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Queue posixtimers which have their signal ignored on the ignored list:
1) When the timer fires and the signal has SIG_IGN set
2) When SIG_IGN is installed via sigaction() and a timer signal
is already queued
This only happens when the signal is for a valid timer, which delivered the
signal in periodic mode. One-shot timer signals are correctly dropped.
Due to the lock order constraints (sighand::siglock nests inside
timer::lock) the signal code cannot access any of the timer fields which
are relevant to make this decision, e.g. timer::it_status.
This is addressed by establishing a protection scheme which requires to
lock both locks on the timer side for modifying decision fields in the
timer struct and therefore makes it possible for the signal delivery to
evaluate with only sighand:siglock being held:
1) Move the NULLification of timer->it_signal into the sighand::siglock
protected section of timer_delete() and check timer::it_signal in the
code path which determines whether the signal is dropped or queued on
the ignore list.
This ensures that a deleted timer cannot be moved onto the ignore
list, which would prevent it from being freed on exit() as it is not
longer in the process' posix timer list.
If the timer got moved to the ignored list before deletion then it is
removed from the ignored list under sighand lock in timer_delete().
2) Provide a new timer::it_sig_periodic flag, which gets set in the
signal queue path with both timer and sighand locks held if the timer
is actually in periodic mode at expiry time.
The ignore list code checks this flag under sighand::siglock and drops
the signal when it is not set.
If it is set, then the signal is moved to the ignored list independent
of the actual state of the timer.
When the signal is un-ignored later then the signal is moved back to
the signal queue. On signal delivery the posix timer side decides
about dropping the signal if the timer was re-armed, dis-armed or
deleted based on the signal sequence counter check.
If the thread/process exits then not yet delivered signals are
discarded which means the reference of the timer containing the
sigqueue is dropped and frees the timer.
This is way cheaper than requiring all code paths to lock
sighand::siglock of the target thread/process on any modification of
timer::it_status or going all the way and removing pending signals
from the signal queues on every rearm, disarm or delete operation.
So the protection scheme here is that on the timer side both timer::lock
and sighand::siglock have to be held for modifying
timer::it_signal
timer::it_sig_periodic
which means that on the signal side holding sighand::siglock is enough to
evaluate these fields.
In posixtimer_deliver_signal() holding timer::lock is sufficient to do the
sequence validation against timer::it_signal_seq because a concurrent
expiry is waiting on timer::lock to be released.
This completes the SIG_IGN handling and such timers are not longer self
rearmed which avoids pointless wakeups.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064214.120756416@linutronix.de
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To handle posix timer signals on sigaction(SIG_IGN) properly, the timers
will be queued on a separate ignored list.
Add the necessary cleanup code for timer_delete() and exit_itimers().
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.987530588@linutronix.de
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To prepare for handling posix timer signals on sigaction(SIG_IGN) properly,
add a list to task::signal.
This list will be used to queue posix timers so their signal can be
requeued when SIG_IGN is lifted later.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.920101900@linutronix.de
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The posix timer signal handling uses siginfo::si_sys_private for handling
the sequence counter check. That indirection is not longer required and the
sequence count value at signal queueing time can be stored in struct
k_itimer itself.
This removes the requirement of treating siginfo::si_sys_private special as
it's now always zero as the kernel does not touch it anymore.
Suggested-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Link: https://lore.kernel.org/all/20241105064213.852619866@linutronix.de
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Remove the leftovers of sigqueue preallocation as it's not longer used.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.786506636@linutronix.de
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To cure the SIG_IGN handling for posix interval timers, the preallocated
sigqueue needs to be embedded into struct k_itimer to prevent life time
races of all sorts.
Now that the prerequisites are in place, embed the sigqueue into struct
k_itimer and fixup the relevant usage sites.
Aside of preparing for proper SIG_IGN handling, this spares an extra
allocation.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.719695194@linutronix.de
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In preparation for handling ignored posix timer signals correctly and
embedding the sigqueue struct into struct k_itimer, hand down a pointer to
the sigqueue struct into posix_timer_deliver_signal() instead of just
having a boolean flag.
No functional change.
Suggested-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Link: https://lore.kernel.org/all/20241105064213.652658158@linutronix.de
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To handle posix timers which have their signal ignored via SIG_IGN properly
it is required to requeue a ignored signal for delivery when SIG_IGN is
lifted so the timer gets rearmed.
Split the required code out of send_sigqueue() so it can be reused in
context of sigaction().
While at it rename send_sigqueue() to posixtimer_send_sigqueue() so its
clear what this is about.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.586453412@linutronix.de
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instead of re-evaluating the signal delivery mode everywhere.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.519086500@linutronix.de
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To cure the SIG_IGN handling for posix interval timers, the preallocated
sigqueue needs to be embedded into struct k_itimer to prevent life time
races of all sorts.
Provide a new function to initialize the embedded sigqueue to prepare for
that.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.450427515@linutronix.de
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To cure the SIG_IGN handling for posix interval timers, the preallocated
sigqueue needs to be embedded into struct k_itimer to prevent life time
races of all sorts.
To make that work correctly it needs reference counting so that timer
deletion does not free the timer prematuraly when there is a signal queued
or delivered concurrently.
Add a rcuref to the posix timer part.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.304756440@linutronix.de
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POSIX CPU timer nanosleep creates a k_itimer on stack and uses the sigq
pointer to detect the nanosleep case in the expiry function.
Prepare for embedding sigqueue into struct k_itimer by using a dedicated
flag for nanosleep.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/20241105064213.238550394@linutronix.de
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The firing flag of a posix CPU timer is tristate:
0: when the timer is not about to deliver a signal
1: when the timer has expired, but the signal has not been delivered yet
-1: when the timer was queued for signal delivery and a rearm operation
raced against it and supressed the signal delivery.
This is a pointless exercise as this can be simply expressed with a
boolean. Only if set, the signal is delivered. This makes delete and rearm
consistent with the rest of the posix timers.
