34080 Commits

Author SHA1 Message Date
Lai Jiangshan
5f5fa7ea89 rcu: Don't use negative nesting depth in __rcu_read_unlock()
Now that RCU flavors have been consolidated, an RCU-preempt
rcu_read_unlock() in an interrupt or softirq handler cannot possibly
end the RCU read-side critical section.  Consider the old vulnerability
involving rcu_read_unlock() being invoked within such a handler that
interrupted an __rcu_read_unlock_special(), in which a wakeup might be
invoked with a scheduler lock held.  Because rcu_read_unlock_special()
no longer does wakeups in such situations, it is no longer necessary
for __rcu_read_unlock() to set the nesting level negative.

This commit therefore removes this recursion-protection code from
__rcu_read_unlock().

[ paulmck: Let rcu_exp_handler() continue to call rcu_report_exp_rdp(). ]
[ paulmck: Adjust other checks given no more negative nesting. ]
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:50 -07:00
Lai Jiangshan
f0bdf6d473 rcu: Remove unused ->rcu_read_unlock_special.b.deferred_qs field
The ->rcu_read_unlock_special.b.deferred_qs field is set to true in
rcu_read_unlock_special() but never set to false.  This is not
particularly useful, so this commit removes this field.

The only possible justification for this field is to ease debugging
of RCU deferred quiscent states, but the combination of the other
->rcu_read_unlock_special fields plus ->rcu_blocked_node and of course
->rcu_read_lock_nesting should cover debugging needs.  And if this last
proves incorrect, this patch can always be reverted, along with the
required setting of ->rcu_read_unlock_special.b.deferred_qs to false
in rcu_preempt_deferred_qs_irqrestore().

Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:50 -07:00
Lai Jiangshan
07b4a930fc rcu: Don't set nesting depth negative in rcu_preempt_deferred_qs()
Now that RCU flavors have been consolidated, an RCU-preempt
rcu_read_unlock() in an interrupt or softirq handler cannot possibly
end the RCU read-side critical section.  Consider the old vulnerability
involving rcu_preempt_deferred_qs() being invoked within such a handler
that interrupted an extended RCU read-side critical section, in which
a wakeup might be invoked with a scheduler lock held.  Because
rcu_read_unlock_special() no longer does wakeups in such situations,
it is no longer necessary for rcu_preempt_deferred_qs() to set the
nesting level negative.

This commit therefore removes this recursion-protection code from
rcu_preempt_deferred_qs().

[ paulmck: Fix typo in commit log per Steve Rostedt. ]
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:50 -07:00
Paul E. McKenney
e4453d8a1c rcu: Make rcu_read_unlock_special() safe for rq/pi locks
The scheduler is currently required to hold rq/pi locks across the entire
RCU read-side critical section or not at all.  This is inconvenient and
leaves traps for the unwary, including the author of this commit.

But now that excessively long grace periods enable scheduling-clock
interrupts for holdout nohz_full CPUs, the nohz_full rescue logic in
rcu_read_unlock_special() can be dispensed with.  In other words, the
rcu_read_unlock_special() function can refrain from doing wakeups unless
such wakeups are guaranteed safe.

This commit therefore avoids unsafe wakeups, freeing the scheduler to
hold rq/pi locks across rcu_read_unlock() even if the corresponding RCU
read-side critical section might have been preempted.  This commit also
updates RCU's requirements documentation.

This commit is inspired by a patch from Lai Jiangshan:
https://lore.kernel.org/lkml/20191102124559.1135-2-laijs@linux.alibaba.com
This commit is further intended to be a step towards his goal of permitting
the inlining of RCU-preempt's rcu_read_lock() and rcu_read_unlock().

Cc: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:50 -07:00
Paul E. McKenney
c76e7e0bce rcu: Add KCSAN stubs to update.c
This commit adds stubs for KCSAN's data_race(), ASSERT_EXCLUSIVE_WRITER(),
and ASSERT_EXCLUSIVE_ACCESS() macros to allow code using these macros
to move ahead.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:03:50 -07:00
Paul E. McKenney
6be7436d22 rcu: Add rcu_gp_might_be_stalled()
This commit adds rcu_gp_might_be_stalled(), which returns true if there
is some reason to believe that the RCU grace period is stalled.  The use
case is where an RCU free-memory path needs to allocate memory in order
to free it, a situation that should be avoided where possible.

But where it is necessary, there is always the alternative of using
synchronize_rcu() to wait for a grace period in order to avoid the
allocation.  And if the grace period is stalled, allocating memory to
asynchronously wait for it is a bad idea of epic proportions: Far better
to let others use the memory, because these others might actually be
able to free that memory before the grace period ends.

