Commit Graph

41771 Commits

Author SHA1 Message Date
Nicholas Piggin
6cad87b0d2 kthread: simplify kthread_use_mm refcounting
Patch series "shoot lazy tlbs (lazy tlb refcount scalability
improvement)", v7.

This series improves scalability of context switching between user and
kernel threads on large systems with a threaded process spread across a
lot of CPUs.

Discussion of v6 here:
https://lore.kernel.org/linux-mm/20230118080011.2258375-1-npiggin@gmail.com/


This patch (of 5):

Remove the special case avoiding refcounting when the mm to be used is the
same as the kernel thread's active (lazy tlb) mm.  kthread_use_mm() should
not be such a performance critical path that this matters much.  This
simplifies a later change to lazy tlb mm refcounting.

Link: https://lkml.kernel.org/r/20230203071837.1136453-1-npiggin@gmail.com
Link: https://lkml.kernel.org/r/20230203071837.1136453-2-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-03-28 16:20:07 -07:00
Masami Hiramatsu (Google)
39d954200b fprobe: Skip exit_handler if entry_handler returns !0
Skip hooking function return and calling exit_handler if the
entry_handler() returns !0.

Link: https://lkml.kernel.org/r/167526699798.433354.10998365726830117303.stgit@mhiramat.roam.corp.google.com

Cc: Florent Revest <revest@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-03-28 18:52:22 -04:00
Masami Hiramatsu (Google)
59a7a29856 fprobe: Add nr_maxactive to specify rethook_node pool size
Add nr_maxactive to specify rethook_node pool size. This means
the maximum number of actively running target functions concurrently
for probing by exit_handler. Note that if the running function is
preempted or sleep, it is still counted as 'active'.

Link: https://lkml.kernel.org/r/167526697917.433354.17779774988245113106.stgit@mhiramat.roam.corp.google.com

Cc: Florent Revest <revest@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-03-28 18:52:22 -04:00
Masami Hiramatsu (Google)
76d0de5729 fprobe: Pass entry_data to handlers
Pass the private entry_data to the entry and exit handlers so that
they can share the context data, something like saved function
arguments etc.
User must specify the private entry_data size by @entry_data_size
field before registering the fprobe.

Link: https://lkml.kernel.org/r/167526696173.433354.17408372048319432574.stgit@mhiramat.roam.corp.google.com

Cc: Florent Revest <revest@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-03-28 18:52:22 -04:00
Desnes Nunes
bd89d69a52 dma-debug: add cacheline to user/kernel space dump messages
Having the cacheline also printed on the debug_dma_dump_mappings() and
dump_show() is useful for debugging. Furthermore, this also standardizes
the messages shown on both dump functions.

Signed-off-by: Desnes Nunes <desnesn@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2023-03-28 10:34:05 +09:00
Desnes Nunes
479623fd0c dma-debug: small dma_debug_entry's comment and variable name updates
Small update on dma_debug_entry's struct commentary and also standardize
the usage of 'dma_addr' variable name from debug_dma_map_page() on
debug_dma_unmap_page(), and similarly on debug_dma_free_coherent()

Signed-off-by: Desnes Nunes <desnesn@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2023-03-28 10:34:05 +09:00
Petr Tesarik
25a4ce5649 dma-direct: cleanup parameters to dma_direct_optimal_gfp_mask
Since both callers of dma_direct_optimal_gfp_mask() pass
dev->coherent_dma_mask as the second argument, it is better to
remove that parameter altogether.

Not only is reducing number of parameters good for readability, but
the new function signature is also more logical: The optimal flags
depend only on data contained in struct device.

While touching this code, let's also rename phys_mask to phys_limit
in dma_direct_alloc_from_pool(), because it is indeed a limit.

Signed-off-by: Petr Tesarik <petrtesarik@huaweicloud.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2023-03-28 10:34:05 +09:00
Paul E. McKenney
6e2044887b rcutorture: Add RCU Tasks Trace and SRCU deadlock scenarios
Add a test number 3 that creates deadlock cycles involving one RCU
Tasks Trace step and L-1 SRCU steps.  Please note that lockdep will not
detect these deadlocks until synchronize_rcu_tasks_trace() is marked
with lockdep's new "sync" annotation, which will probably not happen
until some time after these markings prove their worth on SRCU.

Please note that these tests are available only in kernels built with
CONFIG_TASKS_TRACE_RCU=y.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
2023-03-27 11:16:12 -07:00
Paul E. McKenney
d94f12e8a4 rcutorture: Add SRCU deadlock scenarios
In order to test the new SRCU-lockdep functionality, this commit adds
an rcutorture.test_srcu_lockdep module parameter that, when non-zero,
selects an SRCU deadlock scenario to execute.  This parameter is a
five-digit number formatted as DNNL, where "D" is 1 to force a deadlock
and 0 to avoid doing so; "NN" is the test number, 0 for SRCU-based, 1
for SRCU/mutex-based, and 2 for SRCU/rwsem-based; and "L" is the number
of steps in the deadlock cycle.