Convert firing to bool and fixup the usage sites accordingly and add
comments why the timer cannot be dequeued right away.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/all/20241105064213.172848618@linutronix.de
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Signals of timers which are reprogammed, disarmed or deleted can deliver
signals related to the past. The POSIX spec is blury about this:
- "The effect of disarming or resetting a timer with pending expiration
notifications is unspecified."
- "The disposition of pending signals for the deleted timer is
unspecified."
In both cases it is reasonable to expect that pending signals are
discarded. Especially in the reprogramming case it does not make sense to
account for previous overruns or to deliver a signal for a timer which has
been disarmed. This makes the behaviour consistent and understandable.
Remove the si_sys_private check from the signal delivery code and invoke
posix_timer_deliver_signal() unconditionally for posix timer related
signals.
Change posix_timer_deliver_signal() so it controls the actual signal
delivery via the return value. It now instructs the signal code to drop the
signal when:
1) The timer does not longer exist in the hash table
2) The timer signal_seq value is not the same as the si_sys_private value
which was set when the signal was queued.
This is also a preparatory change to embed the sigqueue into the k_itimer
structure, which in turn allows to remove the si_sys_private magic.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/all/20241105064213.040348644@linutronix.de
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Add a driver for the T-HEAD C900 ACLINT SSWI device. This device allows
the system with T-HEAD cpus to send ipi via fast device interface.
Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20241031060859.722258-3-inochiama@gmail.com
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Pull NFS client fixes from Anna Schumaker:
"These are mostly fixes that came up during the nfs bakeathon the other
week.
Stable Fixes:
- Fix KMSAN warning in decode_getfattr_attrs()
Other Bugfixes:
- Handle -ENOTCONN in xs_tcp_setup_socked()
- NFSv3: only use NFS timeout for MOUNT when protocols are compatible
- Fix attribute delegation behavior on exclusive create and a/mtime
changes
- Fix localio to cope with racing nfs_local_probe()
- Avoid i_lock contention in fs_clear_invalid_mapping()"
* tag 'nfs-for-6.12-3' of git://git.linux-nfs.org/projects/anna/linux-nfs:
nfs: avoid i_lock contention in nfs_clear_invalid_mapping
nfs_common: fix localio to cope with racing nfs_local_probe()
NFS: Further fixes to attribute delegation a/mtime changes
NFS: Fix attribute delegation behaviour on exclusive create
nfs: Fix KMSAN warning in decode_getfattr_attrs()
NFSv3: only use NFS timeout for MOUNT when protocols are compatible
sunrpc: handle -ENOTCONN in xs_tcp_setup_socket()
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Some computers with CPUs that lack Thunderbolt features use discrete
Thunderbolt chips to add Thunderbolt functionality. These Thunderbolt
chips are located within the chassis; between the Root Port labeled
ExternalFacingPort and the USB-C port.
These Thunderbolt PCIe devices should be labeled as fixed and trusted, as
they are built into the computer. Otherwise, security policies that rely on
those flags may have unintended results, such as preventing USB-C ports
from enumerating.
Detect the above scenario through the process of elimination.
1) Integrated Thunderbolt host controllers already have Thunderbolt
implemented, so anything outside their external facing Root Port is
removable and untrusted.
Detect them using the following properties:
- Most integrated host controllers have the "usb4-host-interface"
ACPI property, as described here:
https://learn.microsoft.com/en-us/windows-hardware/drivers/pci/dsd-for-pcie-root-ports#mapping-native-protocols-pcie-displayport-tunneled-through-usb4-to-usb4-host-routers
- Integrated Thunderbolt PCIe Root Ports before Alder Lake do not
have the "usb4-host-interface" ACPI property. Identify those by
their PCI IDs instead.
2) If a Root Port does not have integrated Thunderbolt capabilities, but
has the "ExternalFacingPort" ACPI property, that means the
manufacturer has opted to use a discrete Thunderbolt host controller
that is built into the computer.
This host controller can be identified by virtue of being located
directly below an external-facing Root Port that lacks integrated
Thunderbolt. Label it as trusted and fixed.
Everything downstream from it is untrusted and removable.
The "ExternalFacingPort" ACPI property is described here:
https://learn.microsoft.com/en-us/windows-hardware/drivers/pci/dsd-for-pcie-root-ports#identifying-externally-exposed-pcie-root-ports
Link: https://lore.kernel.org/r/20240910-trust-tbt-fix-v5-1-7a7a42a5f496@chromium.org
Suggested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Esther Shimanovich <eshimanovich@chromium.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
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Add the static napi tracking strategy. That allows the user to manually
manage the napi ids list for busy polling, and eliminate the overhead of
dynamically updating the list from the fast path.
Signed-off-by: Olivier Langlois <olivier@trillion01.com>
Link: https://lore.kernel.org/r/96943de14968c35a5c599352259ad98f3c0770ba.1728828877.git.olivier@trillion01.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Rather than store the task_struct itself in struct io_kiocb, store
the io_uring specific task_struct. The life times are the same in terms
of io_uring, and this avoids doing some dereferences through the
task_struct. For the hot path of putting local task references, we can
deref req->tctx instead, which we'll need anyway in that function
regardless of whether it's local or remote references.
This is mostly straight forward, except the original task PF_EXITING
check needs a bit of tweaking. task_work is _always_ run from the
originating task, except in the fallback case, where it's run from a
kernel thread. Replace the potentially racy (in case of fallback work)
checks for req->task->flags with current->flags. It's either the still
the original task, in which case PF_EXITING will be sane, or it has
PF_KTHREAD set, in which case it's fallback work. Both cases should
prevent moving forward with the given request.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Currently the io_rsrc_node assignment in io_kiocb is an array of two
pointers, as two nodes may be assigned to a request - one file node,
and one buffer node. However, the buffer node can co-exist with the
provided buffers, as currently it's not supported to use both provided
and registered buffers at the same time.
