pstore_dump() is called when both preemption and local IRQ are disabled,
and a spinlock is obtained, which is problematic for the RT kernel because
in this configuration, spinlocks are sleep locks.
Replace the spinlock_t with raw_spinlock_t to avoid sleeping in atomic context.
Signed-off-by: Wen Yang <wen.yang@linux.dev>
Cc: Kees Cook <kees@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Guilherme G. Piccoli <gpiccoli@igalia.com>
Cc: linux-hardening@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20240819145945.61274-1-wen.yang@linux.dev
Signed-off-by: Kees Cook <kees@kernel.org>
* reserve_mem command line parameter to allow creation of named memory
reservation at boot time.
The driving use-case is to improve the ability of pstore to retain
ramoops data across reboots.
* cleaunps and small improvements in memblock and mm_init
* new tests cases in memblock test suite
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Merge tag 'memblock-v6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock
Pull memblock updates from Mike Rapoport:
- 'reserve_mem' command line parameter to allow creation of named
memory reservation at boot time.
The driving use-case is to improve the ability of pstore to retain
ramoops data across reboots.
- cleanups and small improvements in memblock and mm_init
- new tests cases in memblock test suite
* tag 'memblock-v6.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock:
memblock tests: fix implicit declaration of function 'numa_valid_node'
memblock: Move late alloc warning down to phys alloc
pstore/ramoops: Add ramoops.mem_name= command line option
mm/memblock: Add "reserve_mem" to reserved named memory at boot up
mm/mm_init.c: don't initialize page->lru again
mm/mm_init.c: not always search next deferred_init_pfn from very beginning
mm/mm_init.c: use deferred_init_mem_pfn_range_in_zone() to decide loop condition
mm/mm_init.c: get the highest zone directly
mm/mm_init.c: move nr_initialised reset down a bit
mm/memblock: fix a typo in description of for_each_mem_region()
mm/mm_init.c: use memblock_region_memory_base_pfn() to get startpfn
mm/memblock: use PAGE_ALIGN_DOWN to get pgend in free_memmap
mm/memblock: return true directly on finding overlap region
memblock tests: add memblock_overlaps_region_checks
mm/memblock: fix comment for memblock_isolate_range()
memblock tests: add memblock_reserve_many_may_conflict_check()
memblock tests: add memblock_reserve_all_locations_check()
mm/memblock: remove empty dummy entry
Add a method to find a region specified by reserve_mem=nn:align:name for
ramoops. Adding a kernel command line parameter:
reserve_mem=12M:4096:oops ramoops.mem_name=oops
Will use the size and location defined by the memmap parameter where it
finds the memory and labels it "oops". The "oops" in the ramoops option
is used to search for it.
This allows for arbitrary RAM to be used for ramoops if it is known that
the memory is not cleared on kernel crashes or soft reboots.
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Kees Cook <kees@kernel.org>
Link: https://lore.kernel.org/r/20240613155527.591647061@goodmis.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
With ARCH=csky, make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in fs/pstore/pstore.o
Add the missing invocation of the MODULE_DESCRIPTION() macro.
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Link: https://lore.kernel.org/r/20240613-md-csky-fs-pstore-v1-1-c525f636b1cb@quicinc.com
Signed-off-by: Kees Cook <kees@kernel.org>
strncpy() is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.
We know that info-device should be NUL-terminated based on its use with
strlen():
| static int __init mtdpstore_init(void)
| {
| int ret;
| struct mtdpstore_context *cxt = &oops_cxt;
| struct pstore_blk_config *info = &cxt->info;
|
| ret = pstore_blk_get_config(info);
| if (unlikely(ret))
| return ret;
|
| if (strlen(info->device) == 0) {
| pr_err("mtd device must be supplied (device name is empty)\n");
...
Considering the above, a suitable replacement is `strscpy` [2] due to
the fact that it guarantees NUL-termination on the destination buffer.
Note that this patch relies on the _new_ 2-argument version of strscpy()
introduced in Commit e6584c3964 ("string: Allow 2-argument strscpy()").
Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
Link: https://github.com/KSPP/linux/issues/90
Cc: <linux-hardening@vger.kernel.org>
Signed-off-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/20240328-strncpy-fs-pstore-blk-c-v1-1-5748cdc22a53@google.com
Signed-off-by: Kees Cook <keescook@chromium.org>
kasprintf() returns a pointer to dynamically allocated memory
which can be NULL upon failure. Ensure the allocation was successful
by checking the pointer validity.
Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
Link: https://lore.kernel.org/r/20240118100206.213928-1-chentao@kylinos.cn
Signed-off-by: Kees Cook <keescook@chromium.org>
Register the compatible for this module on the module device table so
it can be automatically loaded when a matching DT node is present,
allowing logging of panics and oopses without any intervention.
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20240110210600.787703-2-nfraprado@collabora.com
Signed-off-by: Kees Cook <keescook@chromium.org>
Unloading a modular pstore backend with records in pstorefs would
trigger the dput() double-drop warning:
WARNING: CPU: 0 PID: 2569 at fs/dcache.c:762 dput.part.0+0x3f3/0x410
Using the combo of d_drop()/dput() (as mentioned in
Documentation/filesystems/vfs.rst) isn't the right approach here, and
leads to the reference counting problem seen above. Use d_invalidate()
and update the code to not bother checking for error codes that can
never happen.
Suggested-by: Alexander Viro <viro@zeniv.linux.org.uk>
Fixes: 609e28bb13 ("pstore: Remove filesystem records when backend is unregistered")
Signed-off-by: Kees Cook <keescook@chromium.org>
---
Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-hardening@vger.kernel.org
Simplify error path for failures where "inode" needs to be freed.
Cc: Guilherme G. Piccoli <gpiccoli@igalia.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: <linux-hardening@vger.kernel.org>
Link: https://lore.kernel.org/r/20231205182622.1329923-3-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Mostly as an example to myself, replace a simple allocation pattern with
the automatic kfree cleanup features now exposed by cleanup.h.
Cc: Guilherme G. Piccoli <gpiccoli@igalia.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: <linux-hardening@vger.kernel.org>
Link: https://lore.kernel.org/r/20231205182622.1329923-1-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
In persistent_ram_init_ecc(), on 64-bit arches DIV_ROUND_UP() will return
64-bit value since persistent_ram_zone::buffer_size has type size_t which
is derived from the 64-bit *unsigned long*, while the ecc_blocks variable
this value gets assigned to has (always 32-bit) *int* type. Even if that
value fits into *int* type, an overflow is still possible when calculating
the size_t typed ecc_total variable further below since there's no cast to
any 64-bit type before multiplication. Declaring the ecc_blocks variable
as *size_t* should fix this mess...
Found by Linux Verification Center (linuxtesting.org) with the SVACE static
analysis tool.
Fixes: 9cc05ad97c ("staging: android: persistent_ram: refactor ecc support")
Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Link: https://lore.kernel.org/r/20231105202936.25694-1-s.shtylyov@omp.ru
Signed-off-by: Kees Cook <keescook@chromium.org>
When the number of cpu cores is adjusted to 7 or other odd numbers,
the zone size will become an odd number.
The address of the zone will become:
addr of zone0 = BASE
addr of zone1 = BASE + zone_size
addr of zone2 = BASE + zone_size*2
...
The address of zone1/3/5/7 will be mapped to non-alignment va.
Eventually crashes will occur when accessing these va.
So, use ALIGN_DOWN() to make sure the zone size is even
to avoid this bug.
Signed-off-by: Weichen Chen <weichen.chen@mediatek.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Tested-by: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Link: https://lore.kernel.org/r/20230224023632.6840-1-weichen.chen@mediatek.com
Signed-off-by: Kees Cook <keescook@chromium.org>
Convert to using the new inode timestamp accessor functions.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20231004185347.80880-60-jlayton@kernel.org
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Add check for the return value of kstrdup() and return the error
if it fails in order to avoid NULL pointer dereference.