Note that rcutorture.test_srcu_lockdep=1 will also force a hard hang.

If a non-zero value of rcutorture.test_srcu_lockdep does not select a
deadlock scenario, a console message is printed and testing continues.

[ paulmck: Apply kernel test robot feedback, add rwsem support. ]
[ paulmck: Apply Dan Carpenter feedback. ]

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
2023-03-27 11:16:10 -07:00
Boqun Feng
0471db447c locking/lockdep: Improve the deadlock scenario print for sync and read lock
Lock scenario print is always a weak spot of lockdep splats. Improvement
can be made if we rework the dependency search and the error printing.

However without touching the graph search, we can improve a little for
the circular deadlock case, since we have the to-be-added lock
dependency, and know whether these two locks are read/write/sync.

In order to know whether a held_lock is sync or not, a bit was
"stolen" from ->references, which reduce our limit for the same lock
class nesting from 2^12 to 2^11, and it should still be good enough.

Besides, since we now have bit in held_lock for sync, we don't need the
"hardirqoffs being 1" trick, and also we can avoid the __lock_release()
if we jump out of __lock_acquire() before the held_lock stored.

With these changes, a deadlock case evolved with read lock and sync gets
a better print-out from:

	[...]  Possible unsafe locking scenario:
	[...]
	[...]        CPU0                    CPU1
	[...]        ----                    ----
	[...]   lock(srcuA);
	[...]                                lock(srcuB);
	[...]                                lock(srcuA);
	[...]   lock(srcuB);

to

	[...]  Possible unsafe locking scenario:
	[...]
	[...]        CPU0                    CPU1
	[...]        ----                    ----
	[...]   rlock(srcuA);
	[...]                                lock(srcuB);
	[...]                                lock(srcuA);
	[...]   sync(srcuB);

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
2023-03-27 11:16:04 -07:00
Boqun Feng
60a1a64ec0 locking: Reduce the number of locks in ww_mutex stress tests
The stress test in test_ww_mutex_init() uses 4095 locks since
lockdep::reference has 12 bits, and since we are going to reduce it to
11 bits to support lock_sync(), and 2047 is still a reasonable number of
the max nesting level for locks, so adjust the test.

Reported-by: kernel test robot <oliver.sang@intel.com>
Link: https://lore.kernel.org/oe-lkp/202302011445.9d99dae2-oliver.sang@intel.com
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
2023-03-27 11:16:01 -07:00
Boqun Feng
f0f44752f5 rcu: Annotate SRCU's update-side lockdep dependencies
Although all flavors of RCU readers are annotated correctly with
lockdep as recursive read locks, they do not set the lock_acquire
'check' parameter.  This means that RCU read locks are not added to
the lockdep dependency graph, which in turn means that lockdep cannot
detect RCU-based deadlocks.  This is not a problem for RCU flavors having
atomic read-side critical sections because context-based annotations can
catch these deadlocks, see for example the RCU_LOCKDEP_WARN() statement
in synchronize_rcu().  But context-based annotations are not helpful
for sleepable RCU, especially given that it is perfectly legal to do
synchronize_srcu(&srcu1) within an srcu_read_lock(&srcu2).

However, we can detect SRCU-based by: (1) Making srcu_read_lock() a
'check'ed recursive read lock and (2) Making synchronize_srcu() a empty
write lock critical section.  Even better, with the newly introduced
lock_sync(), we can avoid false positives about irq-unsafe/safe.
This commit therefore makes it so.

Note that NMI-safe SRCU read side critical sections are currently not
annotated, but might be annotated in the future.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
[ boqun: Add comments for annotation per Waiman's suggestion ]
[ boqun: Fix comment warning reported by Stephen Rothwell ]
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
2023-03-27 11:15:59 -07:00
Boqun Feng
2f1f043e7b locking/lockdep: Introduce lock_sync()
Currently, functions like synchronize_srcu() do not have lockdep
annotations resembling those of other write-side locking primitives.
Such annotations might look as follows:

	lock_acquire();
	lock_release();

Such annotations would tell lockdep that synchronize_srcu() acts like
an empty critical section that waits for other (read-side) critical
sections to finish.  This would definitely catch some deadlock, but
as pointed out by Paul Mckenney [1], this could also introduce false
positives because of irq-safe/unsafe detection.  Of course, there are
tricks could help with this:

	might_sleep(); // Existing statement in __synchronize_srcu().
	if (IS_ENABLED(CONFIG_PROVE_LOCKING)) {
		local_irq_disable();
		lock_acquire();
		lock_release();
		local_irq_enable();
	}

But it would be better for lockdep to provide a separate annonation for
functions like synchronize_srcu(), so that people won't need to repeat
the ugly tricks above.

Therefore introduce lock_sync(), which is simply an lock+unlock
pair with no irq safe/unsafe deadlock check.  This works because the
to-be-annontated functions do not create real critical sections, and
there is therefore no way that irq can create extra dependencies.