This crucially brings struct io_kiocb down to 4 cache lines again, as
before it spilled into the 5th cacheline.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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arch_init_invariance_cppc() is called at the end of
acpi_cppc_processor_probe() in order to configure frequency invariance
based upon the values from _CPC.
This however doesn't work on AMD CPPC shared memory designs that have
AMD preferred cores enabled because _CPC needs to be analyzed from all
cores to judge if preferred cores are enabled.
This issue manifests to users as a warning since commit 21fb59ab4b97
("ACPI: CPPC: Adjust debug messages in amd_set_max_freq_ratio() to warn"):
```
Could not retrieve highest performance (-19)
```
However the warning isn't the cause of this, it was actually
commit 279f838a61f9 ("x86/amd: Detect preferred cores in
amd_get_boost_ratio_numerator()") which exposed the issue.
To fix this problem, change arch_init_invariance_cppc() into a new weak
symbol that is called at the end of acpi_processor_driver_init().
Each architecture that supports it can declare the symbol to override
the weak one.
Define it for x86, in arch/x86/kernel/acpi/cppc.c, and for all of the
architectures using the generic arch_topology.c code.
Fixes: 279f838a61f9 ("x86/amd: Detect preferred cores in amd_get_boost_ratio_numerator()")
Reported-by: Ivan Shapovalov <intelfx@intelfx.name>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219431
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://patch.msgid.link/20241104222855.3959267-1-superm1@kernel.org
[ rjw: Changelog edit ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Add the four syscalls setxattrat(), getxattrat(), listxattrat() and
removexattrat(). Those can be used to operate on extended attributes,
especially security related ones, either relative to a pinned directory
or on a file descriptor without read access, avoiding a
/proc/<pid>/fd/<fd> detour, requiring a mounted procfs.
One use case will be setfiles(8) setting SELinux file contexts
("security.selinux") without race conditions and without a file
descriptor opened with read access requiring SELinux read permission.
Use the do_{name}at() pattern from fs/open.c.
Pass the value of the extended attribute, its length, and for
setxattrat(2) the command (XATTR_CREATE or XATTR_REPLACE) via an added
struct xattr_args to not exceed six syscall arguments and not
merging the AT_* and XATTR_* flags.
[AV: fixes by Christian Brauner folded in, the entire thing rebased on
top of {filename,file}_...xattr() primitives, treatment of empty
pathnames regularized. As the result, AT_EMPTY_PATH+NULL handling
is cheap, so f...(2) can use it]
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Link: https://lore.kernel.org/r/20240426162042.191916-1-cgoettsche@seltendoof.de
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
CC: x86@kernel.org
CC: linux-alpha@vger.kernel.org
CC: linux-kernel@vger.kernel.org
CC: linux-arm-kernel@lists.infradead.org
CC: linux-ia64@vger.kernel.org
CC: linux-m68k@lists.linux-m68k.org
CC: linux-mips@vger.kernel.org
CC: linux-parisc@vger.kernel.org
CC: linuxppc-dev@lists.ozlabs.org
CC: linux-s390@vger.kernel.org
CC: linux-sh@vger.kernel.org
CC: sparclinux@vger.kernel.org
CC: linux-fsdevel@vger.kernel.org
CC: audit@vger.kernel.org
CC: linux-arch@vger.kernel.org
CC: linux-api@vger.kernel.org
CC: linux-security-module@vger.kernel.org
CC: selinux@vger.kernel.org
[brauner: slight tweaks]
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Stable tag for bpf-next's uprobe work.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
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Fix the indentation of the return values from
generic_ci_validate_strict_name() to properly render the comment and to
address a `make htmldocs` warning:
Documentation/filesystems/api-summary:14: include/linux/fs.h:3504:
WARNING: Bullet list ends without a blank line; unexpected unindent.
Fixes: 0e152beb5aa1 ("libfs: Create the helper function generic_ci_validate_strict_name()")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Closes: https://lore.kernel.org/lkml/20241030162435.05425f60@canb.auug.org.au/
Signed-off-by: André Almeida <andrealmeid@igalia.com>
Link: https://lore.kernel.org/r/20241101164251.327884-2-andrealmeid@igalia.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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There is NULL pointer issue observed if from Process A where hid device
being added which results in adding a led_cdev addition and later a
another call to access of led_cdev attribute from Process B can result
in NULL pointer issue.
Use mutex led_cdev->led_access to protect access to led->cdev and its
attribute inside brightness_show() and max_brightness_show() and also
update the comment for mutex that it should be used to protect the led
class device fields.
Process A Process B
kthread+0x114
worker_thread+0x244
process_scheduled_works+0x248
uhid_device_add_worker+0x24
hid_add_device+0x120
device_add+0x268
bus_probe_device+0x94
device_initial_probe+0x14
__device_attach+0xfc
bus_for_each_drv+0x10c
__device_attach_driver+0x14c
driver_probe_device+0x3c
__driver_probe_device+0xa0
really_probe+0x190
hid_device_probe+0x130
ps_probe+0x990
ps_led_register+0x94
devm_led_classdev_register_ext+0x58
led_classdev_register_ext+0x1f8
device_create_with_groups+0x48
device_create_groups_vargs+0xc8
device_add+0x244
kobject_uevent+0x14
kobject_uevent_env[jt]+0x224
mutex_unlock[jt]+0xc4
__mutex_unlock_slowpath+0xd4
wake_up_q+0x70
try_to_wake_up[jt]+0x48c
preempt_schedule_common+0x28
__schedule+0x628
__switch_to+0x174
el0t_64_sync+0x1a8/0x1ac
el0t_64_sync_handler+0x68/0xbc
el0_svc+0x38/0x68
do_el0_svc+0x1c/0x28
el0_svc_common+0x80/0xe0
invoke_syscall+0x58/0x114
__arm64_sys_read+0x1c/0x2c
ksys_read+0x78/0xe8
vfs_read+0x1e0/0x2c8
kernfs_fop_read_iter+0x68/0x1b4
seq_read_iter+0x158/0x4ec
kernfs_seq_show+0x44/0x54
sysfs_kf_seq_show+0xb4/0x130
dev_attr_show+0x38/0x74
brightness_show+0x20/0x4c
dualshock4_led_get_brightness+0xc/0x74
[ 3313.874295][ T4013] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000060
[ 3313.874301][ T4013] Mem abort info:
[ 3313.874303][ T4013] ESR = 0x0000000096000006
[ 3313.874305][ T4013] EC = 0x25: DABT (current EL), IL = 32 bits
[ 3313.874307][ T4013] SET = 0, FnV = 0
[ 3313.874309][ T4013] EA = 0, S1PTW = 0
[ 3313.874311][ T4013] FSC = 0x06: level 2 translation fault
[ 3313.874313][ T4013] Data abort info:
[ 3313.874314][ T4013] ISV = 0, ISS = 0x00000006, ISS2 = 0x00000000
[ 3313.874316][ T4013] CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[ 3313.874318][ T4013] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[ 3313.874320][ T4013] user pgtable: 4k pages, 39-bit VAs, pgdp=00000008f2b0a000
..