Fixes: 563ca40ddf ("pstore/platform: Switch pstore_info::name to const")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Link: https://lore.kernel.org/r/20230623022706.32125-1-jiasheng@iscas.ac.cn
Signed-off-by: Kees Cook <keescook@chromium.org>
Commit 1756ddea69 ("pstore: Remove worst-case compression size logic")
removed some clunky per-algorithm worst case size estimation routines on
the basis that we can always store pstore records uncompressed, and
these worst case estimations are about how much the size might
inadvertently *increase* due to encapsulation overhead when the input
cannot be compressed at all. So if compression results in a size
increase, we just store the original data instead.
However, it seems that the original code was misinterpreting these
calculations as an estimation of how much uncompressed data might fit
into a compressed buffer of a given size, and it was using the results
to consume the input data in larger chunks than the pstore record size,
relying on the compression to ensure that what ultimately gets stored
fits into the available space.
One result of this, as observed and reported by Linus, is that upgrading
to a newer kernel that includes the given commit may result in pstore
decompression errors reported in the kernel log. This is due to the fact
that the existing records may unexpectedly decompress to a size that is
larger than the pstore record size.
Another potential problem caused by this change is that we may
underutilize the fixed sized records on pstore backends such as ramoops.
And on pstore backends with variable sized records such as EFI, we will
end up creating many more entries than before to store the same amount
of compressed data.
So let's fix both issues, by bringing back the typical case estimation of
how much ASCII text captured from the dmesg log might fit into a pstore
record of a given size after compression. The original implementation
used the computation given below for zlib:
switch (size) {
/* buffer range for efivars */
case 1000 ... 2000:
cmpr = 56;
break;
case 2001 ... 3000:
cmpr = 54;
break;
case 3001 ... 3999:
cmpr = 52;
break;
/* buffer range for nvram, erst */
case 4000 ... 10000:
cmpr = 45;
break;
default:
cmpr = 60;
break;
}
return (size * 100) / cmpr;
We will use the previous worst-case of 60% for compression. For
decompression go extra large (3x) so we make sure there's enough space
for anything.
While at it, rate limit the error message so we don't flood the log
unnecessarily on systems that have accumulated a lot of pstore history.
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20230830212238.135900-1-ardb@kernel.org
Co-developed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Fix the warning for the description of struct persistent_ram_buffer and
improve the descriptions of the other struct members while I'm here.
Signed-off-by: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Link: https://lore.kernel.org/r/20230818201253.2729485-1-willy@infradead.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Currently pstore record buffers are allocated using kmalloc() which has
a maximum size based on page size. If a large "pmsg-size" module
parameter is specified, pmsg will fail to copy the contents since
memdup_user() is limited to kmalloc() allocation sizes.
Since we don't need physically contiguous memory for any of the pstore
record buffers, use kvzalloc() to avoid such limitations in the core of
pstore and in the ram backend, and explicitly read from userspace using
vmemdup_user(). This also means that any other backends that want to
(or do already) support larger record sizes will Just Work now.
Signed-off-by: Yuxiao Zhang <yuxiaozhang@google.com>
Link: https://lore.kernel.org/r/20230627202540.881909-2-yuxiaozhang@google.com
Co-developed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
After commit 30696378f6 ("pstore/ram: Do not treat empty buffers as
valid"), initialization would assume a prz was valid after seeing that
the buffer_size is zero (regardless of the buffer start position). This
unchecked start value means it could be outside the bounds of the buffer,
leading to future access panics when written to:
sysdump_panic_event+0x3b4/0x5b8
atomic_notifier_call_chain+0x54/0x90
panic+0x1c8/0x42c
die+0x29c/0x2a8
die_kernel_fault+0x68/0x78
__do_kernel_fault+0x1c4/0x1e0
do_bad_area+0x40/0x100
do_translation_fault+0x68/0x80
do_mem_abort+0x68/0xf8
el1_da+0x1c/0xc0
__raw_writeb+0x38/0x174
__memcpy_toio+0x40/0xac
persistent_ram_update+0x44/0x12c
persistent_ram_write+0x1a8/0x1b8
ramoops_pstore_write+0x198/0x1e8
pstore_console_write+0x94/0xe0
...
To avoid this, also check if the prz start is 0 during the initialization
phase. If not, the next prz sanity check case will discover it (start >
size) and zap the buffer back to a sane state.
