If there's more than one registered tracer to the unwind deferred
infrastructure, it is currently possible that one tracer could cause extra
callbacks to happen for another tracer if the former requests a deferred
stacktrace after the latter's callback was executed and before the task
went back to user space.
Here's an example of how this could occur:
[Task enters kernel]
tracer 1 request -> add cookie to its buffer
tracer 1 request -> add cookie to its buffer
<..>
[ task work executes ]
tracer 1 callback -> add trace + cookie to its buffer
[tracer 2 requests and triggers the task work again]
[ task work executes again ]
tracer 1 callback -> add trace + cookie to its buffer
tracer 2 callback -> add trace + cookie to its buffer
[Task exits back to user space]
This is because the bit for tracer 1 gets set in the task's unwind_mask
when it did its request and does not get cleared until the task returns
back to user space. But if another tracer were to request another deferred
stacktrace, then the next task work will executed all tracer's callbacks
that have their bits set in the task's unwind_mask.
To fix this issue, add another mask called unwind_completed and place it
into the task's info->cache structure. The cache structure is allocated
on the first occurrence of a deferred stacktrace and this unwind_completed
mask is not needed until then. It's better to have it in the cache than to
permanently waste space in the task_struct.
After a tracer's callback is executed, it's bit gets set in this
unwind_completed mask. When the task_work enters, it will AND the task's
unwind_mask with the inverse of the unwind_completed which will eliminate
any work that already had its callback executed since the task entered the
kernel.
When the task leaves the kernel, it will reset this unwind_completed mask
just like it resets the other values as it enters user space.
Link: https://lore.kernel.org/all/20250716142609.47f0e4a5@batman.local.home/
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Indu Bhagat <indu.bhagat@oracle.com>
Cc: "Jose E. Marchesi" <jemarch@gnu.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Jens Remus <jremus@linux.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Sam James <sam@gentoo.org>
Link: https://lore.kernel.org/20250729182405.989222722@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
In order to know which registered callback requested a stacktrace for when
the task goes back to user space, add a bitmask to keep track of all
registered tracers. The bitmask is the size of long, which means that on a
32 bit machine, it can have at most 32 registered tracers, and on 64 bit,
it can have at most 64 registered tracers. This should not be an issue as
there should not be more than 10 (unless BPF can abuse this?).
When a tracer registers with unwind_deferred_init() it will get a bit
number assigned to it. When a tracer requests a stacktrace, it will have
its bit set within the task_struct. When the task returns back to user
space, it will call the callbacks for all the registered tracers where
their bits are set in the task's mask.
When a tracer is removed by the unwind_deferred_cancel() all current tasks
will clear the associated bit, just in case another tracer gets registered
immediately afterward and then gets their callback called unexpectedly.
To prevent live locks from happening if an event that happens between the
task_work and when the task goes back to user space, triggers the deferred
unwind, have the unwind_mask get cleared on exit to user space and not
after the callback is made.
Move the pending bit from a value on the task_struct to bit zero of the
unwind_mask (saves space on the task_struct). This will allow modifying
the pending bit along with the work bits atomically.
Instead of clearing a work's bit after its callback is called, it is
delayed until exit. If the work is requested again, the task_work is not
queued again and the request will be notified that the task has already been
called by returning a positive number (the same as if it was already
pending).
The pending bit is cleared before calling the callback functions but the
current work bits remain. If one of the called works registers again, it
will not trigger a task_work if its bit is still present in the task's
unwind_mask.
If a new work requests a deferred unwind, then it will set both the
pending bit and its own bit. Note this will also cause any work that was
previously queued and had their callback already executed to be executed
again. Future work will remove these spurious callbacks.
The use of atomic_long bit operations were suggested by Peter Zijlstra:
Link: https://lore.kernel.org/all/20250715102912.GQ1613200@noisy.programming.kicks-ass.net/
The unwind_mask could not be converted to atomic_long_t do to atomic_long
not having all the bit operations needed by unwind_mask. Instead it
follows other use cases in the kernel and just typecasts the unwind_mask
to atomic_long_t when using the two atomic_long functions.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Indu Bhagat <indu.bhagat@oracle.com>
Cc: "Jose E. Marchesi" <jemarch@gnu.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Jens Remus <jremus@linux.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Sam James <sam@gentoo.org>
Link: https://lore.kernel.org/20250729182405.822789300@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Add an interface for scheduling task work to unwind the user space stack
before returning to user space. This solves several problems for its
callers:
- Ensure the unwind happens in task context even if the caller may be
running in interrupt context.
- Avoid duplicate unwinds, whether called multiple times by the same
caller or by different callers.
- Create a "context cookie" which allows trace post-processing to
correlate kernel unwinds/traces with the user unwind.
