A race condition between the .runtime_idle() callback and the .remove()
callback in the rtsx_pcr PCI driver leads to a kernel crash due to an
unhandled page fault [1].
The problem is that rtsx_pci_runtime_idle() is not expected to be running
after pm_runtime_get_sync() has been called, but the latter doesn't really
guarantee that. It only guarantees that the suspend and resume callbacks
will not be running when it returns.
However, if a .runtime_idle() callback is already running when
pm_runtime_get_sync() is called, the latter will notice that the runtime PM
status of the device is RPM_ACTIVE and it will return right away without
waiting for the former to complete. In fact, it cannot wait for
.runtime_idle() to complete because it may be called from that callback (it
arguably does not make much sense to do that, but it is not strictly
prohibited).
Thus in general, whoever is providing a .runtime_idle() callback needs
to protect it from running in parallel with whatever code runs after
pm_runtime_get_sync(). [Note that .runtime_idle() will not start after
pm_runtime_get_sync() has returned, but it may continue running then if it
has started earlier.]
One way to address that race condition is to call pm_runtime_barrier()
after pm_runtime_get_sync() (not before it, because a nonzero value of the
runtime PM usage counter is necessary to prevent runtime PM callbacks from
being invoked) to wait for the .runtime_idle() callback to complete should
it be running at that point. A suitable place for doing that is in
pci_device_remove() which calls pm_runtime_get_sync() before removing the
driver, so it may as well call pm_runtime_barrier() subsequently, which
will prevent the race in question from occurring, not just in the rtsx_pcr
driver, but in any PCI drivers providing .runtime_idle() callbacks.
Link: https://lore.kernel.org/lkml/20240229062201.49500-1-kai.heng.feng@canonical.com/ # [1]
Link: https://lore.kernel.org/r/5761426.DvuYhMxLoT@kreacher
Reported-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Ricky Wu <ricky_wu@realtek.com>
Acked-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc: <stable@vger.kernel.org>
Commit c5eb119007 ("PCI / PM: Allow runtime PM without callback
functions") eliminated the need for PM callbacks in
pci_pm_runtime_suspend() and pci_pm_runtime_resume(), but
didn't do the same for pci_pm_runtime_idle().
Therefore, runtime suspend worked as long as the driver implemented at
least one PM callback. But if the driver doesn't implement any PM
callbacks at all (driver->pm is NULL), pci_pm_runtime_idle() returned
-ENOSYS, which prevented runtime suspend.
Modify pci_pm_runtime_idle() to allow PCI device power state transitions
without runtime PM callbacks and complete the original intention of commit
c5eb119007 ("PCI / PM: Allow runtime PM without callback functions").
Link: https://lore.kernel.org/r/20240227062648.16579-1-raag.jadav@intel.com
Signed-off-by: Raag Jadav <raag.jadav@intel.com>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
The Asus B1400 with original shipped firmware versions and VMD disabled
cannot resume from suspend: the NVMe device becomes unresponsive and
inaccessible.
This appears to be an untested D3cold transition by the vendor; Intel
socwatch shows that Windows leaves the NVMe device and parent bridge in D0
during suspend, even though these firmware versions have StorageD3Enable=1.
The NVMe device and parent PCI bridge both share the same "PXP" ACPI power
resource, which gets turned off as both devices are put into D3cold during
suspend. The _OFF() method calls DL23() which sets a L23E bit at offset
0xe2 into the PCI configuration space for this root port. This is the
specific write that the _ON() routine is unable to recover from. This
register is not documented in the public chipset datasheet.
Disallow D3cold on the PCI bridge to enable successful suspend/resume.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215742
Link: https://lore.kernel.org/r/20240228075316.7404-1-drake@endlessos.org
Signed-off-by: Daniel Drake <drake@endlessos.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Jian-Hong Pan <jhp@endlessos.org>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Pull more bcachefs updates from Kent Overstreet:
"Some fixes, Some refactoring, some minor features:
- Assorted prep work for disk space accounting rewrite
- BTREE_TRIGGER_ATOMIC: after combining our trigger callbacks, this
makes our trigger context more explicit
- A few fixes to avoid excessive transaction restarts on
multithreaded workloads: fstests (in addition to ktest tests) are
now checking slowpath counters, and that's shaking out a few bugs
- Assorted tracepoint improvements
- Starting to break up bcachefs_format.h and move on disk types so
they're with the code they belong to; this will make room to start
documenting the on disk format better.
