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Fix accessing the __rcu pointer direct_functions with RCU protection.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260730150411.88667-4-leon.hwang@linux.dev
Fixes: e93672f770d7 ("ftrace: Add update_ftrace_direct_mod function")
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Fix accessing the __rcu pointer direct_functions with RCU protection.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260730150411.88667-3-leon.hwang@linux.dev
Fixes: 8d2c1233f371 ("ftrace: Add update_ftrace_direct_del function")
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Fix accessing the __rcu pointer direct_functions with RCU protection.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260730150411.88667-2-leon.hwang@linux.dev
Fixes: d05cb470663a ("ftrace: Fix modification of direct_function hash while in use")
Acked-by: Jiri Olsa <jolsa@kernel.org>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev
Pull fbdev fixes from Helge Deller:
"A few patches for the core fbdev layer which stabilize or fix
potential issues with text font rendering after screen rotation or
after user initiated font changes and locking fixes for sysfb during
modifications of the graphics mode database"
* tag 'fbdev-for-7.2-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev:
fbdev: bitblit: bound-check glyph index in bit_cursor()
fbdev: Fix out-of-bounds access when rotating console after font resize
fbdev: core: Fix pointer desynchronization in fb_io_read()
fbdev: serialize mode sysfs access with lock_fb_info()
fbdev: clear fb_info->mode before deleting a videomode
fbdev: bound mode sysfs output to the sysfs buffer
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When an eventfs inode is freed, it sets ei->is_freed and then uses its
ei->list to add it to the srcu link list as the list field is a union with
the rcu list head. As the ei->list is used to iterate over an SRCU
protected list without taking the eventfs_mutex, there's nothing stopping
the iteration over that list to see the ei->rcu instead of the ei->list
and it will read a corrupt target.
To fix this, change the union of the rcu list head with the children list.
On freeing the eventfs inode, set the is_free and execute a smp_wmb()
before adding the eventfs inode to the SRCU list.
On iteration of the ei->children list, at the start, execute a smp_rmb()
and then read the is_freed of the ei to see if the children list is still
valid. If is_freed is set, then the ei_child read is not valid and the
loop should exit immediately.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260808094215.4252430d@robin
Fixes: 704f960dbee2f ("eventfs: Read ei->entries before ei->children in eventfs_iterate()")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20260806022719.375354-1-shuangpeng.kernel%40gmail.com
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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eventfs_remove_rec() recursively removes the child at the current loop
position. After the recursive call returns, list_for_each_entry() advances
by reading list.next from the removed child.
If free_ei() drops the final reference, release_ei() reuses the list/rcu
union to queue an SRCU callback. The child may be freed before that read.
The eventfs_mutex serializes list updates, but it does not keep the removed
child alive or prevent the SRCU callback from running.
Use list_for_each_entry_safe() to save the next sibling before recursively
removing the current child.
Cc: stable@vger.kernel.org
Fixes: 43aa6f97c2d0 ("eventfs: Get rid of dentry pointers without refcounts")
Link: https://patch.msgid.link/20260806022719.375354-1-shuangpeng.kernel@gmail.com
Signed-off-by: Shuangpeng Bai <shuangpeng.kernel@gmail.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core
Pull driver core fixes from Danilo Krummrich:
- Fix Rust build failure on s390 by gating ioremap() / iounmap()
helpers and the io::mem module on CONFIG_HAS_IOMEM; gate affected
doctests as well.
- Add missing kernel-doc for show_const / store_const union members in
struct device_attribute.
* tag 'driver-core-7.2-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core:
rust: io: gate ioremap doctests on CONFIG_HAS_IOMEM
rust: io: gate ioremap/iounmap on CONFIG_HAS_IOMEM
driver core: add missing kernel-doc for union members
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git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
Pull input updates from Dmitry Torokhov:
- Fixes for information leaks and OOB accesses across several drivers,
including evdev, focaltech, edt-ft5x06, iforce, and cs40l50-vibra
- Improvements to the synaptics-rmi4 driver to properly handle F54
worker errors and prevent buffer overflows
- Input validation fixes in the hynitron_cstxxx touchscreen driver to
prevent issues with invalid finger IDs and touch counts
- Fixes for use-after-free and initialization bugs in the byd mouse and
psxpad-spi drivers
- New quirks for the atkbd driver to make keyboard work on HONOR and
Xiaomi laptops
- Support for the ZENAIM LEVERLESS controller in the xpad driver.