[ 3313.874332][ T4013] Dumping ftrace buffer:
[ 3313.874334][ T4013] (ftrace buffer empty)
..
..
[ dd3313.874639][ T4013] CPU: 6 PID: 4013 Comm: InputReader
[ 3313.874648][ T4013] pc : dualshock4_led_get_brightness+0xc/0x74
[ 3313.874653][ T4013] lr : led_update_brightness+0x38/0x60
[ 3313.874656][ T4013] sp : ffffffc0b910bbd0
..
..
[ 3313.874685][ T4013] Call trace:
[ 3313.874687][ T4013] dualshock4_led_get_brightness+0xc/0x74
[ 3313.874690][ T4013] brightness_show+0x20/0x4c
[ 3313.874692][ T4013] dev_attr_show+0x38/0x74
[ 3313.874696][ T4013] sysfs_kf_seq_show+0xb4/0x130
[ 3313.874700][ T4013] kernfs_seq_show+0x44/0x54
[ 3313.874703][ T4013] seq_read_iter+0x158/0x4ec
[ 3313.874705][ T4013] kernfs_fop_read_iter+0x68/0x1b4
[ 3313.874708][ T4013] vfs_read+0x1e0/0x2c8
[ 3313.874711][ T4013] ksys_read+0x78/0xe8
[ 3313.874714][ T4013] __arm64_sys_read+0x1c/0x2c
[ 3313.874718][ T4013] invoke_syscall+0x58/0x114
[ 3313.874721][ T4013] el0_svc_common+0x80/0xe0
[ 3313.874724][ T4013] do_el0_svc+0x1c/0x28
[ 3313.874727][ T4013] el0_svc+0x38/0x68
[ 3313.874730][ T4013] el0t_64_sync_handler+0x68/0xbc
[ 3313.874732][ T4013] el0t_64_sync+0x1a8/0x1ac
Signed-off-by: Mukesh Ojha <quic_mojha@quicinc.com>
Reviewed-by: Anish Kumar <yesanishhere@gmail.com>
Link: https://lore.kernel.org/r/20241103160527.82487-1-quic_mojha@quicinc.com
Signed-off-by: Lee Jones <lee@kernel.org>
|
|
This allows to setup ordered workqueue for LEDs events. This may be
useful, because default 'system_wq' does not guarantee execution order
of each work_struct, thus for several brightness update requests (for
multiple LEDs), real brightness switch could be in random order.
Yes, for sysfs-based LEDs we have flush_work() call inside
brightness_store() operation, but it's blocking call, so userspace
caller can be blocked at a long time, which means LEDs animation stream
can be broken.
Ordered workqueue has the same behaviour as system_wq + flush_work(),
but all scheduled works are async and userspace caller is not blocked,
which it better for userspace animation scheduling.
Signed-off-by: Alexey Romanov <avromanov@salutedevices.com>
Signed-off-by: Dmitry Rokosov <ddrokosov@salutedevices.com>
Link: https://lore.kernel.org/r/20240903223936.21292-1-ddrokosov@salutedevices.com
[Lee: Couple of style fix-ups]
Signed-off-by: Lee Jones <lee@kernel.org>
|
|
Add devm_clk_hw_register_gate_parent_hw() macro to allow registering
devres managed gate clocks providing struct clk_hw object as parent.
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://lore.kernel.org/20241101095720.2247815-3-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
|
|
The non-inline min heap API can result in an indirect function call to the
custom swap function. This becomes particularly costly when
CONFIG_MITIGATION_RETPOLINE is enabled, as indirect function calls are
expensive in this case.
To address this, copy the code from lib/sort.c and provide a default
builtin swap implementation that performs element swaps based on the
element size. This change allows most users to avoid the overhead of
indirect function calls, improving efficiency.
Link: https://lkml.kernel.org/r/20241020040200.939973-4-visitorckw@gmail.com
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Ching-Chun (Jim) Huang <jserv@ccns.ncku.edu.tw>
Cc: Coly Li <colyli@suse.de>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: "Liang, Kan" <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Sakai <msakai@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Improve the efficiency of the min heap by prescaling counters, eliminating
the need to repeatedly compute 'index * element_size' when accessing
elements. By doing so, we avoid the overhead associated with
recalculating the byte offset for each heap operation.
However, with prescaling, the calculation for the parent element's
location is no longer as simple as '(i - 1) / 2'. To address this, we
copy the parent function from 'lib/sort.c', which calculates the parent
offset in a branchless manner without using any division instructions.
This optimization should result in a more efficient heap implementation by
reducing the computational overhead of finding parent and child offsets.
Link: https://lkml.kernel.org/r/20241020040200.939973-3-visitorckw@gmail.com
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Ching-Chun (Jim) Huang <jserv@ccns.ncku.edu.tw>
Cc: Coly Li <colyli@suse.de>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: "Liang, Kan" <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Sakai <msakai@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "Enhance min heap API with non-inline functions and
optimizations", v2.