[1]: https://lore.kernel.org/lkml/20180412021233.ewncg5jjuzjw3x62@tardis/

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
[ boqun: Fix typos reported by Davidlohr Bueso and Paul E. Mckenney ]
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
2023-03-27 11:15:23 -07:00
Linus Torvalds
18940c888c Merge tag 'sched_urgent_for_v6.3_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fix from Borislav Petkov:

 - Fix a corner case where vruntime of a task is not being sanitized

* tag 'sched_urgent_for_v6.3_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Sanitize vruntime of entity being migrated
2023-03-26 09:18:30 -07:00
Linus Torvalds
f6cdaeb08b Merge tag 'core_urgent_for_v6.3_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core fixes from Borislav Petkov:

 - Do the delayed RCU wakeup for kthreads in the proper order so that
   former doesn't get ignored

 - A noinstr warning fix

* tag 'core_urgent_for_v6.3_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  entry/rcu: Check TIF_RESCHED _after_ delayed RCU wake-up
  entry: Fix noinstr warning in __enter_from_user_mode()
2023-03-26 09:06:20 -07:00
Martin KaFai Lau
6ae9d5e99e bpf: Use bpf_mem_cache_alloc/free for bpf_local_storage
This patch uses bpf_mem_cache_alloc/free for allocating and freeing
bpf_local_storage for task and cgroup storage.

The changes are similar to the previous patch. A few things that
worth to mention for bpf_local_storage:

The local_storage is freed when the last selem is deleted.
Before deleting a selem from local_storage, it needs to retrieve the
local_storage->smap because the bpf_selem_unlink_storage_nolock()
may have set it to NULL. Note that local_storage->smap may have
already been NULL when the selem created this local_storage has
been removed. In this case, call_rcu will be used to free the
local_storage.
Also, the bpf_ma (true or false) value is needed before calling
bpf_local_storage_free(). The bpf_ma can either be obtained from
the local_storage->smap (if available) or any of its selem's smap.
A new helper check_storage_bpf_ma() is added to obtain
bpf_ma for a deleting bpf_local_storage.

When bpf_local_storage_alloc getting a reused memory, all
fields are either in the correct values or will be initialized.
'cache[]' must already be all NULLs. 'list' must be empty.
Others will be initialized.

Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20230322215246.1675516-4-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-03-25 19:52:52 -07:00
Martin KaFai Lau
08a7ce384e bpf: Use bpf_mem_cache_alloc/free in bpf_local_storage_elem
This patch uses bpf_mem_alloc for the task and cgroup local storage that
the bpf prog can easily get a hold of the storage owner's PTR_TO_BTF_ID.
eg. bpf_get_current_task_btf() can be used in some of the kmalloc code
path which will cause deadlock/recursion. bpf_mem_cache_alloc is
deadlock free and will solve a legit use case in [1].

For sk storage, its batch creation benchmark shows a few percent
regression when the sk create/destroy batch size is larger than 32.
The sk creation/destruction happens much more often and
depends on external traffic. Considering it is hypothetical
to be able to cause deadlock with sk storage, it can cross
the bridge to use bpf_mem_alloc till a legit (ie. useful)
use case comes up.

For inode storage, bpf_local_storage_destroy() is called before
waiting for a rcu gp and its memory cannot be reused immediately.
inode stays with kmalloc/kfree after the rcu [or tasks_trace] gp.

A 'bool bpf_ma' argument is added to bpf_local_storage_map_alloc().
Only task and cgroup storage have 'bpf_ma == true' which
means to use bpf_mem_cache_alloc/free(). This patch only changes
selem to use bpf_mem_alloc for task and cgroup. The next patch
will change the local_storage to use bpf_mem_alloc also for
task and cgroup.

Here is some more details on the changes:

* memory allocation:
After bpf_mem_cache_alloc(), the SDATA(selem)->data is zero-ed because
bpf_mem_cache_alloc() could return a reused selem. It is to keep
the existing bpf_map_kzalloc() behavior. Only SDATA(selem)->data
is zero-ed. SDATA(selem)->data is the visible part to the bpf prog.
No need to use zero_map_value() to do the zeroing because
bpf_selem_free(..., reuse_now = true) ensures no bpf prog is using
the selem before returning the selem through bpf_mem_cache_free().
For the internal fields of selem, they will be initialized when
linking to the new smap and the new local_storage.

When 'bpf_ma == false', nothing changes in this patch. It will
stay with the bpf_map_kzalloc().

* memory free:
The bpf_selem_free() and bpf_selem_free_rcu() are modified to handle
the bpf_ma == true case.

For the common selem free path where its owner is also being destroyed,
the mem is freed in bpf_local_storage_destroy(), the owner (task
and cgroup) has gone through a rcu gp. The memory can be reused
immediately, so bpf_local_storage_destroy() will call
bpf_selem_free(..., reuse_now = true) which will do
bpf_mem_cache_free() for immediate reuse consideration.