A concept of a "cookie" is created to detect when the stacktrace is the
same. A cookie is generated the first time a user space stacktrace is
requested after the task enters the kernel. As the stacktrace is saved on
the task_struct while the task is in the kernel, if another request comes
in, if the cookie is still the same, it will use the saved stacktrace,
and not have to regenerate one.
The cookie is passed to the caller on request, and when the stacktrace is
generated upon returning to user space, it calls the requester's callback
with the cookie as well as the stacktrace. The cookie is cleared
when it goes back to user space. Note, this currently adds another
conditional to the unwind_reset_info() path that is always called
returning to user space, but future changes will put this back to a single
conditional.
A global list is created and protected by a global mutex that holds
tracers that register with the unwind infrastructure. The number of
registered tracers will be limited in future changes. Each perf program or
ftrace instance will register its own descriptor to use for deferred
unwind stack traces.
Note, in the function unwind_deferred_task_work() that gets called when
returning to user space, it uses a global mutex for synchronization which
will cause a big bottleneck. This will be replaced by SRCU, but that
change adds some complex synchronization that deservers its own commit.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Indu Bhagat <indu.bhagat@oracle.com>
Cc: "Jose E. Marchesi" <jemarch@gnu.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Jens Remus <jremus@linux.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Sam James <sam@gentoo.org>
Link: https://lore.kernel.org/20250729182405.488066537@kernel.org
Co-developed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Pull /proc/sys dcache lookup fix from Al Viro:
"Fix for the breakage spotted by Neil in the interplay between
/proc/sys ->d_compare() weirdness and parallel lookups"
* tag 'pull-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fix proc_sys_compare() handling of in-lookup dentries
Pull scheduler fixes from Borislav Petkov:
- Fix the calculation of the deadline server task's runtime as this
mishap was preventing realtime tasks from running
- Avoid a race condition during migrate-swapping two tasks
- Fix the string reported for the "none" dynamic preemption option
* tag 'sched_urgent_for_v6.16_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/deadline: Fix dl_server runtime calculation formula
sched/core: Fix migrate_swap() vs. hotplug
sched: Fix preemption string of preempt_dynamic_none
Pull objtool fix from Borislav Petkov:
- Fix the compilation of an x86 kernel on a big engian machine due to a
missed endianness conversion
* tag 'objtool_urgent_for_v6.16_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
objtool: Add missing endian conversion to read_annotate()
Pull perf fixes from Borislav Petkov:
- Revert uprobes to using CAP_SYS_ADMIN again as currently they can
destructively modify kernel code from an unprivileged process
- Move a warning to where it belongs
* tag 'perf_urgent_for_v6.16_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf: Revert to requiring CAP_SYS_ADMIN for uprobes
perf/core: Fix the WARN_ON_ONCE is out of lock protected region
Pull x86 fix from Borislav Petkov:
- Make sure AMD SEV guests using secure TSC, include a TSC_FACTOR which
prevents their TSCs from going skewed from the hypervisor's
* tag 'x86_urgent_for_v6.16_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/sev: Use TSC_FACTOR for Secure TSC frequency calculation
Pull locking fixes from Borislav Petkov:
- Disable FUTEX_PRIVATE_HASH for this cycle due to a performance
regression
- Add a selftests compilation product to the corresponding .gitignore
file
* tag 'locking_urgent_for_v6.16_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
selftests/futex: Add futex_numa to .gitignore
futex: Temporary disable FUTEX_PRIVATE_HASH
Pull EDAC fix from Borislav Petkov:
- Initialize sysfs attributes properly to avoid lockdep complaining
about an uninitialized lock class
* tag 'edac_urgent_for_v6.16_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/ras/ras:
EDAC: Initialize EDAC features sysfs attributes
Pull RAS fixes from Borislav Petkov:
- Do not remove the MCE sysfs hierarchy if thresholding sysfs nodes
init fails due to new/unknown banks present, which in itself is not
fatal anyway; add default names for new banks
- Make sure MCE polling settings are honored after CMCI storms
- Make sure MCE threshold limit is reset after the thresholding
interrupt has been serviced
- Clean up properly and disable CMCI banks on shutdown so that a
second/kexec-ed kernel can rediscover those banks again
* tag 'ras_urgent_for_v6.16_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mce: Make sure CMCI banks are cleared during shutdown on Intel
