In the case we trigger dlm_free_rsb() that does a call_rcu() and the
responding kfree() of res_lvbptr and a kmem_cache_free() of the rsb
pointer we need to wait until this pending operation is done before
calling kmem_cache_destroy(). We doing that by using rcu_barrier() that
waits until all pending call_rcu() are done. This avoids that
kmem_cache_destroy() complains about active objects around that are not
being freed yet by call_rcu().
There is currently more discussions about to make this behaviour better,
see:
https://lore.kernel.org/netdev/20240609082726.32742-1-Julia.Lawall@inria.fr/
However this is only for call_rcu() if the callback calls
kmem_cache_destroy() only to replace it by kfree_rcu() call which has
currently some issue. This isn't our case because we also free the
res_lvbptr if being set.
For our case, to avoid the above race rcu_barrier() should be used before
calling kmem_cache_destroy() to be sure that there are no active objects
around. This is exactly what net/batman-adv is also doing before calling their
kmem_cache_destroy() in module unloading.
Fixes: 01fdeca1cc ("dlm: use rcu to avoid an extra rsb struct lookup")
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
The DLM rcom handling has a check that all exflags are the same for the
whole lockspace membership nodes. There are some flags that requires
such handling, however DLM_LSFL_SOFTIRQ does not require this handling
and it should be backwards compatibility with other lockspaces that does
not set this flag.
Fixes: f328a26eeb ("dlm: introduce DLM_LSFL_SOFTIRQ_SAFE")
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
The last use of 'dlm_processed_nodes' was removed in
commit 1696c75f18 ("fs: dlm: add send ack threshold and append acks to
msgs").
Remove it.
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Signed-off-by: David Teigland <teigland@redhat.com>
Use the recently added DLM_LSFL_SOFTIRQ flag in dlm_new_lockspace(),
signalling the ability to handle callbacks being run from softirq
context. The md-cluster callback functions only call complete(),
which is suitable for softirq. This should make dlm lock request
completions more efficient by avoiding the workqueue context switch.
Acked-by: Heming Zhao <heming.zhao@suse.com>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
When a lockspace user allows it, run callback functions directly from
softirq context, instead of queueing callbacks to be run from the
dlm_callback workqueue context.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Introduce a new external lockspace flag DLM_LSFL_SOFTIRQ_SAFE. A
lockspace user will set this flag if it can handle dlm running the
callback functions from softirq context. When not set, dlm will
continue to run callback functions from the dlm_callback workqueue.
The new lockspace flag cannot be used for user space lockspaces, so
a uapi placeholder definition is used for the new flag value.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
The existing external lockspace flag DLM_LSFL_FS is now also
saved as an internal flag LSFL_FS, so it can be checked from
other code locations which want to know if a lockspace is
used from the kernel or user space.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Use rcu to free rsb structs, and hold the rcu read lock
while looking up rsb structs. This allows us to avoid an
extra hash table lookup for an rsb. A new rsb flag HASHED
is added which is set while the rsb is in the hash table.
This flag is checked in place of repeating the hash table
lookup.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Remove a few calls to add_scan() and del_scan() in cases where
the rsb is a dir record, so the rsb should never be placed on
the scan list at all. Add WARN_ON to catch cases where this
is done.
Signed-off-by: David Teigland <teigland@redhat.com>
The old terminology of "toss" and "keep" is no longer an
accurate description of the rsb states and lists, so change
the names to "inactive" and "active". The old names had
also been copied into the scanning code, which is changed
back to use the "scan" name.
- "active" rsb structs have lkb's attached, and are ref counted.
- "inactive" rsb structs have no lkb's attached, are not ref counted.
- "scan" list is for rsb's that can be freed after a timeout period.
- "slow" lists are for infrequent iterations through active or
inactive rsb structs.
- inactive rsb structs that are directory records will not be put
on the scan list, since they are not freed based on timeouts.
- inactive rsb structs that are not directory records will be
put on the scan list to be freed, since they are not longer needed.
