e.g. SCSI LUNs) then the
block layer core keeps track of the number of active request queues in
tags->active_queues. blk_mq_tag_busy() and blk_mq_tag_idle() update that
atomic counter if the hctx flag BLK_MQ_F_TAG_QUEUE_SHARED is set. Make
sure that blk_mq_exit_queue() calls blk_mq_tag_idle() before that flag is
cleared by blk_mq_del_queue_tag_set().
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Fixes: 0d2602ca30e4 ("blk-mq: improve support for shared tags maps")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20210513171529.7977-1-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
|
In case of shared sbitmap, request won't be held in plug list any more
sine commit 32bc15afed04 ("blk-mq: Facilitate a shared sbitmap per
tagset"), this way makes request merge from flush plug list & batching
submission not possible, so cause performance regression.
Yanhui reports performance regression when running sequential IO
test(libaio, 16 jobs, 8 depth for each job) in VM, and the VM disk
is emulated with image stored on xfs/megaraid_sas.
Fix the issue by recovering original behavior to allow to hold request
in plug list.
Cc: Yanhui Ma <yama@redhat.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: kashyap.desai@broadcom.com
Fixes: 32bc15afed04 ("blk-mq: Facilitate a shared sbitmap per tagset")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20210514022052.1047665-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
|
xen_swiotlb_init calls swiotlb_late_init_with_tbl, which fails with
-ENOMEM if the swiotlb has already been initialized.
Add an explicit check io_tlb_default_mem != NULL at the beginning of
xen_swiotlb_init. If the swiotlb is already initialized print a warning
and return -EEXIST.
On x86, the error propagates.
On ARM, we don't actually need a special swiotlb buffer (yet), any
buffer would do. So ignore the error and continue.
CC: boris.ostrovsky@oracle.com
CC: jgross@suse.com
Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
Reviewed-by: Boris Ostrovsky <boris.ostrvsky@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210512201823.1963-3-sstabellini@kernel.org
Signed-off-by: Juergen Gross <jgross@suse.com>
|
|
Although SWIOTLB_NO_FORCE is meant to allow later calls to swiotlb_init,
today dma_direct_map_page returns error if SWIOTLB_NO_FORCE.
For now, without a larger overhaul of SWIOTLB_NO_FORCE, the best we can
do is to avoid setting SWIOTLB_NO_FORCE in mem_init when we know that it
is going to be required later (e.g. Xen requires it).
CC: boris.ostrovsky@oracle.com
CC: jgross@suse.com
CC: catalin.marinas@arm.com
CC: will@kernel.org
CC: linux-arm-kernel@lists.infradead.org
Fixes: 2726bf3ff252 ("swiotlb: Make SWIOTLB_NO_FORCE perform no allocation")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210512201823.1963-2-sstabellini@kernel.org
Signed-off-by: Juergen Gross <jgross@suse.com>
|
|
Move xen_swiotlb_detect to a static inline function to make it available
to !CONFIG_XEN builds.
CC: boris.ostrovsky@oracle.com
CC: jgross@suse.com
Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20210512201823.1963-1-sstabellini@kernel.org
Signed-off-by: Juergen Gross <jgross@suse.com>
|
|
Mohammed reports (https://bugzilla.kernel.org/show_bug.cgi?id=213029)
the commit e4ab4658f1cf ("clocksource/drivers/hyper-v: Handle vDSO
differences inline") broke vDSO on x86. The problem appears to be that
VDSO_CLOCKMODE_HVCLOCK is an enum value in 'enum vdso_clock_mode' and
'#ifdef VDSO_CLOCKMODE_HVCLOCK' branch evaluates to false (it is not
a define).
Use a dedicated HAVE_VDSO_CLOCKMODE_HVCLOCK define instead.