Add non-inline versions of the min heap API functions in lib/min_heap.c
and updates all users outside of kernel/events/core.c to use these
non-inline versions. To mitigate the performance impact of indirect
function calls caused by the non-inline versions of the swap and compare
functions, a builtin swap has been introduced that swaps elements based on
their size. Additionally, it micro-optimizes the efficiency of the min
heap by pre-scaling the counter, following the same approach as in
lib/sort.c. Documentation for the min heap API has also been added to the
core-api section.
This patch (of 10):
All current min heap API functions are marked with '__always_inline'.
However, as the number of users increases, inlining these functions
everywhere leads to a increase in kernel size.
In performance-critical paths, such as when perf events are enabled and
min heap functions are called on every context switch, it is important to
retain the inline versions for optimal performance. To balance this, the
original inline functions are kept, and additional non-inline versions of
the functions have been added in lib/min_heap.c.
Link: https://lkml.kernel.org/r/20241020040200.939973-1-visitorckw@gmail.com
Link: https://lore.kernel.org/20240522161048.8d8bbc7b153b4ecd92c50666@linux-foundation.org
Link: https://lkml.kernel.org/r/20241020040200.939973-2-visitorckw@gmail.com
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Ching-Chun (Jim) Huang <jserv@ccns.ncku.edu.tw>
Cc: Coly Li <colyli@suse.de>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Kuan-Wei Chiu <visitorckw@gmail.com>
Cc: "Liang, Kan" <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Sakai <msakai@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Cast pointer from percpu address space to generic (kernel) address space
in PERCPU_PTR() macro via unsigned long intermediate cast [1]. This
intermediate cast is also required to avoid build failure when GCC's
strict named address space checks for x86 targets [2] are enabled.
Found by GCC's named address space checks.
[1] https://sparse.docs.kernel.org/en/latest/annotations.html#address-space-name
[2] https://gcc.gnu.org/onlinedocs/gcc/Named-Address-Spaces.html#x86-Named-Address-Spaces
Link: https://lkml.kernel.org/r/20241021080856.48746-3-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Introduce PERCPU_PTR() macro to cast the percpu pointer from the percpu
address space to a generic (kernel) address space. Use it in
per_cpu_ptr() and related SHIFT_PERCPU_PTR() macros.
Also remove common knowledge from SHIFT_PERCPU_PTR() comment, "weird cast"
is just a standard way to inform sparse of a cast from the percpu address
space to a generic address space.
Link: https://lkml.kernel.org/r/20241021080856.48746-2-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Merge VERIFY_PERCPU_PTR() into non-CONFIG_SMP per_cpu_ptr() to make macro
similar to CONFIG_SMP per_cpu_ptr(). This will allow a follow-up patch to
refactor common code to a macro.
No functional changes, non-CONFIG_SMP per_cpu_ptr() was the only user of
VERIFY_PERCPU_PTR().
Link: https://lkml.kernel.org/r/20241021080856.48746-1-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Replace the 'One' with 'On'.
Link: https://lkml.kernel.org/r/20241012100817.323007-1-sui.jingfeng@linux.dev
Fixes: af2880ec4402 ("scatterlist: add dedicated config for DMA flags")
Signed-off-by: Sui Jingfeng <sui.jingfeng@linux.dev>
Reviewed-by: Petr Tesarik <petr@tesarici.cz>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Michael Kelley <mhklinux@outlook.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
All the functions related to the reboot notifier list are in
kernel/reboot.c. Move the list itself, too. As there are no direct users
anymore, make the declaration static.
Link: https://lkml.kernel.org/r/20241012-reboot_notifier_list-v1-1-6093bb9455ce@weissschuh.net
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "Improve the copy of task comm", v8.
Using {memcpy,strncpy,strcpy,kstrdup} to copy the task comm relies on the
length of task comm. Changes in the task comm could result in a
destination string that is overflow. Therefore, we should explicitly
ensure the destination string is always NUL-terminated, regardless of the
task comm. This approach will facilitate future extensions to the task
comm.
As suggested by Linus [0], we can identify all relevant code with the
following git grep command:
git grep 'memcpy.*->comm\>'
git grep 'kstrdup.*->comm\>'
git grep 'strncpy.*->comm\>'
git grep 'strcpy.*->comm\>'
PATCH #2~#4: memcpy
PATCH #5~#6: kstrdup
PATCH #7: strcpy
Please note that strncpy() is not included in this series as it is being
tracked by another effort. [1]
This patch (of 7):
We want to eliminate the use of __get_task_comm() for the following
reasons:
- The task_lock() is unnecessary
Quoted from Linus [0]:
: Since user space can randomly change their names anyway, using locking
: was always wrong for readers (for writers it probably does make sense
: to have some lock - although practically speaking nobody cares there
: either, but at least for a writer some kind of race could have
: long-term mixed results
Link: https://lkml.kernel.org/r/20241007144911.27693-1-laoar.shao@gmail.com
Link: https://lkml.kernel.org/r/20241007144911.27693-2-laoar.shao@gmail.com
Link: https://lore.kernel.org/all/CAHk-=wivfrF0_zvf+oj6==Sh=-npJooP8chLPEfaFV0oNYTTBA@mail.gmail.com [0]
Link: https://lore.kernel.org/all/CAHk-=whWtUC-AjmGJveAETKOMeMFSTwKwu99v7+b6AyHMmaDFA@mail.gmail.com/
Link: https://lore.kernel.org/all/CAHk-=wjAmmHUg6vho1KjzQi2=psR30+CogFd4aXrThr2gsiS4g@mail.gmail.com/ [0]
Link: https://github.com/KSPP/linux/issues/90 [1]
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Matus Jokay <matus.jokay@stuba.sk>
Cc: Alejandro Colomar <alx@kernel.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@gmail.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Ondrej Mosnacek <omosnace@redhat.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Quentin Monnet <qmo@kernel.org>
Cc: Simon Horman <horms@kernel.org>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Bits of LRU_REFS_MASK are not inherited during migration which lead to new
folio start from tier0 when MGLRU enabled. Try to bring as much bits of
folio->flags as possible since compaction and alloc_contig_range which
introduce migration do happen at times.
