This commit marks kfuncs as such inside the .BTF_ids section. The upshot
of these annotations is that we'll be able to automatically generate
kfunc prototypes for downstream users. The process is as follows:
1. In source, use BTF_KFUNCS_START/END macro pair to mark kfuncs
2. During build, pahole injects into BTF a "bpf_kfunc" BTF_DECL_TAG for
each function inside BTF_KFUNCS sets
3. At runtime, vmlinux or module BTF is made available in sysfs
4. At runtime, bpftool (or similar) can look at provided BTF and
generate appropriate prototypes for functions with "bpf_kfunc" tag
To ensure future kfunc are similarly tagged, we now also return error
inside kfunc registration for untagged kfuncs. For vmlinux kfuncs,
we also WARN(), as initcall machinery does not handle errors.
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Acked-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/e55150ceecbf0a5d961e608941165c0bee7bc943.1706491398.git.dxu@dxuuu.xyz
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The return type for ring_buffer_poll_wait() is __poll_t. This is behind
the scenes an unsigned where we can set event bits. In case of a
non-allocated CPU, we do return instead -EINVAL (0xffffffea). Lucky us,
this ends up setting few error bits (EPOLLERR | EPOLLHUP | EPOLLNVAL), so
user-space at least is aware something went wrong.
Nonetheless, this is an incorrect code. Replace that -EINVAL with a
proper EPOLLERR to clean that output. As this doesn't change the
behaviour, there's no need to treat this change as a bug fix.
Link: https://lore.kernel.org/linux-trace-kernel/20240131140955.3322792-1-vdonnefort@google.com
Cc: stable@vger.kernel.org
Fixes: 6721cb6002 ("ring-buffer: Do not poll non allocated cpu buffers")
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
System workqueues are allocated early during boot from
workqueue_init_early(). While allocating unbound workqueues,
wq_update_node_max_active() is invoked from apply_workqueue_attrs() and
accesses NUMA topology to initialize wq->node_nr_active[].max.
However, topology information may not be set up at this point.
wq_update_node_max_active() is explicitly invoked from
workqueue_init_topology() later when topology information is known to be
available.
This doesn't seem to crash anything but it's doing useless work with dubious
data. Let's skip the premature and duplicate node_max_active updates by
initializing the field to WQ_DFL_MIN_ACTIVE on allocation and making
wq_update_node_max_active() noop until workqueue_init_topology().
Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/workqueue.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 9221a4c57ae1..a65081ec6780 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -386,6 +386,8 @@ static const char *wq_affn_names[WQ_AFFN_NR_TYPES] = {
[WQ_AFFN_SYSTEM] = "system",
};
+static bool wq_topo_initialized = false;
+
/*
* Per-cpu work items which run for longer than the following threshold are
* automatically considered CPU intensive and excluded from concurrency
@@ -1510,6 +1512,9 @@ static void wq_update_node_max_active(struct workqueue_struct *wq, int off_cpu)
lockdep_assert_held(&wq->mutex);
+ if (!wq_topo_initialized)
+ return;
+
if (!cpumask_test_cpu(off_cpu, effective))
off_cpu = -1;
@@ -4356,6 +4361,7 @@ static void free_node_nr_active(struct wq_node_nr_active **nna_ar)
static void init_node_nr_active(struct wq_node_nr_active *nna)
{
+ nna->max = WQ_DFL_MIN_ACTIVE;
atomic_set(&nna->nr, 0);
raw_spin_lock_init(&nna->lock);
INIT_LIST_HEAD(&nna->pending_pwqs);
@@ -7400,6 +7406,8 @@ void __init workqueue_init_topology(void)
init_pod_type(&wq_pod_types[WQ_AFFN_CACHE], cpus_share_cache);
init_pod_type(&wq_pod_types[WQ_AFFN_NUMA], cpus_share_numa);
+ wq_topo_initialized = true;
+
mutex_lock(&wq_pool_mutex);
/*
For wq_update_node_max_active(), @off_cpu of -1 indicates that no CPU is
going down. The function was incorrectly calling cpumask_test_cpu() with -1
CPU leading to oopses like the following on some archs:
Unable to handle kernel paging request at virtual address ffff0002100296e0
..
pc : wq_update_node_max_active+0x50/0x1fc
lr : wq_update_node_max_active+0x1f0/0x1fc
...
Call trace:
wq_update_node_max_active+0x50/0x1fc
apply_wqattrs_commit+0xf0/0x114
apply_workqueue_attrs_locked+0x58/0xa0
alloc_workqueue+0x5ac/0x774
workqueue_init_early+0x460/0x540
start_kernel+0x258/0x684
__primary_switched+0xb8/0xc0
Code: 9100a273 35000d01 53067f00 d0016dc1 (f8607a60)
---[ end trace 0000000000000000 ]---
Kernel panic - not syncing: Attempted to kill the idle task!