An exception is the delete elem code path. The delete elem code path
is called from the helper bpf_*_storage_delete() and the syscall
bpf_map_delete_elem(). This path is an unusual case for local
storage because the common use case is to have the local storage
staying with its owner life time so that the bpf prog and the user
space does not have to monitor the owner's destruction. For the delete
elem path, the selem cannot be reused immediately because there could
be bpf prog using it. It will call bpf_selem_free(..., reuse_now = false)
and it will wait for a rcu tasks trace gp before freeing the elem. The
rcu callback is changed to do bpf_mem_cache_raw_free() instead of kfree().

When 'bpf_ma == false', it should be the same as before.
__bpf_selem_free() is added to do the kfree_rcu and call_tasks_trace_rcu().
A few words on the 'reuse_now == true'. When 'reuse_now == true',
it is still racing with bpf_local_storage_map_free which is under rcu
protection, so it still needs to wait for a rcu gp instead of kfree().
Otherwise, the selem may be reused by slab for a totally different struct
while the bpf_local_storage_map_free() is still using it (as a
rcu reader). For the inode case, there may be other rcu readers also.
In short, when bpf_ma == false and reuse_now == true => vanilla rcu.

[1]: https://lore.kernel.org/bpf/20221118190109.1512674-1-namhyung@kernel.org/

Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20230322215246.1675516-3-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-03-25 19:52:52 -07:00
Martin KaFai Lau
e65a5c6edb bpf: Add a few bpf mem allocator functions
This patch adds a few bpf mem allocator functions which will
be used in the bpf_local_storage in a later patch.

bpf_mem_cache_alloc_flags(..., gfp_t flags) is added. When the
flags == GFP_KERNEL, it will fallback to __alloc(..., GFP_KERNEL).
bpf_local_storage knows its running context is sleepable (GFP_KERNEL)
and provides a better guarantee on memory allocation.

bpf_local_storage has some uncommon cases that its selem
cannot be reused immediately. It handles its own
rcu_head and goes through a rcu_trace gp and then free it.
bpf_mem_cache_raw_free() is added for direct free purpose
without leaking the LLIST_NODE_SZ internal knowledge.
During free time, the 'struct bpf_mem_alloc *ma' is no longer
available. However, the caller should know if it is
percpu memory or not and it can call different raw_free functions.
bpf_local_storage does not support percpu value, so only
the non-percpu 'bpf_mem_cache_raw_free()' is added in
this patch.

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20230322215246.1675516-2-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-03-25 19:52:51 -07:00
David Vernet
6c831c4684 bpf: Treat KF_RELEASE kfuncs as KF_TRUSTED_ARGS
KF_RELEASE kfuncs are not currently treated as having KF_TRUSTED_ARGS,
even though they have a superset of the requirements of KF_TRUSTED_ARGS.
Like KF_TRUSTED_ARGS, KF_RELEASE kfuncs require a 0-offset argument, and
don't allow NULL-able arguments. Unlike KF_TRUSTED_ARGS which require
_either_ an argument with ref_obj_id > 0, _or_ (ref->type &
BPF_REG_TRUSTED_MODIFIERS) (and no unsafe modifiers allowed), KF_RELEASE
only allows for ref_obj_id > 0.  Because KF_RELEASE today doesn't
automatically imply KF_TRUSTED_ARGS, some of these requirements are
enforced in different ways that can make the behavior of the verifier
feel unpredictable. For example, a KF_RELEASE kfunc with a NULL-able
argument will currently fail in the verifier with a message like, "arg#0
is ptr_or_null_ expected ptr_ or socket" rather than "Possibly NULL
pointer passed to trusted arg0". Our intention is the same, but the
semantics are different due to implemenetation details that kfunc authors
and BPF program writers should not need to care about.

Let's make the behavior of the verifier more consistent and intuitive by
having KF_RELEASE kfuncs imply the presence of KF_TRUSTED_ARGS. Our
eventual goal is to have all kfuncs assume KF_TRUSTED_ARGS by default
anyways, so this takes us a step in that direction.

Note that it does not make sense to assume KF_TRUSTED_ARGS for all
KF_ACQUIRE kfuncs. KF_ACQUIRE kfuncs can have looser semantics than
KF_RELEASE, with e.g. KF_RCU | KF_RET_NULL. We may want to have
KF_ACQUIRE imply KF_TRUSTED_ARGS _unless_ KF_RCU is specified, but that
can be left to another patch set, and there are no such subtleties to
address for KF_RELEASE.

Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230325213144.486885-4-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-03-25 16:56:22 -07:00
David Vernet
fb2211a57c bpf: Remove now-unnecessary NULL checks for KF_RELEASE kfuncs
Now that we're not invoking kfunc destructors when the kptr in a map was
NULL, we no longer require NULL checks in many of our KF_RELEASE kfuncs.
This patch removes those NULL checks.

Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230325213144.486885-3-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-03-25 16:56:22 -07:00
David Vernet
1431d0b584 bpf: Only invoke kptr dtor following non-NULL xchg
When a map value is being freed, we loop over all of the fields of the
corresponding BPF object and issue the appropriate cleanup calls
corresponding to the field's type. If the field is a referenced kptr, we
atomically xchg the value out of the map, and invoke the kptr's
destructor on whatever was there before (or bpf_obj_drop() it if it was
a local kptr).

Currently, we always invoke the destructor (either bpf_obj_drop() or the
kptr's registered destructor) on any KPTR_REF-type field in a map, even
if there wasn't a value in the map. This means that any function serving
as the kptr's KF_RELEASE destructor must always treat the argument as
possibly NULL, as the following can and regularly does happen:

void *xchgd_field;

/* No value was in the map, so xchgd_field is NULL */
xchgd_field = (void *)xchg(unsigned long *field_ptr, 0);
field->kptr.dtor(xchgd_field);

These are odd semantics to impose on KF_RELEASE kfuncs -- BPF programs
are prohibited by the verifier from passing NULL pointers to KF_RELEASE
kfuncs, so it doesn't make sense to require this of BPF programs, but
not the main kernel destructor path. It's also unnecessary to invoke any
cleanup logic for local kptrs. If there is no object there, there's
nothing to drop.

So as to allow KF_RELEASE kfuncs to fully assume that an argument is
non-NULL, this patch updates a KPTR_REF's destructor to only be invoked
when a non-NULL value is xchg'd out of the kptr map field.

Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230325213144.486885-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-03-25 16:56:22 -07:00
Linus Torvalds
f768b35a23 Merge tag 'xfs-6.3-fixes-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull xfs percpu counter fixes from Darrick Wong:
 "We discovered a filesystem summary counter corruption problem that was
  traced to cpu hot-remove racing with the call to percpu_counter_sum
  that sets the free block count in the superblock when writing it to
  disk. The root cause is that percpu_counter_sum doesn't cull from
  dying cpus and hence misses those counter values if the cpu shutdown
  hooks have not yet run to merge the values.

  I'm hoping this is a fairly painless fix to the problem, since the
  dying cpu mask should generally be empty. It's been in for-next for a
  week without any complaints from the bots.

   - Fix a race in the percpu counters summation code where the
     summation failed to add in the values for any CPUs that were dying
     but not yet dead. This fixes some minor discrepancies and incorrect
     assertions when running generic/650"

* tag 'xfs-6.3-fixes-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  pcpcntr: remove percpu_counter_sum_all()
  fork: remove use of percpu_counter_sum_all
  pcpcntrs: fix dying cpu summation race
  cpumask: introduce for_each_cpu_or
2023-03-25 12:57:34 -07:00
Kees Cook
b69edab47f kheaders: Use array declaration instead of char
Under CONFIG_FORTIFY_SOURCE, memcpy() will check the size of destination
and source buffers. Defining kernel_headers_data as "char" would trip
this check. Since these addresses are treated as byte arrays, define
them as arrays (as done everywhere else).

This was seen with:

  $ cat /sys/kernel/kheaders.tar.xz >> /dev/null

  detected buffer overflow in memcpy
  kernel BUG at lib/string_helpers.c:1027!
  ...
  RIP: 0010:fortify_panic+0xf/0x20
  [...]
  Call Trace:
   <TASK>
   ikheaders_read+0x45/0x50 [kheaders]
   kernfs_fop_read_iter+0x1a4/0x2f0
  ...

Reported-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/bpf/20230302112130.6e402a98@kernel.org/
Acked-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reviewed-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Tested-by: Jakub Kicinski <kuba@kernel.org>
Fixes: 43d8ce9d65 ("Provide in-kernel headers to make extending kernel easier")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230302224946.never.243-kees@kernel.org
2023-03-24 20:10:59 -07:00
Linus Torvalds
65aca32efd Merge tag 'mm-hotfixes-stable-2023-03-24-17-09' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc fixes from Andrew Morton:
 "21 hotfixes, 8 of which are cc:stable. 11 are for MM, the remainder
  are for other subsystems"

* tag 'mm-hotfixes-stable-2023-03-24-17-09' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (21 commits)
  mm: mmap: remove newline at the end of the trace
  mailmap: add entries for Richard Leitner
  kcsan: avoid passing -g for test
  kfence: avoid passing -g for test
  mm: kfence: fix using kfence_metadata without initialization in show_object()
  lib: dhry: fix unstable smp_processor_id(_) usage
  mailmap: add entry for Enric Balletbo i Serra
  mailmap: map Sai Prakash Ranjan's old address to his current one
  mailmap: map Rajendra Nayak's old address to his current one
  Revert "kasan: drop skip_kasan_poison variable in free_pages_prepare"
  mailmap: add entry for Tobias Klauser
  kasan, powerpc: don't rename memintrinsics if compiler adds prefixes
  mm/ksm: fix race with VMA iteration and mm_struct teardown
  kselftest: vm: fix unused variable warning
  mm: fix error handling for map_deny_write_exec
  mm: deduplicate error handling for map_deny_write_exec
  checksyscalls: ignore fstat to silence build warning on LoongArch
  nilfs2: fix kernel-infoleak in nilfs_ioctl_wrap_copy()
  test_maple_tree: add more testing for mas_empty_area()
  maple_tree: fix mas_skip_node() end slot detection
  ...
2023-03-24 18:06:11 -07:00
Martin KaFai Lau
55fbae0547 bpf: Check IS_ERR for the bpf_map_get() return value
This patch fixes a mistake in checking NULL instead of
checking IS_ERR for the bpf_map_get() return value.