Link: https://lkml.kernel.org/r/20240926050647.5653-1-zhaoyang.huang@unisoc.com
Signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
Suggested-by: Yu Zhao <yuzhao@google.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Now no users are using the pte_offset_map_nolock(), remove it.
Link: https://lkml.kernel.org/r/d04f9bbbcde048fb6ffa6f2bdbc6f9b22d5286f9.1727332572.git.zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "introduce pte_offset_map_{ro|rw}_nolock()", v5.
As proposed by David Hildenbrand [1], this series introduces the following
two new helper functions to replace pte_offset_map_nolock().
1. pte_offset_map_ro_nolock()
2. pte_offset_map_rw_nolock()
As the name suggests, pte_offset_map_ro_nolock() is used for read-only
case. In this case, only read-only operations will be performed on PTE
page after the PTL is held. The RCU lock in pte_offset_map_nolock() will
ensure that the PTE page will not be freed, and there is no need to worry
about whether the pmd entry is modified. Therefore
pte_offset_map_ro_nolock() is just a renamed version of
pte_offset_map_nolock().
pte_offset_map_rw_nolock() is used for may-write case. In this case, the
pte or pmd entry may be modified after the PTL is held, so we need to
ensure that the pmd entry has not been modified concurrently. So in
addition to the name change, it also outputs the pmdval when successful.
The users should make sure the page table is stable like checking
pte_same() or checking pmd_same() by using the output pmdval before
performing the write operations.
This series will convert all pte_offset_map_nolock() into the above two
helper functions one by one, and finally completely delete it.
This also a preparation for reclaiming the empty user PTE page table
pages.
This patch (of 13):
Currently, the usage of pte_offset_map_nolock() can be divided into the
following two cases:
1) After acquiring PTL, only read-only operations are performed on the PTE
page. In this case, the RCU lock in pte_offset_map_nolock() will ensure
that the PTE page will not be freed, and there is no need to worry
about whether the pmd entry is modified.
2) After acquiring PTL, the pte or pmd entries may be modified. At this
time, we need to ensure that the pmd entry has not been modified
concurrently.
To more clearing distinguish between these two cases, this commit
introduces two new helper functions to replace pte_offset_map_nolock().
For 1), just rename it to pte_offset_map_ro_nolock(). For 2), in addition
to changing the name to pte_offset_map_rw_nolock(), it also outputs the
pmdval when successful. It is applicable for may-write cases where any
modification operations to the page table may happen after the
corresponding spinlock is held afterwards. But the users should make sure
the page table is stable like checking pte_same() or checking pmd_same()
by using the output pmdval before performing the write operations.
Note: "RO" / "RW" expresses the intended semantics, not that the *kmap*
will be read-only/read-write protected.
Subsequent commits will convert pte_offset_map_nolock() into the above
two functions one by one, and finally completely delete it.
Link: https://lkml.kernel.org/r/cover.1727332572.git.zhengqi.arch@bytedance.com
Link: https://lkml.kernel.org/r/5aeecfa131600a454b1f3a038a1a54282ca3b856.1727332572.git.zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The types of mm flags are now far beyond the core dump related features.
This patch moves mm flags from linux/sched/coredump.h to linux/mm_types.h.
The linux/sched/coredump.h has include the mm_types.h, so the C files
related to coredump does not need to change head file inclusion. In
addition, the inclusion of sched/coredump.h now can be deleted from the C
files that irrelevant to core dump.
Link: https://lkml.kernel.org/r/20240926074922.2721274-1-sunnanyong@huawei.com
Signed-off-by: Nanyong Sun <sunnanyong@huawei.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Fix typo in mempolicy.h and Correct the number of allowed memory policy
Link: https://lkml.kernel.org/r/20240926183516.4034-2-tanyaagarwal25699@gmail.com
Signed-off-by: Tanya Agarwal <tanyaagarwal25699@gmail.com>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Cc: Anup Sharma <anupnewsmail@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
into one operation
When compiling kernel source 'make -j $(nproc)' with the up-and-running
KASAN-enabled kernel on a 256-core machine, the following soft lockup is
shown:
watchdog: BUG: soft lockup - CPU#28 stuck for 22s! [kworker/28:1:1760]
CPU: 28 PID: 1760 Comm: kworker/28:1 Kdump: loaded Not tainted 6.10.0-rc5 #95
Workqueue: events drain_vmap_area_work
RIP: 0010:smp_call_function_many_cond+0x1d8/0xbb0
Code: 38 c8 7c 08 84 c9 0f 85 49 08 00 00 8b 45 08 a8 01 74 2e 48 89 f1 49 89 f7 48 c1 e9 03 41 83 e7 07 4c 01 e9 41 83 c7 03 f3 90 <0f> b6 01 41 38 c7 7c 08 84 c0 0f 85 d4 06 00 00 8b 45 08 a8 01 75
