Convert the brd driver to use the blk_alloc_disk and blk_cleanup_disk
helpers to simplify gendisk and request_queue allocation. This also
allows to remove the request_queue pointer in struct request_queue,
and to simplify the initialization as blk_cleanup_disk can be called
on any disk returned from blk_alloc_disk.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20210521055116.1053587-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a flag to indicate that __device_add_disk did grab a queue reference
so that disk_release only drops it if we actually had it. This sort
out one of the major pitfals with partially initialized gendisk that
a lot of drivers did get wrong or still do.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20210521055116.1053587-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The tags used for an IO scheduler are currently per hctx.
As such, when q->nr_hw_queues grows, so does the request queue total IO
scheduler tag depth.
This may cause problems for SCSI MQ HBAs whose total driver depth is
fixed.
Ming and Yanhui report higher CPU usage and lower throughput in scenarios
where the fixed total driver tag depth is appreciably lower than the total
scheduler tag depth:
https://lore.kernel.org/linux-block/440dfcfc-1a2c-bd98-1161-cec4d78c6dfc@huawei.com/T/#mc0d6d4f95275a2743d1c8c3e4dc9ff6c9aa3a76b
In that scenario, since the scheduler tag is got first, much contention
is introduced since a driver tag may not be available after we have got
the sched tag.
Improve this scenario by introducing request queue-wide tags for when
a tagset-wide sbitmap is used. The static sched requests are still
allocated per hctx, as requests are initialised per hctx, as in
blk_mq_init_request(..., hctx_idx, ...) ->
set->ops->init_request(.., hctx_idx, ...).
For simplicity of resizing the request queue sbitmap when updating the
request queue depth, just init at the max possible size, so we don't need
to deal with the possibly with swapping out a new sbitmap for old if
we need to grow.
Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/1620907258-30910-3-git-send-email-john.garry@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
refcount_inc_not_zero() in bt_tags_iter() still may read one freed
request.
Fix the issue by the following approach:
1) hold a per-tags spinlock when reading ->rqs[tag] and calling
refcount_inc_not_zero in bt_tags_iter()
2) clearing stale request referred via ->rqs[tag] before freeing
request pool, the per-tags spinlock is held for clearing stale
->rq[tag]
So after we cleared stale requests, bt_tags_iter() won't observe
freed request any more, also the clearing will wait for pending
request reference.
The idea of clearing ->rqs[] is borrowed from John Garry's previous
patch and one recent David's patch.
Tested-by: John Garry <john.garry@huawei.com>
Reviewed-by: David Jeffery <djeffery@redhat.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20210511152236.763464-4-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Grab rq->refcount before calling ->fn in blk_mq_tagset_busy_iter(), and
this way will prevent the request from being re-used when ->fn is
running. The approach is same as what we do during handling timeout.
Fix request use-after-free(UAF) related with completion race or queue
releasing:
- If one rq is referred before rq->q is frozen, then queue won't be
frozen before the request is released during iteration.
- If one rq is referred after rq->q is frozen, refcount_inc_not_zero()
will return false, and we won't iterate over this request.
However, still one request UAF not covered: refcount_inc_not_zero() may
read one freed request, and it will be handled in next patch.
Tested-by: John Garry <john.garry@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20210511152236.763464-3-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For flush request, rq->end_io() may be called two times, one is from
timeout handling(blk_mq_check_expired()), another is from normal
completion(__blk_mq_end_request()).
Move blk_account_io_flush() after flush_rq->ref drops to zero, so
io accounting can be done just once for flush request.
Fixes: b686631865 ("block: add iostat counters for flush requests")
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: John Garry <john.garry@huawei.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20210511152236.763464-2-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blkcg has always rejected to attach if any of the member tasks has shared
io_context. The rationale was that io_contexts can be shared across
different cgroups making it impossible to define what the appropriate
control behavior should be. However, this check causes more problems than it
solves:
* The check prevents controller enable and migrations but not CLONE_IO
itself, which can lead to surprises as the outcome changes depending on
the order of operations.
* Sharing within a cgroup is fine but the check can't distinguish that. This
leads to unnecessary conflicts with the recent CLONE_IO usage in io_uring.
io_context sharing doesn't make any difference for rq_qos based controllers
and the way it's used is safe as long as tasks aren't migrated dynamically
which is the vast majority of use cases. While we can try to make the check
more precise to avoid false positives, the added complexity doesn't seem
worthwhile. Let's just drop blkcg_can_attach().