x86/mce/amd: Fix threshold limit reset
x86/mce/amd: Add default names for MCA banks and blocks
x86/mce: Ensure user polling settings are honored when restarting timer
x86/mce: Don't remove sysfs if thresholding sysfs init fails
Pull irq fix from Borislav Petkov:
- Have irq-msi-lib select CONFIG_GENERIC_MSI_IRQ explicitly as it uses
its facilities
* tag 'irq_urgent_for_v6.16_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip/irq-msi-lib: Select CONFIG_GENERIC_MSI_IRQ
Pull HID fixes from Jiri Kosina:
- Memory corruption fixes in hid-appletb-kbd driver (Qasim Ijaz)
- New device ID in hid-elecom driver (Leonard Dizon)
- Fixed several HID debugfs contants (Vicki Pfau)
* tag 'hid-for-linus-2025070502' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid:
HID: appletb-kbd: fix slab use-after-free bug in appletb_kbd_probe
HID: Fix debug name for BTN_GEAR_DOWN, BTN_GEAR_UP, BTN_WHEEL
HID: elecom: add support for ELECOM HUGE 019B variant
HID: appletb-kbd: fix memory corruption of input_handler_list
Pull smb client fixes from Steve French:
- Two reconnect fixes including one for a reboot/reconnect race
- Fix for incorrect file type that can be returned by SMB3.1.1 POSIX
extensions
- tcon initialization fix
- Fix for resolving Windows symlinks with absolute paths
* tag 'v6.16-rc4-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6:
smb: client: fix native SMB symlink traversal
smb: client: fix race condition in negotiate timeout by using more precise timing
cifs: all initializations for tcon should happen in tcon_info_alloc
smb: client: fix warning when reconnecting channel
smb: client: fix readdir returning wrong type with POSIX extensions
Pull i2c fixes from Wolfram Sang:
- designware: initialise msg_write_idx during transfer
- microchip: check return value from core xfer call
- realtek: add 'reg' property constraint to the device tree
* tag 'i2c-for-6.16-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
dt-bindings: i2c: realtek,rtl9301: Fix missing 'reg' constraint
i2c: microchip-core: re-fix fake detections w/ i2cdetect
i2c/designware: Fix an initialization issue
Pull power management fixes from Rafael Wysocki:
"These address system suspend failures under memory pressure in some
configurations, fix up RAPL handling on platforms where PL1 cannot be
disabled, and fix a documentation typo:
- Prevent the Intel RAPL power capping driver from allowing PL1 to be
exceeded by mistake on systems when PL1 cannot be disabled (Zhang
Rui)
- Fix a typo in the ABI documentation (Sumanth Gavini)
- Allow swap to be used a bit longer during system suspend and
hibernation to avoid suspend failures under memory pressure (Mario
Limonciello)"
* tag 'pm-6.16-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
PM: sleep: docs: Replace "diasble" with "disable"
powercap: intel_rapl: Do not change CLAMPING bit if ENABLE bit cannot be changed
PM: Restrict swap use to later in the suspend sequence
Pull ACPI fix from Rafael Wysocki:
"Revert a problematic ACPI battery driver change merged recently"
* tag 'acpi-6.16-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
Revert "ACPI: battery: negate current when discharging"
Merge fixes related to system sleep for 6.16-rc5:
- Fix typo in the ABI documentation (Sumanth Gavini).
- Allow swap to be used a bit longer during system suspend and
hibernation to avoid suspend failures under memory pressure (Mario
Limonciello).
* pm-sleep:
PM: sleep: docs: Replace "diasble" with "disable"
PM: Restrict swap use to later in the suspend sequence
Pull SoC fixes from Arnd Bergmann:
"A couple of fixes for firmware drivers have come up, addressing kernel
side bugs in op-tee and ff-a code, as well as compatibility issues
with exynos-acpm and ff-a protocols.
The only devicetree fixes are for the Apple platform, addressing
issues with conformance to the bindings for the wlan, spi and mipi
nodes"
* tag 'soc-fixes-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc:
arm64: dts: apple: Move touchbar mipi {address,size}-cells from dtsi to dts
arm64: dts: apple: Drop {address,size}-cells from SPI NOR
arm64: dts: apple: t8103: Fix PCIe BCM4377 nodename
optee: ffa: fix sleep in atomic context
firmware: exynos-acpm: fix timeouts on xfers handling
arm64: defconfig: update renamed PHY_SNPS_EUSB2
firmware: arm_ffa: Fix the missing entry in struct ffa_indirect_msg_hdr
firmware: arm_ffa: Replace mutex with rwlock to avoid sleep in atomic context
firmware: arm_ffa: Move memory allocation outside the mutex locking
firmware: arm_ffa: Fix memory leak by freeing notifier callback node
Pull RISC-V fixes from Palmer Dabbelt:
- kCFI is restricted to clang-17 or newer, as earlier versions have
known bugs
- sbi_hsm_hart_start is now staticly allocated, to avoid tripping up
the SBI HSM page mapping on sparse systems.