---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]---
Fix it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: http://lkml.kernel.org/r/91eacde0-df99-4d5c-a980-91046f66e612@samsung.com
Fixes: 5797b1c189 ("workqueue: Implement system-wide nr_active enforcement for unbound workqueues")
Add ability to mark arg:trusted arguments with optional arg:nullable
tag to mark it as PTR_TO_BTF_ID_OR_NULL variant, which will allow
callers to pass NULL, and subsequently will force global subprog's code
to do NULL check. This allows to have "optional" PTR_TO_BTF_ID values
passed into global subprogs.
For now arg:nullable cannot be combined with anything else.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240130000648.2144827-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add support for passing PTR_TO_BTF_ID registers to global subprogs.
Currently only PTR_TRUSTED flavor of PTR_TO_BTF_ID is supported.
Non-NULL semantics is assumed, so caller will be forced to prove
PTR_TO_BTF_ID can't be NULL.
Note, we disallow global subprogs to destroy passed in PTR_TO_BTF_ID
arguments, even the trusted one. We achieve that by not setting
ref_obj_id when validating subprog code. This basically enforces (in
Rust terms) borrowing semantics vs move semantics. Borrowing semantics
seems to be a better fit for isolated global subprog validation
approach.
Implementation-wise, we utilize existing logic for matching
user-provided BTF type to kernel-side BTF type, used by BPF CO-RE logic
and following same matching rules. We enforce a unique match for types.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240130000648.2144827-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Pull tracing fixes from Steven Rostedt:
"Two small fixes for tracefs and eventfs:
- Fix register_snapshot_trigger() on allocation error
If the snapshot fails to allocate, the register_snapshot_trigger()
can still return success. If the call to
tracing_alloc_snapshot_instance() returned anything but 0, it
returned 0, but it should have been returning the error code from
that allocation function.
- Remove leftover code from tracefs doing a dentry walk on remount.
The update_gid() function was called by the tracefs code on remount
to update the gid of eventfs, but that is no longer the case, but
that code wasn't deleted. Nothing calls it. Remove it"
* tag 'trace-v6.8-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracefs: remove stale 'update_gid' code
tracing/trigger: Fix to return error if failed to alloc snapshot
When __queue_delayed_work() is called, it chooses a cpu for handling the
timer interrupt. As of today, it will pick either the cpu passed as
parameter or the last cpu used for this.
This is not good if a system does use CPU isolation, because it can take
away some valuable cpu time to:
1 - deal with the timer interrupt,
2 - schedule-out the desired task,
3 - queue work on a random workqueue, and
4 - schedule the desired task back to the cpu.
So to fix this, during __queue_delayed_work(), if cpu isolation is in
place, pick a random non-isolated cpu to handle the timer interrupt.
As an optimization, if the current cpu is not isolated, use it instead
of looking for another candidate.
Signed-off-by: Leonardo Bras <leobras@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Pull misc fixes from Andrew Morton:
"22 hotfixes. 11 are cc:stable and the remainder address post-6.7
issues or aren't considered appropriate for backporting"
* tag 'mm-hotfixes-stable-2024-01-28-23-21' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (22 commits)
mm: thp_get_unmapped_area must honour topdown preference
mm: huge_memory: don't force huge page alignment on 32 bit
userfaultfd: fix mmap_changing checking in mfill_atomic_hugetlb
selftests/mm: ksm_tests should only MADV_HUGEPAGE valid memory
scs: add CONFIG_MMU dependency for vfree_atomic()
mm/memory: fix folio_set_dirty() vs. folio_mark_dirty() in zap_pte_range()
mm/huge_memory: fix folio_set_dirty() vs. folio_mark_dirty()
selftests/mm: Update va_high_addr_switch.sh to check CPU for la57 flag
selftests: mm: fix map_hugetlb failure on 64K page size systems
MAINTAINERS: supplement of zswap maintainers update
stackdepot: make fast paths lock-less again
stackdepot: add stats counters exported via debugfs
mm, kmsan: fix infinite recursion due to RCU critical section
mm/writeback: fix possible divide-by-zero in wb_dirty_limits(), again
selftests/mm: switch to bash from sh
MAINTAINERS: add man-pages git trees
mm: memcontrol: don't throttle dying tasks on memory.high
mm: mmap: map MAP_STACK to VM_NOHUGEPAGE
uprobes: use pagesize-aligned virtual address when replacing pages
selftests/mm: mremap_test: fix build warning
...
It's a bit puzzling to see a call to module_enable_nx() followed by a
call to module_enable_x(). This is because one applies on text while
the other applies on data.