RSP: 0018:ffffc9000cb3fb60 EFLAGS: 00000202
RAX: 0000000000000011 RBX: ffff8883bc4469c0 RCX: ffffed10776e9949
RDX: 0000000000000002 RSI: ffff8883bb74ca48 RDI: ffffffff8434dc50
RBP: ffff8883bb74ca40 R08: ffff888103585dc0 R09: ffff8884533a1800
R10: 0000000000000004 R11: ffffffffffffffff R12: ffffed1077888d39
R13: dffffc0000000000 R14: ffffed1077888d38 R15: 0000000000000003
FS: 0000000000000000(0000) GS:ffff8883bc400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005577b5c8d158 CR3: 0000000004850000 CR4: 0000000000350ef0
Call Trace:
<IRQ>
? watchdog_timer_fn+0x2cd/0x390
? __pfx_watchdog_timer_fn+0x10/0x10
? __hrtimer_run_queues+0x300/0x6d0
? sched_clock_cpu+0x69/0x4e0
? __pfx___hrtimer_run_queues+0x10/0x10
? srso_return_thunk+0x5/0x5f
? ktime_get_update_offsets_now+0x7f/0x2a0
? srso_return_thunk+0x5/0x5f
? srso_return_thunk+0x5/0x5f
? hrtimer_interrupt+0x2ca/0x760
? __sysvec_apic_timer_interrupt+0x8c/0x2b0
? sysvec_apic_timer_interrupt+0x6a/0x90
</IRQ>
<TASK>
? asm_sysvec_apic_timer_interrupt+0x16/0x20
? smp_call_function_many_cond+0x1d8/0xbb0
? __pfx_do_kernel_range_flush+0x10/0x10
on_each_cpu_cond_mask+0x20/0x40
flush_tlb_kernel_range+0x19b/0x250
? srso_return_thunk+0x5/0x5f
? kasan_release_vmalloc+0xa7/0xc0
purge_vmap_node+0x357/0x820
? __pfx_purge_vmap_node+0x10/0x10
__purge_vmap_area_lazy+0x5b8/0xa10
drain_vmap_area_work+0x21/0x30
process_one_work+0x661/0x10b0
worker_thread+0x844/0x10e0
? srso_return_thunk+0x5/0x5f
? __kthread_parkme+0x82/0x140
? __pfx_worker_thread+0x10/0x10
kthread+0x2a5/0x370
? __pfx_kthread+0x10/0x10
ret_from_fork+0x30/0x70
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1a/0x30
</TASK>
Debugging Analysis:
1. The following ftrace log shows that the lockup CPU spends too much
time iterating vmap_nodes and flushing TLB when purging vm_area
structures. (Some info is trimmed).
kworker: funcgraph_entry: | drain_vmap_area_work() {
kworker: funcgraph_entry: | mutex_lock() {
kworker: funcgraph_entry: 1.092 us | __cond_resched();
kworker: funcgraph_exit: 3.306 us | }
... ...
kworker: funcgraph_entry: | flush_tlb_kernel_range() {
... ...
kworker: funcgraph_exit: # 7533.649 us | }
... ...
kworker: funcgraph_entry: 2.344 us | mutex_unlock();
kworker: funcgraph_exit: $ 23871554 us | }
The drain_vmap_area_work() spends over 23 seconds.
There are 2805 flush_tlb_kernel_range() calls in the ftrace log.
* One is called in __purge_vmap_area_lazy().
* Others are called by purge_vmap_node->kasan_release_vmalloc.
purge_vmap_node() iteratively releases kasan vmalloc
allocations and flushes TLB for each vmap_area.
- [Rough calculation] Each flush_tlb_kernel_range() runs
about 7.5ms.
-- 2804 * 7.5ms = 21.03 seconds.
-- That's why a soft lock is triggered.
2. Extending the soft lockup time can work around the issue (For example,
# echo 60 > /proc/sys/kernel/watchdog_thresh). This confirms the
above-mentioned speculation: drain_vmap_area_work() spends too much
time.
If we combine all TLB flush operations of the KASAN shadow virtual
address into one operation in the call path
'purge_vmap_node()->kasan_release_vmalloc()', the running time of
drain_vmap_area_work() can be saved greatly. The idea is from the
flush_tlb_kernel_range() call in __purge_vmap_area_lazy(). And, the
soft lockup won't be triggered.
Here is the test result based on 6.10:
[6.10 wo/ the patch]
1. ftrace latency profiling (record a trace if the latency > 20s).
echo 20000000 > /sys/kernel/debug/tracing/tracing_thresh
echo drain_vmap_area_work > /sys/kernel/debug/tracing/set_graph_function
echo function_graph > /sys/kernel/debug/tracing/current_tracer
echo 1 > /sys/kernel/debug/tracing/tracing_on
2. Run `make -j $(nproc)` to compile the kernel source
3. Once the soft lockup is reproduced, check the ftrace log:
cat /sys/kernel/debug/tracing/trace
# tracer: function_graph
#
# CPU DURATION FUNCTION CALLS
# | | | | | | |
76) $ 50412985 us | } /* __purge_vmap_area_lazy */
76) $ 50412997 us | } /* drain_vmap_area_work */
76) $ 29165911 us | } /* __purge_vmap_area_lazy */
76) $ 29165926 us | } /* drain_vmap_area_work */
91) $ 53629423 us | } /* __purge_vmap_area_lazy */
91) $ 53629434 us | } /* drain_vmap_area_work */
91) $ 28121014 us | } /* __purge_vmap_area_lazy */
91) $ 28121026 us | } /* drain_vmap_area_work */
[6.10 w/ the patch]
1. Repeat step 1-2 in "[6.10 wo/ the patch]"
2. The soft lockup is not triggered and ftrace log is empty.
cat /sys/kernel/debug/tracing/trace
# tracer: function_graph
#
# CPU DURATION FUNCTION CALLS
# | | | | | | |
3. Setting 'tracing_thresh' to 10/5 seconds does not get any ftrace
log.
4. Setting 'tracing_thresh' to 1 second gets ftrace log.
cat /sys/kernel/debug/tracing/trace
# tracer: function_graph
#
# CPU DURATION FUNCTION CALLS
# | | | | | | |
23) $ 1074942 us | } /* __purge_vmap_area_lazy */
23) $ 1074950 us | } /* drain_vmap_area_work */
The worst execution time of drain_vmap_area_work() is about 1 second.