* tag 'input-for-v7.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
Input: evdev - sanitize event type index when fetching event masks
Input: synaptics-rmi4 - propagate F54 worker errors to V4L2 queue
Input: synaptics-rmi4 - block s_input when F54 queue is busy
Input: synaptics-rmi4 - bound the F54 report size to the allocated buffer
Input: synaptics-rmi4 - zero report size on F54 work error
Input: synaptics-rmi4 - fix F55 transmitter electrode count typo
Input: hynitron_cstxxx - validate touch count and finger IDs
Input: evdev - fix information leak in evdev_pass_values()
fixp-arith: convert comments to kernel-doc format
Input: focaltech - fix array out-of-bounds in focaltech_process_rel_packet
Input: atkbd - skip deactivate for HONOR ZQC-P
Input: atkbd - skip deactivate for Xiaomi Book Pro 14's internal keyboard
Input: iforce - validate input packet lengths
Input: psxpad-spi - set driver data before use
Input: cs40l50-vibra - validate custom data from user space
Input: xpad - add support for ZENAIM LEVERLESS
Input: edt-ft5x06 - ignore contacts with an out-of-range slot id
Input: byd - synchronize timer deletion before freeing private data
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git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fixes from Madhavan Srinivasan:
- A couple of fixes for a memory leak and a underflow case
Thanks to George Wilson and R Nageswara Sastry
* tag 'powerpc-7.2-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/pseries: lparcfg - fix kbuf[] underflow
powerpc/pseries: pci - logic bug
powerpc/pseries: papr-phy-attest - validate cmd.length, plug mem leak
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When a CPU is taken offline or enters deep idle states, hypervisor CSR
state is lost. The kvm_former_vcpu fast-path optimization caches the
last VCPU that ran on each CPU to avoid expensive CSR restoration when
the same VCPU is re-scheduled on the same CPU. However, if this cache
is not cleared when CSR state is lost, the next VCPU entry will
incorrectly skip CSR restoration, leading to corrupt hypervisor state.
Add kvm_riscv_clear_former_vcpu() to invalidate the per-CPU cache and
call it from kvm_arch_disable_virtualization_cpu() to ensure proper CSR
restoration after CPU offline or system suspend events.
Fixes: 1323a5cfe52c ("KVM: riscv: Skip CSR restore if VCPU is reloaded on the same core")
Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
Reviewed-by: Nutty Liu <nutty.liu@hotmail.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20260721-kvm-cpu-pm-v4-1-146bf942547d@sifive.com
Signed-off-by: Anup Patel <anup@brainfault.org>
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SBI PMU EVENT_GET_INFO stores guest-controlled num_events * sizeof(*einfo)
in a 32-bit integer. On RV64, num_events = 0x10000001 makes 0x100000010
truncate to 16. KVM then allocates one entry but loops over the original
num_events, causing out-of-bounds reads and writes. A nested guest
triggered:
BUG: KASAN: slab-out-of-bounds in kvm_riscv_vcpu_pmu_event_info+0xa4/0x142
Read of size 4 at addr ff600000074d46b0 by task init/1
Call Trace:
[<ffffffff8006471c>] kvm_riscv_vcpu_pmu_event_info+0xa4/0x142
[<ffffffff800690c0>] kvm_sbi_ext_pmu_handler+0xca/0x268
[<ffffffff8006779e>] kvm_riscv_vcpu_sbi_ecall+0xec/0x1e6
[<ffffffff8006008c>] kvm_riscv_vcpu_exit+0x48c/0x540
[<ffffffff8005ea0a>] kvm_arch_vcpu_ioctl_run+0x37e/0xc80
Allocated by task 1:
__kmalloc_noprof+0x19e/0x4b0
kvm_riscv_vcpu_pmu_event_info+0x72/0x142
kvm_sbi_ext_pmu_handler+0xca/0x268
kvm_riscv_vcpu_sbi_ecall+0xec/0x1e6
kvm_riscv_vcpu_exit+0x48c/0x540
kvm_arch_vcpu_ioctl_run+0x37e/0xc80
The buggy address is located 0 bytes to the right of
allocated 16-byte region [ff600000074d46a0, ff600000074d46b0)
Store the shared-memory size in size_t and reject multiplication overflow.
Allocate the guest-driven array with GFP_KERNEL_ACCOUNT so it is charged
to kmemcg, and use __GFP_NOWARN to suppress allocation failure warnings.
Use kvcalloc() to allow vmalloc fallback and an unsigned long loop index
to match num_events.
Reported-by: Naveed Khan <naveed@digiscrypt.com>
Closes: https://lore.kernel.org/kvm/178345245327.72065.13249716450708539854@digiscrypt.com/
Fixes: e309fd113b9f ("RISC-V: KVM: Implement get event info function")
Cc: stable@vger.kernel.org
Signed-off-by: Guidong Han <2045gemini@gmail.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20260730092533.1369531-1-2045gemini@gmail.com
Signed-off-by: Anup Patel <anup@brainfault.org>
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renesas_i3c_daa() derives the number of newly assigned dynamic addresses
from cmd->rx_count, which the response ISR sets to the number of address
slots ENTDAA left unassigned. It starts out as zero, which already means
"every address was assigned", so a timed out transfer leaves that value
in place and it gets used as a result.
On a bus with no target connected the ENTDAA times out and the driver
registers RENESAS_I3C_MAX_DEVS devices that are not there, each costing
the core two seconds on a GETPID that can only time out:
i3c i3c-0: Failed to add I3C device at address 9, error -110
...
i3c i3c-0: Failed to add I3C device at address 16, error -110
Start from maxdevs instead: no address is assigned before ENTDAA runs,
and the existing rx_count >= maxdevs check then reports an empty bus.
Fixes: d028219a9f14 ("i3c: master: Add basic driver for the Renesas I3C controller")
Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Tested-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com> # on RZ/G3S
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260731070150.2519825-1-tommaso.merciai.xr@bp.renesas.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
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Implement ->set_speed() so the I3C core can switch open-drain timing for
the first broadcast address per spec: I3C_OPEN_DRAIN_SLOW_SPEED programs
tHIGH_INIT (200 ns) before RSTDAA, and I3C_OPEN_DRAIN_NORMAL_SPEED restores
normal OD timing afterward. Cache the normal OD register value during bus
init and use a separate od_hcnt for the slow path so SDR extended timing
remains derived from the normal PP hcnt.