Change name to make that more clear.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
A couple of architectures seem concerned about calling set_memory_ro()
and set_memory_x() too frequently and have implemented a version of
set_memory_rox(), see commit 60463628c9 ("x86/mm: Implement native
set_memory_rox()") and commit 22e99fa564 ("s390/mm: implement
set_memory_rox()")
Use set_memory_rox() in modules when STRICT_MODULES_RWX is set.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
A pool_workqueue (pwq) represents the connection between a workqueue and a
worker_pool. One of the roles that a pwq plays is enforcement of the
max_active concurrency limit. Before 636b927eba ("workqueue: Make unbound
workqueues to use per-cpu pool_workqueues"), there was one pwq per each CPU
for per-cpu workqueues and per each NUMA node for unbound workqueues, which
was a natural result of per-cpu workqueues being served by per-cpu pools and
unbound by per-NUMA pools.
In terms of max_active enforcement, this was, while not perfect, workable.
For per-cpu workqueues, it was fine. For unbound, it wasn't great in that
NUMA machines would get max_active that's multiplied by the number of nodes
but didn't cause huge problems because NUMA machines are relatively rare and
the node count is usually pretty low.
However, cache layouts are more complex now and sharing a worker pool across
a whole node didn't really work well for unbound workqueues. Thus, a series
of commits culminating on 8639ecebc9 ("workqueue: Make unbound workqueues
to use per-cpu pool_workqueues") implemented more flexible affinity
mechanism for unbound workqueues which enables using e.g. last-level-cache
aligned pools. In the process, 636b927eba ("workqueue: Make unbound
workqueues to use per-cpu pool_workqueues") made unbound workqueues use
per-cpu pwqs like per-cpu workqueues.
While the change was necessary to enable more flexible affinity scopes, this
came with the side effect of blowing up the effective max_active for unbound
workqueues. Before, the effective max_active for unbound workqueues was
multiplied by the number of nodes. After, by the number of CPUs.
636b927eba ("workqueue: Make unbound workqueues to use per-cpu
pool_workqueues") claims that this should generally be okay. It is okay for
users which self-regulates concurrency level which are the vast majority;
however, there are enough use cases which actually depend on max_active to
prevent the level of concurrency from going bonkers including several IO
handling workqueues that can issue a work item for each in-flight IO. With
targeted benchmarks, the misbehavior can easily be exposed as reported in
http://lkml.kernel.org/r/dbu6wiwu3sdhmhikb2w6lns7b27gbobfavhjj57kwi2quafgwl@htjcc5oikcr3.
Unfortunately, there is no way to express what these use cases need using
per-cpu max_active. A CPU may issue most of in-flight IOs, so we don't want
to set max_active too low but as soon as we increase max_active a bit, we
can end up with unreasonable number of in-flight work items when many CPUs
issue IOs at the same time. ie. The acceptable lowest max_active is higher
than the acceptable highest max_active.
Ideally, max_active for an unbound workqueue should be system-wide so that
the users can regulate the total level of concurrency regardless of node and
cache layout. The reasons workqueue hasn't implemented that yet are:
- One max_active enforcement decouples from pool boundaires, chaining
execution after a work item finishes requires inter-pool operations which
would require lock dancing, which is nasty.
- Sharing a single nr_active count across the whole system can be pretty
expensive on NUMA machines.
- Per-pwq enforcement had been more or less okay while we were using
per-node pools.
It looks like we no longer can avoid decoupling max_active enforcement from
pool boundaries. This patch implements system-wide nr_active mechanism with
the following design characteristics:
- To avoid sharing a single counter across multiple nodes, the configured
max_active is split across nodes according to the proportion of each
workqueue's online effective CPUs per node. e.g. A node with twice more
online effective CPUs will get twice higher portion of max_active.
- Workqueue used to be able to process a chain of interdependent work items
which is as long as max_active. We can't do this anymore as max_active is
distributed across the nodes. Instead, a new parameter min_active is
introduced which determines the minimum level of concurrency within a node
regardless of how max_active distribution comes out to be.
It is set to the smaller of max_active and WQ_DFL_MIN_ACTIVE which is 8.
This can lead to higher effective max_weight than configured and also
deadlocks if a workqueue was depending on being able to handle chains of
interdependent work items that are longer than 8.
I believe these should be fine given that the number of CPUs in each NUMA
node is usually higher than 8 and work item chain longer than 8 is pretty
unlikely. However, if these assumptions turn out to be wrong, we'll need
to add an interface to adjust min_active.
- Each unbound wq has an array of struct wq_node_nr_active which tracks
per-node nr_active. When its pwq wants to run a work item, it has to
obtain the matching node's nr_active. If over the node's max_active, the
pwq is queued on wq_node_nr_active->pending_pwqs. As work items finish,
the completion path round-robins the pending pwqs activating the first
inactive work item of each, which involves some pool lock dancing and
kicking other pools. It's not the simplest code but doesn't look too bad.
v4: - wq_adjust_max_active() updated to invoke wq_update_node_max_active().