- A few minor fixes"
* tag 'bcachefs-2024-01-21' of https://evilpiepirate.org/git/bcachefs: (46 commits)
bcachefs: Improve inode_to_text()
bcachefs: logged_ops_format.h
bcachefs: reflink_format.h
bcachefs; extents_format.h
bcachefs: ec_format.h
bcachefs: subvolume_format.h
bcachefs: snapshot_format.h
bcachefs: alloc_background_format.h
bcachefs: xattr_format.h
bcachefs: dirent_format.h
bcachefs: inode_format.h
bcachefs; quota_format.h
bcachefs: sb-counters_format.h
bcachefs: counters.c -> sb-counters.c
bcachefs: comment bch_subvolume
bcachefs: bch_snapshot::btime
bcachefs: add missing __GFP_NOWARN
bcachefs: opts->compression can now also be applied in the background
bcachefs: Prep work for variable size btree node buffers
bcachefs: grab s_umount only if snapshotting
...
Pull timer updates from Thomas Gleixner:
"Updates for time and clocksources:
- A fix for the idle and iowait time accounting vs CPU hotplug.
The time is reset on CPU hotplug which makes the accumulated
systemwide time jump backwards.
- Assorted fixes and improvements for clocksource/event drivers"
* tag 'timers-core-2024-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
tick-sched: Fix idle and iowait sleeptime accounting vs CPU hotplug
clocksource/drivers/ep93xx: Fix error handling during probe
clocksource/drivers/cadence-ttc: Fix some kernel-doc warnings
clocksource/drivers/timer-ti-dm: Fix make W=n kerneldoc warnings
clocksource/timer-riscv: Add riscv_clock_shutdown callback
dt-bindings: timer: Add StarFive JH8100 clint
dt-bindings: timer: thead,c900-aclint-mtimer: separate mtime and mtimecmp regs
Pull powerpc fixes from Aneesh Kumar:
- Increase default stack size to 32KB for Book3S
Thanks to Michael Ellerman.
* tag 'powerpc-6.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/64s: Increase default stack size to 32KB
Add a field to bch_snapshot for creation time; this will be important
when we start exposing the snapshot tree to userspace.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
The "apply this compression method in the background" paths now use the
compression option if background_compression is not set; this means that
setting or changing the compression option will cause existing data to
be compressed accordingly in the background.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
bcachefs btree nodes are big - typically 256k - and btree roots are
pinned in memory. As we're now up to 18 btrees, we now have significant
memory overhead in mostly empty btree roots.
And in the future we're going to start enforcing that certain btree node
boundaries exist, to solve lock contention issues - analagous to XFS's
AGIs.
Thus, we need to start allocating smaller btree node buffers when we
can. This patch changes code that refers to the filesystem constant
c->opts.btree_node_size to refer to the btree node buffer size -
btree_buf_bytes() - where appropriate.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
The variable tmp is being assigned a value but it isn't being
read afterwards. The assignment is redundant and so tmp can be
removed.
Cleans up clang scan build warning:
warning: Although the value stored to 'ret' is used in the enclosing
expression, the value is never actually read from 'ret'
[deadcode.DeadStores]
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
drop_locks_do() should not be used in a fastpath without first trying
the do in nonblocking mode - the unlock and relock will cause excessive
transaction restarts and potentially livelocking with other threads that
are contending for the same locks.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Factor out bch2_journal_bufs_to_text(), and use it in the
journal_entry_full() tracepoint; when we can't get a journal reservation
we need to know the outstanding journal entry sizes to know if the
problem is due to excessive flushing.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
When issuing discards, we may need to flush the journal if there's too
many buckets that can't be discarded until a journal flush.
But the heuristic was bad; we should be comparing the number of buckets
that need to flushes against the number of free buckets, not the number
of buckets we saw.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Also print out the data_opts, so that we can see what specifically is
being done to an extent.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This fixes a bug with rebalance IOs getting stuck with reads completed,
but writes never being issued.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Drop t he loop in bch2_kthread_io_clock_wait(): this allows the code
that uses it to be woken up for other reasons, and fixes a bug where
rebalance wouldn't wake up when a scan was requested.
This raises the possibility of spurious wakeups, but callers should
always be able to handle that reasonably well.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Pull header fix from Kent Overstreet:
"Just one small fixup for the RT build"
* tag 'header_cleanup-2024-01-20' of https://evilpiepirate.org/git/bcachefs:
spinlock: Fix failing build for PREEMPT_RT
We don't have to take locks in any particular ordering - we'll make
forward progress just fine - but if we try to stick to an ordering, it
can help to avoid excessive would_deadlock transaction restarts.
This tweaks the reflink path to take extents btree locks in the right
order.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
The disk space accounting rewrite is splitting out accounting for each
replicas set - those are moving to btree keys, instead of percpu
counters.
This breaks bch2_trans_fs_usage_apply() up, splitting out the part we
will still need.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Split out base filesystem usage into its own type; prep work for
breaking up bch2_trans_fs_usage_apply().
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