Thus, rcu_gp_might_be_stalled() can be used to help decide whether
allocating memory on an RCU free path is a semi-reasonable course
of action.

Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Uladzislau Rezki <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:02:50 -07:00
Joel Fernandes (Google)
a6a82ce18b rcu/tree: Count number of batched kfree_rcu() locklessly
We can relax the correctness of counting of number of queued objects in
favor of not hurting performance, by locklessly sampling per-cpu
counters. This should be Ok since under high memory pressure, it should not
matter if we are off by a few objects while counting. The shrinker will
still do the reclaim.

Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
[ paulmck: Remove unused "flags" variable. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:02:50 -07:00
Joel Fernandes (Google)
9154244c1a rcu/tree: Add a shrinker to prevent OOM due to kfree_rcu() batching
To reduce grace periods and improve kfree() performance, we have done
batching recently dramatically bringing down the number of grace periods
while giving us the ability to use kfree_bulk() for efficient kfree'ing.

However, this has increased the likelihood of OOM condition under heavy
kfree_rcu() flood on small memory systems. This patch introduces a
shrinker which starts grace periods right away if the system is under
memory pressure due to existence of objects that have still not started
a grace period.

With this patch, I do not observe an OOM anymore on a system with 512MB
RAM and 8 CPUs, with the following rcuperf options:

rcuperf.kfree_loops=20000 rcuperf.kfree_alloc_num=8000
rcuperf.kfree_rcu_test=1 rcuperf.kfree_mult=2

Otherwise it easily OOMs with the above parameters.

NOTE:
1. On systems with no memory pressure, the patch has no effect as intended.
2. In the future, we can use this same mechanism to prevent grace periods
   from happening even more, by relying on shrinkers carefully.

Cc: urezki@gmail.com
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:02:50 -07:00
Joel Fernandes (Google)
f87dc80800 rcuperf: Add ability to increase object allocation size
This allows us to increase memory pressure dynamically using a new
rcuperf boot command line parameter called 'rcumult'.

Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:02:50 -07:00
Paul E. McKenney
e2f3ccfa62 rcu: Convert rcu_nohz_full_cpu() ULONG_CMP_LT() to time_before()
This commit converts the ULONG_CMP_LT() in rcu_nohz_full_cpu() to
time_before() to reflect the fact that it is comparing a timestamp to
the jiffies counter.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:01:17 -07:00
Paul E. McKenney
7b2413111a rcu: Convert rcu_initiate_boost() ULONG_CMP_GE() to time_after()
This commit converts the ULONG_CMP_GE() in rcu_initiate_boost() to
time_after() to reflect the fact that it is comparing a timestamp to
the jiffies counter.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:01:16 -07:00
Paul E. McKenney
29ffebc5fc rcu: Convert ULONG_CMP_GE() to time_after() for jiffy comparison
This commit converts the ULONG_CMP_GE() in rcu_gp_fqs_loop() to
time_after() to reflect the fact that it is comparing a timestamp to
the jiffies counter.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:01:16 -07:00
Jules Irenge
da44cd6c8e rcu: Replace 1 by true
Coccinelle reports a warning at use_softirq declaration

WARNING: Assignment of 0/1 to bool variable

The root cause is
use_softirq a variable of bool type is initialised with the integer 1
Replacing 1 with value true solve the issue.

Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:01:16 -07:00
Jules Irenge
a66dbda789 rcu: Replace assigned pointer ret value by corresponding boolean value
Coccinelle reports warnings at rcu_read_lock_held_common()

WARNING: Assignment of 0/1 to bool variable

To fix this,
the assigned  pointer ret values are replaced by corresponding boolean value.
Given that ret is a pointer of bool type

Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:01:16 -07:00
Paul E. McKenney
62ae19511f rcu: Mark rcu_state.gp_seq to detect more concurrent writes
The rcu_state structure's gp_seq field is only to be modified by the RCU
grace-period kthread, which is single-threaded.  This commit therefore
enlists KCSAN's help in enforcing this restriction.  This commit applies
KCSAN-specific primitives, so cannot go upstream until KCSAN does.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:01:16 -07:00
Mauro Carvalho Chehab
c28d5c09d0 rcu: Get rid of some doc warnings in update.c
This commit escapes *ret, because otherwise the documentation system
thinks that this is an incomplete emphasis block:

	./kernel/rcu/update.c:65: WARNING: Inline emphasis start-string without end-string.
	./kernel/rcu/update.c:65: WARNING: Inline emphasis start-string without end-string.
	./kernel/rcu/update.c:70: WARNING: Inline emphasis start-string without end-string.
	./kernel/rcu/update.c:82: WARNING: Inline emphasis start-string without end-string.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:01:16 -07:00
Zhaolong Zhang
fcbcc0e700 rcu: Fix the (t=0 jiffies) false positive
It is possible that an over-long grace period will end while the RCU
CPU stall warning message is printing.  In this case, the estimate of
the offending grace period's duration can be erroneous due to refetching
of rcu_state.gp_start, which will now be the time of the newly started
grace period.  Computation of this duration clearly needs to use the
start time for the old over-long grace period, not the fresh new one.
This commit avoids such errors by causing both print_other_cpu_stall() and
print_cpu_stall() to reuse the value previously fetched by their caller.