For AMD_I3C_OD_PP_TIMING, cache AMD_I3C_OD_TIMING as the normal OD
baseline and stop rewriting OD timing in send_ccc_cmd()/runtime resume so
I3C_OPEN_DRAIN_SLOW_SPEED is preserved through RSTDAA.
Use PM_RUNTIME_ACQUIRE_AUTOSUSPEND() in set_speed(). Compute od_hcnt with
DIV_ROUND_UP_ULL() for 32-bit safety and clamp it to U8_MAX to match the
8-bit I3C_OD_HCNT field.
Fixes I2C devices with spike filters not being detected on mixed buses.
Signed-off-by: Tze Yee Ng <tze.yee.ng@altera.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/d789219ca0418898a1ef2bf9295b4f96ca7b4209.1785484707.git.tze.yee.ng@altera.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
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Set master->ibi_wakeup during probe when the associated system device
advertises wakeup capability, allowing the I3C core to mark IBI-capable
I3C devices as wakeup capable.
Tweak the comment for i3c_hci_sysdev() to mention the new usage.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260807145638.168865-15-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
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The MIPI I3C HCI driver needs to identify the underlying system device
used for DMA mapping and PM operations. The logic for determining that
device is currently embedded in the DMA implementation.
Factor this code out into i3c_hci_sysdev() so it can be shared by other
parts of the driver and keep the device-selection logic in one place.
The explanatory comment moves with the code, reworked as kernel-doc now
that it documents a function rather than an inline block.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Acked-by: Mukesh Savaliya <mukesh.savaliya@oss.qualcomm.com>
Link: https://patch.msgid.link/20260807145638.168865-14-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
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Keep the PCI wakeup state aligned with the wakeup requirements of the
devices served by the controller(s).
The PCI function is the wakeup source for HCI instances exposed beneath
it. However, wakeup is only needed when at least one attached I3C device
is enabled as a wakeup source.
During suspend, check whether any HCI instance has a wakeup-enabled I3C
device and enable wakeup for the PCI function only in that case.
Otherwise leave PCI wakeup disabled.
Note, the suspend callback is used for both system and runtime suspend.
Although this change may update the PCI wakeup state during runtime
suspend, it does so only when the required wakeup state changes.
Moreover, PCI wakeup-capable devices already have PME wakeup armed for
runtime suspend, so changing the wakeup-enabled state does not affect
runtime PM wakeup behavior.
Note also, since the PCI wakeup state is derived from the wakeup
configuration of the attached I3C devices, the PCI device power/wakeup
sysfs attribute no longer provides independent wakeup control.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260807145638.168865-13-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
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i3c_device_request_ibi() does not verify that a device advertises IBI
support before attempting to set up IBI handling.
Add a check for I3C_BCR_IBI_REQ_CAP and fail with -EOPNOTSUPP when IBI
support is not reported by the device. This keeps IBI setup consistent
with other IBI-related functionality, such as exposing wakeup capability
only for IBI-capable devices.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260807145638.168865-12-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
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Add i3c_master_has_wakeup_enabled_devs(), which iterates over the devices
on an I3C bus and reports whether any of them are enabled for system
wakeup and have IBI enabled.
Controller drivers can use this helper to determine whether wakeup
support must remain available while the system is suspended.
Acked-by : Mukesh Savaliya <mukesh.savaliya@oss.qualcomm.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260807145638.168865-11-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
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An I3C device configured as a wakeup source can wake the system by
generating an In-Band Interrupt (IBI).
When an IBI is queued for processing, record a wakeup event for the
device if wakeup is enabled. Use a 100 ms processing interval to give
the I3C device driver time to process the IBI.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260807145638.168865-10-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
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An I3C controller acts as a bus controller for one or more I3C devices.
If the controller can wake the system in response to an In-Band
Interrupt (IBI), then any device on that bus that is capable of
generating IBIs can potentially be used as a wakeup source.
Add an ibi_wakeup flag to struct i3c_master_controller so controller
drivers can advertise support for IBI-based wakeup.
If set, mark IBI-capable I3C devices as wakeup capable when they are
registered, allowing wakeup management through the standard device
wakeup framework.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Acked-by: Mukesh Savaliya <mukesh.savaliya@oss.qualcomm.com>
Link: https://patch.msgid.link/20260807145638.168865-9-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
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i3c_device_match() dereferences i3cdev->desc without holding the bus
normal-use lock. Since the descriptor pointer can be replaced
concurrently, the dereference can race with descriptor replacement and
result in a use-after-free.
Protect access to i3cdev->desc with the normal-use lock. While the lock
is held, the descriptor is guaranteed to remain valid, so the NULL check
is also unnecessary and can be removed.
This change depends on "i3c: master: Fix recursive locking during device
registration". Prior to that change, taking the normal-use lock in
i3c_device_match() could recurse on bus->lock during device
registration.
