[ Upstream commit abad3d0bad ]
Lonial reported that an out-of-bounds access in cgroup local storage
can be crafted via tail calls. Given two programs each utilizing a
cgroup local storage with a different value size, and one program
doing a tail call into the other. The verifier will validate each of
the indivial programs just fine. However, in the runtime context
the bpf_cg_run_ctx holds an bpf_prog_array_item which contains the
BPF program as well as any cgroup local storage flavor the program
uses. Helpers such as bpf_get_local_storage() pick this up from the
runtime context:
ctx = container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx);
storage = ctx->prog_item->cgroup_storage[stype];
if (stype == BPF_CGROUP_STORAGE_SHARED)
ptr = &READ_ONCE(storage->buf)->data[0];
else
ptr = this_cpu_ptr(storage->percpu_buf);
For the second program which was called from the originally attached
one, this means bpf_get_local_storage() will pick up the former
program's map, not its own. With mismatching sizes, this can result
in an unintended out-of-bounds access.
To fix this issue, we need to extend bpf_map_owner with an array of
storage_cookie[] to match on i) the exact maps from the original
program if the second program was using bpf_get_local_storage(), or
ii) allow the tail call combination if the second program was not
using any of the cgroup local storage maps.
Fixes: 7d9c342789 ("bpf: Make cgroup storages shared between programs on the same cgroup")
Reported-by: Lonial Con <kongln9170@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20250730234733.530041-4-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit fd1c98f0ef ]
Given this is only relevant for BPF tail call maps, it is adding up space
and penalizing other map types. We also need to extend this with further
objects to track / compare to. Therefore, lets move this out into a separate
structure and dynamically allocate it only for BPF tail call maps.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20250730234733.530041-2-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Stable-dep-of: abad3d0bad ("bpf: Fix oob access in cgroup local storage")
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 89a2d212bd upstream.
When CONFIG_DMA_DIRECT_REMAP is enabled, atomic pool pages are
remapped via dma_common_contiguous_remap() using the supplied
pgprot. Currently, the mapping uses
pgprot_dmacoherent(PAGE_KERNEL), which leaves the memory encrypted
on systems with memory encryption enabled (e.g., ARM CCA Realms).
This can cause the DMA layer to fail or crash when accessing the
memory, as the underlying physical pages are not configured as
expected.
Fix this by requesting a decrypted mapping in the vmap() call:
pgprot_decrypted(pgprot_dmacoherent(PAGE_KERNEL))
This ensures that atomic pool memory is consistently mapped
unencrypted.
Cc: stable@vger.kernel.org
Signed-off-by: Shanker Donthineni <sdonthineni@nvidia.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20250811181759.998805-1-sdonthineni@nvidia.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 4013aef2ce ]
When calling ftrace_dump_one() concurrently with reading trace_pipe,
a WARN_ON_ONCE() in trace_printk_seq() can be triggered due to a race
condition.
The issue occurs because:
CPU0 (ftrace_dump) CPU1 (reader)
echo z > /proc/sysrq-trigger
!trace_empty(&iter)
trace_iterator_reset(&iter) <- len = size = 0
cat /sys/kernel/tracing/trace_pipe
trace_find_next_entry_inc(&iter)
__find_next_entry
ring_buffer_empty_cpu <- all empty
return NULL
trace_printk_seq(&iter.seq)
WARN_ON_ONCE(s->seq.len >= s->seq.size)
In the context between trace_empty() and trace_find_next_entry_inc()
during ftrace_dump, the ring buffer data was consumed by other readers.
This caused trace_find_next_entry_inc to return NULL, failing to populate
`iter.seq`. At this point, due to the prior trace_iterator_reset, both
`iter.seq.len` and `iter.seq.size` were set to 0. Since they are equal,
the WARN_ON_ONCE condition is triggered.
Move the trace_printk_seq() into the if block that checks to make sure the
return value of trace_find_next_entry_inc() is non-NULL in
ftrace_dump_one(), ensuring the 'iter.seq' is properly populated before
subsequent operations.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Ingo Molnar <mingo@elte.hu>
Link: https://lore.kernel.org/20250822033343.3000289-1-wutengda@huaweicloud.com
Fixes: d769041f86 ("ring_buffer: implement new locking")
Signed-off-by: Tengda Wu <wutengda@huaweicloud.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit edede7a6dc ]
This warning was triggered during testing on v6.16:
notifier callback ftrace_suspend_notifier_call already registered
WARNING: CPU: 2 PID: 86 at kernel/notifier.c:23 notifier_chain_register+0x44/0xb0
...
Call Trace:
<TASK>
blocking_notifier_chain_register+0x34/0x60
register_ftrace_graph+0x330/0x410
ftrace_profile_write+0x1e9/0x340
vfs_write+0xf8/0x420
? filp_flush+0x8a/0xa0
? filp_close+0x1f/0x30
? do_dup2+0xaf/0x160
ksys_write+0x65/0xe0
do_syscall_64+0xa4/0x260
entry_SYSCALL_64_after_hwframe+0x77/0x7f
When writing to the function_profile_enabled interface, the notifier was
not unregistered after start_graph_tracing failed, causing a warning the
next time function_profile_enabled was written.
Fixed by adding unregister_pm_notifier in the exception path.
Link: https://lore.kernel.org/20250818073332.3890629-1-yeweihua4@huawei.com
Fixes: 4a2b8dda3f ("tracing/function-graph-tracer: fix a regression while suspend to disk")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Ye Weihua <yeweihua4@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 150e298ae0 ]
It was found during testing that an invalid leaf partition with an
empty effective exclusive CPU list can become a valid empty partition
with no CPU afer an offline/online operation of an unrelated CPU. An
empty partition root is allowed in the special case that it has no
task in its cgroup and has distributed out all its CPUs to its child
partitions. That is certainly not the case here.
The problem is in the cpumask_subsets() test in the hotplug case
(update with no new mask) of update_parent_effective_cpumask() as it
also returns true if the effective exclusive CPU list is empty. Fix that
by addding the cpumask_empty() test to root out this exception case.