It also fixes the return value in link_update_map() from -EINVAL
to PTR_ERR(*_map).

Reported-by: syzbot+71ccc0fe37abb458406b@syzkaller.appspotmail.com
Fixes: 68b04864ca ("bpf: Create links for BPF struct_ops maps.")
Fixes: aef56f2e91 ("bpf: Update the struct_ops of a bpf_link.")
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Kui-Feng Lee <kuifeng@meta.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230324184241.1387437-1-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-03-24 12:40:47 -07:00
Jim Cromie
33c951f629 module: already_uses() - reduce pr_debug output volume
already_uses() is unnecessarily chatty.

`modprobe i915` yields 491 messages like:

  [   64.108744] i915 uses drm!

This is a normal situation, and isn't worth all the log entries.

NOTE: I've preserved the "does not use %s" messages, which happens
less often, but does happen.  Its not clear to me what it tells a
reader, or what info might improve the pr_debug's utility.

[ 6847.584999] main:already_uses:569: amdgpu does not use ttm!
[ 6847.585001] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585014] main:already_uses:569: amdgpu does not use drm!
[ 6847.585016] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585024] main:already_uses:569: amdgpu does not use drm_display_helper!
[ 6847.585025] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585084] main:already_uses:569: amdgpu does not use drm_kms_helper!
[ 6847.585086] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585175] main:already_uses:569: amdgpu does not use drm_buddy!
[ 6847.585176] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585202] main:already_uses:569: amdgpu does not use i2c_algo_bit!
[ 6847.585204] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585249] main:already_uses:569: amdgpu does not use gpu_sched!
[ 6847.585250] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585314] main:already_uses:569: amdgpu does not use video!
[ 6847.585315] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585409] main:already_uses:569: amdgpu does not use iommu_v2!
[ 6847.585410] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6847.585816] main:already_uses:569: amdgpu does not use drm_ttm_helper!
[ 6847.585818] main:add_module_usage:584: Allocating new usage for amdgpu.
[ 6848.762268] dyndbg: add-module: amdgpu.2533 sites

no functional changes.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-03-24 11:33:09 -07:00
Jim Cromie
66a2301edf module: add section-size to move_module pr_debug
move_module() pr_debug's "Final section addresses for $modname".
Add section addresses to the message, for anyone looking at these.

no functional changes.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-03-24 11:33:09 -07:00
Jim Cromie
b10addf37b module: add symbol-name to pr_debug Absolute symbol
The pr_debug("Absolute symbol" ..) reports value, (which is usually
0), but not the name, which is more informative.  So add it.

no functional changes

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-03-24 11:33:09 -07:00
Jim Cromie
6ed81802d4 module: in layout_sections, move_module: add the modname
layout_sections() and move_module() each issue ~50 messages for each
module loaded.  Add mod-name into their 2 header lines, to help the
reader find his module.

no functional changes.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-03-24 11:33:09 -07:00
Luis Chamberlain
25be451aa4 module: fold usermode helper kmod into modules directory
The kernel/kmod.c is already only built if we enabled modules, so
just stuff it under kernel/module/kmod.c and unify the MAINTAINERS
file for it.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-03-24 11:33:08 -07:00
Luis Chamberlain
3d40bb903e module: merge remnants of setup_load_info() to elf validation
The setup_load_info() was actually had ELF validation checks of its
own. To later cache useful variables as an secondary step just means
looping again over the ELF sections we just validated. We can simply
keep tabs of the key sections of interest as we validate the module
ELF section in one swoop, so do that and merge the two routines
together.

Expand a bit on the documentation / intent / goals.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-03-24 11:33:08 -07:00
Luis Chamberlain
1bb49db991 module: move more elf validity checks to elf_validity_check()
The symbol and strings section validation currently happen in
setup_load_info() but since they are also doing validity checks
move this to elf_validity_check().

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-03-24 11:33:08 -07:00
Luis Chamberlain
c7ee8aebf6 module: add stop-grap sanity check on module memcpy()
The integrity of the struct module we load is important, and although
our ELF validator already checks that the module section must match
struct module, add a stop-gap check before we memcpy() the final minted
module. This also makes those inspecting the code what the goal is.