Signed-off-by: David Teigland <teigland@redhat.com>
According to kdoc idr is deprecated and xarrays should be used nowadays.
This patch is moving the recover idr implementation to xarray
datastructure.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
According to kernel doc idr is deprecated and xarrays should be used
nowadays. This patch is moving the lkb idr implementation to xarrays.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch drops the own written rsb pre allocation mechanism as this is
already done by using kmem caches, we don't need another layer on top of
that to running some pre allocation scheme.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch removes ls_local_handle from struct dlm_ls as it stores the
ls pointer of the top level structure itesef and this isn't necessary.
There is a lookup functionality to lookup the lockspace in
dlm_find_lockspace_local() but the given input parameter is the pointer
already. This might be more safe to lookup a lockspace but given a wrong
lockspace pointer is a bug in the code and we save the additional lookup
here. The dlm_ls structure can be still hidden by using dlm_lockspace_t
handle pointer.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch removes an parameter which is currently not used by
dlm_midcomms_addr().
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch removes a kref_init() that isn't necessary because the rsb is
created for toss list. Under toss list the rsb should not have any
reference counting logic. If in theory the rsb gets to into keep list
then a kref_init() for res_ref will be initiated.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This patch removes some leftover related code from dlm_scand that was
dropped in commit b1f2381c1a ("dlm: drop dlm_scand kthread and use
timers").
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
percpu.h depends on smp.h, but doesn't include it directly because of
circular header dependency issues; percpu.h is needed in a bunch of low
level headers.
This fixes a randconfig build error on mips:
include/linux/alloc_tag.h: In function '__alloc_tag_ref_set':
include/asm-generic/percpu.h:31:40: error: implicit declaration of function 'raw_smp_processor_id' [-Werror=implicit-function-declaration]
Reported-by: kernel test robot <lkp@intel.com>
Fixes: 24e44cc22a ("mm: percpu: enable per-cpu allocation tagging")
Closes: https://lore.kernel.org/oe-kbuild-all/202405210052.DIrMXJNz-lkp@intel.com/
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull perf tool fix from Arnaldo Carvalho de Melo:
"Revert a patch causing a regression.
This made a simple 'perf record -e cycles:pp make -j199' stop working
on the Ampere ARM64 system Linus uses to test ARM64 kernels".
* tag 'perf-tools-fixes-for-v6.10-1-2024-05-26' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools:
Revert "perf parse-events: Prefer sysfs/JSON hardware events over legacy"
Pull smb client fixes from Steve French:
- two important netfs integration fixes - including for a data
corruption and also fixes for multiple xfstests
- reenable swap support over SMB3
* tag '6.10-rc-smb3-fixes-part2' of git://git.samba.org/sfrench/cifs-2.6:
cifs: Fix missing set of remote_i_size
cifs: Fix smb3_insert_range() to move the zero_point
cifs: update internal version number
smb3: reenable swapfiles over SMB3 mounts
Pull misc fixes from Andrew Morton:
"16 hotfixes, 11 of which are cc:stable.