Fixes: e4ab4658f1cf ("clocksource/drivers/hyper-v: Handle vDSO differences inline")
Reported-by: Mohammed Gamal <mgamal@redhat.com>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210513073246.1715070-1-vkuznets@redhat.com
|
|
Since recent changes instead of storing a large array of struct
io_mapped_ubuf, we store pointers to them, that is 4 times slimmer and
we should not to so worry about restricting max number of registererd
buffer slots, increase the limit 4 times.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d3dee1da37f46da416aa96a16bf9e5094e10584d.1620990371.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
|
There are three types of requests that left disabled for sqpoll, namely
epoll ctx, statx, and resources update. Since SQPOLL task is now closely
mimics a userspace thread, remove the restrictions.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/909b52d70c45636d8d7897582474ea5aab5eed34.1620990306.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
|
Always remove linked timeout on io_link_timeout_fn() from the master
request link list, otherwise we may get use-after-free when first
io_link_timeout_fn() puts linked timeout in the fail path, and then
will be found and put on master's free.
Cc: stable@vger.kernel.org # 5.10+
Fixes: 90cd7e424969d ("io_uring: track link timeout's master explicitly")
Reported-and-tested-by: syzbot+5a864149dd970b546223@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/69c46bf6ce37fec4fdcd98f0882e18eb07ce693a.1620990121.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
|
Some interrupt handlers have an "extra" that saves 1 or 2
registers (r14, r15) in the paca save area and makes them available to
use by the handler.
The change to always save nvgprs in exception handlers lead to some
interrupt handlers saving those scratch r14 / r15 registers into the
interrupt frame's GPR saves, which get restored on interrupt exit.
Fix this by always reloading those scratch registers from paca before
the EXCEPTION_COMMON that saves nvgprs.
Fixes: 4228b2c3d20e ("powerpc/64e/interrupt: always save nvgprs on interrupt")
Reported-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Tested-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210514044008.1955783-1-npiggin@gmail.com
|
|
scv support introduced the notion of code that implicitly soft-masks
irqs due to the instruction addresses. This is required because scv
enters the kernel with MSR[EE]=1.
If a NMI (including soft-NMI) interrupt hits when we are implicitly
soft-masked then its regs->softe does not reflect this because it is
derived from the explicit soft mask state (paca->irq_soft_mask). This
makes arch_irq_disabled_regs(regs) return false.
This can trigger a warning in the soft-NMI watchdog code (shown below).
Fix it by having NMI interrupts set regs->softe to disabled in case of
interrupting an implicit soft-masked region.
------------[ cut here ]------------
WARNING: CPU: 41 PID: 1103 at arch/powerpc/kernel/watchdog.c:259 soft_nmi_interrupt+0x3e4/0x5f0
CPU: 41 PID: 1103 Comm: (spawn) Not tainted
NIP: c000000000039534 LR: c000000000039234 CTR: c000000000009a00
REGS: c000007fffbcf940 TRAP: 0700 Not tainted
MSR: 9000000000021033 <SF,HV,ME,IR,DR,RI,LE> CR: 22042482 XER: 200400ad
CFAR: c000000000039260 IRQMASK: 3
GPR00: c000000000039204 c000007fffbcfbe0 c000000001d6c300 0000000000000003
GPR04: 00007ffffa45d078 0000000000000000 0000000000000008 0000000000000020
GPR08: 0000007ffd4e0000 0000000000000000 c000007ffffceb00 7265677368657265
GPR12: 9000000000009033 c000007ffffceb00 00000f7075bf4480 000000000000002a
GPR16: 00000f705745a528 00007ffffa45ddd8 00000f70574d0008 0000000000000000
GPR20: 00000f7075c58d70 00000f7057459c38 0000000000000001 0000000000000040
GPR24: 0000000000000000 0000000000000029 c000000001dae058 0000000000000029
GPR28: 0000000000000000 0000000000000800 0000000000000009 c000007fffbcfd60