- wq_adjust_max_active() is now protected by wq->mutex instead of
wq_pool_mutex.
v3: - wq_node_max_active() used to calculate per-node max_active on the fly
based on system-wide CPU online states. Lai pointed out that this can
lead to skewed distributions for workqueues with restricted cpumasks.
Update the max_active distribution to use per-workqueue effective
online CPU counts instead of system-wide and cache the calculation
results in node_nr_active->max.
v2: - wq->min/max_active now uses WRITE/READ_ONCE() as suggested by Lai.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Naohiro Aota <Naohiro.Aota@wdc.com>
Link: http://lkml.kernel.org/r/dbu6wiwu3sdhmhikb2w6lns7b27gbobfavhjj57kwi2quafgwl@htjcc5oikcr3
Fixes: 636b927eba ("workqueue: Make unbound workqueues to use per-cpu pool_workqueues")
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
Currently, for both percpu and unbound workqueues, max_active applies
per-cpu, which is a recent change for unbound workqueues. The change for
unbound workqueues was a significant departure from the previous behavior of
per-node application. It made some use cases create undesirable number of
concurrent work items and left no good way of fixing them. To address the
problem, workqueue is implementing a NUMA node segmented global nr_active
mechanism, which will be explained further in the next patch.
As a preparation, this patch introduces struct wq_node_nr_active. It's a
data structured allocated for each workqueue and NUMA node pair and
currently only tracks the workqueue's number of active work items on the
node. This is split out from the next patch to make it easier to understand
and review.
Note that there is an extra wq_node_nr_active allocated for the invalid node
nr_node_ids which is used to track nr_active for pools which don't have NUMA
node associated such as the default fallback system-wide pool.
This doesn't cause any behavior changes visible to userland yet. The next
patch will expand to implement the control mechanism on top.
v4: - Fixed out-of-bound access when freeing per-cpu workqueues.
v3: - Use flexible array for wq->node_nr_active as suggested by Lai.
v2: - wq->max_active now uses WRITE/READ_ONCE() as suggested by Lai.
- Lai pointed out that pwq_tryinc_nr_active() incorrectly dropped
pwq->max_active check. Restored. As the next patch replaces the
max_active enforcement mechanism, this doesn't change the end result.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
The planned shared nr_active handling for unbound workqueues will make
pwq_dec_nr_active() sometimes drop the pool lock temporarily to acquire
other pool locks, which is necessary as retirement of an nr_active count
from one pool may need kick off an inactive work item in another pool.
This patch moves pwq_dec_nr_in_flight() call in try_to_grab_pending() to the
end of work item handling so that work item state changes stay atomic.
process_one_work() which is the other user of pwq_dec_nr_in_flight() already
calls it at the end of work item handling. Comments are added to both call
sites and pwq_dec_nr_in_flight().
This shouldn't cause any behavior changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
wq->cpu_pwq is RCU protected but wq->dfl_pwq isn't. This is okay because
currently wq->dfl_pwq is used only accessed to install it into wq->cpu_pwq
which doesn't require RCU access. However, we want to be able to access
wq->dfl_pwq under RCU in the future to access its __pod_cpumask and the code
can be made easier to read by making the two pwq fields behave in the same
way.
- Make wq->dfl_pwq RCU protected.
- Add unbound_pwq_slot() and unbound_pwq() which can access both ->dfl_pwq
and ->cpu_pwq. The former returns the double pointer that can be used
access and update the pwqs. The latter performs locking check and
dereferences the double pointer.
- pwq accesses and updates are converted to use unbound_pwq[_slot]().
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
wq_adjust_max_active() needs to activate work items after max_active is
increased. Previously, it did that by visiting each pwq once activating all
that could be activated. While this makes sense with per-pwq nr_active,
nr_active will be shared across multiple pwqs for unbound wqs. Then, we'd
want to round-robin through pwqs to be fairer.
In preparation, this patch makes wq_adjust_max_active() round-robin pwqs
while activating. While the activation ordering changes, this shouldn't
cause user-noticeable behavior changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
__queue_work(), pwq_dec_nr_in_flight() and wq_adjust_max_active() were
open-coding nr_active handling, which is fine given that the operations are
trivial. However, the planned unbound nr_active update will make them more
complicated, so let's move them into helpers.
- pwq_tryinc_nr_active() is added. It increments nr_active if under
max_active limit and return a boolean indicating whether inc was
successful. Note that the function is structured to accommodate future
changes. __queue_work() is updated to use the new helper.
- pwq_activate_first_inactive() is updated to use pwq_tryinc_nr_active() and
thus no longer assumes that nr_active is under max_active and returns a
boolean to indicate whether a work item has been activated.