Also add the cpumask_empty() test in cpuset_hotplug_update_tasks()
to avoid calling update_parent_effective_cpumask() for this special case.
Fixes: 0c7f293efc ("cgroup/cpuset: Add cpuset.cpus.exclusive.effective for v2")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 65f97cc81b ]
The following lockdep splat was observed.
[ 812.359086] ============================================
[ 812.359089] WARNING: possible recursive locking detected
[ 812.359097] --------------------------------------------
[ 812.359100] runtest.sh/30042 is trying to acquire lock:
[ 812.359105] ffffffffa7f27420 (cpu_hotplug_lock){++++}-{0:0}, at: static_key_enable+0xe/0x20
[ 812.359131]
[ 812.359131] but task is already holding lock:
[ 812.359134] ffffffffa7f27420 (cpu_hotplug_lock){++++}-{0:0}, at: cpuset_write_resmask+0x98/0xa70
:
[ 812.359267] Call Trace:
[ 812.359272] <TASK>
[ 812.359367] cpus_read_lock+0x3c/0xe0
[ 812.359382] static_key_enable+0xe/0x20
[ 812.359389] check_insane_mems_config.part.0+0x11/0x30
[ 812.359398] cpuset_write_resmask+0x9f2/0xa70
[ 812.359411] cgroup_file_write+0x1c7/0x660
[ 812.359467] kernfs_fop_write_iter+0x358/0x530
[ 812.359479] vfs_write+0xabe/0x1250
[ 812.359529] ksys_write+0xf9/0x1d0
[ 812.359558] do_syscall_64+0x5f/0xe0
Since commit d74b27d63a ("cgroup/cpuset: Change cpuset_rwsem
and hotplug lock order"), the ordering of cpu hotplug lock
and cpuset_mutex had been reversed. That patch correctly
used the cpuslocked version of the static branch API to enable
cpusets_pre_enable_key and cpusets_enabled_key, but it didn't do the
same for cpusets_insane_config_key.
The cpusets_insane_config_key can be enabled in the
check_insane_mems_config() which is called from update_nodemask()
or cpuset_hotplug_update_tasks() with both cpu hotplug lock and
cpuset_mutex held. Deadlock can happen with a pending hotplug event that
tries to acquire the cpu hotplug write lock which will block further
cpus_read_lock() attempt from check_insane_mems_config(). Fix that by
switching to use static_branch_enable_cpuslocked().
Fixes: d74b27d63a ("cgroup/cpuset: Change cpuset_rwsem and hotplug lock order")
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 6a909ea83f ]
When the length of the string written to set_ftrace_filter exceeds
FTRACE_BUFF_MAX, the following KASAN alarm will be triggered:
BUG: KASAN: slab-out-of-bounds in strsep+0x18c/0x1b0
Read of size 1 at addr ffff0000d00bd5ba by task ash/165
CPU: 1 UID: 0 PID: 165 Comm: ash Not tainted 6.16.0-g6bcdbd62bd56-dirty
Hardware name: linux,dummy-virt (DT)
Call trace:
show_stack+0x34/0x50 (C)
dump_stack_lvl+0xa0/0x158
print_address_description.constprop.0+0x88/0x398
print_report+0xb0/0x280
kasan_report+0xa4/0xf0
__asan_report_load1_noabort+0x20/0x30
strsep+0x18c/0x1b0
ftrace_process_regex.isra.0+0x100/0x2d8
ftrace_regex_release+0x484/0x618
__fput+0x364/0xa58
____fput+0x28/0x40
task_work_run+0x154/0x278
do_notify_resume+0x1f0/0x220
el0_svc+0xec/0xf0
el0t_64_sync_handler+0xa0/0xe8
el0t_64_sync+0x1ac/0x1b0
The reason is that trace_get_user will fail when processing a string
longer than FTRACE_BUFF_MAX, but not set the end of parser->buffer to 0.
Then an OOB access will be triggered in ftrace_regex_release->
ftrace_process_regex->strsep->strpbrk. We can solve this problem by
limiting access to parser->buffer when trace_get_user failed.
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/20250813040232.1344527-1-pulehui@huaweicloud.com
Fixes: 8c9af478c0 ("ftrace: Handle commands when closing set_ftrace_filter file")
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f0c6eab5e4 upstream.
A BPF scheduler may want to use the built-in idle cpumasks in ops.init()
before the scheduler is fully initialized, either directly or through a
BPF timer for example.
However, this would result in an error, since the idle state has not
been properly initialized yet.
This can be easily verified by modifying scx_simple to call
scx_bpf_get_idle_cpumask() in ops.init():
$ sudo scx_simple
DEBUG DUMP
===========================================================================
scx_simple[121] triggered exit kind 1024:
runtime error (built-in idle tracking is disabled)
...
Fix this by properly initializing the idle state before ops.init() is
called. With this change applied:
$ sudo scx_simple
local=2 global=0
local=19 global=11
local=23 global=11
...
Fixes: d73249f887 ("sched_ext: idle: Make idle static keys private")
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
[ Backport to 6.12:
- Original commit doesn't apply cleanly to 6.12 since d73249f887 is
not present.
- This backport applies the same logical fix to prevent BPF scheduler
failures while accessing idle cpumasks from ops.init(). ]
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ddf7233fca upstream.
When enabling a sched_ext scheduler, we may trigger invalid task state
transitions, resulting in warnings like the following (which can be
easily reproduced by running the hotplug selftest in a loop):
sched_ext: Invalid task state transition 0 -> 3 for fish[770]
WARNING: CPU: 18 PID: 787 at kernel/sched/ext.c:3862 scx_set_task_state+0x7c/0xc0
...
RIP: 0010:scx_set_task_state+0x7c/0xc0
...