A few nilfs2 fixes, the remainder are for MM: a couple of selftests
fixes, various singletons fixing various issues in various parts"
* tag 'mm-hotfixes-stable-2024-05-25-09-13' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
mm/ksm: fix possible UAF of stable_node
mm/memory-failure: fix handling of dissolved but not taken off from buddy pages
mm: /proc/pid/smaps_rollup: avoid skipping vma after getting mmap_lock again
nilfs2: fix potential hang in nilfs_detach_log_writer()
nilfs2: fix unexpected freezing of nilfs_segctor_sync()
nilfs2: fix use-after-free of timer for log writer thread
selftests/mm: fix build warnings on ppc64
arm64: patching: fix handling of execmem addresses
selftests/mm: compaction_test: fix bogus test success and reduce probability of OOM-killer invocation
selftests/mm: compaction_test: fix incorrect write of zero to nr_hugepages
selftests/mm: compaction_test: fix bogus test success on Aarch64
mailmap: update email address for Satya Priya
mm/huge_memory: don't unpoison huge_zero_folio
kasan, fortify: properly rename memintrinsics
lib: add version into /proc/allocinfo output
mm/vmalloc: fix vmalloc which may return null if called with __GFP_NOFAIL
Pull irq fixes from Ingo Molnar:
- Fix x86 IRQ vector leak caused by a CPU offlining race
- Fix build failure in the riscv-imsic irqchip driver
caused by an API-change semantic conflict
- Fix use-after-free in irq_find_at_or_after()
* tag 'irq-urgent-2024-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
genirq/irqdesc: Prevent use-after-free in irq_find_at_or_after()
genirq/cpuhotplug, x86/vector: Prevent vector leak during CPU offline
irqchip/riscv-imsic: Fixup riscv_ipi_set_virq_range() conflict
Pull x86 fixes from Ingo Molnar:
- Fix regressions of the new x86 CPU VFM (vendor/family/model)
enumeration/matching code
- Fix crash kernel detection on buggy firmware with
non-compliant ACPI MADT tables
- Address Kconfig warning
* tag 'x86-urgent-2024-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/cpu: Fix x86_match_cpu() to match just X86_VENDOR_INTEL
crypto: x86/aes-xts - switch to new Intel CPU model defines
x86/topology: Handle bogus ACPI tables correctly
x86/kconfig: Select ARCH_WANT_FRAME_POINTERS again when UNWINDER_FRAME_POINTER=y
Pull ipmi updates from Corey Minyard:
"Mostly updates for deprecated interfaces, platform.remove and
converting from a tasklet to a BH workqueue.
Also use HAS_IOPORT for disabling inb()/outb()"
* tag 'for-linus-6.10-1' of https://github.com/cminyard/linux-ipmi:
ipmi: kcs_bmc_npcm7xx: Convert to platform remove callback returning void
ipmi: kcs_bmc_aspeed: Convert to platform remove callback returning void
ipmi: ipmi_ssif: Convert to platform remove callback returning void
ipmi: ipmi_si_platform: Convert to platform remove callback returning void
ipmi: ipmi_powernv: Convert to platform remove callback returning void
ipmi: bt-bmc: Convert to platform remove callback returning void
char: ipmi: handle HAS_IOPORT dependencies
ipmi: Convert from tasklet to BH workqueue
Pull ceph updates from Ilya Dryomov:
"A series from Xiubo that adds support for additional access checks
based on MDS auth caps which were recently made available to clients.
This is needed to prevent scenarios where the MDS quietly discards
updates that a UID-restricted client previously (wrongfully) acked to
the user.
Other than that, just a documentation fixup"
* tag 'ceph-for-6.10-rc1' of https://github.com/ceph/ceph-client:
doc: ceph: update userspace command to get CephFS metadata
ceph: add CEPHFS_FEATURE_MDS_AUTH_CAPS_CHECK feature bit
ceph: check the cephx mds auth access for async dirop
ceph: check the cephx mds auth access for open
ceph: check the cephx mds auth access for setattr
ceph: add ceph_mds_check_access() helper
ceph: save cap_auths in MDS client when session is opened
Pull ntfs3 updates from Konstantin Komarov:
"Fixes:
- reusing of the file index (could cause the file to be trimmed)
- infinite dir enumeration
- taking DOS names into account during link counting
- le32_to_cpu conversion, 32 bit overflow, NULL check
- some code was refactored
Changes:
- removed max link count info display during driver init
Remove:
- atomic_open has been removed for lack of use"
* tag 'ntfs3_for_6.10' of https://github.com/Paragon-Software-Group/linux-ntfs3:
fs/ntfs3: Break dir enumeration if directory contents error
fs/ntfs3: Fix case when index is reused during tree transformation
fs/ntfs3: Mark volume as dirty if xattr is broken
fs/ntfs3: Always make file nonresident on fallocate call
fs/ntfs3: Redesign ntfs_create_inode to return error code instead of inode
fs/ntfs3: Use variable length array instead of fixed size
fs/ntfs3: Use 64 bit variable to avoid 32 bit overflow
fs/ntfs3: Check 'folio' pointer for NULL
fs/ntfs3: Missed le32_to_cpu conversion
fs/ntfs3: Remove max link count info display during driver init
fs/ntfs3: Taking DOS names into account during link counting
fs/ntfs3: remove atomic_open
fs/ntfs3: use kcalloc() instead of kzalloc()
Pull smb server fixes from Steve French:
"Two ksmbd server fixes, both for stable"
* tag '6.10-rc-ksmbd-server-fixes' of git://git.samba.org/ksmbd:
ksmbd: ignore trailing slashes in share paths
ksmbd: avoid to send duplicate oplock break notifications
Pull RTC updates from Alexandre Belloni:
"There is one new driver and then most of the changes are the device
tree bindings conversions to yaml.