Fixes: 30696378f6 ("pstore/ram: Do not treat empty buffers as valid")
Cc: Yunlong Xing <yunlong.xing@unisoc.com>
Cc: stable@vger.kernel.org
Signed-off-by: Enlin Mu <enlin.mu@unisoc.com>
Link: https://lore.kernel.org/r/20230801060432.1307717-1-yunlong.xing@unisoc.com
[kees: update commit log with backtrace and clarifications]
Signed-off-by: Kees Cook <keescook@chromium.org>
In later patches, we're going to change how the inode's ctime field is
used. Switch to using accessor functions instead of raw accesses of
inode->i_ctime.
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Message-Id: <20230705190309.579783-66-jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Pstore supports compression using a variety of algorithms exposed by the
crypto API. This uses the deprecated comp (as opposed to scomp/acomp)
API, and so we should stop using that, and either move to the new API,
or switch to a different approach entirely.
Given that we only compress ASCII text in pstore, and considering that
this happens when the system is likely to be in an unstable state, the
flexibility that the complex crypto API provides does not outweigh its
impact on the risk that we might encounter additional problems when
trying to commit the kernel log contents to the pstore backend.
So let's switch [back] to the zlib deflate library API, and remove all
the complexity that really has no place in a low-level diagnostic
facility. Note that, while more modern compression algorithms have been
added to the kernel in recent years, the code size of zlib deflate is
substantially smaller than, e.g., zstd, while its performance in terms
of compression ratio is comparable for ASCII text, and speed is deemed
irrelevant in this context.
Note that this means that compressed pstore records may no longer be
accessible after a kernel upgrade, but this has never been part of the
contract. (The choice of compression algorithm is not stored in the
pstore records either)
Tested-by: "Guilherme G. Piccoli" <gpiccoli@igalia.com> # Steam Deck
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20230712162332.2670437-3-ardb@kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
The worst case compression size used by pstore gives an upper bound for
how much the data might inadvertently *grow* due to encapsulation
overhead if the input is not compressible at all.
Given that pstore records have individual 'compressed' flags, we can
simply store the uncompressed data if compressing it would end up using
more space, making the worst case identical to the uncompressed case.
This means we can just drop all the elaborate logic that reasons about
upper bounds for each individual compression algorithm, and just store
the uncompressed data directly if compression fails for any reason.
Co-developed-by: Kees Cook <keescook@chromium.org>
Tested-by: "Guilherme G. Piccoli" <gpiccoli@igalia.com> # Steam Deck
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20230712162332.2670437-2-ardb@kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Add check for the return value of kstrdup() and return the error
if it fails in order to avoid NULL pointer dereference.
Fixes: e163fdb3f7 ("pstore/ram: Regularize prz label allocation lifetime")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230614093733.36048-1-jiasheng@iscas.ac.cn
name_to_dev_t has a very misleading name, that doesn't make clear
it should only be used by the early init code, and also has a bad
calling convention that doesn't allow returning different kinds of
errors. Rename it to early_lookup_bdev to make the use case clear,
and return an errno, where -EINVAL means the string could not be
parsed, and -ENODEV means it the string was valid, but there was
no device found for it.
Also stub out the whole call for !CONFIG_BLOCK as all the non-block
root cases are always covered in the caller.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230531125535.676098-14-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.
Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230401120000.2487153-1-u.kleine-koenig@pengutronix.de
- Revert pmsg_lock back to a normal mutex (John Stultz)
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Merge tag 'pstore-v6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull pstore update from Kees Cook:
- Revert pmsg_lock back to a normal mutex (John Stultz)
* tag 'pstore-v6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
pstore: Revert pmsg_lock back to a normal mutex
The module pointer in class_create() never actually did anything, and it
shouldn't have been requred to be set as a parameter even if it did
something. So just remove it and fix up all callers of the function in
the kernel tree at the same time.
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20230313181843.1207845-4-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 76d62f24db.
So while priority inversion on the pmsg_lock is an occasional
problem that an rt_mutex would help with, in uses where logging
is writing to pmsg heavily from multiple threads, the pmsg_lock
can be heavily contended.
After this change landed, it was reported that cases where the
mutex locking overhead was commonly adding on the order of 10s
of usecs delay had suddenly jumped to ~msec delay with rtmutex.