Call Trace:
<TASK>
scx_enable_task+0x11f/0x2e0
switching_to_scx+0x24/0x110
scx_enable.isra.0+0xd14/0x13d0
bpf_struct_ops_link_create+0x136/0x1a0
__sys_bpf+0x1edd/0x2c30
__x64_sys_bpf+0x21/0x30
do_syscall_64+0xbb/0x370
entry_SYSCALL_64_after_hwframe+0x77/0x7f
This happens because we skip initialization for tasks that are already
dead (with their usage counter set to zero), but we don't exclude them
during the scheduling class transition phase.
Fix this by also skipping dead tasks during class swiching, preventing
invalid task state transitions.
Fixes: a8532fac7b ("sched_ext: TASK_DEAD tasks must be switched into SCX on ops_enable")
Cc: stable@vger.kernel.org # v6.12+
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ec879e1a0b upstream.
Fprobe event accepts wildcards for the target functions, but unless user
specifies its event name, it makes an event with the wildcards.
/sys/kernel/tracing # echo 'f mutex*' >> dynamic_events
/sys/kernel/tracing # cat dynamic_events
f:fprobes/mutex*__entry mutex*
/sys/kernel/tracing # ls events/fprobes/
enable filter mutex*__entry
To fix this, replace the wildcard ('*') with an underscore.
Link: https://lore.kernel.org/all/175535345114.282990.12294108192847938710.stgit@devnote2/
Fixes: 334e5519c3 ("tracing/probes: Add fprobe events for tracing function entry and exit.")
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 61399e0c54 upstream.
RCU re-initializes the deferred QS irq work everytime before attempting
to queue it. However there are situations where the irq work is
attempted to be queued even though it is already queued. In that case
re-initializing messes-up with the irq work queue that is about to be
handled.
The chances for that to happen are higher when the architecture doesn't
support self-IPIs and irq work are then all lazy, such as with the
following sequence:
1) rcu_read_unlock() is called when IRQs are disabled and there is a
grace period involving blocked tasks on the node. The irq work
is then initialized and queued.
2) The related tasks are unblocked and the CPU quiescent state
is reported. rdp->defer_qs_iw_pending is reset to DEFER_QS_IDLE,
allowing the irq work to be requeued in the future (note the previous
one hasn't fired yet).
3) A new grace period starts and the node has blocked tasks.
4) rcu_read_unlock() is called when IRQs are disabled again. The irq work
is re-initialized (but it's queued! and its node is cleared) and
requeued. Which means it's requeued to itself.
5) The irq work finally fires with the tick. But since it was requeued
to itself, it loops and hangs.
Fix this with initializing the irq work only once before the CPU boots.
Fixes: b41642c877 ("rcu: Fix rcu_read_unlock() deadloop due to IRQ work")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202508071303.c1134cce-lkp@intel.com
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.upadhyay@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 571c1ea91a ]
If a console printer is interrupted during panic, it will never
be able to reacquire ownership in order to perform and cleanup.
That in itself is not a problem, since the non-panic CPU will
simply quiesce in an endless loop within nbcon_reacquire_nobuf().
However, in this state, platforms that do not support a true NMI
to interrupt the quiesced CPU will not be able to shutdown that
CPU from within panic(). This then causes problems for such as
being unable to load and run a kdump kernel.
Fix this by allowing non-panic CPUs to reacquire ownership using
a direct acquire. Then the non-panic CPUs can successfullyl exit
the nbcon_reacquire_nobuf() loop and the console driver can
perform any necessary cleanup. But more importantly, the CPU is
no longer quiesced and is free to process any interrupts
necessary for panic() to shutdown the CPU.
All other forms of acquire are still not allowed for non-panic
CPUs since it is safer to have them avoid gaining console
ownership that is not strictly necessary.
Reported-by: Michael Kelley <mhklinux@outlook.com>
Closes: https://lore.kernel.org/r/SN6PR02MB4157A4C5E8CB219A75263A17D46DA@SN6PR02MB4157.namprd02.prod.outlook.com
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Link: https://patch.msgid.link/20250606185549.900611-1-john.ogness@linutronix.de
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit a6323bd4e6 ]
Passing a module name longer than MODULE_NAME_LEN to the delete_module
syscall results in its silent truncation. This really isn't much of
a problem in practice, but it could theoretically lead to the removal of an
incorrect module. It is more sensible to return ENAMETOOLONG or ENOENT in
such a case.
Update the syscall to return ENOENT, as documented in the delete_module(2)
man page to mean "No module by that name exists." This is appropriate
because a module with a name longer than MODULE_NAME_LEN cannot be loaded
in the first place.
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Reviewed-by: Daniel Gomez <da.gomez@samsung.com>
Link: https://lore.kernel.org/r/20250630143535.267745-2-petr.pavlu@suse.com
Signed-off-by: Daniel Gomez <da.gomez@samsung.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit b41642c877 ]
During rcu_read_unlock_special(), if this happens during irq_exit(), we
can lockup if an IPI is issued. This is because the IPI itself triggers
the irq_exit() path causing a recursive lock up.
This is precisely what Xiongfeng found when invoking a BPF program on
the trace_tick_stop() tracepoint As shown in the trace below. Fix by
managing the irq_work state correctly.
irq_exit()
__irq_exit_rcu()
/* in_hardirq() returns false after this */
preempt_count_sub(HARDIRQ_OFFSET)
tick_irq_exit()
tick_nohz_irq_exit()
tick_nohz_stop_sched_tick()
trace_tick_stop() /* a bpf prog is hooked on this trace point */
__bpf_trace_tick_stop()
bpf_trace_run2()
rcu_read_unlock_special()
/* will send a IPI to itself */
irq_work_queue_on(&rdp->defer_qs_iw, rdp->cpu);
A simple reproducer can also be obtained by doing the following in
tick_irq_exit(). It will hang on boot without the patch:
static inline void tick_irq_exit(void)
{
+ rcu_read_lock();
+ WRITE_ONCE(current->rcu_read_unlock_special.b.need_qs, true);
+ rcu_read_unlock();
+
Reported-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Closes: https://lore.kernel.org/all/9acd5f9f-6732-7701-6880-4b51190aa070@huawei.com/
Tested-by: Qi Xi <xiqi2@huawei.com>
Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Reviewed-by: "Paul E. McKenney" <paulmck@kernel.org>
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
[neeraj: Apply Frederic's suggested fix for PREEMPT_RT]
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.upadhyay@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 5534e58f2e ]
When reg->type is CONST_PTR_TO_MAP, it can not be null. However the
verifier explores the branches under rX == 0 in check_cond_jmp_op()
even if reg->type is CONST_PTR_TO_MAP, because it was not checked for
in reg_not_null().