New driver:
- Epson RX8111
Drivers:
- Many Device Tree bindings conversions to dtschema
- pcf8563: wakeup-source support"
* tag 'rtc-6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux:
pcf8563: add wakeup-source support
rtc: rx8111: handle VLOW flag
rtc: rx8111: demote warnings to debug level
rtc: rx6110: Constify struct regmap_config
dt-bindings: rtc: convert trivial devices into dtschema
dt-bindings: rtc: stmp3xxx-rtc: convert to dtschema
dt-bindings: rtc: pxa-rtc: convert to dtschema
rtc: Add driver for Epson RX8111
dt-bindings: rtc: Add Epson RX8111
rtc: mcp795: drop unneeded MODULE_ALIAS
rtc: nuvoton: Modify part number value
rtc: test: Split rtc unit test into slow and normal speed test
dt-bindings: rtc: nxp,lpc1788-rtc: convert to dtschema
dt-bindings: rtc: digicolor-rtc: move to trivial-rtc
dt-bindings: rtc: alphascale,asm9260-rtc: convert to dtschema
dt-bindings: rtc: armada-380-rtc: convert to dtschema
rtc: cros-ec: provide ID table for avoiding fallback match
Pull i3c updates from Alexandre Belloni:
"Runtime PM (power management) is improved and hot-join support has
been added to the dw controller driver.
Core:
- Allow device driver to trigger controller runtime PM
Drivers:
- dw: hot-join support
- svc: better IBI handling"
* tag 'i3c/for-6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux:
i3c: dw: Add hot-join support.
i3c: master: Enable runtime PM for master controller
i3c: master: svc: fix invalidate IBI type and miss call client IBI handler
i3c: master: svc: change ENXIO to EAGAIN when IBI occurs during start frame
i3c: Add comment for -EAGAIN in i3c_device_do_priv_xfers()
Pull UML updates from Richard Weinberger:
- Fixes for -Wmissing-prototypes warnings and further cleanup
- Remove callback returning void from rtc and virtio drivers
- Fix bash location
* tag 'uml-for-linus-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux: (26 commits)
um: virtio_uml: Convert to platform remove callback returning void
um: rtc: Convert to platform remove callback returning void
um: Remove unused do_get_thread_area function
um: Fix -Wmissing-prototypes warnings for __vdso_*
um: Add an internal header shared among the user code
um: Fix the declaration of kasan_map_memory
um: Fix the -Wmissing-prototypes warning for get_thread_reg
um: Fix the -Wmissing-prototypes warning for __switch_mm
um: Fix -Wmissing-prototypes warnings for (rt_)sigreturn
um: Stop tracking host PID in cpu_tasks
um: process: remove unused 'n' variable
um: vector: remove unused len variable/calculation
um: vector: fix bpfflash parameter evaluation
um: slirp: remove set but unused variable 'pid'
um: signal: move pid variable where needed
um: Makefile: use bash from the environment
um: Add winch to winch_handlers before registering winch IRQ
um: Fix -Wmissing-prototypes warnings for __warp_* and foo
um: Fix -Wmissing-prototypes warnings for text_poke*
um: Move declarations to proper headers
...