Link: https://lore.kernel.org/lkml/ZqFlawuVnOMY2k3E@pc638.lan/
Link: https://lkml.kernel.org/r/20240726165246.31326-1-ahuang12@lenovo.com
Fixes: 282631cb2447 ("mm: vmalloc: remove global purge_vmap_area_root rb-tree")
Signed-off-by: Adrian Huang <ahuang12@lenovo.com>
Co-developed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Tested-by: Jiwei Sun <sunjw10@lenovo.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Shmem has a separate interface (different from anonymous pages) to control
huge page allocation, that means shmem THP can be enabled while anonymous
THP is disabled. However, in this case, khugepaged will not start to
collapse shmem THP, which is unreasonable.
To fix this issue, we should call start_stop_khugepaged() to activate or
deactivate the khugepaged thread when setting shmem mTHP interfaces.
Moreover, add a new helper shmem_hpage_pmd_enabled() to help to check
whether shmem THP is enabled, which will determine if khugepaged should be
activated.
Link: https://lkml.kernel.org/r/9b9c6cbc4499bf44c6455367fd9e0f6036525680.1726978977.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reported-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Currently MTE is permitted in two circumstances (desiring to use MTE
having been specified by the VM_MTE flag) - where MAP_ANONYMOUS is
specified, as checked by arch_calc_vm_flag_bits() and actualised by
setting the VM_MTE_ALLOWED flag, or if the file backing the mapping is
shmem, in which case we set VM_MTE_ALLOWED in shmem_mmap() when the mmap
hook is activated in mmap_region().
The function that checks that, if VM_MTE is set, VM_MTE_ALLOWED is also
set is the arm64 implementation of arch_validate_flags().
Unfortunately, we intend to refactor mmap_region() to perform this check
earlier, meaning that in the case of a shmem backing we will not have
invoked shmem_mmap() yet, causing the mapping to fail spuriously.
It is inappropriate to set this architecture-specific flag in general mm
code anyway, so a sensible resolution of this issue is to instead move the
check somewhere else.
We resolve this by setting VM_MTE_ALLOWED much earlier in do_mmap(), via
the arch_calc_vm_flag_bits() call.
This is an appropriate place to do this as we already check for the
MAP_ANONYMOUS case here, and the shmem file case is simply a variant of
the same idea - we permit RAM-backed memory.
This requires a modification to the arch_calc_vm_flag_bits() signature to
pass in a pointer to the struct file associated with the mapping, however
this is not too egregious as this is only used by two architectures anyway
- arm64 and parisc.
So this patch performs this adjustment and removes the unnecessary
assignment of VM_MTE_ALLOWED in shmem_mmap().
[akpm@linux-foundation.org: fix whitespace, per Catalin]
Link: https://lkml.kernel.org/r/ec251b20ba1964fb64cf1607d2ad80c47f3873df.1730224667.git.lorenzo.stoakes@oracle.com
Fixes: deb0f6562884 ("mm/mmap: undo ->mmap() when arch_validate_flags() fails")
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Jann Horn <jannh@google.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Helge Deller <deller@gmx.de>
Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Refactor the map_deny_write_exec() to not unnecessarily require a VMA
parameter but rather to accept VMA flags parameters, which allows us to
use this function early in mmap_region() in a subsequent commit.
While we're here, we refactor the function to be more readable and add
some additional documentation.
Link: https://lkml.kernel.org/r/6be8bb59cd7c68006ebb006eb9d8dc27104b1f70.1730224667.git.lorenzo.stoakes@oracle.com
Fixes: deb0f6562884 ("mm/mmap: undo ->mmap() when arch_validate_flags() fails")
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reported-by: Jann Horn <jannh@google.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Jann Horn <jannh@google.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Helge Deller <deller@gmx.de>
Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Sometimes it is useful to observe (and maybe modify) data coming from
an input device, but only do that if there are other users of such input
device. An example is touchpad switching functionality on Lenovo IdeaPad
Z570 where it is desirable to suppress events coming from the touchpad
if user toggles touchpad on/off button (on this laptop the firmware does
not stop the device).
Introduce notion of passive observers for input handlers to solve this
issue. An input handler marked as passive observer behaves exactly like
any other input handler or filter, but with one exception: it does not
open/start underlying input device when attaching to it.
Link: https://lore.kernel.org/r/ZxlEROX7bMo5cbZP@google.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
|
|
File systems might have boundaries over which merges aren't possible.
In fact these are very common, although most of the time some kind of
header at the beginning of this region (e.g. XFS alloation groups, ext4
block groups) automatically create a merge barrier. But if that is
not present, say for a device purely used for data we need to manually
communicate that to iomap.
Add a IOMAP_F_BOUNDARY flag to never merge I/O into a previous mapping.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
|
|
To make it possible to put struct bin_attribute into read-only memory,
the sysfs core has to stop passing mutable pointers to the read() and
write() callbacks.
As there are numerous implementors of these callbacks throughout the
tree it's not possible to change all of them at once.
To enable a step-by-step transition, add new variants of the read() and
write() callbacks which differ only in the constness of the struct
bin_attribute argument.
As most binary attributes are defined through macros, extend these
macros to transparently handle both variants of callbacks to minimize
the churn during the transition.
As soon as all handlers are switch to the const variant, the non-const
one can be removed together with the transition machinery.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Krzysztof Wilczyński <kw@linux.com>
Link: https://lore.kernel.org/r/20241103-sysfs-const-bin_attr-v2-9-71110628844c@weissschuh.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
The preparations for the upcoming constification of struct bin_attribute
requires some logic in the structure definition macros.
To avoid duplication of that logic in multiple macros, reimplement all
other macros in terms of __BIN_ATTR().
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Krzysztof Wilczyński <kw@linux.com>
Link: https://lore.kernel.org/r/20241103-sysfs-const-bin_attr-v2-8-71110628844c@weissschuh.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
The llseek() callbacks should not modify the struct
bin_attribute passed as argument.
Enforce this by marking the argument as const.
As there are not many callback implementers perform this change
throughout the tree at once.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Krzysztof Wilczyński <kw@linux.com>
Link: https://lore.kernel.org/r/20241103-sysfs-const-bin_attr-v2-7-71110628844c@weissschuh.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