Fix this by adding CONST_PTR_TO_MAP to the set of types that are
considered non nullable in reg_not_null().
An old "unpriv: cmp map pointer with zero" selftest fails with this
change, because now early out correctly triggers in
check_cond_jmp_op(), making the verification to pass.
In practice verifier may allow pointer to null comparison in unpriv,
since in many cases the relevant branch and comparison op are removed
as dead code. So change the expected test result to __success_unpriv.
Signed-off-by: Ihor Solodrai <isolodrai@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250609183024.359974-2-isolodrai@meta.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 1bba3900ca ]
In the preparation stage of CPU online, if the corresponding
the rdp's->nocb_cb_kthread does not exist, will be created,
there is a situation where the rdp's rcuop kthreads creation fails,
and then de-offload this CPU's rdp, does not assign this CPU's
rdp->nocb_cb_kthread pointer, but this rdp's->nocb_gp_rdp and
rdp's->rdp_gp->nocb_gp_kthread is still valid.
This will cause the subsequent re-offload operation of this offline
CPU, which will pass the conditional check and the kthread_unpark()
will access invalid rdp's->nocb_cb_kthread pointer.
This commit therefore use rdp's->nocb_gp_kthread instead of
rdp_gp's->nocb_gp_kthread for safety check.
Signed-off-by: Zqiang <qiang.zhang1211@gmail.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.upadhyay@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 155213a2ae ]
schbench (https://github.com/masoncl/schbench.git) is showing a
regression from previous production kernels that bisected down to:
sched/fair: Remove sysctl_sched_migration_cost condition (c5b0a7eefc)
The schbench command line was:
schbench -L -m 4 -M auto -t 256 -n 0 -r 0 -s 0
This creates 4 message threads pinned to CPUs 0-3, and 256x4 worker
threads spread across the rest of the CPUs. Neither the worker threads
or the message threads do any work, they just wake each other up and go
back to sleep as soon as possible.
The end result is the first 4 CPUs are pegged waking up those 1024
workers, and the rest of the CPUs are constantly banging in and out of
idle. If I take a v6.9 Linus kernel and revert that one commit,
performance goes from 3.4M RPS to 5.4M RPS.
schedstat shows there are ~100x more new idle balance operations, and
profiling shows the worker threads are spending ~20% of their CPU time
on new idle balance. schedstats also shows that almost all of these new
idle balance attemps are failing to find busy groups.
The fix used here is to crank up the cost of the newidle balance whenever it
fails. Since we don't want sd->max_newidle_lb_cost to grow out of
control, this also changes update_newidle_cost() to use
sysctl_sched_migration_cost as the upper limit on max_newidle_lb_cost.
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20250626144017.1510594-2-clm@fb.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 6279846b9b ]
Syzbot reported a kernel warning due to a range invariant violation on
the following BPF program.
0: call bpf_get_netns_cookie
1: if r0 == 0 goto <exit>
2: if r0 & Oxffffffff goto <exit>
The issue is on the path where we fall through both jumps.
That path is unreachable at runtime: after insn 1, we know r0 != 0, but
with the sign extension on the jset, we would only fallthrough insn 2
if r0 == 0. Unfortunately, is_branch_taken() isn't currently able to
figure this out, so the verifier walks all branches. The verifier then
refines the register bounds using the second condition and we end
up with inconsistent bounds on this unreachable path:
1: if r0 == 0 goto <exit>
r0: u64=[0x1, 0xffffffffffffffff] var_off=(0, 0xffffffffffffffff)
2: if r0 & 0xffffffff goto <exit>
r0 before reg_bounds_sync: u64=[0x1, 0xffffffffffffffff] var_off=(0, 0)
r0 after reg_bounds_sync: u64=[0x1, 0] var_off=(0, 0)
Improving the range refinement for JSET to cover all cases is tricky. We
also don't expect many users to rely on JSET given LLVM doesn't generate
those instructions. So instead of improving the range refinement for
JSETs, Eduard suggested we forget the ranges whenever we're narrowing
tnums after a JSET. This patch implements that approach.
Reported-by: syzbot+c711ce17dd78e5d4fdcf@syzkaller.appspotmail.com
Suggested-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com>
Link: https://lore.kernel.org/r/9d4fd6432a095d281f815770608fdcd16028ce0b.1752171365.git.paul.chaignon@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 90c09d57ca ]
On kernels built with CONFIG_IRQ_WORK=y, when rcu_read_unlock() is
invoked within an interrupts-disabled region of code [1], it will invoke
rcu_read_unlock_special(), which uses an irq-work handler to force the
system to notice when the RCU read-side critical section actually ends.
That end won't happen until interrupts are enabled at the soonest.
In some kernels, such as those booted with rcutree.use_softirq=y, the
irq-work handler is used unconditionally.