Pull drm fixes from Dave Airlie:
"Some fixes for the end of the merge window, mostly amdgpu and panthor,
with one nouveau uAPI change that fixes a bad decision we made a few
months back.
nouveau:
- fix bo metadata uAPI for vm bind
panthor:
- Fixes for panthor's heap logical block.
- Reset on unrecoverable fault
- Fix VM references.
- Reset fix.
xlnx:
- xlnx compile and doc fixes.
amdgpu:
- Handle vbios table integrated info v2.3
amdkfd:
- Handle duplicate BOs in reserve_bo_and_cond_vms
- Handle memory limitations on small APUs
dp/mst:
- MST null deref fix.
bridge:
- Don't let next bridge create connector in adv7511 to make probe
work"
* tag 'drm-next-2024-05-25' of https://gitlab.freedesktop.org/drm/kernel:
drm/amdgpu/atomfirmware: add intergrated info v2.3 table
drm/mst: Fix NULL pointer dereference at drm_dp_add_payload_part2
drm/amdkfd: Let VRAM allocations go to GTT domain on small APUs
drm/amdkfd: handle duplicate BOs in reserve_bo_and_cond_vms
drm/bridge: adv7511: Attach next bridge without creating connector
drm/buddy: Fix the warn on's during force merge
drm/nouveau: use tile_mode and pte_kind for VM_BIND bo allocations
drm/panthor: Call panthor_sched_post_reset() even if the reset failed
drm/panthor: Reset the FW VM to NULL on unplug
drm/panthor: Keep a ref to the VM at the panthor_kernel_bo level
drm/panthor: Force an immediate reset on unrecoverable faults
drm/panthor: Document drm_panthor_tiler_heap_destroy::handle validity constraints
drm/panthor: Fix an off-by-one in the heap context retrieval logic
drm/panthor: Relax the constraints on the tiler chunk size
drm/panthor: Make sure the tiler initial/max chunks are consistent
drm/panthor: Fix tiler OOM handling to allow incremental rendering
drm: xlnx: zynqmp_dpsub: Fix compilation error
drm: xlnx: zynqmp_dpsub: Fix few function comments
Occasionally, the generic/001 xfstest will fail indicating corruption in
one of the copy chains when run on cifs against a server that supports
FSCTL_DUPLICATE_EXTENTS_TO_FILE (eg. Samba with a share on btrfs). The
problem is that the remote_i_size value isn't updated by cifs_setsize()
when called by smb2_duplicate_extents(), but i_size *is*.
This may cause cifs_remap_file_range() to then skip the bit after calling
->duplicate_extents() that sets sizes.
Fix this by calling netfs_resize_file() in smb2_duplicate_extents() before
calling cifs_setsize() to set i_size.
This means we don't then need to call netfs_resize_file() upon return from
->duplicate_extents(), but we also fix the test to compare against the pre-dup
inode size.
[Note that this goes back before the addition of remote_i_size with the
netfs_inode struct. It should probably have been setting cifsi->server_eof
previously.]
Fixes: cfc63fc812 ("smb3: fix cached file size problems in duplicate extents (reflink)")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
cc: Paulo Alcantara <pc@manguebit.com>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: Rohith Surabattula <rohiths.msft@gmail.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
cc: netfs@lists.linux.dev
Signed-off-by: Steve French <stfrench@microsoft.com>
Pull more mm updates from Andrew Morton:
"Jeff Xu's implementation of the mseal() syscall"
* tag 'mm-stable-2024-05-24-11-49' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
selftest mm/mseal read-only elf memory segment
mseal: add documentation
selftest mm/mseal memory sealing
mseal: add mseal syscall
mseal: wire up mseal syscall
The commit 2c653d0ee2 ("ksm: introduce ksm_max_page_sharing per page
deduplication limit") introduced a possible failure case in the
stable_tree_insert(), where we may free the new allocated stable_node_dup
if we fail to prepare the missing chain node.