* tag 'riscv-for-linus-6.16-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
riscv: cpu_ops_sbi: Use static array for boot_data
riscv: Require clang-17 or newer for kCFI
Pull regulator fixes from Mark Brown:
"A few driver fixes (the GPIO one being potentially nasty, though it
has been there for a while without anyone reporting it), and one core
fix for the rarely used combination of coupled regulators and
unbinding"
* tag 'regulator-fix-v6.16-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator:
regulator: gpio: Fix the out-of-bounds access to drvdata::gpiods
regulator: mp886x: Fix ID table driver_data
regulator: sy8824x: Fix ID table driver_data
regulator: tps65219: Fix devm_kmalloc size allocation
regulator: core: fix NULL dereference on unbind due to stale coupling data
Pull spi fixes from Mark Brown:
"As well as a few driver specific fixes we've got a core change here
which raises the hard coded limit on the number of devices we can
support on one SPI bus since some FPGA based systems are running into
the existing limit. This is not a good solution but it's one suitable
for this point in the release cycle, we should dynamically size the
relevant data structures which I hope will happen in the next couple
of merge windows.
We also pull in a MTD fix for the Qualcomm SNAND driver, the two fixes
cover the same issue and merging them together minimises bisection
issues"
* tag 'spi-fix-v6.16-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
spi: cadence-quadspi: fix cleanup of rx_chan on failure paths
spi: spi-fsl-dspi: Clear completion counter before initiating transfer
spi: Raise limit on number of chip selects to 24
mtd: nand: qpic_common: prevent out of bounds access of BAM arrays
spi: spi-qpic-snand: reallocate BAM transactions
Pull x86 platform drivers fixes from Ilpo Järvinen:
"Mostly a few lines fixed here and there except amd/isp4 which improves
swnodes relationships but that is a new driver not in any stable
kernels yet. The think-lmi driver changes also look relatively large
but there are just many fixes to it.
The i2c/piix4 change is a effectively a revert of the commit
7e173eb82a ("i2c: piix4: Make CONFIG_I2C_PIIX4 dependent on
CONFIG_X86") but that required moving the header out from arch/x86
under include/linux/platform_data/
Summary:
- amd/isp4: Improve swnode graph (new driver exception)
- asus-nb-wmi: Use duo keyboard quirk for Zenbook Duo UX8406CA
- dell-lis3lv02d: Add Latitude 5500 accelerometer address
- dell-wmi-sysman: Fix WMI data block retrieval and class dev unreg
- hp-bioscfg: Fix class device unregistration
- i2c: piix4: Re-enable on non-x86 + move FCH header under platform_data/
- intel/hid: Wildcat Lake support
- mellanox:
- mlxbf-pmc: Fix duplicate event ID
- mlxbf-tmfifo: Fix vring_desc.len assignment
- mlxreg-lc: Fix bit-not-set logic check
- nvsw-sn2201: Fix bus number in error message & spelling errors
- portwell-ec: Move watchdog device under correct platform hierarchy
- think-lmi: Error handling fixes (sysfs, kset, kobject, class dev unreg)
- thinkpad_acpi: Handle HKEY 0x1402 event (2025 Thinkpads)
- wmi: Fix WMI event enablement"
* tag 'platform-drivers-x86-v6.16-3' of git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86: (22 commits)
platform/x86: think-lmi: Fix sysfs group cleanup
platform/x86: think-lmi: Fix kobject cleanup
platform/x86: think-lmi: Create ksets consecutively
platform/mellanox: mlxreg-lc: Fix logic error in power state check
i2c: Re-enable piix4 driver on non-x86
Move FCH header to a location accessible by all archs
platform/x86/intel/hid: Add Wildcat Lake support
platform/x86: dell-wmi-sysman: Fix class device unregistration
platform/x86: think-lmi: Fix class device unregistration
platform/x86: hp-bioscfg: Fix class device unregistration
platform/x86: Update swnode graph for amd isp4
platform/x86: dell-wmi-sysman: Fix WMI data block retrieval in sysfs callbacks
platform/x86: wmi: Update documentation of WCxx/WExx ACPI methods
platform/x86: wmi: Fix WMI event enablement
platform/mellanox: nvsw-sn2201: Fix bus number in adapter error message
platform/mellanox: Fix spelling and comment clarity in Mellanox drivers
platform/mellanox: mlxbf-pmc: Fix duplicate event ID for CACHE_DATA1
platform/x86: thinkpad_acpi: handle HKEY 0x1402 event
platform/x86: asus-nb-wmi: add DMI quirk for ASUS Zenbook Duo UX8406CA
platform/x86: dell-lis3lv02d: Add Latitude 5500
...