Signed-off-by: Zhaolong Zhang <zhangzl2013@126.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:01:16 -07:00
Paul E. McKenney
1fca4d12f4 rcu: Expedite first two FQS scans under callback-overload conditions
Even if some CPUs have excessive numbers of callbacks, RCU's grace-period
kthread will still wait normally between successive force-quiescent-state
scans.  The first two are the most important, as they are the ones that
enlist aid from the scheduler when overloaded.  This commit therefore
omits the wait before the first and the second force-quiescent-state
scan under callback-overload conditions.

This approach was inspired by a discussion with Jeff Roberson.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:01:16 -07:00
Paul E. McKenney
47fbb07453 rcu: Use data_race() for RCU CPU stall-warning prints
Although the accesses used to determine whether or not a stall should
be printed are an integral part of the concurrency algorithm governing
use of the corresponding variables, the values that are simply printed
are ancillary.  As such, it is best to use data_race() for these accesses
in order to provide the greatest latitude in the use of KCSAN for the
other accesses that are an integral part of the algorithm.  This commit
therefore changes the relevant uses of READ_ONCE() to data_race().

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:01:16 -07:00
Paul E. McKenney
5822b8126f rcu: Add WRITE_ONCE() to rcu_node ->boost_tasks
The rcu_node structure's ->boost_tasks field is read locklessly, so this
commit adds the WRITE_ONCE() to an update in order to provide proper
documentation and READ_ONCE()/WRITE_ONCE() pairing.

This data race was reported by KCSAN.  Not appropriate for backporting
due to failure being unlikely.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:01:16 -07:00
Paul E. McKenney
b68c614651 srcu: Add data_race() to ->srcu_lock_count and ->srcu_unlock_count arrays
The srcu_data structure's ->srcu_lock_count and ->srcu_unlock_count arrays
are read and written locklessly, so this commit adds the data_race()
to the diagnostic-print loads from these arrays in order mark them as
known and approved data-racy accesses.

This data race was reported by KCSAN. Not appropriate for backporting due
to failure being unlikely and due to this being used only by rcutorture.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:01:16 -07:00
Paul E. McKenney
065a6db12a rcu: Add READ_ONCE and data_race() to rcu_node ->boost_tasks
The rcu_node structure's ->boost_tasks field is read locklessly, so this
commit adds the READ_ONCE() to one load in order to avoid destructive
compiler optimizations.  The other load is from a diagnostic print,
so data_race() suffices.

This data race was reported by KCSAN.  Not appropriate for backporting
due to failure being unlikely.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:01:16 -07:00
Paul E. McKenney
314eeb43e5 rcu: Add *_ONCE() and data_race() to rcu_node ->exp_tasks plus locking
There are lockless loads from the rcu_node structure's ->exp_tasks field,
so this commit causes all stores to use WRITE_ONCE() and all lockless
loads to use READ_ONCE() or data_race(), with the latter for debug
prints.  This code also did a unprotected traversal of the linked list
pointed into by ->exp_tasks, so this commit also acquires the rcu_node
structure's ->lock to properly protect this traversal.  This list was
traversed unprotected only when printing an RCU CPU stall warning for
an expedited grace period, so the odds of seeing this in production are
not all that high.