The per-CPU rcu_data structure's ->defer_qs_iw_pending field is
updated by the irq-work handler and is both read and updated by
rcu_read_unlock_special(). This resulted in the following KCSAN splat:
------------------------------------------------------------------------
BUG: KCSAN: data-race in rcu_preempt_deferred_qs_handler / rcu_read_unlock_special
read to 0xffff96b95f42d8d8 of 1 bytes by task 90 on cpu 8:
rcu_read_unlock_special+0x175/0x260
__rcu_read_unlock+0x92/0xa0
rt_spin_unlock+0x9b/0xc0
__local_bh_enable+0x10d/0x170
__local_bh_enable_ip+0xfb/0x150
rcu_do_batch+0x595/0xc40
rcu_cpu_kthread+0x4e9/0x830
smpboot_thread_fn+0x24d/0x3b0
kthread+0x3bd/0x410
ret_from_fork+0x35/0x40
ret_from_fork_asm+0x1a/0x30
write to 0xffff96b95f42d8d8 of 1 bytes by task 88 on cpu 8:
rcu_preempt_deferred_qs_handler+0x1e/0x30
irq_work_single+0xaf/0x160
run_irq_workd+0x91/0xc0
smpboot_thread_fn+0x24d/0x3b0
kthread+0x3bd/0x410
ret_from_fork+0x35/0x40
ret_from_fork_asm+0x1a/0x30
no locks held by irq_work/8/88.
irq event stamp: 200272
hardirqs last enabled at (200272): [<ffffffffb0f56121>] finish_task_switch+0x131/0x320
hardirqs last disabled at (200271): [<ffffffffb25c7859>] __schedule+0x129/0xd70
softirqs last enabled at (0): [<ffffffffb0ee093f>] copy_process+0x4df/0x1cc0
softirqs last disabled at (0): [<0000000000000000>] 0x0
------------------------------------------------------------------------
The problem is that irq-work handlers run with interrupts enabled, which
means that rcu_preempt_deferred_qs_handler() could be interrupted,
and that interrupt handler might contain an RCU read-side critical
section, which might invoke rcu_read_unlock_special(). In the strict
KCSAN mode of operation used by RCU, this constitutes a data race on
the ->defer_qs_iw_pending field.
This commit therefore disables interrupts across the portion of the
rcu_preempt_deferred_qs_handler() that updates the ->defer_qs_iw_pending
field. This suffices because this handler is not a fast path.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.upadhyay@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 4266e8fa56 ]
When the computer enters sleep status without a monitor
connected, the system switches the console to the virtual
terminal tty63(SUSPEND_CONSOLE).
If a monitor is subsequently connected before waking up,
the system skips the required VT restoration process
during wake-up, leaving the console on tty63 instead of
switching back to tty1.
To fix this issue, a global flag vt_switch_done is introduced
to record whether the system has successfully switched to
the suspend console via vt_move_to_console() during suspend.
If the switch was completed, vt_switch_done is set to 1.
Later during resume, this flag is checked to ensure that
the original console is restored properly by calling
vt_move_to_console(orig_fgconsole, 0).
This prevents scenarios where the resume logic skips console
restoration due to incorrect detection of the console state,
especially when a monitor is reconnected before waking up.
Signed-off-by: tuhaowen <tuhaowen@uniontech.com>
Link: https://patch.msgid.link/20250611032345.29962-1-tuhaowen@uniontech.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit b024d7b56c upstream.
The perf mmap code is careful about mmap()'ing the user page with the
ringbuffer and additionally the auxiliary buffer, when the event supports
it. Once the first mapping is established, subsequent mapping have to use
the same offset and the same size in both cases. The reference counting for
the ringbuffer and the auxiliary buffer depends on this being correct.
Though perf does not prevent that a related mapping is split via mmap(2),
munmap(2) or mremap(2). A split of a VMA results in perf_mmap_open() calls,
which take reference counts, but then the subsequent perf_mmap_close()
calls are not longer fulfilling the offset and size checks. This leads to
reference count leaks.
As perf already has the requirement for subsequent mappings to match the
initial mapping, the obvious consequence is that VMA splits, caused by
resizing of a mapping or partial unmapping, have to be prevented.
Implement the vm_operations_struct::may_split() callback and return
unconditionally -EINVAL.
That ensures that the mapping offsets and sizes cannot be changed after the
fact. Remapping to a different fixed address with the same size is still
possible as it takes the references for the new mapping and drops those of
the old mapping.
Fixes: 45bfb2e504 ("perf/core: Add AUX area to ring buffer for raw data streams")
Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-27504
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 07091aade3 upstream.
When perf_mmap() fails to allocate a buffer, it still invokes the
event_mapped() callback of the related event. On X86 this might increase
the perf_rdpmc_allowed reference counter. But nothing undoes this as
perf_mmap_close() is never called in this case, which causes another
reference count leak.
Return early on failure to prevent that.
Fixes: 1e0fb9ec67 ("perf/core: Add pmu callbacks to track event mapping and unmapping")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 99b773d720 ]
With the seqcount moved out of the group into a global psi_seq,
re-initializing the seqcount on group creation is causing seqcount
corruption.
Fixes: 570c8efd5e ("sched/psi: Optimize psi_group_change() cpu_clock() usage")
Reported-by: Chris Mason <clm@meta.com>
Suggested-by: Beata Michalska <beata.michalska@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit f8cd9193b6 ]
The type of u argument of atomic_long_inc_below() should be long to avoid
unwanted truncation to int.
The patch fixes the wrong argument type of an internal function to
prevent unwanted argument truncation. It fixes an internal locking
primitive; it should not have any direct effect on userspace.
Mark said
: AFAICT there's no problem in practice because atomic_long_inc_below()
: is only used by inc_ucount(), and it looks like the value is
: constrained between 0 and INT_MAX.
:
: In inc_ucount() the limit value is taken from
: user_namespace::ucount_max[], and AFAICT that's only written by
: sysctls, to the table setup by setup_userns_sysctls(), where
: UCOUNT_ENTRY() limits the value between 0 and INT_MAX.
:
: This is certainly a cleanup, but there might be no functional issue in
: practice as above.