While at it, clarify the goal behind updating the sh_addr address.
The current comment is pretty misleading.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-03-24 11:33:08 -07:00
Luis Chamberlain
46752820f9 module: add sanity check for ELF module section
The ELF ".gnu.linkonce.this_module" section is special, it is what we
use to construct the struct module __this_module, which THIS_MODULE
points to. When userspace loads a module we always deal first with a
copy of the userspace buffer, and twiddle with the userspace copy's
version of the struct module. Eventually we allocate memory to do a
memcpy() of that struct module, under the assumption that the module
size is right. But we have no validity checks against the size or
the requirements for the section.

Add some validity checks for the special module section early and while
at it, cache the module section index early, so we don't have to do that
later.

While at it, just move over the assigment of the info->mod to make the
code clearer. The validity checker also adds an explicit size check to
ensure the module section size matches the kernel's run time size for
sizeof(struct module). This should prevent sloppy loads of modules
which are built today *without* actually increasing the size of
the struct module. A developer today can for example expand the size
of struct module, rebuild a directoroy 'make fs/xfs/' for example and
then try to insmode the driver there. That module would in effect have
an incorrect size. This new size check would put a stop gap against such
mistakes.

This also makes the entire goal of ".gnu.linkonce.this_module" pretty
clear. Before this patch verification of the goal / intent required some
Indian Jones whips, torches and cleaning up big old spider webs.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-03-24 11:33:08 -07:00
Luis Chamberlain
419e1a20f7 module: rename check_module_license_and_versions() to check_export_symbol_versions()
This makes the routine easier to understand what the check its checking for.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-03-24 11:33:08 -07:00
Luis Chamberlain
72f08b3cc6 module: converge taint work together
Converge on a compromise: so long as we have a module hit our linked
list of modules we taint. That is, the module was about to become live.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-03-24 11:33:08 -07:00
Luis Chamberlain
c3bbf62ebf module: move signature taint to module_augment_kernel_taints()
Just move the signature taint into the helper:

  module_augment_kernel_taints()

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-03-24 11:33:08 -07:00
Luis Chamberlain
a12b94511c module: move tainting until after a module hits our linked list
It is silly to have taints spread out all over, we can just compromise
and add them if the module ever hit our linked list. Our sanity checkers
should just prevent crappy drivers / bogus ELF modules / etc and kconfig
options should be enough to let you *not* load things you don't want.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-03-24 11:33:08 -07:00
Luis Chamberlain
437c1f9cc6 module: split taint adding with info checking
check_modinfo() actually does two things:

 a) sanity checks, some of which are fatal, and so we
    prevent the user from completing trying to load a module
 b) taints the kernel

The taints are pretty heavy handed because we're tainting the kernel
*before* we ever even get to load the module into the modules linked
list. That is, it it can fail for other reasons later as we review the
module's structure.

But this commit makes no functional changes, it just makes the intent
clearer and splits the code up where needed to make that happen.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-03-24 11:33:08 -07:00
Luis Chamberlain
ed52cabecb module: split taint work out of check_modinfo_livepatch()
The work to taint the kernel due to a module should be split
up eventually. To aid with this, split up the tainting on
check_modinfo_livepatch().

This let's us bring more early checks together which do return
a value, and makes changes easier to read later where we stuff
all the work to do the taints in one single routine.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-03-24 11:33:08 -07:00
Luis Chamberlain
ad8d3a36e9 module: rename set_license() to module_license_taint_check()
The set_license() routine would seem to a reader to do some sort of
setting, but it does not. It just adds a taint if the license is
not set or proprietary.

This makes what the code is doing clearer, so much we can remove
the comment about it.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-03-24 11:33:08 -07:00
Luis Chamberlain
02da2cbab4 module: move check_modinfo() early to early_mod_check()
This moves check_modinfo() to early_mod_check(). This
doesn't make any functional changes either, as check_modinfo()
was the first call on layout_and_allocate(), so we're just
moving it back one routine and at the end.

This let's us keep separate the checkers from the allocator.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-03-24 11:33:06 -07:00
Luis Chamberlain
85e6f61c13 module: move early sanity checks into a helper
Move early sanity checkers for the module into a helper.
This let's us make it clear when we are working with the
local copy of the module prior to allocation.

This produces no functional changes, it just makes subsequent
changes easier to read.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-03-24 11:31:35 -07:00
Luis Chamberlain
1e68417235 module: add a for_each_modinfo_entry()
Add a for_each_modinfo_entry() to make it easier to read and use.
This produces no functional changes but makes this code easiert
to read as we are used to with loops in the kernel and trims more
lines of code.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-03-24 11:05:15 -07:00
Luis Chamberlain
feb5b784a2 module: rename next_string() to module_next_tag_pair()
This makes it clearer what it is doing. While at it,
make it available to other code other than main.c.
This will be used in the subsequent patch and make
the changes easier to read.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-03-24 11:05:15 -07:00
Luis Chamberlain
b66973b82d module: move get_modinfo() helpers all above
Instead of forward declaring routines for get_modinfo() just move
everything up. This makes no functional changes.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2023-03-24 11:05:15 -07:00
Jakub Kicinski
dc0a7b5200 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Conflicts:

drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
  6e9d51b1a5 ("net/mlx5e: Initialize link speed to zero")
  1bffcea429 ("net/mlx5e: Add devlink hairpin queues parameters")
https://lore.kernel.org/all/20230324120623.4ebbc66f@canb.auug.org.au/
https://lore.kernel.org/all/20230321211135.47711-1-saeed@kernel.org/