It seems the slight differences in the locks under this level
of contention causes the normal mutexes to utilize the spinning
optimizations, while the rtmutexes end up in the sleeping
slowpath (which allows additional threads to pile on trying
to take the lock).
In this case, it devolves to a worse case senerio where the lock
acquisition and scheduling overhead dominates, and each thread
is waiting on the order of ~ms to do ~us of work.
Obviously, having tons of threads all contending on a single
lock for logging is non-optimal, so the proper fix is probably
reworking pstore pmsg to have per-cpu buffers so we don't have
contention.
Additionally, Steven Rostedt has provided some furhter
optimizations for rtmutexes that improves the rtmutex spinning
path, but at least in my testing, I still see the test tripping
into the sleeping path on rtmutexes while utilizing the spinning
path with mutexes.
But in the short term, lets revert the change to the rt_mutex
and go back to normal mutexes to avoid a potentially major
performance regression. And we can work on optimizations to both
rtmutexes and finer-grained locking for pstore pmsg in the
future.
Cc: Wei Wang <wvw@google.com>
Cc: Midas Chien<midaschieh@google.com>
Cc: "Chunhui Li (李春辉)" <chunhui.li@mediatek.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: kernel-team@android.com
Fixes: 76d62f24db ("pstore: Switch pmsg_lock to an rt_mutex to avoid priority inversion")
Reported-by: "Chunhui Li (李春辉)" <chunhui.li@mediatek.com>
Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230308204043.2061631-1-jstultz@google.com
If mem-type is specified in the device tree
it would end up overriding the record_size
field instead of populating mem_type.
As record_size is currently parsed after the
improper assignment with default size 0 it
continued to work as expected regardless of the
value found in the device tree.
Simply changing the target field of the struct
is enough to get mem-type working as expected.
Fixes: 9d843e8faf ("pstore: Add mem_type property DT parsing support")
Cc: stable@vger.kernel.org
Signed-off-by: Luca Stefani <luca@osomprivacy.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20221222131049.286288-1-luca@osomprivacy.com
In commit 76d62f24db ("pstore: Switch pmsg_lock to an rt_mutex
to avoid priority inversion") I changed a lock to an rt_mutex.
However, its possible that CONFIG_RT_MUTEXES is not enabled,
which then results in a build failure, as the 0day bot detected:
https://lore.kernel.org/linux-mm/202212211244.TwzWZD3H-lkp@intel.com/
Thus this patch changes CONFIG_PSTORE_PMSG to select
CONFIG_RT_MUTEXES, which ensures the build will not fail.
Cc: Wei Wang <wvw@google.com>
Cc: Midas Chien<midaschieh@google.com>
Cc: Connor O'Brien <connoro@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: kernel test robot <lkp@intel.com>
Cc: kernel-team@android.com
Fixes: 76d62f24db ("pstore: Switch pmsg_lock to an rt_mutex to avoid priority inversion")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20221221051855.15761-1-jstultz@google.com
Here is the set of driver core and kernfs changes for 6.2-rc1.
The "big" change in here is the addition of a new macro,
container_of_const() that will preserve the "const-ness" of a pointer
passed into it.
The "problem" of the current container_of() macro is that if you pass in
a "const *", out of it can comes a non-const pointer unless you
specifically ask for it. For many usages, we want to preserve the
"const" attribute by using the same call. For a specific example, this
series changes the kobj_to_dev() macro to use it, allowing it to be used
no matter what the const value is. This prevents every subsystem from
having to declare 2 different individual macros (i.e.
kobj_const_to_dev() and kobj_to_dev()) and having the compiler enforce
the const value at build time, which having 2 macros would not do
either.
The driver for all of this have been discussions with the Rust kernel
developers as to how to properly mark driver core, and kobject, objects
as being "non-mutable". The changes to the kobject and driver core in
this pull request are the result of that, as there are lots of paths
where kobjects and device pointers are not modified at all, so marking
them as "const" allows the compiler to enforce this.
So, a nice side affect of the Rust development effort has been already
to clean up the driver core code to be more obvious about object rules.