Link: https://lkml.kernel.org/r/20250721174610.28361-1-ubizjak@gmail.com
Fixes: f9c82a4ea8 ("Increase size of ucounts to atomic_long_t")
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Alexey Gladkov <legion@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: MengEn Sun <mengensun@tencent.com>
Cc: "Thomas Weißschuh" <linux@weissschuh.net>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 9872916ad1 ]
Newer compiler versions rightfully point out:
kernel/kcsan/kcsan_test.c:591:41: error: variable 'dummy' is
uninitialized when passed as a const pointer argument here
[-Werror,-Wuninitialized-const-pointer]
591 | KCSAN_EXPECT_READ_BARRIER(atomic_read(&dummy), false);
| ^~~~~
1 error generated.
Although this particular test does not care about the value stored in
the dummy atomic variable, let's silence the warning.
Link: https://lkml.kernel.org/r/CA+G9fYu8JY=k-r0hnBRSkQQrFJ1Bz+ShdXNwC1TNeMt0eXaxeA@mail.gmail.com
Fixes: 8bc32b3481 ("kcsan: test: Add test cases for memory barrier instrumentation")
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Reviewed-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 119a5d5736 ]
When the ring buffer was first introduced, reading the non-consuming
"trace" file required disabling the writing of the ring buffer. To make
sure the writing was fully disabled before iterating the buffer with a
non-consuming read, it would set the disable flag of the buffer and then
call an RCU synchronization to make sure all the buffers were
synchronized.
The function ring_buffer_read_start() originally would initialize the
iterator and call an RCU synchronization, but this was for each individual
per CPU buffer where this would get called many times on a machine with
many CPUs before the trace file could be read. The commit 72c9ddfd4c
("ring-buffer: Make non-consuming read less expensive with lots of cpus.")
separated ring_buffer_read_start into ring_buffer_read_prepare(),
ring_buffer_read_sync() and then ring_buffer_read_start() to allow each of
the per CPU buffers to be prepared, call the read_buffer_read_sync() once,
and then the ring_buffer_read_start() for each of the CPUs which made
things much faster.
The commit 1039221cc2 ("ring-buffer: Do not disable recording when there
is an iterator") removed the requirement of disabling the recording of the
ring buffer in order to iterate it, but it did not remove the
synchronization that was happening that was required to wait for all the
buffers to have no more writers. It's now OK for the buffers to have
writers and no synchronization is needed.
Remove the synchronization and put back the interface for the ring buffer
iterator back before commit 72c9ddfd4c was applied.
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20250630180440.3eabb514@batman.local.home
Reported-by: David Howells <dhowells@redhat.com>
Fixes: 1039221cc2 ("ring-buffer: Do not disable recording when there is an iterator")
Tested-by: David Howells <dhowells@redhat.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 463d46044f ]
We observed a regression in our customer’s environment after enabling
CONFIG_LAZY_RCU. In the Android Update Engine scenario, where ioctl() is
used heavily, we found that callbacks queued via call_rcu_hurry (such as
percpu_ref_switch_to_atomic_rcu) can sometimes be delayed by up to 5
seconds before execution. This occurs because the new grace period does
not start immediately after the previous one completes.
The root cause is that the wake_nocb_gp_defer() function now checks
"rdp->nocb_defer_wakeup" instead of "rdp_gp->nocb_defer_wakeup". On CPUs
that are not rcuog, "rdp->nocb_defer_wakeup" may always be
RCU_NOCB_WAKE_NOT. This can cause "rdp_gp->nocb_defer_wakeup" to be
downgraded and the "rdp_gp->nocb_timer" to be postponed by up to 10
seconds, delaying the execution of hurry RCU callbacks.
The trace log of one scenario we encountered is as follow:
// previous GP ends at this point
rcu_preempt [000] d..1. 137.240210: rcu_grace_period: rcu_preempt 8369 end
rcu_preempt [000] ..... 137.240212: rcu_grace_period: rcu_preempt 8372 reqwait
// call_rcu_hurry enqueues "percpu_ref_switch_to_atomic_rcu", the callback waited on by UpdateEngine
update_engine [002] d..1. 137.301593: __call_rcu_common: wyy: unlikely p_ref = 00000000********. lazy = 0
// FirstQ on cpu 2 rdp_gp->nocb_timer is set to fire after 1 jiffy (4ms)
// and the rdp_gp->nocb_defer_wakeup is set to RCU_NOCB_WAKE
update_engine [002] d..2. 137.301595: rcu_nocb_wake: rcu_preempt 2 FirstQ on cpu2 with rdp_gp (cpu0).
// FirstBQ event on cpu2 during the 1 jiffy, make the timer postpond 10 seconds later.
// also, the rdp_gp->nocb_defer_wakeup is overwrite to RCU_NOCB_WAKE_LAZY
update_engine [002] d..1. 137.301601: rcu_nocb_wake: rcu_preempt 2 WakeEmptyIsDeferred
...
...
...
// before the 10 seconds timeout, cpu0 received another call_rcu_hurry
// reset the timer to jiffies+1 and set the waketype = RCU_NOCB_WAKE.
kworker/u32:0 [000] d..2. 142.557564: rcu_nocb_wake: rcu_preempt 0 FirstQ
kworker/u32:0 [000] d..1. 142.557576: rcu_nocb_wake: rcu_preempt 0 WakeEmptyIsDeferred
kworker/u32:0 [000] d..1. 142.558296: rcu_nocb_wake: rcu_preempt 0 WakeNot
kworker/u32:0 [000] d..1. 142.558562: rcu_nocb_wake: rcu_preempt 0 WakeNot
// idle(do_nocb_deferred_wakeup) wake rcuog due to waketype == RCU_NOCB_WAKE
<idle> [000] d..1. 142.558786: rcu_nocb_wake: rcu_preempt 0 DoWake
<idle> [000] dN.1. 142.558839: rcu_nocb_wake: rcu_preempt 0 DeferredWake
rcuog/0 [000] ..... 142.558871: rcu_nocb_wake: rcu_preempt 0 EndSleep
rcuog/0 [000] ..... 142.558877: rcu_nocb_wake: rcu_preempt 0 Check
// finally rcuog request a new GP at this point (5 seconds after the FirstQ event)
rcuog/0 [000] d..2. 142.558886: rcu_grace_period: rcu_preempt 8372 newreq
rcu_preempt [001] d..1. 142.559458: rcu_grace_period: rcu_preempt 8373 start
...
rcu_preempt [000] d..1. 142.564258: rcu_grace_period: rcu_preempt 8373 end
rcuop/2 [000] D..1. 142.566337: rcu_batch_start: rcu_preempt CBs=219 bl=10
// the hurry CB is invoked at this point
rcuop/2 [000] b.... 142.566352: blk_queue_usage_counter_release: wyy: wakeup. p_ref = 00000000********.