Pull USB fixes from Greg KH:
"Here are some USB driver fixes for 6.16-rc5. I originally wanted this
to get into -rc4, but there were some regressions that had to be
handled first. Now all looks good. Included in here are the following
fixes:
- cdns3 driver fixes
- xhci driver fixes
- typec driver fixes
- USB hub fixes (this is what took the longest to get right)
- new USB driver quirks added
- chipidea driver fixes
All of these have been in linux-next for a while and now we have no
more reported problems with them"
* tag 'usb-6.16-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (21 commits)
usb: hub: Fix flushing of delayed work used for post resume purposes
xhci: dbc: Flush queued requests before stopping dbc
xhci: dbctty: disable ECHO flag by default
xhci: Disable stream for xHC controller with XHCI_BROKEN_STREAMS
usb: xhci: quirk for data loss in ISOC transfers
usb: dwc3: gadget: Fix TRB reclaim logic for short transfers and ZLPs
usb: hub: Fix flushing and scheduling of delayed work that tunes runtime pm
usb: typec: displayport: Fix potential deadlock
usb: typec: altmodes/displayport: do not index invalid pin_assignments
usb: cdnsp: Fix issue with CV Bad Descriptor test
usb: typec: tcpm: apply vbus before data bringup in tcpm_src_attach
Revert "usb: xhci: Implement xhci_handshake_check_state() helper"
usb: xhci: Skip xhci_reset in xhci_resume if xhci is being removed
usb: gadget: u_serial: Fix race condition in TTY wakeup
Revert "usb: gadget: u_serial: Add null pointer check in gs_start_io"
usb: chipidea: udc: disconnect/reconnect from host when do suspend/resume
usb: acpi: fix device link removal
usb: hub: fix detection of high tier USB3 devices behind suspended hubs
Logitech C-270 even more broken
usb: dwc3: Abort suspend on soft disconnect failure
...
Pull input updates from Dmitry Torokhov:
- support for Acer NGR 200 Controller added to xpad driver
- xpad driver will no longer log errors about URBs at sudden disconnect
- a fix for potential NULL dereference in cs40l50-vibra driver
- several drivers have been switched to using scnprintf() to suppress
warnings about potential output truncation
* tag 'input-for-v6.16-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
Input: cs40l50-vibra - fix potential NULL dereference in cs40l50_upload_owt()
Input: alps - use scnprintf() to suppress truncation warning
Input: iqs7222 - explicitly define number of external channels
Input: xpad - support Acer NGR 200 Controller
Input: xpad - return errors from xpad_try_sending_next_out_packet() up
Input: xpad - adjust error handling for disconnect
Input: apple_z2 - drop default ARCH_APPLE in Kconfig
Input: Fully open-code compatible for grepping
dt-bindings: HID: i2c-hid: elan: Introduce Elan eKTH8D18
Input: psmouse - switch to use scnprintf() to suppress truncation warning
Input: lifebook - switch to use scnprintf() to suppress truncation warning
Input: alps - switch to use scnprintf() to suppress truncation warning
Input: atkbd - switch to use scnprintf() to suppress truncation warning
Input: fsia6b - suppress buffer truncation warning for phys
Input: iqs626a - replace snprintf() with scnprintf()
Pull drm fixes from Dave Airlie:
"Weekly drm fixes, bit of a bumper crop, the usual amdgpu/xe/i915
suspects, then there is a large scattering of fixes across core and
drivers. I think the simple panel lookup fix is probably the largest,
the sched race fix is also fun, but I don't see anything standing out
too badly.
dma-buf:
- fix timeout handling
gem:
- fix framebuffer object references
sched:
- fix spsc queue job count race
bridge:
- fix aux hpd bridge of node
- panel: move missing flag handling
- samsung-dsim: fix %pK usage to %p
panel:
- fix problem with simple panel lookup
ttm:
- fix error path handling
amdgpu:
- SDMA 5.x reset fix
- Add missing firmware declaration
- Fix leak in amdgpu_ctx_mgr_entity_fini()
- Freesync fix
- OLED backlight fix
amdkfd:
- mtype fix for ext coherent system memory
- MMU notifier fix
- gfx7/8 fix
xe:
- Fix chunking the PTE updates and overflowing the maximum number of
dwords with with MI_STORE_DATA_IMM
- Move WA BB to the LRC BO to mitigate hangs on context switch
- Fix frequency/flush WAs for BMG
- Fix kconfig prompt title and description
- Do not require kunit
- Extend 14018094691 WA to BMG
- Fix wedging the device on signal
i915:
- Make mei interrupt top half irq disabled to fix RT builds
- Fix timeline left held on VMA alloc error
- Fix NULL pointer deref in vlv_dphy_param_init()
- Fix selftest mock_request() to avoid NULL deref
exynos:
- switch to using %p instead of %pK
- fix vblank NULL ptr race
- fix lockup on samsung peach-pit/pi chromebooks
vesadrm:
- NULL ptr fix
vmwgfx:
- fix encrypted memory allocation bug
v3d:
- fix irq enabled during reset"
* tag 'drm-fixes-2025-07-04' of https://gitlab.freedesktop.org/drm/kernel: (41 commits)
drm/xe: Do not wedge device on killed exec queues
drm/xe: Extend WA 14018094691 to BMG
drm/v3d: Disable interrupts before resetting the GPU
drm/gem: Acquire references on GEM handles for framebuffers
drm/sched: Increment job count before swapping tail spsc queue
drm/xe: Allow dropping kunit dependency as built-in
drm/xe: Fix kconfig prompt
drm/xe/bmg: Update Wa_22019338487
drm/xe/bmg: Update Wa_14022085890
drm/xe: Split xe_device_td_flush()
drm/xe/xe_guc_pc: Lock once to update stashed frequencies
drm/xe/guc_pc: Add _locked variant for min/max freq
drm/xe: Make WA BB part of LRC BO
drm/xe: Fix out-of-bounds field write in MI_STORE_DATA_IMM
drm/i915/gsc: mei interrupt top half should be in irq disabled context
drm/i915/gt: Fix timeline left held on VMA alloc error
drm/vmwgfx: Fix guests running with TDX/SEV
drm/amd/display: Don't allow OLED to go down to fully off
drm/amd/display: Added case for when RR equals panel's max RR using freesync
drm/amdkfd: add hqd_sdma_get_doorbell callbacks for gfx7/8
...