Fixes: 3456baa2110c ("i3c: master: match I3C device through DT and ACPI")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260807145638.168865-8-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
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i3c_device_uevent() dereferences i3cdev->desc without holding the bus
normal-use lock. Since the descriptor pointer can be replaced
concurrently, including when a uevent is generated from sysfs, this can
result in dereferencing a stale descriptor and lead to a use-after-free.
Use i3c_device_get_info() instead, which protects access to the
descriptor with the normal-use lock.
Commit 6cf7b65f7029 ("i3c: Use i3cdev->desc->info instead of calling
i3c_device_get_info() to avoid deadlock") replaced the accessor with a
direct descriptor dereference because i3c_device_get_info() would
recursively acquire bus->lock during device registration.
This change depends on "i3c: master: Fix recursive locking during device
registration", which moves device registration out from under bus->lock
and removes the possibility of that deadlock. Without that change,
restoring the i3c_device_get_info() call would reintroduce the deadlock.
Fixes: 6cf7b65f7029 ("i3c: Use i3cdev->desc->info instead of calling i3c_device_get_info() to avoid deadlock")
Cc: stable@vger.kernel.org # requires "i3c: master: Fix recursive locking during device registration"
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Mukesh Savaliya <mukesh.savaliya@oss.qualcomm.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260807145638.168865-7-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
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i3c_device_get_info() takes the bus normal-use lock before accessing
dev->desc. Under that lock, the descriptor pointer is guaranteed to be
valid for the duration of the access.
Remove the unnecessary NULL check on dev->desc so the code more clearly
reflects the locking rules and expected descriptor lifetime.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Mukesh Savaliya <mukesh.savaliya@oss.qualcomm.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260807145638.168865-6-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
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sysfs attribute callbacks for the master controller device dereference
master->this. However, master->this is freed in
i3c_master_detach_free_devs() before the master device itself is
released.
As a result, sysfs accesses can dereference a freed master->this
pointer, leading to a use-after-free.
Keep master->this alive until i3c_masterdev_release(), which is called
after the master device and its sysfs state are being torn down. Do not
free master->this as part of the normal device detach path.
On the error path in i3c_master_set_info(), reset master->this and
bus.cur_master to NULL before freeing the allocated device.
Fixes: 3a379bbcea0a ("i3c: Add core I3C infrastructure")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260807145638.168865-5-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
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i3c_master_search_i3c_dev_duplicate() searches the bus for another I3C
device with the same PID as the reference device. The search can match
master->this, causing the controller itself to be returned as a
duplicate.
Since the controller is not a target device, it cannot be a duplicate of
one. Exclude master->this from matching so that the function only
returns real duplicate target devices.
Fixes: 3a379bbcea0a ("i3c: Add core I3C infrastructure")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Acked-by: Mukesh Savaliya <mukesh.savaliya@oss.qualcomm.com>
Link: https://patch.msgid.link/20260807145638.168865-4-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
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i3c_device_get_supported_xfer_mode()
i3c_device_get_supported_xfer_mode() uses dev->desc to obtain the
master controller. However, dev->desc must not be dereferenced unless
bus->lock is held, and this function does not take that lock.
The function only needs access to the master controller associated with
the device's bus. Use dev->bus instead, which is always valid for the
lifetime of the device and does not require dereferencing dev->desc.
Fixes: 256a21743d91 ("i3c: Add HDR API support")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260807145638.168865-3-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
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i3c_master_register_new_i3c_devs() registers newly discovered devices
while holding i3c_bus_normaluse_lock(), a down_read(). device_register()
can immediately probe the device, and probe callbacks typically invoke
I3C helpers that take i3c_bus_normaluse_lock() again, leading to a
recursive acquisition of the same rwsem. rwsems do not support recursive
read locking and can deadlock when a writer is waiting. See the
"Recursive read locks" section of Documentation/locking/lockdep-design.rst.
For example, with Intel LPSS I3C, LOCKDEP generates a WARNING like:
# echo intel-lpss-i3c.0 > /sys/bus/platform/drivers/mipi-i3c-hci/unbind
# echo intel-lpss-i3c.0 > /sys/bus/platform/drivers/mipi-i3c-hci/bind
WARNING: possible recursive locking detected
kworker/5:1/94 is trying to acquire lock:
ffff88811c810d78 (&i3cbus->lock){++++}-{4:4}, at: i3c_device_match_id+0x45/0x370
but task is already holding lock:
ffff88811c810d78 (&i3cbus->lock){++++}-{4:4}, at: i3c_master_reg_work_fn+0x21/0x5f0
Fix this by separating device creation from device registration.
Populate desc->dev under the maintenance lock, collect the devices that
still need registration into a local list, then release the lock before
calling device_register(). Finally retake the lock and clean up any
devices that failed to register.
Use the maintenance lock rather than the normal-use lock while adding
device objects. A write-side maintenance lock prevents readers from
observing a partially initialized desc->dev during initial device
population, or desc->dev disappearing if registration fails.
The local list requires a list node, so add a list node member to struct
i3c_device.
Fixes: 3a379bbcea0a ("i3c: Add core I3C infrastructure")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260807145638.168865-2-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
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Boot-time tracing currently supports kprobe-events and synthetic-events
under per-event configuration options.