NIP [c000000000039534] soft_nmi_interrupt+0x3e4/0x5f0
LR [c000000000039234] soft_nmi_interrupt+0xe4/0x5f0
Call Trace:
[c000007fffbcfbe0] [c000000000039204] soft_nmi_interrupt+0xb4/0x5f0 (unreliable)
[c000007fffbcfcf0] [c00000000000c0e8] soft_nmi_common+0x138/0x1c4
--- interrupt: 900 at end_real_trampolines+0x0/0x1000
NIP: c000000000003000 LR: 00007ca426adb03c CTR: 900000000280f033
REGS: c000007fffbcfd60 TRAP: 0900
MSR: 9000000000009033 <SF,HV,EE,ME,IR,DR,RI,LE> CR: 44042482 XER: 200400ad
CFAR: 00007ca426946020 IRQMASK: 0
GPR00: 00000000000000ad 00007ffffa45d050 00007ca426b07f00 0000000000000035
GPR04: 00007ffffa45d078 0000000000000000 0000000000000008 0000000000000020
GPR08: 0000000000000000 0000000000100000 0000000010000000 00007ffffa45d110
GPR12: 0000000000000001 00007ca426d4e680 00000f7075bf4480 000000000000002a
GPR16: 00000f705745a528 00007ffffa45ddd8 00000f70574d0008 0000000000000000
GPR20: 00000f7075c58d70 00000f7057459c38 0000000000000001 0000000000000040
GPR24: 0000000000000000 00000f7057473f68 0000000000000003 000000000000041b
GPR28: 00007ffffa45d4c4 0000000000000035 0000000000000000 00000f7057473f68
NIP [c000000000003000] end_real_trampolines+0x0/0x1000
LR [00007ca426adb03c] 0x7ca426adb03c
--- interrupt: 900
Instruction dump:
60000000 60000000 60420000 38600001 482b3ae5 60000000 e93f0138 a36d0008
7daa6b78 71290001 7f7907b4 4082fd34 <0fe00000> 4bfffd2c 60420000 ea6100a8
---[ end trace dc75f67d819779da ]---
Fixes: 118178e62e2e ("powerpc: move NMI entry/exit code into wrapper")
Reported-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210503111708.758261-1-npiggin@gmail.com
|
|
The stf entry barrier fallback is unsafe to execute in a semi-patched
state, which can happen when enabling/disabling the mitigation with
strict kernel RWX enabled and using the hash MMU.
See the previous commit for more details.
Fix it by changing the order in which we patch the instructions.
Note the stf barrier fallback is only used on Power6 or earlier.
Fixes: bd573a81312f ("powerpc/mm/64s: Allow STRICT_KERNEL_RWX again")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210513140800.1391706-2-mpe@ellerman.id.au
|
|
The entry flush mitigation can be enabled/disabled at runtime. When this
happens it results in the kernel patching its own instructions to
enable/disable the mitigation sequence.
With strict kernel RWX enabled instruction patching happens via a
secondary mapping of the kernel text, so that we don't have to make the
primary mapping writable. With the hash MMU this leads to a hash fault,
which causes us to execute the exception entry which contains the entry
flush mitigation.
This means we end up executing the entry flush in a semi-patched state,
ie. after we have patched the first instruction but before we patch the
second or third instruction of the sequence.
On machines with updated firmware the entry flush is a series of special
nops, and it's safe to to execute in a semi-patched state.
However when using the fallback flush the sequence is mflr/branch/mtlr,
and so it's not safe to execute if we have patched out the mflr but not
the other two instructions. Doing so leads to us corrputing LR, leading
to an oops, for example:
# echo 0 > /sys/kernel/debug/powerpc/entry_flush
kernel tried to execute exec-protected page (c000000002971000) - exploit attempt? (uid: 0)
BUG: Unable to handle kernel instruction fetch
Faulting instruction address: 0xc000000002971000
Oops: Kernel access of bad area, sig: 11 [#1]
LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
CPU: 0 PID: 2215 Comm: bash Not tainted 5.13.0-rc1-00010-gda3bb206c9ce #1
NIP: c000000002971000 LR: c000000002971000 CTR: c000000000120c40
REGS: c000000013243840 TRAP: 0400 Not tainted (5.13.0-rc1-00010-gda3bb206c9ce)
MSR: 8000000010009033 <SF,EE,ME,IR,DR,RI,LE> CR: 48428482 XER: 00000000
...