All of this has been bike-shedded in quite a lot of detail on lkml with
different names and implementations resulting in the tiny version we
have in here, much better than my original proposal. Lots of subsystem
maintainers have acked the changes as well.
Other than this change, included in here are smaller stuff like:
- kernfs fixes and updates to handle lock contention better
- vmlinux.lds.h fixes and updates
- sysfs and debugfs documentation updates
- device property updates
All of these have been in the linux-next tree for quite a while with no
problems, OTHER than some merge issues with other trees that should be
obvious when you hit them (block tree deletes a driver that this tree
modifies, iommufd tree modifies code that this tree also touches). If
there are merge problems with these trees, please let me know.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core updates from Greg KH:
"Here is the set of driver core and kernfs changes for 6.2-rc1.
The "big" change in here is the addition of a new macro,
container_of_const() that will preserve the "const-ness" of a pointer
passed into it.
The "problem" of the current container_of() macro is that if you pass
in a "const *", out of it can comes a non-const pointer unless you
specifically ask for it. For many usages, we want to preserve the
"const" attribute by using the same call. For a specific example, this
series changes the kobj_to_dev() macro to use it, allowing it to be
used no matter what the const value is. This prevents every subsystem
from having to declare 2 different individual macros (i.e.
kobj_const_to_dev() and kobj_to_dev()) and having the compiler enforce
the const value at build time, which having 2 macros would not do
either.
The driver for all of this have been discussions with the Rust kernel
developers as to how to properly mark driver core, and kobject,
objects as being "non-mutable". The changes to the kobject and driver
core in this pull request are the result of that, as there are lots of
paths where kobjects and device pointers are not modified at all, so
marking them as "const" allows the compiler to enforce this.
So, a nice side affect of the Rust development effort has been already
to clean up the driver core code to be more obvious about object
rules.
All of this has been bike-shedded in quite a lot of detail on lkml
with different names and implementations resulting in the tiny version
we have in here, much better than my original proposal. Lots of
subsystem maintainers have acked the changes as well.
Other than this change, included in here are smaller stuff like:
- kernfs fixes and updates to handle lock contention better
- vmlinux.lds.h fixes and updates
- sysfs and debugfs documentation updates
- device property updates
All of these have been in the linux-next tree for quite a while with
no problems"
* tag 'driver-core-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (58 commits)
device property: Fix documentation for fwnode_get_next_parent()
firmware_loader: fix up to_fw_sysfs() to preserve const
usb.h: take advantage of container_of_const()
device.h: move kobj_to_dev() to use container_of_const()
container_of: add container_of_const() that preserves const-ness of the pointer
driver core: fix up missed drivers/s390/char/hmcdrv_dev.c class.devnode() conversion.
driver core: fix up missed scsi/cxlflash class.devnode() conversion.
driver core: fix up some missing class.devnode() conversions.
driver core: make struct class.devnode() take a const *
driver core: make struct class.dev_uevent() take a const *
cacheinfo: Remove of_node_put() for fw_token
device property: Add a blank line in Kconfig of tests
device property: Rename goto label to be more precise
device property: Move PROPERTY_ENTRY_BOOL() a bit down
device property: Get rid of __PROPERTY_ENTRY_ARRAY_EL*SIZE*()
kernfs: fix all kernel-doc warnings and multiple typos
driver core: pass a const * into of_device_uevent()
kobject: kset_uevent_ops: make name() callback take a const *
kobject: kset_uevent_ops: make filter() callback take a const *
kobject: make kobject_namespace take a const *
...
Wei Wang reported seeing priority inversion caused latencies
caused by contention on pmsg_lock, and suggested it be switched
to a rt_mutex.
I was initially hesitant this would help, as the tasks in that
trace all seemed to be SCHED_NORMAL, so the benefit would be
limited to only nice boosting.
However, another similar issue was raised where the priority
inversion was seen did involve a blocked RT task so it is clear
this would be helpful in that case.