Extend boot-time tracing to support newly added dynamic probe types:
- event probes (eprobe) under the "eprobes" event group
- function probes (fprobe) under the "fprobes" event group
- tracepoint probes (tprobe) under the "tracepoints" or "tprobes"
event group
To support this cleanly, update dyn_event_create() in trace_dynevent.c
so that passing NULL as the type parameter delegates to
create_dyn_event(), allowing generic creation of any registered
dynamic event type from a raw command string.
Update Documentation/trace/boottime-trace.rst accordingly to describe
the new per-event bootconfig options.
Link: https://lore.kernel.org/all/178613905149.259829.18185480460810689421.stgit@devnote2/
Assisted-by: Antigravity:gemini-3.6-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Changes in v3:
- Check return values of strscpy() and snprintf() in trace_boot_add_probe_event()
to prevent silent buffer truncation when constructing probe event strings.
Changes in v2:
- Fix raw command detection logic for eprobes, fprobes, and tprobes
by requiring ':' or isspace() after type prefix.
- Consolidate duplicate loop logic into trace_boot_add_probe_event()
helper function.
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Kmemleak doesn't know about runtime_const stuff and figures we're leaking
__futex_queues. So add this little annotation to tell it all is well.
Fixes: b78b0b658252 ("futex: Use runtime constants for __futex_hash() hot path")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202608071053.6db6276e-lkp@intel.com
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260807152353.GP687043@noisy.programming.kicks-ass.net
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Kumar Kartikeya Dwivedi says:
====================
Add arena argument support to kfuncs and struct_ops
This is a continuation of patches in [0], with mostly minor changes and
reordering. The motivation is covered in that link. A major change is
moving to two tags (__arena and __arena__nullable) and moving the changes
to JIT to emit more optimized sequences.
Please see commit logs for details.
[0]: https://lore.kernel.org/bpf/20260713024414.3759854-1-tj@kernel.org
Changelog:
----------
v4 -> v5
v4: https://lore.kernel.org/bpf/20260805210427.3218326-1-memxor@gmail.com
* Remove the redundant patch-8 capability comment and duplicate
nullable kfunc test coverage. (Eduard)
* Introduce the final bpf_tramp_arena_base() interface directly with
function-model argument flags, avoiding temporary slot bitmaps and
arena_nullable state; simplify struct_ops pointer validation. (Eduard)
* Simplify kfunc arena nullability classification by using the common
nullable path for both arena suffixes while leaving the function model
to distinguish JIT NULL preservation. (Amery)
* Keep bpf_prog_has_arena_ctx_arg() in bpf_verifier.h from its
introduction so trampoline and verifier users share one inline
definition, avoiding BPF_JIT/BPF_SYSCALL link dependencies.
(Eduard, BPF CI Bot)
* Reject both tracing and extension attachments to struct_ops programs
with arena context arguments, and add fentry, fexit, and freplace
rejection tests. (Eduard, Sashiko)
v3 -> v4
v3: https://lore.kernel.org/bpf/20260803125115.2264733-1-memxor@gmail.com
* Rename __arena_nullable to __arena__nullable and prioritize the
composite suffix over __nullable during argument classification.
(Sashiko, Eduard)
* Resolve instructions before collecting subprograms and kfuncs so kfunc
prototype validation can use associated arena state.
* Move the arena kfunc and JIT-sequence test entry points into
prog_tests/verifier.c. (Eduard)
* Match the generated L0 target and call in nullable JIT assertions.
(Eduard)
* Route arena kfunc validation through the common argument-checking path.
(Amery)
* Reuse btf_func_model argument flags for struct_ops arena arguments
instead of maintaining separate trampoline slot metadata. (Eduard)
* Check the generic-trampoline arena argument invariant at link time and
warn once on violations. (Eduard)
* Reject tracing attachments to struct_ops programs with arena context
arguments whose indirect trampolines convert the pointers. (Sashiko)
v2 -> v3
v2: https://lore.kernel.org/bpf/20260726013105.3689867-1-memxor@gmail.com
* Rebase onto current bpf-next to resolve conflicts.
v1 -> v2
v1: https://lore.kernel.org/bpf/20260715220052.1590783-1-memxor@gmail.com
* Fix documentation to only mention x86 for now. (Sashiko)
* Move arg bitmap from insn_aux_data to kfunc descriptor. (Eduard)
====================
Link: https://patch.msgid.link/20260808003938.3486067-1-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
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Exercise fentry, fexit, and freplace programs that target a struct_ops
callback with an arena context argument. Verify each load is rejected with
-EOPNOTSUPP and the arena-specific verifier diagnostic.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-15-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
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Reject tracing and freplace attachments to a target program with arena
context arguments. The struct_ops indirect trampoline converts those
arguments before entering the target, so a generic tracing trampoline
would otherwise expose arena offsets using the target BTF pointer type.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-14-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
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Add a test_arena_stack member with eight leading scalar arguments so the
arena pointer is passed on the stack.
The callback validates the first and last scalar ctx slots before
dereferencing the pointer in ctx[8]. This exercises the indirect
trampoline stack layout and arena conversion together, and prevents a
regression where stack arguments are read one slot late.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Tested-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-13-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
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save_args() reads stack-passed arguments relative to rbp assuming two
return addresses sit between the saved rbp and the arguments, which
holds when the trampoline is entered through the fentry call from a
traced function. An indirect trampoline is called through a function
pointer, so only the caller's return address is on the stack and the
arguments start at rbp + 16, not rbp + 24. Every stack-passed argument
of a struct_ops callback with more than six argument slots is read one
slot off.