Then that kfolio return and unlock with a freed stable_node set... And
any MM activities can come in to access kfolio->mapping, so UAF.
Fix it by moving folio_set_stable_node() to the end after stable_node
is inserted successfully.
Link: https://lkml.kernel.org/r/20240513-b4-ksm-stable-node-uaf-v1-1-f687de76f452@linux.dev
Fixes: 2c653d0ee2 ("ksm: introduce ksm_max_page_sharing per page deduplication limit")
Signed-off-by: Chengming Zhou <chengming.zhou@linux.dev>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Stefan Roesch <shr@devkernel.io>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Syzbot has reported a potential hang in nilfs_detach_log_writer() called
during nilfs2 unmount.
Analysis revealed that this is because nilfs_segctor_sync(), which
synchronizes with the log writer thread, can be called after
nilfs_segctor_destroy() terminates that thread, as shown in the call trace
below:
nilfs_detach_log_writer
nilfs_segctor_destroy
nilfs_segctor_kill_thread --> Shut down log writer thread
flush_work
nilfs_iput_work_func
nilfs_dispose_list
iput
nilfs_evict_inode
nilfs_transaction_commit
nilfs_construct_segment (if inode needs sync)
nilfs_segctor_sync --> Attempt to synchronize with
log writer thread
*** DEADLOCK ***
Fix this issue by changing nilfs_segctor_sync() so that the log writer
thread returns normally without synchronizing after it terminates, and by
forcing tasks that are already waiting to complete once after the thread
terminates.
The skipped inode metadata flushout will then be processed together in the
subsequent cleanup work in nilfs_segctor_destroy().
Link: https://lkml.kernel.org/r/20240520132621.4054-4-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+e3973c409251e136fdd0@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=e3973c409251e136fdd0
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Cc: "Bai, Shuangpeng" <sjb7183@psu.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
A potential and reproducible race issue has been identified where
nilfs_segctor_sync() would block even after the log writer thread writes a
checkpoint, unless there is an interrupt or other trigger to resume log
writing.
This turned out to be because, depending on the execution timing of the
log writer thread running in parallel, the log writer thread may skip
responding to nilfs_segctor_sync(), which causes a call to schedule()
waiting for completion within nilfs_segctor_sync() to lose the opportunity
to wake up.
The reason why waking up the task waiting in nilfs_segctor_sync() may be
skipped is that updating the request generation issued using a shared
sequence counter and adding an wait queue entry to the request wait queue
to the log writer, are not done atomically. There is a possibility that
log writing and request completion notification by nilfs_segctor_wakeup()
may occur between the two operations, and in that case, the wait queue
entry is not yet visible to nilfs_segctor_wakeup() and the wake-up of
nilfs_segctor_sync() will be carried over until the next request occurs.
Fix this issue by performing these two operations simultaneously within
the lock section of sc_state_lock. Also, following the memory barrier
guidelines for event waiting loops, move the call to set_current_state()
in the same location into the event waiting loop to ensure that a memory
barrier is inserted just before the event condition determination.
Link: https://lkml.kernel.org/r/20240520132621.4054-3-konishi.ryusuke@gmail.com
Fixes: 9ff05123e3 ("nilfs2: segment constructor")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Cc: "Bai, Shuangpeng" <sjb7183@psu.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "nilfs2: fix log writer related issues".
This bug fix series covers three nilfs2 log writer-related issues,
including a timer use-after-free issue and potential deadlock issue on
unmount, and a potential freeze issue in event synchronization found
during their analysis. Details are described in each commit log.
This patch (of 3):
A use-after-free issue has been reported regarding the timer sc_timer on
the nilfs_sc_info structure.
The problem is that even though it is used to wake up a sleeping log
writer thread, sc_timer is not shut down until the nilfs_sc_info structure
is about to be freed, and is used regardless of the thread's lifetime.
Fix this issue by limiting the use of sc_timer only while the log writer
thread is alive.