Cc: Wei Wang <wvw@google.com>
Cc: Midas Chien<midaschieh@google.com>
Cc: Connor O'Brien <connoro@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: kernel-team@android.com
Fixes: 9d5438f462 ("pstore: Add pmsg - user-space accessible pstore object")
Reported-by: Wei Wang <wvw@google.com>
Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20221214231834.3711880-1-jstultz@google.com
An oops can be induced by running 'cat /proc/kcore > /dev/null' on
devices using pstore with the ram backend because kmap_atomic() assumes
lowmem pages are accessible with __va().
Unable to handle kernel paging request at virtual address ffffff807ff2b000
Mem abort info:
ESR = 0x96000006
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x06: level 2 translation fault
Data abort info:
ISV = 0, ISS = 0x00000006
CM = 0, WnR = 0
swapper pgtable: 4k pages, 39-bit VAs, pgdp=0000000081d87000
[ffffff807ff2b000] pgd=180000017fe18003, p4d=180000017fe18003, pud=180000017fe18003, pmd=0000000000000000
Internal error: Oops: 96000006 [#1] PREEMPT SMP
Modules linked in: dm_integrity
CPU: 7 PID: 21179 Comm: perf Not tainted 5.15.67-10882-ge4eb2eb988cd #1 baa443fb8e8477896a370b31a821eb2009f9bfba
Hardware name: Google Lazor (rev3 - 8) (DT)
pstate: a0400009 (NzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __memcpy+0x110/0x260
lr : vread+0x194/0x294
sp : ffffffc013ee39d0
x29: ffffffc013ee39f0 x28: 0000000000001000 x27: ffffff807ff2b000
x26: 0000000000001000 x25: ffffffc0085a2000 x24: ffffff802d4b3000
x23: ffffff80f8a60000 x22: ffffff802d4b3000 x21: ffffffc0085a2000
x20: ffffff8080b7bc68 x19: 0000000000001000 x18: 0000000000000000
x17: 0000000000000000 x16: 0000000000000000 x15: ffffffd3073f2e60
x14: ffffffffad588000 x13: 0000000000000000 x12: 0000000000000001
x11: 00000000000001a2 x10: 00680000fff2bf0b x9 : 03fffffff807ff2b
x8 : 0000000000000001 x7 : 0000000000000000 x6 : 0000000000000000
x5 : ffffff802d4b4000 x4 : ffffff807ff2c000 x3 : ffffffc013ee3a78
x2 : 0000000000001000 x1 : ffffff807ff2b000 x0 : ffffff802d4b3000
Call trace:
__memcpy+0x110/0x260
read_kcore+0x584/0x778
proc_reg_read+0xb4/0xe4
During early boot, memblock reserves the pages for the ramoops reserved
memory node in DT that would otherwise be part of the direct lowmem
mapping. Pstore's ram backend reuses those reserved pages to change the
memory type (writeback or non-cached) by passing the pages to vmap()
(see pfn_to_page() usage in persistent_ram_vmap() for more details) with
specific flags. When read_kcore() starts iterating over the vmalloc
region, it runs over the virtual address that vmap() returned for
ramoops. In aligned_vread() the virtual address is passed to
vmalloc_to_page() which returns the page struct for the reserved lowmem
area. That lowmem page is passed to kmap_atomic(), which effectively
calls page_to_virt() that assumes a lowmem page struct must be directly
accessible with __va() and friends. These pages are mapped via vmap()
though, and the lowmem mapping was never made, so accessing them via the
lowmem virtual address oopses like above.
Let's side-step this problem by passing VM_IOREMAP to vmap(). This will
tell vread() to not include the ramoops region in the kcore. Instead the
area will look like a bunch of zeros. The alternative is to teach kmap()
about vmalloc areas that intersect with lowmem. Presumably such a change
isn't a one-liner, and there isn't much interest in inspecting the
ramoops region in kcore files anyway, so the most expedient route is
taken for now.
Cc: Brian Geffon <bgeffon@google.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 404a604338 ("staging: android: persistent_ram: handle reserving and mapping memory")
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20221205233136.3420802-1-swboyd@chromium.org
In the if (dev_of_node(dev) && !pdata) path, the "err" may be assigned a
value of 0, so the error return code -EINVAL may be incorrectly set
to 0. To fix set valid return code before calling to goto.