This has gone unnoticed because no in-tree struct_ops member passes
arguments on the stack. The jmp-entry form already accounts for having
a single return address; treat BPF_TRAMP_F_INDIRECT the same way.
Fixes: 473e3150e30a ("bpf, x86: allow function arguments up to 12 for TRACING")
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Tested-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-12-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
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Add test_arena and test_arena_nullable members to bpf_testmod_ops3 with
arena-tagged stub arguments and kfuncs that forward a caller-provided
pointer to them. The kfuncs take arena-tagged arguments, so each round
trip exercises both conversion directions end to end: the kfunc receives
a kernel arena address and the trampoline converts it back to an arena
pointer for the callback.
The non-nullable callback dereferences its argument with no NULL branch
and captures the raw ctx value, which the trigger program compares
against the arena offset of the passed object, pinning the exact
(u32)(kaddr - kern_vm_start) conversion. The nullable callback verifies
that only a true kernel NULL arrives as NULL. Failure coverage: a
program with no arena is rejected when it loads. The tests run on x86-64
and skip elsewhere, as the programs fail verification where the JIT
lacks arena argument support.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-11-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
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Pin the exact rebase sequences the JITs emit for __arena and
__arena__nullable kfunc arguments with __jited assertions on x86-64: the
unconditional truncate-and-add, the nullable test-and-skip variant, and
all five argument registers in one call, which also covers the
REX-prefixed encoding of r8 on x86. The capture kfuncs take the argument
without dereferencing, so only the emitted code is under test. The
tests skip without LLVM disassembler support.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-10-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
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Add arena-argument kfuncs to bpf_testmod, which also exercises the
argument rebasing on module kfuncs, and tests covering the accepted
argument forms (arena pointer, low 32 bits as a scalar, full user
address as a scalar), the exact rebase semantics via capture kfuncs
returning the raw argument (zero low 32 bits arrive as the arena kernel
base under __arena and as NULL under __arena__nullable), five arena
arguments in one call, a mixed __arena plus __arena__nullable call
exercising both bitmasks on one call site, a kernel-side dereference of
an unpopulated page recovering through the scratch page, and the
rejections (no arena in the program, incompatible register type).
The tests run on x86-64 and skip elsewhere, as programs with
arena-tagged kfunc args fail verification where the JIT lacks support.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-9-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
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Implement the struct_ops arena argument conversion on x86. save_args()
receives the arena base from bpf_tramp_arena_base() and consults the
btf_func_model argument flags as it copies each native argument into the
BPF ctx, routing a marked argument through RAX:
movl %esrc, %eax /* truncate and clear the upper 32 bits */
subl $base_lo, %eax
movq %rax, ctx_slot
A nullable argument tests the full 64-bit kernel pointer first:
movq %rsrc, %rax
testq %rax, %rax
jz 1f
subl $base_lo, %eax
1:
movq %rax, ctx_slot
The 32-bit subtraction is sufficient since (u32)(kaddr - base) ==
(u32)kaddr - (u32)base, and it clears the upper half as the JITs require
of arena pointer registers. Stack-passed arguments already reload
through RAX, so only the subtraction (and the NULL test) is inserted
there.
Keep arena and nullable classification in btf_func_model.
bpf_tramp_arena_base() returns a base only for a single-program
struct_ops indirect trampoline; other trampolines pass zero and perform
no conversion. The size probe reruns the same emission with the same
model and nodes, so the image size matches by construction.
With both the kfunc and struct_ops directions implemented, flip
bpf_jit_supports_arena_args() on for x86.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-8-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
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Implement arena argument rebasing for kfunc calls on x86. R12 already
holds kern_vm_start whenever the prog has an arena, so each tagged
argument costs two instructions emitted right before the call:
movl %eN, %eN /* truncate, clear the upper 32 bits */
addq %r12, %rN
A nullable argument tests the truncated value and jumps over the add:
movl %eN, %eN
testl %eN, %eN
jz 1f
addq %r12, %rN
1:
addq carries a REX prefix for every argument register and is always
three bytes, so the jz displacement is constant. The sequence is native
code generated after constant blinding has run on the BPF instruction
stream, so blinding never sees the rebase and needs no special handling.
bpf_jit_supports_arena_args() is not flipped yet; that happens when the
struct_ops trampoline side is in place as well.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-7-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
|
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A struct_ops callback cannot receive an arena pointer directly, so
passing one takes two steps. The pointer arrives as a bare u64 that the
callback casts, and because the two sides address the arena through
different bases it also has to be rebased by hand on the way in.
Add the __arena and __arena__nullable stub argument suffixes to make this
convenient. The callback declares the parameter as an arena pointer,
receives it as a PTR_TO_ARENA register, and dereferences it directly,
while the kernel caller just passes the natural kernel arena address
(kaddr). The trampoline converts the value while saving the arguments
into the BPF ctx, ctx[slot] = (u32)(kaddr - kern_vm_start), so the
program never sees a kernel address and nothing rewrites the ctx after
the fact. The converted value keeps the upper 32 bits clear as the JITs
require of arena pointer registers and behaves like any cast_kern'ed
arena pointer, so cast_user recovers the full user-visible address.