Link: https://lkml.kernel.org/r/20240520132621.4054-1-konishi.ryusuke@gmail.com
Link: https://lkml.kernel.org/r/20240520132621.4054-2-konishi.ryusuke@gmail.com
Fixes: fdce895ea5 ("nilfs2: change sc_timer from a pointer to an embedded one in struct nilfs_sc_info")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: "Bai, Shuangpeng" <sjb7183@psu.edu>
Closes: https://groups.google.com/g/syzkaller/c/MK_LYqtt8ko/m/8rgdWeseAwAJ
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reset nr_hugepages to zero before the start of the test.
If a non-zero number of hugepages is already set before the start of the
test, the following problems arise:
- The probability of the test getting OOM-killed increases. Proof:
The test wants to run on 80% of available memory to prevent OOM-killing
(see original code comments). Let the value of mem_free at the start
of the test, when nr_hugepages = 0, be x. In the other case, when
nr_hugepages > 0, let the memory consumed by hugepages be y. In the
former case, the test operates on 0.8 * x of memory. In the latter,
the test operates on 0.8 * (x - y) of memory, with y already filled,
hence, memory consumed is y + 0.8 * (x - y) = 0.8 * x + 0.2 * y > 0.8 *
x. Q.E.D
- The probability of a bogus test success increases. Proof: Let the
memory consumed by hugepages be greater than 25% of x, with x and y
defined as above. The definition of compaction_index is c_index = (x -
y)/z where z is the memory consumed by hugepages after trying to
increase them again. In check_compaction(), we set the number of
hugepages to zero, and then increase them back; the probability that
they will be set back to consume at least y amount of memory again is
very high (since there is not much delay between the two attempts of
changing nr_hugepages). Hence, z >= y > (x/4) (by the 25% assumption).
Therefore, c_index = (x - y)/z <= (x - y)/y = x/y - 1 < 4 - 1 = 3
hence, c_index can always be forced to be less than 3, thereby the test
succeeding always. Q.E.D
Link: https://lkml.kernel.org/r/20240521074358.675031-4-dev.jain@arm.com
Fixes: bd67d5c15c ("Test compaction of mlocked memory")
Signed-off-by: Dev Jain <dev.jain@arm.com>
Cc: <stable@vger.kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Sri Jayaramappa <sjayaram@akamai.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Fixes for compaction_test", v2.
The compaction_test memory selftest introduces fragmentation in memory
and then tries to allocate as many hugepages as possible. This series
addresses some problems.
On Aarch64, if nr_hugepages == 0, then the test trivially succeeds since
compaction_index becomes 0, which is less than 3, due to no division by
zero exception being raised. We fix that by checking for division by
zero.
Secondly, correctly set the number of hugepages to zero before trying
to set a large number of them.
Now, consider a situation in which, at the start of the test, a non-zero
number of hugepages have been already set (while running the entire
selftests/mm suite, or manually by the admin). The test operates on 80%
of memory to avoid OOM-killer invocation, and because some memory is
already blocked by hugepages, it would increase the chance of OOM-killing.
Also, since mem_free used in check_compaction() is the value before we
set nr_hugepages to zero, the chance that the compaction_index will
be small is very high if the preset nr_hugepages was high, leading to a
bogus test success.
This patch (of 3):
Currently, if at runtime we are not able to allocate a huge page, the test
will trivially pass on Aarch64 due to no exception being raised on
division by zero while computing compaction_index. Fix that by checking
for nr_hugepages == 0. Anyways, in general, avoid a division by zero by
exiting the program beforehand. While at it, fix a typo, and handle the
case where the number of hugepages may overflow an integer.
Link: https://lkml.kernel.org/r/20240521074358.675031-1-dev.jain@arm.com
Link: https://lkml.kernel.org/r/20240521074358.675031-2-dev.jain@arm.com
Fixes: bd67d5c15c ("Test compaction of mlocked memory")
Signed-off-by: Dev Jain <dev.jain@arm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Sri Jayaramappa <sjayaram@akamai.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