Pull iommu fixes from Joerg Roedel:
- Rockchip: fix infinite loop caused by probing race condition
- Intel VT-d: assign devtlb cache tag on ATS enablement
* tag 'iommu-fixes-v6.16-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux:
iommu/vt-d: Assign devtlb cache tag on ATS enablement
iommu/rockchip: prevent iommus dead loop when two masters share one IOMMU
Pull block fixes from Jens Axboe:
- NVMe fixes via Christoph:
- fix incorrect cdw15 value in passthru error logging (Alok Tiwari)
- fix memory leak of bio integrity in nvmet (Dmitry Bogdanov)
- refresh visible attrs after being checked (Eugen Hristev)
- fix suspicious RCU usage warning in the multipath code (Geliang Tang)
- correctly account for namespace head reference counter (Nilay Shroff)
- Fix for a regression introduced in ublk in this cycle, where it would
attempt to queue a canceled request.
- brd RCU sleeping fix, also introduced in this cycle. Bare bones fix,
should be improved upon for the next release.
* tag 'block-6.16-20250704' of git://git.kernel.dk/linux:
brd: fix sleeping function called from invalid context in brd_insert_page()
ublk: don't queue request if the associated uring_cmd is canceled
nvme-multipath: fix suspicious RCU usage warning
nvme-pci: refresh visible attrs after being checked
nvmet: fix memory leak of bio integrity
nvme: correctly account for namespace head reference counter
nvme: Fix incorrect cdw15 value in passthru error logging
i2c-host-fixes for v6.16-rc5
designware: initialise msg_write_idx during transfer
microchip: check return value from core xfer call
realtek: add 'reg' property constraint to the device tree
Pull bcachefs fixes from Kent Overstreet:
"The 'opts.casefold_disabled' patch is non critical, but would be a
6.15 backport; it's to address the casefolding + overlayfs
incompatibility that was discovvered late.
It's late because I was hoping that this would be addressed on the
overlayfs side (and will be in 6.17), but user reports keep coming in
on this one (lots of people are using docker these days)"
* tag 'bcachefs-2025-07-03' of git://evilpiepirate.org/bcachefs:
bcachefs: opts.casefold_disabled
bcachefs: Work around deadlock to btree node rewrites in journal replay
bcachefs: Fix incorrect transaction restart handling
bcachefs: fix btree_trans_peek_prev_journal()
bcachefs: mark invalid_btree_id autofix
Pull vfs fixes from Christian Brauner:
- Fix a regression caused by the anonymous inode rework. Making them
regular files causes various places in the kernel to tip over
starting with io_uring.
Revert to the former status quo and port our assertion to be based on
checking the inode so we don't lose the valuable VFS_*_ON_*()
assertions that have already helped discover weird behavior our
outright bugs.
- Fix the the upper bound calculation in fuse_fill_write_pages()
- Fix priority inversion issues in the eventpoll code
- Make secretmen use anon_inode_make_secure_inode() to avoid bypassing
the LSM layer
- Fix a netfs hang due to missing case in final DIO read result
collection
- Fix a double put of the netfs_io_request struct
- Provide some helpers to abstract out NETFS_RREQ_IN_PROGRESS flag
wrangling
- Fix infinite looping in netfs_wait_for_pause/request()
- Fix a netfs ref leak on an extra subrequest inserted into a request's
list of subreqs
- Fix various cifs RPC callbacks to set NETFS_SREQ_NEED_RETRY if a
subrequest fails retriably
- Fix a cifs warning in the workqueue code when reconnecting a channel
- Fix the updating of i_size in netfs to avoid a race between testing
if we should have extended the file with a DIO write and changing
i_size
- Merge the places in netfs that update i_size on write
- Fix coredump socket selftests
* tag 'vfs-6.16-rc5.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
anon_inode: rework assertions
netfs: Update tracepoints in a number of ways
netfs: Renumber the NETFS_RREQ_* flags to make traces easier to read
netfs: Merge i_size update functions
netfs: Fix i_size updating
smb: client: set missing retry flag in cifs_writev_callback()
smb: client: set missing retry flag in cifs_readv_callback()
smb: client: set missing retry flag in smb2_writev_callback()
netfs: Fix ref leak on inserted extra subreq in write retry
netfs: Fix looping in wait functions
netfs: Provide helpers to perform NETFS_RREQ_IN_PROGRESS flag wangling
netfs: Fix double put of request
netfs: Fix hang due to missing case in final DIO read result collection
eventpoll: Fix priority inversion problem
fuse: fix fuse_fill_write_pages() upper bound calculation
fs: export anon_inode_make_secure_inode() and fix secretmem LSM bypass
selftests/coredump: Fix "socket_detect_userspace_client" test failure
In our testing with 6.12 based kernel on a big.LITTLE system, we were
seeing instances of RT tasks being blocked from running on the LITTLE
cpus for multiple seconds of time, apparently by the dl_server. This
far exceeds the default configured 50ms per second runtime.