This data race was reported by KCSAN.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:01:15 -07:00
Paul E. McKenney
2f08469563 rcu: Mark rcu_state.ncpus to detect concurrent writes
The rcu_state structure's ncpus field is only to be modified by the
CPU-hotplug CPU-online code path, which is single-threaded.  This
commit therefore enlists KCSAN's help in enforcing this restriction.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:01:15 -07:00
Paul E. McKenney
4f58820fd7 srcu: Add KCSAN stubs
This commit adds stubs for KCSAN's data_race(), ASSERT_EXCLUSIVE_WRITER(),
and ASSERT_EXCLUSIVE_ACCESS() macros to allow code using these macros to
move ahead.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:01:15 -07:00
Paul E. McKenney
353159365e rcu: Add KCSAN stubs
This commit adds stubs for KCSAN's data_race(), ASSERT_EXCLUSIVE_WRITER(),
and ASSERT_EXCLUSIVE_ACCESS() macros to allow code using these macros to
move ahead.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-27 11:00:06 -07:00
Alex Shi
23b5ae2e8e locking/rtmutex: Remove unused rt_mutex_cmpxchg_relaxed()
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1587135032-188866-1-git-send-email-alex.shi@linux.alibaba.com
2020-04-27 12:26:40 +02:00
Dexuan Cui
2351f8d295 PM: hibernate: Freeze kernel threads in software_resume()
Currently the kernel threads are not frozen in software_resume(), so
between dpm_suspend_start(PMSG_QUIESCE) and resume_target_kernel(),
system_freezable_power_efficient_wq can still try to submit SCSI
commands and this can cause a panic since the low level SCSI driver
(e.g. hv_storvsc) has quiesced the SCSI adapter and can not accept
any SCSI commands: https://lkml.org/lkml/2020/4/10/47

At first I posted a fix (https://lkml.org/lkml/2020/4/21/1318) trying
to resolve the issue from hv_storvsc, but with the help of
Bart Van Assche, I realized it's better to fix software_resume(),
since this looks like a generic issue, not only pertaining to SCSI.

Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-04-27 10:30:30 +02:00
Christoph Hellwig
32927393dc sysctl: pass kernel pointers to ->proc_handler
Instead of having all the sysctl handlers deal with user pointers, which
is rather hairy in terms of the BPF interaction, copy the input to and
from  userspace in common code.  This also means that the strings are
always NUL-terminated by the common code, making the API a little bit
safer.

As most handler just pass through the data to one of the common handlers
a lot of the changes are mechnical.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-04-27 02:07:40 -04:00
Christoph Hellwig
f461d2dcd5 sysctl: avoid forward declarations
Move the sysctl tables to the end of the file to avoid lots of pointless
forward declarations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-04-27 02:07:26 -04:00
Christoph Hellwig
2374c09b1c sysctl: remove all extern declaration from sysctl.c
Extern declarations in .c files are a bad style and can lead to
mismatches.  Use existing definitions in headers where they exist,
and otherwise move the external declarations to suitable header
files.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-04-27 02:06:53 -04:00
Christoph Hellwig
26363af564 mm: remove watermark_boost_factor_sysctl_handler
watermark_boost_factor_sysctl_handler is just a pointless wrapper for
proc_dointvec_minmax, so remove it and use proc_dointvec_minmax
directly.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-04-27 02:06:52 -04:00
Andrii Nakryiko
6f8a57ccf8 bpf: Make verifier log more relevant by default
To make BPF verifier verbose log more releavant and easier to use to debug
verification failures, "pop" parts of log that were successfully verified.
This has effect of leaving only verifier logs that correspond to code branches
that lead to verification failure, which in practice should result in much
shorter and more relevant verifier log dumps. This behavior is made the
default behavior and can be overriden to do exhaustive logging by specifying
BPF_LOG_LEVEL2 log level.

Using BPF_LOG_LEVEL2 to disable this behavior is not ideal, because in some
cases it's good to have BPF_LOG_LEVEL2 per-instruction register dump
verbosity, but still have only relevant verifier branches logged. But for this
patch, I didn't want to add any new flags. It might be worth-while to just
rethink how BPF verifier logging is performed and requested and streamline it
a bit. But this trimming of successfully verified branches seems to be useful
and a good default behavior.

To test this, I modified runqslower slightly to introduce read of
uninitialized stack variable. Log (**truncated in the middle** to save many
lines out of this commit message) BEFORE this change:

; int handle__sched_switch(u64 *ctx)
0: (bf) r6 = r1
; struct task_struct *prev = (struct task_struct *)ctx[1];
1: (79) r1 = *(u64 *)(r6 +8)
func 'sched_switch' arg1 has btf_id 151 type STRUCT 'task_struct'
2: (b7) r2 = 0
; struct event event = {};
3: (7b) *(u64 *)(r10 -24) = r2
last_idx 3 first_idx 0
regs=4 stack=0 before 2: (b7) r2 = 0
4: (7b) *(u64 *)(r10 -32) = r2
5: (7b) *(u64 *)(r10 -40) = r2
6: (7b) *(u64 *)(r10 -48) = r2
; if (prev->state == TASK_RUNNING)

[ ... instruction dump from insn #7 through #50 are cut out ... ]