Fixes: 35da60941e ("pstore/ram: add Device Tree bindings")
Signed-off-by: Wang Yufen <wangyufen@huawei.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/1669969374-46582-1-git-send-email-wangyufen@huawei.com
The devnode() in struct class should not be modifying the device that is
passed into it, so mark it as a const * and propagate the function
signature changes out into all relevant subsystems that use this
callback.
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Reinette Chatre <reinette.chatre@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Justin Sanders <justin@coraid.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Benjamin Gaignard <benjamin.gaignard@collabora.com>
Cc: Liam Mark <lmark@codeaurora.org>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Brian Starkey <Brian.Starkey@arm.com>
Cc: John Stultz <jstultz@google.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Sean Young <sean@mess.org>
Cc: Frank Haverkamp <haver@linux.ibm.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Cornelia Huck <cohuck@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Xie Yongji <xieyongji@bytedance.com>
Cc: Gautam Dawar <gautam.dawar@xilinx.com>
Cc: Dan Carpenter <error27@gmail.com>
Cc: Eli Cohen <elic@nvidia.com>
Cc: Parav Pandit <parav@nvidia.com>
Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
Cc: alsa-devel@alsa-project.org
Cc: dri-devel@lists.freedesktop.org
Cc: kvm@vger.kernel.org
Cc: linaro-mm-sig@lists.linaro.org
Cc: linux-block@vger.kernel.org
Cc: linux-input@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-media@vger.kernel.org
Cc: linux-rdma@vger.kernel.org
Cc: linux-scsi@vger.kernel.org
Cc: linux-usb@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
Link: https://lore.kernel.org/r/20221123122523.1332370-2-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The pstore dump function doesn't alert at all on errors - despite
pstore is usually a last resource and if it fails users won't be
able to read the kernel log, this is not the case for server users
with serial access, for example.
So, let's at least attempt to inform such advanced users on the first
backend writing error detected during the kmsg dump - this is also
very useful for pstore debugging purposes.
Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20221013210648.137452-2-gpiccoli@igalia.com
For good measure, set all the freed addresses to NULL when managing
przs.
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-and-tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Link: https://lore.kernel.org/r/20221011200112.731334-5-keescook@chromium.org
Most of the details of the ram backend are entirely internal to the
backend itself. Leave only what is needed to instantiate a ram backend
in the kernel-wide header.
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-and-tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Link: https://lore.kernel.org/r/20221011200112.731334-4-keescook@chromium.org
Since the ftrace area can vary in size based on CPU count, move pmsg
initialization earlier so it will have a stable location.
Suggested-by: Paramjit Oberoi <pso@chromium.org>
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed: Guilherme G. Piccoli <gpiccoli@igalia.com>
Link: https://lore.kernel.org/r/20221011200112.731334-3-keescook@chromium.org
There's no reason to keep separate kfree() paths: either all allocations
succeeded, or not. Everything is torn down in the case of failure, so
adjust the callers to reflect this.
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-and-tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Link: https://lore.kernel.org/r/20221011200112.731334-2-keescook@chromium.org
Currently we only show the registered ones in the kernel
log; users that change backend for some reason require
first to unregister the current one, so let's confirm this
operation with a message in the log.
Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20221006224212.569555-4-gpiccoli@igalia.com
Currently this tuning is only exposed as a filesystem option,
but most Linux distros automatically mount pstore, hence changing
this setting requires remounting it. Also, if that mount option
wasn't explicitly set it doesn't show up in mount information,
so users cannot check what is the current value of kmsg_bytes.
Let's then expose it as a module parameter, allowing both user
visibility at all times (even if not manually set) and also the
possibility of setting that as a boot/module parameter.
Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20221006224212.569555-3-gpiccoli@igalia.com
The pstore infrastructure supports one single backend at a time;
trying to load a another backend causes an error and displays a
message, introduced on commit 0d7cd09a3d ("pstore: Improve
register_pstore() error reporting").
Happens that this message is not really clear about the situation,
also the current error returned (-EPERM) isn't accurate, whereas
-EBUSY makes more sense. We have another place in the code that
relies in the -EBUSY return for a similar check.
So, make it consistent here by returning -EBUSY and using a
similar message in both scenarios.
Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20221006224212.569555-2-gpiccoli@igalia.com