Adjacent changes:

drivers/net/phy/phy.c
  323fe43cf9 ("net: phy: Improved PHY error reporting in state machine")
  4203d84032 ("net: phy: Ensure state transitions are processed from phy_stop()")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-03-24 10:10:20 -07:00
Thomas Weißschuh
9f33a88c0a kernel/ksysfs.c: use sysfs_emit for sysfs show handlers
sysfs_emit() is the recommended way to format strings for sysfs as per
Documentation/filesystems/sysfs.rst.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20230324-ksysfs-sysfs_emit-v1-1-67c03cddc8a6@weissschuh.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-24 17:09:14 +01:00
Linus Torvalds
608f1b1366 Merge tag 'net-6.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Jakub Kicinski:
 "Including fixes from bpf, wifi and bluetooth.

  Current release - regressions:

   - wifi: mt76: mt7915: add back 160MHz channel width support for
     MT7915

   - libbpf: revert poisoning of strlcpy, it broke uClibc-ng

  Current release - new code bugs:

   - bpf: improve the coverage of the "allow reads from uninit stack"
     feature to fix verification complexity problems

   - eth: am65-cpts: reset PPS genf adj settings on enable

  Previous releases - regressions:

   - wifi: mac80211: serialize ieee80211_handle_wake_tx_queue()

   - wifi: mt76: do not run mt76_unregister_device() on unregistered hw,
     fix null-deref

   - Bluetooth: btqcomsmd: fix command timeout after setting BD address

   - eth: igb: revert rtnl_lock() that causes a deadlock

   - dsa: mscc: ocelot: fix device specific statistics

  Previous releases - always broken:

   - xsk: add missing overflow check in xdp_umem_reg()

   - wifi: mac80211:
      - fix QoS on mesh interfaces
      - fix mesh path discovery based on unicast packets

   - Bluetooth:
      - ISO: fix timestamped HCI ISO data packet parsing
      - remove "Power-on" check from Mesh feature

   - usbnet: more fixes to drivers trusting packet length

   - wifi: iwlwifi: mvm: fix mvmtxq->stopped handling

   - Bluetooth: btintel: iterate only bluetooth device ACPI entries

   - eth: iavf: fix inverted Rx hash condition leading to disabled hash

   - eth: igc: fix the validation logic for taprio's gate list

   - dsa: tag_brcm: legacy: fix daisy-chained switches

  Misc:

   - bpf: adjust insufficient default bpf_jit_limit to account for
     growth of BPF use over the last 5 years

   - xdp: bpf_xdp_metadata() use EOPNOTSUPP as unique errno indicating
     no driver support"

* tag 'net-6.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (84 commits)
  Bluetooth: HCI: Fix global-out-of-bounds
  Bluetooth: mgmt: Fix MGMT add advmon with RSSI command
  Bluetooth: btsdio: fix use after free bug in btsdio_remove due to unfinished work
  Bluetooth: L2CAP: Fix responding with wrong PDU type
  Bluetooth: btqcomsmd: Fix command timeout after setting BD address
  Bluetooth: btinel: Check ACPI handle for NULL before accessing
  net: mdio: thunder: Add missing fwnode_handle_put()
  net: dsa: mt7530: move setting ssc_delta to PHY_INTERFACE_MODE_TRGMII case
  net: dsa: mt7530: move lowering TRGMII driving to mt7530_setup()
  net: dsa: mt7530: move enabling disabling core clock to mt7530_pll_setup()
  net: asix: fix modprobe "sysfs: cannot create duplicate filename"
  gve: Cache link_speed value from device
  tools: ynl: Fix genlmsg header encoding formats
  net: enetc: fix aggregate RMON counters not showing the ranges
  Bluetooth: Remove "Power-on" check from Mesh feature
  Bluetooth: Fix race condition in hci_cmd_sync_clear
  Bluetooth: btintel: Iterate only bluetooth device ACPI entries
  Bluetooth: ISO: fix timestamped HCI ISO data packet parsing
  Bluetooth: btusb: Remove detection of ISO packets over bulk
  Bluetooth: hci_core: Detect if an ACL packet is in fact an ISO packet
  ...
2023-03-24 08:48:12 -07:00
Peter Zijlstra
5c3124975e trace,smp: Trace all smp_function_call*() invocations
(Ab)use the trace_ipi_send_cpu*() family to trace all
smp_function_call*() invocations, not only those that result in an
actual IPI.

The queued entries log their callback function while the actual IPIs
are traced on generic_smp_call_function_single_interrupt().

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2023-03-24 11:01:30 +01:00