51: (b7) r2 = 16
52: (85) call bpf_get_current_comm#16
last_idx 52 first_idx 42
regs=4 stack=0 before 51: (b7) r2 = 16
; bpf_perf_event_output(ctx, &events, BPF_F_CURRENT_CPU,
53: (bf) r1 = r6
54: (18) r2 = 0xffff8881f3868800
56: (18) r3 = 0xffffffff
58: (bf) r4 = r7
59: (b7) r5 = 32
60: (85) call bpf_perf_event_output#25
last_idx 60 first_idx 53
regs=20 stack=0 before 59: (b7) r5 = 32
61: (bf) r2 = r10
; event.pid = pid;
62: (07) r2 += -16
; bpf_map_delete_elem(&start, &pid);
63: (18) r1 = 0xffff8881f3868000
65: (85) call bpf_map_delete_elem#3
; }
66: (b7) r0 = 0
67: (95) exit

from 44 to 66: safe

from 34 to 66: safe

from 11 to 28: R1_w=inv0 R2_w=inv0 R6_w=ctx(id=0,off=0,imm=0) R10=fp0 fp-8=mmmm???? fp-24_w=00000000 fp-32_w=00000000 fp-40_w=00000000 fp-48_w=00000000
; bpf_map_update_elem(&start, &pid, &ts, 0);
28: (bf) r2 = r10
;
29: (07) r2 += -16
; tsp = bpf_map_lookup_elem(&start, &pid);
30: (18) r1 = 0xffff8881f3868000
32: (85) call bpf_map_lookup_elem#1
invalid indirect read from stack off -16+0 size 4
processed 65 insns (limit 1000000) max_states_per_insn 1 total_states 5 peak_states 5 mark_read 4

Notice how there is a successful code path from instruction 0 through 67, few
successfully verified jumps (44->66, 34->66), and only after that 11->28 jump
plus error on instruction #32.

AFTER this change (full verifier log, **no truncation**):

; int handle__sched_switch(u64 *ctx)
0: (bf) r6 = r1
; struct task_struct *prev = (struct task_struct *)ctx[1];
1: (79) r1 = *(u64 *)(r6 +8)
func 'sched_switch' arg1 has btf_id 151 type STRUCT 'task_struct'
2: (b7) r2 = 0
; struct event event = {};
3: (7b) *(u64 *)(r10 -24) = r2
last_idx 3 first_idx 0
regs=4 stack=0 before 2: (b7) r2 = 0
4: (7b) *(u64 *)(r10 -32) = r2
5: (7b) *(u64 *)(r10 -40) = r2
6: (7b) *(u64 *)(r10 -48) = r2
; if (prev->state == TASK_RUNNING)
7: (79) r2 = *(u64 *)(r1 +16)
; if (prev->state == TASK_RUNNING)
8: (55) if r2 != 0x0 goto pc+19
 R1_w=ptr_task_struct(id=0,off=0,imm=0) R2_w=inv0 R6_w=ctx(id=0,off=0,imm=0) R10=fp0 fp-24_w=00000000 fp-32_w=00000000 fp-40_w=00000000 fp-48_w=00000000
; trace_enqueue(prev->tgid, prev->pid);
9: (61) r1 = *(u32 *)(r1 +1184)
10: (63) *(u32 *)(r10 -4) = r1
; if (!pid || (targ_pid && targ_pid != pid))
11: (15) if r1 == 0x0 goto pc+16

from 11 to 28: R1_w=inv0 R2_w=inv0 R6_w=ctx(id=0,off=0,imm=0) R10=fp0 fp-8=mmmm???? fp-24_w=00000000 fp-32_w=00000000 fp-40_w=00000000 fp-48_w=00000000
; bpf_map_update_elem(&start, &pid, &ts, 0);
28: (bf) r2 = r10
;
29: (07) r2 += -16
; tsp = bpf_map_lookup_elem(&start, &pid);
30: (18) r1 = 0xffff8881db3ce800
32: (85) call bpf_map_lookup_elem#1
invalid indirect read from stack off -16+0 size 4
processed 65 insns (limit 1000000) max_states_per_insn 1 total_states 5 peak_states 5 mark_read 4

Notice how in this case, there are 0-11 instructions + jump from 11 to
28 is recorded + 28-32 instructions with error on insn #32.

test_verifier test runner was updated to specify BPF_LOG_LEVEL2 for
VERBOSE_ACCEPT expected result due to potentially "incomplete" success verbose
log at BPF_LOG_LEVEL1.