NIP 0xc000000002971000
LR 0xc000000002971000
Call Trace:
do_patch_instruction+0xc4/0x340 (unreliable)
do_entry_flush_fixups+0x100/0x3b0
entry_flush_set+0x50/0xe0
simple_attr_write+0x160/0x1a0
full_proxy_write+0x8c/0x110
vfs_write+0xf0/0x340
ksys_write+0x84/0x140
system_call_exception+0x164/0x2d0
system_call_common+0xec/0x278
The simplest fix is to change the order in which we patch the
instructions, so that the sequence is always safe to execute. For the
non-fallback flushes it doesn't matter what order we patch in.
Fixes: bd573a81312f ("powerpc/mm/64s: Allow STRICT_KERNEL_RWX again")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210513140800.1391706-1-mpe@ellerman.id.au
|
|
The entry flush mitigation can be enabled/disabled at runtime via a
debugfs file (entry_flush), which causes the kernel to patch itself to
enable/disable the relevant mitigations.
However depending on which mitigation we're using, it may not be safe to
do that patching while other CPUs are active. For example the following
crash:
sleeper[15639]: segfault (11) at c000000000004c20 nip c000000000004c20 lr c000000000004c20
Shows that we returned to userspace with a corrupted LR that points into
the kernel, due to executing the partially patched call to the fallback
entry flush (ie. we missed the LR restore).
Fix it by doing the patching under stop machine. The CPUs that aren't
doing the patching will be spinning in the core of the stop machine
logic. That is currently sufficient for our purposes, because none of
the patching we do is to that code or anywhere in the vicinity.
Fixes: f79643787e0a ("powerpc/64s: flush L1D on kernel entry")
Cc: stable@vger.kernel.org # v5.10+
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210506044959.1298123-2-mpe@ellerman.id.au
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The STF (store-to-load forwarding) barrier mitigation can be
enabled/disabled at runtime via a debugfs file (stf_barrier), which
causes the kernel to patch itself to enable/disable the relevant
mitigations.
However depending on which mitigation we're using, it may not be safe to
do that patching while other CPUs are active. For example the following
crash:
User access of kernel address (c00000003fff5af0) - exploit attempt? (uid: 0)
segfault (11) at c00000003fff5af0 nip 7fff8ad12198 lr 7fff8ad121f8 code 1
code: 40820128 e93c00d0 e9290058 7c292840 40810058 38600000 4bfd9a81 e8410018
code: 2c030006 41810154 3860ffb6 e9210098 <e94d8ff0> 7d295279 39400000 40820a3c
Shows that we returned to userspace without restoring the user r13
value, due to executing the partially patched STF exit code.
Fix it by doing the patching under stop machine. The CPUs that aren't
doing the patching will be spinning in the core of the stop machine
logic. That is currently sufficient for our purposes, because none of
the patching we do is to that code or anywhere in the vicinity.
Fixes: a048a07d7f45 ("powerpc/64s: Add support for a store forwarding barrier at kernel entry/exit")
Cc: stable@vger.kernel.org # v4.17+
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210506044959.1298123-1-mpe@ellerman.id.au
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If a trace event uses the %*.s notation, the trace_check_vprintf() will
fail and will warn about a bad processing of strings, because it does not
take into account the length field when processing the star (*) part.
Have it handle this case as well.
Link: https://lore.kernel.org/linux-nfs/238C0E2D-C2A4-4578-ADD2-C565B3B99842@oracle.com/
Reported-by: Chuck Lever III <chuck.lever@oracle.com>
Fixes: 9a6944fee68e2 ("tracing: Add a verifier to check string pointers for trace events")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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David Gow
Mauro Carvalho Chehab
Brendan Higgins
Daniel Latypov
Linus Torvalds
Tetsuo Handa
Christophe Leroy
Rasmus Villemoes
Jouni Roivas
Matthew Wilcox (Oracle)
Peter Collingbourne
Hugh Dickins
Axel Rasmussen
Phillip Lougher
Alistair Popple
Vlastimil Babka
Peter Xu
Catalin Marinas
Bart Van Assche
Ming Lei
Stefano Stabellini
Christoph Hellwig
Vitaly Kuznetsov
Pavel Begunkov
Nicholas Piggin
Michael Ellerman
Steven Rostedt (VMware)