- wq_adjust_max_active() no longer tests directly whether a work item can be
activated. Instead, it's updated to use the return value of
pwq_activate_first_inactive() to tell whether a work item has been
activated.
- nr_active decrement and activating the first inactive work item is
factored into pwq_dec_nr_active().
v3: - WARN_ON_ONCE(!WORK_STRUCT_INACTIVE) added to __pwq_activate_work() as
now we're calling the function unconditionally from
pwq_activate_first_inactive().
v2: - wq->max_active now uses WRITE/READ_ONCE() as suggested by Lai.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
To prepare for unbound nr_active handling improvements, move work activation
part of pwq_activate_inactive_work() into __pwq_activate_work() and add
pwq_activate_work() which tests WORK_STRUCT_INACTIVE and updates nr_active.
pwq_activate_first_inactive() and try_to_grab_pending() are updated to use
pwq_activate_work(). The latter conversion is functionally identical. For
the former, this conversion adds an unnecessary WORK_STRUCT_INACTIVE
testing. This is temporary and will be removed by the next patch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
"!pwq->nr_active && list_empty(&pwq->inactive_works)" test is repeated
multiple times. Let's factor it out into pwq_is_empty().
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
max_active is a workqueue-wide setting and the configured value is stored in
wq->saved_max_active; however, the effective value was stored in
pwq->max_active. While this is harmless, it makes max_active update process
more complicated and gets in the way of the planned max_active semantic
updates for unbound workqueues.
This patches moves pwq->max_active to wq->max_active. This simplifies the
code and makes freezing and noop max_active updates cheaper too. No
user-visible behavior change is intended.
As wq->max_active is updated while holding wq mutex but read without any
locking, it now uses WRITE/READ_ONCE(). A new locking locking rule WO is
added for it.
v2: wq->max_active now uses WRITE/READ_ONCE() as suggested by Lai.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
Pull locking fix from Borislav Petkov:
- Prevent an inconsistent futex operation leading to stale state
exposure
* tag 'locking_urgent_for_v6.8_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
futex: Prevent the reuse of stale pi_state
Pull irq fix from Borislav Petkov:
- Initialize the resend node of each IRQ descriptor, not only the first
one
* tag 'irq_urgent_for_v6.8_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
genirq: Initialize resend_node hlist for all interrupt descriptors
Pull timer fixes from Borislav Petkov:
- Preserve the number of idle calls and sleep entries across CPU
hotplug events in order to be able to compute correct averages
- Limit the duration of the clocksource watchdog checking interval as
too long intervals lead to wrongly marking the TSC as unstable
* tag 'timers_urgent_for_v6.8_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
tick/sched: Preserve number of idle sleeps across CPU hotplug events
clocksource: Skip watchdog check for large watchdog intervals
Daniel Borkmann says:
====================
pull-request: bpf-next 2024-01-26
We've added 107 non-merge commits during the last 4 day(s) which contain
a total of 101 files changed, 6009 insertions(+), 1260 deletions(-).
The main changes are:
1) Add BPF token support to delegate a subset of BPF subsystem
functionality from privileged system-wide daemons such as systemd
through special mount options for userns-bound BPF fs to a trusted
& unprivileged application. With addressed changes from Christian
and Linus' reviews, from Andrii Nakryiko.
2) Support registration of struct_ops types from modules which helps
projects like fuse-bpf that seeks to implement a new struct_ops type,
from Kui-Feng Lee.
3) Add support for retrieval of cookies for perf/kprobe multi links,
from Jiri Olsa.
4) Bigger batch of prep-work for the BPF verifier to eventually support
preserving boundaries and tracking scalars on narrowing fills,
from Maxim Mikityanskiy.
5) Extend the tc BPF flavor to support arbitrary TCP SYN cookies to help
with the scenario of SYN floods, from Kuniyuki Iwashima.
6) Add code generation to inline the bpf_kptr_xchg() helper which
improves performance when stashing/popping the allocated BPF objects,
from Hou Tao.
7) Extend BPF verifier to track aligned ST stores as imprecise spilled
registers, from Yonghong Song.
8) Several fixes to BPF selftests around inline asm constraints and
unsupported VLA code generation, from Jose E. Marchesi.
9) Various updates to the BPF IETF instruction set draft document such
as the introduction of conformance groups for instructions,
from Dave Thaler.
10) Fix BPF verifier to make infinite loop detection in is_state_visited()
exact to catch some too lax spill/fill corner cases,
from Eduard Zingerman.
11) Refactor the BPF verifier pointer ALU check to allow ALU explicitly
instead of implicitly for various register types, from Hao Sun.
12) Fix the flaky tc_redirect_dtime BPF selftest due to slowness
in neighbor advertisement at setup time, from Martin KaFai Lau.
13) Change BPF selftests to skip callback tests for the case when the
JIT is disabled, from Tiezhu Yang.