On success, verbose log will only have a summary of number of processed
instructions, etc, but no branch tracing log. Having just a last succesful
branch tracing seemed weird and confusing. Having small and clean summary log
in success case seems quite logical and nice, though.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200423195850.1259827-1-andriin@fb.com
2020-04-26 09:47:37 -07:00
Maciej Żenczykowski
71d1921477 bpf: add bpf_ktime_get_boot_ns()
On a device like a cellphone which is constantly suspending
and resuming CLOCK_MONOTONIC is not particularly useful for
keeping track of or reacting to external network events.
Instead you want to use CLOCK_BOOTTIME.

Hence add bpf_ktime_get_boot_ns() as a mirror of bpf_ktime_get_ns()
based around CLOCK_BOOTTIME instead of CLOCK_MONOTONIC.

Signed-off-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2020-04-26 09:43:05 -07:00
Maciej Żenczykowski
082b57e3eb net: bpf: Make bpf_ktime_get_ns() available to non GPL programs
The entire implementation is in kernel/bpf/helpers.c:

BPF_CALL_0(bpf_ktime_get_ns) {
       /* NMI safe access to clock monotonic */
       return ktime_get_mono_fast_ns();
}

const struct bpf_func_proto bpf_ktime_get_ns_proto = {
       .func           = bpf_ktime_get_ns,
       .gpl_only       = false,
       .ret_type       = RET_INTEGER,
};

and this was presumably marked GPL due to kernel/time/timekeeping.c:
  EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns);

and while that may make sense for kernel modules (although even that
is doubtful), there is currently AFAICT no other source of time
available to ebpf.

Furthermore this is really just equivalent to clock_gettime(CLOCK_MONOTONIC)
which is exposed to userspace (via vdso even to make it performant)...

As such, I see no reason to keep the GPL restriction.
(In the future I'd like to have access to time from Apache licensed ebpf code)

Signed-off-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2020-04-26 09:04:14 -07:00
Stanislav Fomichev
6890896bd7 bpf: Fix missing bpf_base_func_proto in cgroup_base_func_proto for CGROUP_NET=n
linux-next build bot reported compile issue [1] with one of its
configs. It looks like when we have CONFIG_NET=n and
CONFIG_BPF{,_SYSCALL}=y, we are missing the bpf_base_func_proto
definition (from net/core/filter.c) in cgroup_base_func_proto.

I'm reshuffling the code a bit to make it work. The common helpers
are moved into kernel/bpf/helpers.c and the bpf_base_func_proto is
exported from there.
Also, bpf_get_raw_cpu_id goes into kernel/bpf/core.c akin to existing
bpf_user_rnd_u32.

[1] https://lore.kernel.org/linux-next/CAKH8qBsBvKHswiX1nx40LgO+BGeTmb1NX8tiTttt_0uu6T3dCA@mail.gmail.com/T/#mff8b0c083314c68c2e2ef0211cb11bc20dc13c72

Fixes: 0456ea170cd6 ("bpf: Enable more helpers for BPF_PROG_TYPE_CGROUP_{DEVICE,SYSCTL,SOCKOPT}")
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200424235941.58382-1-sdf@google.com
2020-04-26 08:53:13 -07:00
Stanislav Fomichev
0456ea170c bpf: Enable more helpers for BPF_PROG_TYPE_CGROUP_{DEVICE,SYSCTL,SOCKOPT}
Currently the following prog types don't fall back to bpf_base_func_proto()
(instead they have cgroup_base_func_proto which has a limited set of
helpers from bpf_base_func_proto):
* BPF_PROG_TYPE_CGROUP_DEVICE
* BPF_PROG_TYPE_CGROUP_SYSCTL
* BPF_PROG_TYPE_CGROUP_SOCKOPT

I don't see any specific reason why we shouldn't use bpf_base_func_proto(),
every other type of program (except bpf-lirc and, understandably, tracing)
use it, so let's fall back to bpf_base_func_proto for those prog types
as well.

This basically boils down to adding access to the following helpers:
* BPF_FUNC_get_prandom_u32
* BPF_FUNC_get_smp_processor_id
* BPF_FUNC_get_numa_node_id
* BPF_FUNC_tail_call
* BPF_FUNC_ktime_get_ns
* BPF_FUNC_spin_lock (CAP_SYS_ADMIN)
* BPF_FUNC_spin_unlock (CAP_SYS_ADMIN)
* BPF_FUNC_jiffies64 (CAP_SYS_ADMIN)

I've also added bpf_perf_event_output() because it's really handy for
logging and debugging.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200420174610.77494-1-sdf@google.com
2020-04-26 08:40:01 -07:00
Mao Wenan
b0b3fb6759 bpf: Remove set but not used variable 'dst_known'
Fixes gcc '-Wunused-but-set-variable' warning:

kernel/bpf/verifier.c:5603:18: warning: variable ‘dst_known’
set but not used [-Wunused-but-set-variable], delete this
variable.