This patch changes the condition to check "rdp_gp->nocb_defer_wakeup" in
the lazy path. This prevents an already scheduled "rdp_gp->nocb_timer"
from being postponed and avoids overwriting "rdp_gp->nocb_defer_wakeup"
when it is not RCU_NOCB_WAKE_NOT.
Fixes: 3cb278e73b ("rcu: Make call_rcu() lazy to save power")
Co-developed-by: Cheng-jui Wang <cheng-jui.wang@mediatek.com>
Signed-off-by: Cheng-jui Wang <cheng-jui.wang@mediatek.com>
Co-developed-by: Lorry.Luo@mediatek.com
Signed-off-by: Lorry.Luo@mediatek.com
Tested-by: weiyangyang@vivo.com
Signed-off-by: weiyangyang@vivo.com
Signed-off-by: Tze-nan Wu <Tze-nan.Wu@mediatek.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.upadhyay@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 570c8efd5e ]
Dietmar reported that commit 3840cbe24c ("sched: psi: fix bogus
pressure spikes from aggregation race") caused a regression for him on
a high context switch rate benchmark (schbench) due to the now
repeating cpu_clock() calls.
In particular the problem is that get_recent_times() will extrapolate
the current state to 'now'. But if an update uses a timestamp from
before the start of the update, it is possible to get two reads
with inconsistent results. It is effectively back-dating an update.
(note that this all hard-relies on the clock being synchronized across
CPUs -- if this is not the case, all bets are off).
Combine this problem with the fact that there are per-group-per-cpu
seqcounts, the commit in question pushed the clock read into the group
iteration, causing tree-depth cpu_clock() calls. On architectures
where cpu_clock() has appreciable overhead, this hurts.
Instead move to a per-cpu seqcount, which allows us to have a single
clock read for all group updates, increasing internal consistency and
lowering update overhead. This comes at the cost of a longer update
side (proportional to the tree depth) which can cause the read side to
retry more often.
Fixes: 3840cbe24c ("sched: psi: fix bogus pressure spikes from aggregation race")
Reported-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>,
Link: https://lkml.kernel.org/20250522084844.GC31726@noisy.programming.kicks-ass.net
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 005b618770 ]
The nreaders and loops variables are exposed as module parameters, which,
in certain combinations, can lead to multiplication overflow.
Besides, loops parameter is defined as long, while through the code is
used as int, which can cause truncation on 64-bit kernels and possible
zeroes where they shouldn't appear.
Since code uses result of multiplication as int anyway, it only makes sense
to replace loops with int. Multiplication overflow check is also added
due to possible multiplication between two very big numbers.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: 653ed64b01 ("refperf: Add a test to measure performance of read-side synchronization")
Signed-off-by: Artem Sadovnikov <a.sadovnikov@ispras.ru>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.upadhyay@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit d090326860 ]
Add a warning to ensure RCU lock is held around tree lookup, and then
fix one of the invocations in bpf_stack_walker. The program has an
active stack frame and won't disappear. Use the opportunity to remove
unneeded invocation of is_bpf_text_address.
Fixes: f18b03faba ("bpf: Implement BPF exceptions")
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250703204818.925464-5-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit ae1ae11fb2 ]
The move of the module sanity check to earlier skipped the audit logging
call in the case of failure and to a place where the previously used
context is unavailable.
Add an audit logging call for the module loading failure case and get
the module name when possible.
Link: https://issues.redhat.com/browse/RHEL-52839
Fixes: 02da2cbab4 ("module: move check_modinfo() early to early_mod_check()")
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 91a229bb7b upstream.
A warning is raised when __request_region() detects a conflict with a
resource whose resource.desc is IORES_DESC_DEVICE_PRIVATE_MEMORY.
But this warning is only valid for iomem_resources.
The hmem device resource uses resource.desc as the numa node id, which can
cause spurious warnings.
This warning appeared on a machine with multiple cxl memory expanders.
One of the NUMA node id is 6, which is the same as the value of
IORES_DESC_DEVICE_PRIVATE_MEMORY.
In this environment it was just a spurious warning, but when I saw the
warning I suspected a real problem so it's better to fix it.
This change fixes this by restricting the warning to only iomem_resource.
This also adds a missing new line to the warning message.
Link: https://lkml.kernel.org/r/20250719112604.25500-1-akinobu.mita@gmail.com
Fixes: 7dab174e2e ("dax/hmem: Move hmem device registration to dax_hmem.ko")
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 67c632b4a7 upstream.
Most drivers only populate the fields cycles and cs_id of system_counterval
in their get_time_fn() callback for get_device_system_crosststamp(), unless
they explicitly provide nanosecond values.
When the use_nsecs field was added to struct system_counterval, most
drivers did not care. Clock sources other than CSID_GENERIC could then get
converted in convert_base_to_cs() based on an uninitialized use_nsecs field,
which usually results in -EINVAL during the following range check.
Pass in a fully zero initialized system_counterval_t to cure that.
Fixes: 6b2e299775 ("timekeeping: Provide infrastructure for converting to/from a base clock")
Signed-off-by: Markus Blöchl <markus@blochl.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <jstultz@google.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20250720-timekeeping_uninit_crossts-v2-1-f513c885b7c2@blochl.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9beb8c5e77 upstream.
Commit cff5f49d43 ("cgroup_freezer: cgroup_freezing: Check if not
frozen") modified the cgroup_freezing() logic to verify that the FROZEN
flag is not set, affecting the return value of the freezing() function,
in order to address a warning in __thaw_task.