This is due to the fair dl_server runtime calculation being scaled
for frequency & capacity of the cpu.
Consider the following case under a Big.LITTLE architecture:
Assume the runtime is: 50,000,000 ns, and Frequency/capacity
scale-invariance defined as below:
Frequency scale-invariance: 100
Capacity scale-invariance: 50
First by Frequency scale-invariance,
the runtime is scaled to 50,000,000 * 100 >> 10 = 4,882,812
Then by capacity scale-invariance,
it is further scaled to 4,882,812 * 50 >> 10 = 238,418.
So it will scaled to 238,418 ns.
This smaller "accounted runtime" value is what ends up being
subtracted against the fair-server's runtime for the current period.
Thus after 50ms of real time, we've only accounted ~238us against the
fair servers runtime. This 209:1 ratio in this example means that on
the smaller cpu the fair server is allowed to continue running,
blocking RT tasks, for over 10 seconds before it exhausts its supposed
50ms of runtime. And on other hardware configurations it can be even
worse.
For the fair deadline_server, to prevent realtime tasks from being
unexpectedly delayed, we really do want to use fixed time, and not
scaled time for smaller capacity/frequency cpus. So remove the scaling
from the fair server's accounting to fix this.
Fixes: a110a81c52 ("sched/deadline: Deferrable dl server")
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Suggested-by: John Stultz <jstultz@google.com>
Signed-off-by: kuyo chang <kuyo.chang@mediatek.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Juri Lelli <juri.lelli@redhat.com>
Acked-by: John Stultz <jstultz@google.com>
Tested-by: John Stultz <jstultz@google.com>
Link: https://lore.kernel.org/r/20250702021440.2594736-1-kuyo.chang@mediatek.com
There's one case where ->d_compare() can be called for an in-lookup
dentry; usually that's nothing special from ->d_compare() point of
view, but... proc_sys_compare() is weird.
The thing is, /proc/sys subdirectories can look differently for
different processes. Up to and including having the same name
resolve to different dentries - all of them hashed.
The way it's done is ->d_compare() refusing to admit a match unless
this dentry is supposed to be visible to this caller. The information
needed to discriminate between them is stored in inode; it is set
during proc_sys_lookup() and until it's done d_splice_alias() we really
can't tell who should that dentry be visible for.
Normally there's no negative dentries in /proc/sys; we can run into
a dying dentry in RCU dcache lookup, but those can be safely rejected.
However, ->d_compare() is also called for in-lookup dentries, before
they get positive - or hashed, for that matter. In case of match
we will wait until dentry leaves in-lookup state and repeat ->d_compare()
afterwards. In other words, the right behaviour is to treat the
name match as sufficient for in-lookup dentries; if dentry is not
for us, we'll see that when we recheck once proc_sys_lookup() is
done with it.
While we are at it, fix the misspelled READ_ONCE and WRITE_ONCE there.
Fixes: d9171b9345 ("parallel lookups machinery, part 4 (and last)")
Reported-by: NeilBrown <neilb@brown.name>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Driver Changes:
- Fix chunking the PTE updates and overflowing the maximum number of
dwords with with MI_STORE_DATA_IMM (Jia Yao)
- Move WA BB to the LRC BO to mitigate hangs on context switch (Matthew
Brost)
- Fix frequency/flush WAs for BMG (Vinay / Lucas)
- Fix kconfig prompt title and description (Lucas)
- Do not require kunit (Harry Austen / Lucas)
- Extend 14018094691 WA to BMG (Daniele)
- Fix wedging the device on signal (Matthew Brost)
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://lore.kernel.org/r/o5662wz6nrlf6xt5sjgxq5oe6qoujefzywuwblm3m626hreifv@foqayqydd6ig
We've seen customers having shares mounted in paths like /??/C:/ or
/??/UNC/foo.example.com/share in order to get their native SMB
symlinks successfully followed from different mounts.