14) Add a small extension to libbpf which allows to auto create
a map-in-map's inner map, from Andrey Grafin.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (107 commits)
selftests/bpf: Add missing line break in test_verifier
bpf, docs: Clarify definitions of various instructions
bpf: Fix error checks against bpf_get_btf_vmlinux().
bpf: One more maintainer for libbpf and BPF selftests
selftests/bpf: Incorporate LSM policy to token-based tests
selftests/bpf: Add tests for LIBBPF_BPF_TOKEN_PATH envvar
libbpf: Support BPF token path setting through LIBBPF_BPF_TOKEN_PATH envvar
selftests/bpf: Add tests for BPF object load with implicit token
selftests/bpf: Add BPF object loading tests with explicit token passing
libbpf: Wire up BPF token support at BPF object level
libbpf: Wire up token_fd into feature probing logic
libbpf: Move feature detection code into its own file
libbpf: Further decouple feature checking logic from bpf_object
libbpf: Split feature detectors definitions from cached results
selftests/bpf: Utilize string values for delegate_xxx mount options
bpf: Support symbolic BPF FS delegation mount options
bpf: Fail BPF_TOKEN_CREATE if no delegation option was set on BPF FS
bpf,selinux: Allocate bpf_security_struct per BPF token
selftests/bpf: Add BPF token-enabled tests
libbpf: Add BPF token support to bpf_prog_load() API
...
====================
Link: https://lore.kernel.org/r/20240126215710.19855-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
workqueue is collecting different sorts of enums into a single unnamed enum
type which can increase confusion around enum width. Also, unnamed enums
can't be accessed from BPF. Let's break up enum definitions according to
their purposes and give them type names.
Signed-off-by: Tejun Heo <tj@kernel.org>
After creating a new worker, create_worker() is calling kick_pool() to wake
up the new worker task. However, as kick_pool() doesn't do anything if there
is no work pending, it also calls wake_up_process() explicitly. There's no
reason to call kick_pool() at all. wake_up_process() is enough by itself.
Drop the unnecessary kick_pool() call.
Signed-off-by: Tejun Heo <tj@kernel.org>
Per filesystems/sysfs.rst, show() should only use sysfs_emit()
or sysfs_emit_at() when formatting the value to be returned to user space.
coccinelle complains that there are still a couple of functions that use
snprintf(). Convert them to sysfs_emit().
No functional change intended.
Signed-off-by: Li Zhijian <lizhijian@fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240116045151.3940401-40-lizhijian@fujitsu.com
uprobes passes an unaligned page mapping address to
folio_add_new_anon_rmap(), which ends up triggering a VM_BUG_ON() we
recently extended in commit 372cbd4d5a ("mm: non-pmd-mappable, large
folios for folio_add_new_anon_rmap()").
Arguably, this is uprobes code doing something wrong; however, for the
time being it would have likely worked in rmap code because
__folio_set_anon() would set folio->index to the same value.
Looking at __replace_page(), we'd also pass slightly wrong values to
mmu_notifier_range_init(), page_vma_mapped_walk(), flush_cache_page(),
ptep_clear_flush() and set_pte_at_notify(). I suspect most of them are
fine, but let's just mark the introducing commit as the one needed fixing.
I don't think CC stable is warranted.
We'll add more sanity checks in rmap code separately, to make sure that we
always get properly aligned addresses.
Link: https://lkml.kernel.org/r/20240115100731.91007-1-david@redhat.com
Fixes: c517ee744b ("uprobes: __replace_page() should not use page_address_in_vma()")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: Jiri Olsa <jolsa@kernel.org>
Closes: https://lkml.kernel.org/r/ZaMR2EWN-HvlCfUl@krava
Tested-by: Jiri Olsa <jolsa@kernel.org>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Since we have set the WQ_NAME_LEN to 32, decrease the name of
events_freezable_power_efficient so that it does not trip the name length
warning when the workqueue is created.
Signed-off-by: Audra Mitchell <audra@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Pull RCU fix from Neeraj Upadhyay:
"This fixes RCU grace period stalls, which are observed when an
outgoing CPU's quiescent state reporting results in wakeup of one of
the grace period kthreads, to complete the grace period.
If those kthreads have SCHED_FIFO policy, the wake up can indirectly
arm the RT bandwith timer to the local offline CPU.
Earlier migration of the hrtimers from the CPU introduced in commit
5c0930ccaa ("hrtimers: Push pending hrtimers away from outgoing CPU
earlier") results in this timer getting ignored.
If the RCU grace period kthreads are waiting for RT bandwidth to be
available, they may never be actually scheduled, resulting in RCU
stall warnings"
* tag 'urgent-rcu.2024.01.24a' of https://github.com/neeraju/linux:
rcu: Defer RCU kthreads wakeup when CPU is dying
Use the new KMEM_CACHE() macro instead of direct kmem_cache_create
to simplify the creation of SLAB caches.
Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
[PM: subject line tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
The ret variable is assigned when it does not need to be defined, as it
has already been assigned before use.
Signed-off-by: Li zeming <zeming@nfschina.com>
[PM: rewrite subject line]
Signed-off-by: Paul Moore <paul@paul-moore.com>
There have been reports of the watchdog marking clocksources unstable on
machines with 8 NUMA nodes:
clocksource: timekeeping watchdog on CPU373:
Marking clocksource 'tsc' as unstable because the skew is too large:
clocksource: 'hpet' wd_nsec: 14523447520
clocksource: 'tsc' cs_nsec: 14524115132
The measured clocksource skew - the absolute difference between cs_nsec
and wd_nsec - was 668 microseconds:
cs_nsec - wd_nsec = 14524115132 - 14523447520 = 667612
The kernel used 200 microseconds for the uncertainty_margin of both the
clocksource and watchdog, resulting in a threshold of 400 microseconds (the
md variable). Both the cs_nsec and the wd_nsec value indicate that the
readout interval was circa 14.5 seconds. The observed behaviour is that
watchdog checks failed for large readout intervals on 8 NUMA node
machines. This indicates that the size of the skew was directly proportinal
to the length of the readout interval on those machines. The measured
clocksource skew, 668 microseconds, was evaluated against a threshold (the
md variable) that is suited for readout intervals of roughly
WATCHDOG_INTERVAL, i.e. HZ >> 1, which is 0.5 second.
The intention of 2e27e793e2 ("clocksource: Reduce clocksource-skew
threshold") was to tighten the threshold for evaluating skew and set the
lower bound for the uncertainty_margin of clocksources to twice
WATCHDOG_MAX_SKEW. Later in c37e85c135 ("clocksource: Loosen clocksource
watchdog constraints"), the WATCHDOG_MAX_SKEW constant was increased to
125 microseconds to fit the limit of NTP, which is able to use a
clocksource that suffers from up to 500 microseconds of skew per second.
Both the TSC and the HPET use default uncertainty_margin. When the
readout interval gets stretched the default uncertainty_margin is no
longer a suitable lower bound for evaluating skew - it imposes a limit
that is far stricter than the skew with which NTP can deal.
The root causes of the skew being directly proportinal to the length of
the readout interval are:
* the inaccuracy of the shift/mult pairs of clocksources and the watchdog
* the conversion to nanoseconds is imprecise for large readout intervals
Prevent this by skipping the current watchdog check if the readout
interval exceeds 2 * WATCHDOG_INTERVAL. Considering the maximum readout
interval of 2 * WATCHDOG_INTERVAL, the current default uncertainty margin
(of the TSC and HPET) corresponds to a limit on clocksource skew of 250
ppm (microseconds of skew per second). To keep the limit imposed by NTP
(500 microseconds of skew per second) for all possible readout intervals,
the margins would have to be scaled so that the threshold value is
proportional to the length of the actual readout interval.
As for why the readout interval may get stretched: Since the watchdog is
executed in softirq context the expiration of the watchdog timer can get
severely delayed on account of a ksoftirqd thread not getting to run in a
timely manner. Surely, a system with such belated softirq execution is not
working well and the scheduling issue should be looked into but the
clocksource watchdog should be able to deal with it accordingly.
Fixes: 2e27e793e2 ("clocksource: Reduce clocksource-skew threshold")
Suggested-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Jiri Wiesner <jwiesner@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Feng Tang <feng.tang@intel.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240122172350.GA740@incl
Besides already supported special "any" value and hex bit mask, support
string-based parsing of delegation masks based on exact enumerator
names. Utilize BTF information of `enum bpf_cmd`, `enum bpf_map_type`,
`enum bpf_prog_type`, and `enum bpf_attach_type` types to find supported
symbolic names (ignoring __MAX_xxx guard values and stripping repetitive
prefixes like BPF_ for cmd and attach types, BPF_MAP_TYPE_ for maps, and
BPF_PROG_TYPE_ for prog types). The case doesn't matter, but it is
normalized to lower case in mount option output. So "PROG_LOAD",
"prog_load", and "MAP_create" are all valid values to specify for
delegate_cmds options, "array" is among supported for map types, etc.
Besides supporting string values, we also support multiple values
specified at the same time, using colon (':') separator.
There are corresponding changes on bpf_show_options side to use known
values to print them in human-readable format, falling back to hex mask
printing, if there are any unrecognized bits. This shouldn't be
necessary when enum BTF information is present, but in general we should
always be able to fall back to this even if kernel was built without BTF.
As mentioned, emitted symbolic names are normalized to be all lower case.