__arena converts unconditionally and the kernel caller must not pass
NULL. __arena__nullable preserves NULL, tested on the full 64-bit kernel
pointer, and surfaces to the verifier as PTR_TO_ARENA (but not as a
PTR_TO_ARENA | PTR_MAYBE_NULL). The reason is that PTR_TO_ARENA in the
program's type state already encompasses NULL-ness, so it is not
meaningful to force a NULL check for the program.
The composite suffix intentionally ends in __nullable. Classify
__arena__nullable before the generic suffix so scalar arena pointees do
not take the generic nullable BTF pointer path.
This patch adds the generic side. prepare_arg_info() records arena and
nullable argument flags in the struct_ops function model, and
bpf_tramp_arena_base() returns the arena base for a single-program
struct_ops indirect trampoline. Only that trampoline converts: its
program's arena is fixed at generation time. Generic trampolines can mix
programs with different arenas and reject arena context arguments
defensively, which is unreachable today as only struct_ops programs
carry them. Architectures that do not implement the conversion are
gated out at verification time with bpf_jit_supports_arena_args().
Co-developed-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-6-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
|
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Passing an arena pointer to a kfunc takes two steps today. There is no
arena pointer argument type, so the pointer crosses the boundary as a
bare scalar, and the kfunc then offsets it by the arena base and casts
it before it can touch the memory. Every such kfunc open-codes the same
translation.
Add the __arena and __arena__nullable argument suffixes to make this more
convenient. The kfunc declares the parameter by its real pointer type
and dereferences it directly, with the JIT rebasing the value at the
call site, rN = kern_vm_start + (u32)rN. No bounds check is needed: the
u32 offset stays within the guard-padded arena kernel mapping, and a
fault on an unpopulated page recovers through the per-arena scratch
page. A suffixed argument accepts a PTR_TO_ARENA or scalar register,
matching global subprog arena arguments.
__arena rebases unconditionally, so the kfunc never sees NULL and a
value with zero in the low 32 bits arrives as the arena base.
__arena__nullable preserves NULL for optional arguments by skipping the
rebase when the truncated value, arena offset 0, is zero. Keeping the
plain form NULL-free saves the NULL test on every call.
The double separator makes the annotations composable:
__arena__nullable also ends in __nullable and naturally follows the
common nullable argument path. Plain __arena follows that path too for
verifier type checking because both forms accept a constant zero; the
function-model flag still determines whether the JIT preserves NULL or
rebases it to the arena base.
This patch adds the verifier side: the suffixes are recognized in
check_kfunc_args() and distilled into argument flags in the function
model stored in the kfunc descriptor. JITs retrieve the model while
emitting the call, avoiding per-call state in insn_aux_data.
JITs declare support with bpf_jit_supports_arena_args() and verification
fails with -ENOTSUPP elsewhere.
Co-developed-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-5-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
|
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The kfunc descriptors include argument prototypes generated while calls are
collected. Some argument classifications need program auxiliary state derived
from referenced maps, such as the arena associated with the program.
This avoids a footgun in get_kfunc_arg_type() checks where we do
validation on whether program has prog->aux->arena and it hasn't been
resolved yet.
check_and_resolve_insns() records used maps and populates that state. It must
remain after bpf_check_btf_info(), which applies kernel-side CO-RE relocations,
so that instruction validation and the program tag observe the relocated
instruction stream.
Move only add_kfuncs() after instruction and resource resolution. Subprogram
discovery and validation remain before the full BTF phase because that phase
needs the complete subprogram layout. Add a short comment describing the
resource resolution phase at the call site.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Reviewed-by: Amery Hung <ameryhung@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-4-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
|
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add_subprog_and_kfunc() combines two operations with different ordering
requirements. Subprogram discovery must precede validation of func_info and
line_info, while kfunc descriptors are only needed by the verifier after its
initial program setup is complete.
Split the helper into add_subprogs() and add_kfuncs() so each operation can be
placed according to its actual dependencies. Keep both calls adjacent and in
their existing phase for now, and add short comments describing their roles.
No functional change is intended for valid programs.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Reviewed-by: Amery Hung <ameryhung@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-3-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
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BTF processing is split around subprogram discovery. The first phase gets
program BTF and imports func_info because a BTF-tagged exception callback
may not be referenced by any instruction. Subprogram discovery needs this
metadata to find it.
The later phase validates func_info and line_info against the complete
subprogram table and applies CO-RE relocations. This split breaks a real
dependency cycle rather than merely running the same checks early.
Rename bpf_check_btf_info_early() and check_btf_func_early() to preparation
names that reflect this role. Add short call-site comments to make the two
phases and their responsibilities clear.
No functional change is intended.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Reviewed-by: Amery Hung <ameryhung@gmail.com>
Link: https://patch.msgid.link/20260808003938.3486067-2-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
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Includes the following test cases:
- a test showing that zero extension flags do not propagate through
state pruning in the unpatched kernel.