After commit 12b466eb52 ("cifs: Fix creating and resolving absolute NT-style symlinks"),
the client would then convert absolute paths from "/??/C:/" to "/mnt/c/"
by default. The absolute paths would vary depending on the value of
symlinkroot= mount option.
Fix this by restoring old behavior of not trying to convert absolute
paths by default. Only do this if symlinkroot= was _explicitly_ set.
Before patch:
$ mount.cifs //w22-fs0/test2 /mnt/1 -o vers=3.1.1,username=xxx,password=yyy
$ ls -l /mnt/1/symlink2
lrwxr-xr-x 1 root root 15 Jun 20 14:22 /mnt/1/symlink2 -> /mnt/c/testfile
$ mkdir -p /??/C:; echo foo > //??/C:/testfile
$ cat /mnt/1/symlink2
cat: /mnt/1/symlink2: No such file or directory
After patch:
$ mount.cifs //w22-fs0/test2 /mnt/1 -o vers=3.1.1,username=xxx,password=yyy
$ ls -l /mnt/1/symlink2
lrwxr-xr-x 1 root root 15 Jun 20 14:22 /mnt/1/symlink2 -> '/??/C:/testfile'
$ mkdir -p /??/C:; echo foo > //??/C:/testfile
$ cat /mnt/1/symlink2
foo
Cc: linux-cifs@vger.kernel.org
Reported-by: Pierguido Lambri <plambri@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Stefan Metzmacher <metze@samba.org>
Fixes: 12b466eb52 ("cifs: Fix creating and resolving absolute NT-style symlinks")
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
When the SMB server reboots and the client immediately accesses the mount
point, a race condition can occur that causes operations to fail with
"Host is down" error.
Reproduction steps:
# Mount SMB share
mount -t cifs //192.168.245.109/TEST /mnt/ -o xxxx
ls /mnt
# Reboot server
ssh root@192.168.245.109 reboot
ssh root@192.168.245.109 /path/to/cifs_server_setup.sh
ssh root@192.168.245.109 systemctl stop firewalld
# Immediate access fails
ls /mnt
ls: cannot access '/mnt': Host is down
# But works if there is a delay
The issue is caused by a race condition between negotiate and reconnect.
The 20-second negotiate timeout mechanism can interfere with the normal
recovery process when both are triggered simultaneously.
ls cifsd
---------------------------------------------------
cifs_getattr
cifs_revalidate_dentry
cifs_get_inode_info
cifs_get_fattr
smb2_query_path_info
smb2_compound_op
SMB2_open_init
smb2_reconnect
cifs_negotiate_protocol
smb2_negotiate
cifs_send_recv
smb_send_rqst
wait_for_response
cifs_demultiplex_thread
cifs_read_from_socket
cifs_readv_from_socket
server_unresponsive
cifs_reconnect
__cifs_reconnect
cifs_abort_connection
mid->mid_state = MID_RETRY_NEEDED
cifs_wake_up_task
cifs_sync_mid_result
// case MID_RETRY_NEEDED
rc = -EAGAIN;
// In smb2_negotiate()
rc = -EHOSTDOWN;
The server_unresponsive() timeout triggers cifs_reconnect(), which aborts
ongoing mid requests and causes the ls command to receive -EAGAIN, leading
to -EHOSTDOWN.
Fix this by introducing a dedicated `neg_start` field to
precisely tracks when the negotiate process begins. The timeout check
now uses this accurate timestamp instead of `lstrp`, ensuring that:
1. Timeout is only triggered after negotiate has actually run for 20s
2. The mechanism doesn't interfere with concurrent recovery processes
3. Uninitialized timestamps (value 0) don't trigger false timeouts
Fixes: 7ccc146546 ("smb: client: fix hang in wait_for_response() for negproto")
Signed-off-by: Wang Zhaolong <wangzhaolong@huaweicloud.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Fixups
- Fixed raw pointer leakage and unsafe behavior in printk()
. Switch from %pK to %p for pointer formatting, as %p is now safer
and prevents issues like raw pointer leakage and acquiring sleeping
locks in atomic contexts.
- Fixed kernel panic during boot
. A NULL pointer dereference issue occasionally occurred
when the vblank interrupt handler was called before
the DRM driver was fully initialized during boot.
So this patch fixes the issue by adding a check in the interrupt handler
to ensure the DRM driver is properly initialized.
- Fixed a lockup issue on Samsung Peach-Pit/Pi Chromebooks
. The issue occurred after commit c9b1150a68 changed
the call order of CRTC enable/disable and bridge pre_enable/post_disable
methods, causing fimd_dp_clock_enable() to be called
before the FIMD device was activated. To fix this,
runtime PM guards were added to fimd_dp_clock_enable()
to ensure proper operation even when CRTC is not enabled.
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Inki Dae <inki.dae@samsung.com>
Link: https://lore.kernel.org/r/20250629083554.28628-1-inki.dae@samsung.com