Example below shows various ways to specify delegate_cmds options
through mount command and how mount options are printed back:
12/14 14:39:07.604
vmuser@archvm:~/local/linux/tools/testing/selftests/bpf
$ mount | rg token
$ sudo mkdir -p /sys/fs/bpf/token
$ sudo mount -t bpf bpffs /sys/fs/bpf/token \
-o delegate_cmds=prog_load:MAP_CREATE \
-o delegate_progs=kprobe \
-o delegate_attachs=xdp
$ mount | grep token
bpffs on /sys/fs/bpf/token type bpf (rw,relatime,delegate_cmds=map_create:prog_load,delegate_progs=kprobe,delegate_attachs=xdp)
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20240124022127.2379740-20-andrii@kernel.org
It's quite confusing in practice when it's possible to successfully
create a BPF token from BPF FS that didn't have any of delegate_xxx
mount options set up. While it's not wrong, it's actually more
meaningful to reject BPF_TOKEN_CREATE with specific error code (-ENOENT)
to let user-space know that no token delegation is setup up.
So, instead of creating empty BPF token that will be always ignored
because it doesn't have any of the allow_xxx bits set, reject it with
-ENOENT. If we ever need empty BPF token to be possible, we can support
that with extra flag passed into BPF_TOKEN_CREATE.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20240124022127.2379740-19-andrii@kernel.org
Wire up bpf_token_create and bpf_token_free LSM hooks, which allow to
allocate LSM security blob (we add `void *security` field to struct
bpf_token for that), but also control who can instantiate BPF token.
This follows existing pattern for BPF map and BPF prog.
Also add security_bpf_token_allow_cmd() and security_bpf_token_capable()
LSM hooks that allow LSM implementation to control and negate (if
necessary) BPF token's delegation of a specific bpf_cmd and capability,
respectively.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Paul Moore <paul@paul-moore.com>
Link: https://lore.kernel.org/bpf/20240124022127.2379740-12-andrii@kernel.org
Similarly to bpf_prog_alloc LSM hook, rename and extend bpf_map_alloc
hook into bpf_map_create, taking not just struct bpf_map, but also
bpf_attr and bpf_token, to give a fuller context to LSMs.
Unlike bpf_prog_alloc, there is no need to move the hook around, as it
currently is firing right before allocating BPF map ID and FD, which
seems to be a sweet spot.
But like bpf_prog_alloc/bpf_prog_free combo, make sure that bpf_map_free
LSM hook is called even if bpf_map_create hook returned error, as if few
LSMs are combined together it could be that one LSM successfully
allocated security blob for its needs, while subsequent LSM rejected BPF
map creation. The former LSM would still need to free up LSM blob, so we
need to ensure security_bpf_map_free() is called regardless of the
outcome.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Paul Moore <paul@paul-moore.com>
Link: https://lore.kernel.org/bpf/20240124022127.2379740-11-andrii@kernel.org
Based on upstream discussion ([0]), rework existing
bpf_prog_alloc_security LSM hook. Rename it to bpf_prog_load and instead
of passing bpf_prog_aux, pass proper bpf_prog pointer for a full BPF
program struct. Also, we pass bpf_attr union with all the user-provided
arguments for BPF_PROG_LOAD command. This will give LSMs as much
information as we can basically provide.
The hook is also BPF token-aware now, and optional bpf_token struct is
passed as a third argument. bpf_prog_load LSM hook is called after
a bunch of sanity checks were performed, bpf_prog and bpf_prog_aux were
allocated and filled out, but right before performing full-fledged BPF
verification step.
bpf_prog_free LSM hook is now accepting struct bpf_prog argument, for
consistency. SELinux code is adjusted to all new names, types, and
signatures.
Note, given that bpf_prog_load (previously bpf_prog_alloc) hook can be
used by some LSMs to allocate extra security blob, but also by other
LSMs to reject BPF program loading, we need to make sure that
bpf_prog_free LSM hook is called after bpf_prog_load/bpf_prog_alloc one
*even* if the hook itself returned error. If we don't do that, we run
the risk of leaking memory. This seems to be possible today when
combining SELinux and BPF LSM, as one example, depending on their
relative ordering.
Also, for BPF LSM setup, add bpf_prog_load and bpf_prog_free to
sleepable LSM hooks list, as they are both executed in sleepable
context. Also drop bpf_prog_load hook from untrusted, as there is no
issue with refcount or anything else anymore, that originally forced us
to add it to untrusted list in c0c852dd18 ("bpf: Do not mark certain LSM
hook arguments as trusted"). We now trigger this hook much later and it
should not be an issue anymore.
[0] https://lore.kernel.org/bpf/9fe88aef7deabbe87d3fc38c4aea3c69.paul@paul-moore.com/
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Paul Moore <paul@paul-moore.com>
Link: https://lore.kernel.org/bpf/20240124022127.2379740-10-andrii@kernel.org