Signed-off-by: Mao Wenan <maowenan@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200418013735.67882-1-maowenan@huawei.com
2020-04-26 08:40:01 -07:00
David S. Miller
d483389678 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Simple overlapping changes to linux/vermagic.h

Signed-off-by: David S. Miller <davem@davemloft.net>
2020-04-25 20:18:53 -07:00
Al Viro
ce5155c4f8 compat sysinfo(2): don't bother with field-by-field copyout
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-04-25 18:06:05 -04:00
Linus Torvalds
b2768df24e Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull pid leak fix from Eric Biederman:
 "Oleg noticed that put_pid(thread_pid) was not getting called when proc
  was not compiled in.

  Let's get that fixed before 5.7 is released and causes problems for
  anyone"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  proc: Put thread_pid in release_task not proc_flush_pid
2020-04-25 12:25:32 -07:00
Linus Torvalds
05db498ad9 Misc fixes:
- an uclamp accounting fix
  - three frequency invariance fixes and a readability improvement
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
 -----BEGIN PGP SIGNATURE-----
 
 iQJFBAABCgAvFiEEBpT5eoXrXCwVQwEKEnMQ0APhK1gFAl6kAS8RHG1pbmdvQGtl
 cm5lbC5vcmcACgkQEnMQ0APhK1g0jg//Su8CnWMzOvs4mzqUvzb3OHV6PeQ8BZva
 yI0h8z8V3S33LchwXjb6FI4VulGaGPwLD7tPZtdAdz+wTCnrhw5Rlgfk2thjROW2
 XnWxUACZrAbcH5H88PF0rVp3Z8oaygwlFZCUhvJxLUOgVi4oipNr+0ZNZVATGwO+
 wpCheVKIty6hlMRmNamUDNOB15xFRvXGSQ+kn0N2h/XIvke5f89AJ7uOgTuZ42Ne
 m1vkgX7J29yieLt4yY6odgxlcqlFNAKegpzaadWkEPNOyqkG29pOKwBX7LpuDRVS
 8jd5vo65snKDEQuBkG/CfActJR3GpNT5CVx8wzft7nDb81sEPEPb5sCCURMv5Ig3
 UpEpvzCqYokC2z+ourjtugvilmHq6odwW9XbD/a8i24X+fo13oPg72EVMF7+PLuL
 xZZfhxuQ3hcUGB+H83COEiA8XsNcFxCk7hcHhPyPZeagbGWUTozrwRn/JItAp5Bv
 xkKmqefOu0bZYDGKwP5fMJZ5BmNiWKNw6PyH7lfzL8Ve6dKXlMWMre5cwEUJXPUe
 scpPjvokvZo7C4FTy8U/7cAZlmVy27Y9Ljyf9nROWLp4KewznP3FBdGEv2+IE8uu
 m90vpYXv3Y/4JsLyxg+MMkhnOb26e8vFh6roWQxtPluhWyFlTilmBYovLmFz2RBO
 eqpS9MVBuRs=
 =5Wor
 -----END PGP SIGNATURE-----

Merge tag 'sched-urgent-2020-04-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fixes from Ingo Molnar:
 "Misc fixes:

   - an uclamp accounting fix

   - three frequency invariance fixes and a readability improvement"

* tag 'sched-urgent-2020-04-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/core: Fix reset-on-fork from RT with uclamp
  x86, sched: Move check for CPU type to caller function
  x86, sched: Don't enable static key when starting secondary CPUs
  x86, sched: Account for CPUs with less than 4 cores in freq. invariance
  x86, sched: Bail out of frequency invariance if base frequency is unknown
2020-04-25 12:11:47 -07:00
Linus Torvalds
e18588005d Two changes:
- fix exit event records
  - extend x86 PMU driver enumeration to add Intel Jasper Lake CPU support.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
 -----BEGIN PGP SIGNATURE-----
 