A race condition exists that may allow tasks to escape being frozen. The
following scenario demonstrates this issue:
CPU 0 (get_signal path) CPU 1 (freezer.state reader)
try_to_freeze read freezer.state
__refrigerator freezer_read
update_if_frozen
WRITE_ONCE(current->__state, TASK_FROZEN);
...
/* Task is now marked frozen */
/* frozen(task) == true */
/* Assuming other tasks are frozen */
freezer->state |= CGROUP_FROZEN;
/* freezing(current) returns false */
/* because cgroup is frozen (not freezing) */
break out
__set_current_state(TASK_RUNNING);
/* Bug: Task resumes running when it should remain frozen */
The existing !frozen(p) check in __thaw_task makes the
WARN_ON_ONCE(freezing(p)) warning redundant. Removing this warning enables
reverting commit cff5f49d43 ("cgroup_freezer: cgroup_freezing: Check if
not frozen") to resolve the issue.
This patch removes the warning from __thaw_task. A subsequent patch will
revert commit cff5f49d43 ("cgroup_freezer: cgroup_freezing: Check if
not frozen") to complete the fix.
Reported-by: Zhong Jiawei<zhongjiawei1@huawei.com>
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 36569780b0 upstream.
The commit e6fe3f422b ("sched: Make multiple runqueue task counters
32-bit") changed nr_uninterruptible to an unsigned int. But the
nr_uninterruptible values for each of the CPU runqueues can grow to
large numbers, sometimes exceeding INT_MAX. This is valid, if, over
time, a large number of tasks are migrated off of one CPU after going
into an uninterruptible state. Only the sum of all nr_interruptible
values across all CPUs yields the correct result, as explained in a
comment in kernel/sched/loadavg.c.
Change the type of nr_uninterruptible back to unsigned long to prevent
overflows, and thus the miscalculation of load average.
Fixes: e6fe3f422b ("sched: Make multiple runqueue task counters 32-bit")
Signed-off-by: Aruna Ramakrishna <aruna.ramakrishna@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20250709173328.606794-1-aruna.ramakrishna@oracle.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 14a67b42cb ]
This reverts commit cff5f49d43.
Commit cff5f49d43 ("cgroup_freezer: cgroup_freezing: Check if not
frozen") modified the cgroup_freezing() logic to verify that the FROZEN
flag is not set, affecting the return value of the freezing() function,
in order to address a warning in __thaw_task.
A race condition exists that may allow tasks to escape being frozen. The
following scenario demonstrates this issue:
CPU 0 (get_signal path) CPU 1 (freezer.state reader)
try_to_freeze read freezer.state
__refrigerator freezer_read
update_if_frozen
WRITE_ONCE(current->__state, TASK_FROZEN);
...
/* Task is now marked frozen */
/* frozen(task) == true */
/* Assuming other tasks are frozen */
freezer->state |= CGROUP_FROZEN;
/* freezing(current) returns false */
/* because cgroup is frozen (not freezing) */
break out
__set_current_state(TASK_RUNNING);
/* Bug: Task resumes running when it should remain frozen */
The existing !frozen(p) check in __thaw_task makes the
WARN_ON_ONCE(freezing(p)) warning redundant. Removing this warning enables
reverting the commit cff5f49d43 ("cgroup_freezer: cgroup_freezing: Check
if not frozen") to resolve the issue.
The warning has been removed in the previous patch. This patch revert the
commit cff5f49d43 ("cgroup_freezer: cgroup_freezing: Check if not
frozen") to complete the fix.
Fixes: cff5f49d43 ("cgroup_freezer: cgroup_freezing: Check if not frozen")
Reported-by: Zhong Jiawei<zhongjiawei1@huawei.com>
Signed-off-by: Chen Ridong <chenridong@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 85a3bce695 upstream.
We have observed kernel panics when using timerlat with stack saving,
with the following dmesg output:
memcpy: detected buffer overflow: 88 byte write of buffer size 0
WARNING: CPU: 2 PID: 8153 at lib/string_helpers.c:1032 __fortify_report+0x55/0xa0
CPU: 2 UID: 0 PID: 8153 Comm: timerlatu/2 Kdump: loaded Not tainted 6.15.3-200.fc42.x86_64 #1 PREEMPT(lazy)
Call Trace:
<TASK>
? trace_buffer_lock_reserve+0x2a/0x60
__fortify_panic+0xd/0xf
__timerlat_dump_stack.cold+0xd/0xd
timerlat_dump_stack.part.0+0x47/0x80
timerlat_fd_read+0x36d/0x390
vfs_read+0xe2/0x390
? syscall_exit_to_user_mode+0x1d5/0x210
ksys_read+0x73/0xe0
do_syscall_64+0x7b/0x160
? exc_page_fault+0x7e/0x1a0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
__timerlat_dump_stack() constructs the ftrace stack entry like this:
struct stack_entry *entry;
...
memcpy(&entry->caller, fstack->calls, size);
entry->size = fstack->nr_entries;
Since commit e7186af7fb ("tracing: Add back FORTIFY_SOURCE logic to
kernel_stack event structure"), struct stack_entry marks its caller
field with __counted_by(size). At the time of the memcpy, entry->size
contains garbage from the ringbuffer, which under some circumstances is
zero, triggering a kernel panic by buffer overflow.
Populate the size field before the memcpy so that the out-of-bounds
check knows the correct size. This is analogous to
__ftrace_trace_stack().
Cc: stable@vger.kernel.org
Cc: John Kacur <jkacur@redhat.com>
Cc: Luis Goncalves <lgoncalv@redhat.com>
Cc: Attila Fazekas <afazekas@redhat.com>
Link: https://lore.kernel.org/20250716143601.7313-1-tglozar@redhat.com
Fixes: e7186af7fb ("tracing: Add back FORTIFY_SOURCE logic to kernel_stack event structure")
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