Signed-off-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/YJrTvHbrRDbJjw+S@slm.duckdns.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We have already delete block_dump feature in mark_inode_dirty() because
it can be replaced by tracepoints, now we also remove the part in
submit_bio() for the same reason. The part of block dump feature in
submit_bio() dump the write process, write region and sectors on the
target disk into kernel message. it can be replaced by
block_bio_queue tracepoint in submit_bio_checks(), so we do not need
block_dump anymore, remove the whole block_dump feature.
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210313030146.2882027-3-yi.zhang@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block_dump is an old debugging interface, one of it's functions is used
to print the information about who write which file on disk. If we
enable block_dump through /proc/sys/vm/block_dump and turn on debug log
level, we can gather information about write process name, target file
name and disk from kernel message. This feature is realized in
block_dump___mark_inode_dirty(), it print above information into kernel
message directly when marking inode dirty, so it is noisy and can easily
trigger log storm. At the same time, get the dentry refcount is also not
safe, we found it will lead to deadlock on ext4 file system with
data=journal mode.
After tracepoints has been introduced into the kernel, we got a
tracepoint in __mark_inode_dirty(), which is a better replacement of
block_dump___mark_inode_dirty(). The only downside is that it only trace
the inode number and not a file name, but it probably doesn't matter
because the original printed file name in block_dump is not accurate in
some cases, and we can still find it through the inode number and device
id. So this patch delete the dirting inode part of block_dump feature.
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210313030146.2882027-2-yi.zhang@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull perf fixes from Thomas Gleixner:
"Two perf fixes:
- Do not check the LBR_TOS MSR when setting up unrelated LBR MSRs as
this can cause malfunction when TOS is not supported
- Allocate the LBR XSAVE buffers along with the DS buffers upfront
because allocating them when adding an event can deadlock"
* tag 'perf-urgent-2021-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/lbr: Remove cpuc->lbr_xsave allocation from atomic context
perf/x86: Avoid touching LBR_TOS MSR for Arch LBR
Pull locking fixes from Thomas Gleixner:
"Two locking fixes:
- Invoke the lockdep tracepoints in the correct place so the ordering
is correct again
- Don't leave the mutex WAITER bit stale when the last waiter is
dropping out early due to a signal as that forces all subsequent
lock operations needlessly into the slowpath until it's cleaned up
again"
* tag 'locking-urgent-2021-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/mutex: clear MUTEX_FLAGS if wait_list is empty due to signal
locking/lockdep: Correct calling tracepoints
Pull irq fixes from Thomas Gleixner:
"A few fixes for irqchip drivers:
- Allocate interrupt descriptors correctly on Mainstone PXA when
SPARSE_IRQ is enabled; otherwise the interrupt association fails
- Make the APPLE AIC chip driver depend on APPLE
- Remove redundant error output on devm_ioremap_resource() failure"
* tag 'irq-urgent-2021-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip: Remove redundant error printing
irqchip/apple-aic: APPLE_AIC should depend on ARCH_APPLE
ARM: PXA: Fix cplds irqdesc allocation when using legacy mode
Pull x86 fixes from Borislav Petkov:
- Fix how SEV handles MMIO accesses by forwarding potential page faults
instead of killing the machine and by using the accessors with the
exact functionality needed when accessing memory.
- Fix a confusion with Clang LTO compiler switches passed to the it
- Handle the case gracefully when VMGEXIT has been executed in
userspace
* tag 'x86_urgent_for_v5.13_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/sev-es: Use __put_user()/__get_user() for data accesses
x86/sev-es: Forward page-faults which happen during emulation
x86/sev-es: Don't return NULL from sev_es_get_ghcb()
x86/build: Fix location of '-plugin-opt=' flags
x86/sev-es: Invalidate the GHCB after completing VMGEXIT
x86/sev-es: Move sev_es_put_ghcb() in prep for follow on patch
Pull powerpc fixes from Michael Ellerman:
- Fix breakage of strace (and other ptracers etc.) when using the new
scv ABI (Power9 or later with glibc >= 2.33).
- Fix early_ioremap() on 64-bit, which broke booting on some machines.
Thanks to Dmitry V. Levin, Nicholas Piggin, Alexey Kardashevskiy, and
Christophe Leroy.