- a 32-bit subregister consumed by MOV32 and ALU32 operations
(never zext'ed);
- a 64-bit MOV (never zext'ed);
- a narrow (32-bit) BPF_LDX load whose result is read as 64-bit;
- 32-bit atomic fetch_add and cmpxchg whose result is read as 64-bit;
- a CFG case where a 32-bit definition's upper half is used only on one
of two branches;
- no zext for dead registers;
- LD_ABS defines only lower 32 bits, hence needs zext when the result
is used as 64-bits;
- helper, kfunc and subprogram parameters are considered to use full
64 bits;
- a 32-bit subregister consumed by JMP32 (X/K) operations;
- a 32-bit subregister consumed by JMP (X/K) operations;
- a 64-bit register consumed by both JMP and JMP32 operations
(never zext'ed);
- ALU64 and address space cast operations on arena pointers;
- memory loads using BPF_PROBE_MEM instructions.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260807-static-zext-v4-7-b6c270013c77@gmail.com
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After the previous commit bpf_is_reg64() is only used in a context
where destination register's property is queried, and only for
instructions for which insn_def_regno() >= 0. Hence, simplify the
function by:
- removing unused parameters;
- removing code paths considering BPF_JMP{,32} instructions;
- streamlining the condition expressions.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260807-static-zext-v4-6-b6c270013c77@gmail.com
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As reported in the thread [1], the verifier's 32-bit operations zero
extension logic is broken. This logic is responsible for correct
semantics of 32-bit operations on s390 architecture.
According to BPF semantics, operation `w1 += 1` is supposed to zero
extend the upper half of the register `r1`. On s390 the JIT relies on
the verifier emitting explicit zero extension before such operations.
The verifier attempts to minimize the amount of zero extensions
inserted by tracking whether upper halves of the 64-bit registers are
ever used. Previously such tracking worked as follows:
- bpf_reg_state->subreg_def field was set by do_check_insn()
for each operation defining lower but not the upper halves
of the register.
- Whenever an operation reading the whole register was verified,
the verifier checked register's subreg_def and set
bpf_insn_aux_data->zext_dst flag as true via a call to
mark_insn_zext() function.
- After the verification was complete, a special pass
bpf_opt_subreg_zext_lo32_rnd_hi32() extended 32-bit operations
with bpf_insn_aux_data->zext_dst set as true by adding
explicit zero extension.
Note that the logic above relies on bpf_reg_state->subreg_def,
which is a property of a current verifier state.
Before the commit [2] two additional steps happened:
- The verifier tracked upper and lower register halves' liveness as
flags REG_LIVE_READ{32,64} in bpf_reg_state->live.
- The function propagate_liveness() called mark_insn_zext()
in order to transfer the knowledge about which registers have
their upper halves alive (and thus might require zero extension).
The commit [2] removed the two steps described above,
hence making possible a situation like below:
- The register's upper half is set and is used on some verification
path P1 and the register happens not to be marked as precise.
- The checkpoint C is created while processing some instruction
between register initialization and usage.
- On some other verification path P2 the register's upper half is not
initialized and that path ends hitting the checkpoint C.
- In such a case the register's initialization on path P2 would lack
zext_dst mark, making it possible for the program to inject
an arbitrary value in the register's upper half.
This commit replaces subreg_def based logic with computing zext_dst
statically, as a part of the bpf_compute_live_registers() analysis:
- The analysis now tracks usage of upper and lower halves of the
registers separately.
- If some instruction defines a 32-bit subregister, but not the whole
register, *and* the upper half of the register is alive after that
instruction, the instruction is marked as zext_dst.
There is one notable drop in precision: whenever a BPF subprogram is
called, all 64 bits of parameter registers are presumed to be used.
The assumption is that such a drop in precision would not inflict
a noticeable performance penalty.
[1] https://lore.kernel.org/bpf/CAGKGUv=sOuqQtA1Ub-5JXfA4FPosJFYKAQE4B79cK+P1erxqtg@mail.gmail.com/
[2] commit 107e16979905 ("bpf: disable and remove registers chain based liveness")
Fixes: 107e16979905 ("bpf: disable and remove registers chain based liveness")
Reported-by: Min-gyu Kim <gimm78064@gmail.com>
Reported-by: STAR Labs SG <info@starlabs.sg>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/CAGKGUv=sOuqQtA1Ub-5JXfA4FPosJFYKAQE4B79cK+P1erxqtg@mail.gmail.com/
Link: https://lore.kernel.org/bpf/20260807-static-zext-v4-5-b6c270013c77@gmail.com
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Extend compute_live_registers() to track upper and lower register
halves' liveness separately. This is mostly straightforward:
- use/def masks are extended to track 2 bits per register;
- compute_insn_live_regs() is updated to properly track these
2 bits according to the instruction semantics.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260807-static-zext-v4-4-b6c270013c77@gmail.com
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The following patches are going to remove bpf_is_reg64() users from
everywhere except fixups.c, and also make it dependent on functions
local to fixups.c. Move the function before hand to simplify the
review. Non functional change.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260807-static-zext-v4-3-b6c270013c77@gmail.com
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bpf_do_misc_fixups() converts the following address space cast
instructions to 32-bit moves:
- cast from address space 1 (user) to address space 0 (kernel)
- cast from address space 0 (kernel) to address space 1 (user)
iff associated arena map has a BPF_F_NO_USER_CONV flag.
Extract a predicate detecting such instructions for use in the
following patches.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260807-static-zext-v4-2-b6c270013c77@gmail.com
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