* tag 'powerpc-5.13-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/64s/syscall: Fix ptrace syscall info with scv syscalls
powerpc/64s/syscall: Use pt_regs.trap to distinguish syscall ABI difference between sc and scv syscalls
powerpc: Fix early setup to make early_ioremap() work
Pull Kbuild fixes from Masahiro Yamada:
- Fix short log indentation for tools builds
- Fix dummy-tools to adjust to the latest stackprotector check
* tag 'kbuild-fixes-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kbuild: dummy-tools: adjust to stricter stackprotector check
scripts/jobserver-exec: Fix a typo ("envirnoment")
tools build: Fix quiet cmd indentation
Merge misc fixes from Andrew Morton:
"10 patches.
Subsystems affected by this patch series: mm (pagealloc, gup, kasan,
and userfaultfd), ipc, selftests, watchdog, bitmap, procfs, and lib"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
userfaultfd: hugetlbfs: fix new flag usage in error path
lib: kunit: suppress a compilation warning of frame size
proc: remove Alexey from MAINTAINERS
linux/bits.h: fix compilation error with GENMASK
watchdog: reliable handling of timestamps
kasan: slab: always reset the tag in get_freepointer_safe()
tools/testing/selftests/exec: fix link error
ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry
Revert "mm/gup: check page posion status for coredump."
mm/shuffle: fix section mismatch warning
lib/bitfield_kunit.c: In function `test_bitfields_constants':
lib/bitfield_kunit.c:93:1: warning: the frame size of 7456 bytes is larger than 2048 bytes [-Wframe-larger-than=]
}
^
As the description of BITFIELD_KUNIT in lib/Kconfig.debug, it "Only useful
for kernel devs running the KUnit test harness, and not intended for
inclusion into a production build". Therefore, it is not worth modifying
variable 'test_bitfields_constants' to clear this warning. Just suppress
it.
Link: https://lkml.kernel.org/r/20210518094533.7652-1-thunder.leizhen@huawei.com
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Vitor Massaru Iha <vitor@massaru.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 9bf3bc949f ("watchdog: cleanup handling of false positives")
tried to handle a virtual host stopped by the host a more
straightforward and cleaner way.
But it introduced a risk of false softlockup reports. The virtual host
might be stopped at any time, for example between
kvm_check_and_clear_guest_paused() and is_softlockup(). As a result,
is_softlockup() might read the updated jiffies and detects a softlockup.
A solution might be to put back kvm_check_and_clear_guest_paused() after
is_softlockup() and detect it. But it would put back the cycle that
complicates the logic.
In fact, the handling of all the timestamps is not reliable. The code
does not guarantee when and how many times the timestamps are read. For
example, "period_ts" might be touched anytime also from NMI and re-read in
is_softlockup(). It works just by chance.
Fix all the problems by making the code even more explicit.
1. Make sure that "now" and "period_ts" timestamps are read only once.
They might be changed at anytime by NMI or when the virtual guest is
stopped by the host. Note that "now" timestamp does this implicitly
because "jiffies" is marked volatile.
2. "now" time must be read first. The state of "period_ts" will
decide whether it will be used or the period will get restarted.
3. kvm_check_and_clear_guest_paused() must be called before reading
"period_ts". It touches the variable when the guest was stopped.
As a result, "now" timestamp is used only when the watchdog was not
touched and the guest not stopped in the meantime. "period_ts" is
restarted in all other situations.
Link: https://lkml.kernel.org/r/YKT55gw+RZfyoFf7@alley
Fixes: 9bf3bc949f ("watchdog: cleanup handling of false positives")
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reported-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix the link error by adding '-static':
gcc -Wall -Wl,-z,max-page-size=0x1000 -pie load_address.c -o /home/yang/linux/tools/testing/selftests/exec/load_address_4096
/usr/bin/ld: /tmp/ccopEGun.o: relocation R_AARCH64_ADR_PREL_PG_HI21 against symbol `stderr@@GLIBC_2.17' which may bind externally can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: /tmp/ccopEGun.o(.text+0x158): unresolvable R_AARCH64_ADR_PREL_PG_HI21 relocation against symbol `stderr@@GLIBC_2.17'
/usr/bin/ld: final link failed: bad value
collect2: error: ld returned 1 exit status
make: *** [Makefile:25: tools/testing/selftests/exec/load_address_4096] Error 1
Link: https://lkml.kernel.org/r/20210514092422.2367367-1-yangyingliang@huawei.com
Fixes: 206e22f019 ("tools/testing/selftests: add self-test for verifying load alignment")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Cc: Chris Kennelly <ckennelly@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