 iQJFBAABCgAvFiEEBpT5eoXrXCwVQwEKEnMQ0APhK1gFAl6j/jURHG1pbmdvQGtl
 cm5lbC5vcmcACgkQEnMQ0APhK1hpjg/+L0FTvxUj42qaknksSGhPrIa6aKNSfsHe
 zSG4WsN59E8XUOuB9SV3D/VDJ7rX7w8jEub/TpWqLJll+UiPE3B0oLOwlVhX+8nc
 fDfIqONA6ZoKvfMG9HUXPUo1Lr2+RtcF06hZFWx56g2ijqe5da1CdniJUv1YPb5s
 K4HFU6Xuitih5QrYoLOiATQdp0/W1cjG36irF4svmjrxXotmeWsp7SDlAsAP2hgw
 D7VchYMVs2bWtVL4GyBkq/+EOhvHwp5PTjF3yz7Scy9+CFitL9Bp5DGkaBolpszK
 mUKwstXjbePw28r0jlfLJaptti2ZTFd5r4Ywqyh374ct8JbsdLR77v9Uo6M9VHu8
 9la9cmz+KUnTtz2Bl2dkj2DClh+p4k9VbRjTyrAIobo6WbX8hTYKJmLn/ehvOWqU
 nPJL1bRtkx4s4tIS+oXnVOOSYdcWEvcbduxmuh1eRP3wlDb06AUZCR6JaUErd6bd
 oYFwrZg9vncscKEQM7boQI8f6PhwloZFnGPbPdXgCNarFdCEugCc57s2NvG4BUFo
 WykXYcOGxoANO3F478e/h52cjOoZNk0trdlAk9z957GcI+g+xwoMXWZf8nMUrlWx
 qrtJmEJlde5sN+5j1X75wjJovOIXBmZH9yXWYgZ+kkmASpqeKQvRkbH+eZBBDBuU
 EHNMzUenU0o=
 =pEo5
 -----END PGP SIGNATURE-----

Merge tag 'perf-urgent-2020-04-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf fixes from Ingo Molnar:
 "Two changes:

   - fix exit event records

   - extend x86 PMU driver enumeration to add Intel Jasper Lake CPU
     support"

* tag 'perf-urgent-2020-04-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: fix parent pid/tid in task exit events
  perf/x86/cstate: Add Jasper Lake CPU support
2020-04-25 12:08:24 -07:00
Peter Collingbourne
298f3db6ee dma-contiguous: fix comment for dma_release_from_contiguous
Commit 90ae409f9eb3 ("dma-direct: fix zone selection
after an unaddressable CMA allocation") changed the logic in
dma_release_from_contiguous to remove the normal pages fallback path,
but did not update the comment. Fix that.

Signed-off-by: Peter Collingbourne <pcc@google.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-04-25 13:17:06 +02:00
David Rientjes
1d659236fb dma-pool: scale the default DMA coherent pool size with memory capacity
When AMD memory encryption is enabled, some devices may use more than
256KB/sec from the atomic pools.  It would be more appropriate to scale
the default size based on memory capacity unless the coherent_pool
option is used on the kernel command line.

This provides a slight optimization on initial expansion and is deemed
appropriate due to the increased reliance on the atomic pools.  Note that
the default size of 128KB per pool will normally be larger than the
single coherent pool implementation since there are now up to three
coherent pools (DMA, DMA32, and kernel).

Note that even prior to this patch, coherent_pool= for sizes larger than
1 << (PAGE_SHIFT + MAX_ORDER-1) can fail.  With new dynamic expansion
support, this would be trivially extensible to allow even larger initial
sizes.

Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-04-25 13:17:06 +02:00
David Rientjes
2edc5bb3c5 dma-pool: add pool sizes to debugfs
The atomic DMA pools can dynamically expand based on non-blocking
allocations that need to use it.

Export the sizes of each of these pools, in bytes, through debugfs for
measurement.

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Rientjes <rientjes@google.com>
[hch: remove the !CONFIG_DEBUG_FS stubs]
Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-04-25 13:17:05 +02:00
David Rientjes
76a19940bd dma-direct: atomic allocations must come from atomic coherent pools
When a device requires unencrypted memory and the context does not allow
blocking, memory must be returned from the atomic coherent pools.

This avoids the remap when CONFIG_DMA_DIRECT_REMAP is not enabled and the
config only requires CONFIG_DMA_COHERENT_POOL.  This will be used for
CONFIG_AMD_MEM_ENCRYPT in a subsequent patch.

Keep all memory in these pools unencrypted.  When set_memory_decrypted()
fails, this prohibits the memory from being added.  If adding memory to
the genpool fails, and set_memory_encrypted() subsequently fails, there
is no alternative other than leaking the memory.

Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-04-25 13:17:05 +02:00
David Rientjes
54adadf9b0 dma-pool: dynamically expanding atomic pools
When an atomic pool becomes fully depleted because it is now relied upon
for all non-blocking allocations through the DMA API, allow background
expansion of each pool by a kworker.

When an atomic pool has less than the default size of memory left, kick
off a kworker to dynamically expand the pool in the background.  The pool
is doubled in size, up to MAX_ORDER-1.  If memory cannot be allocated at
the requested order, smaller allocation(s) are attempted.

This allows the default size to be kept quite low when one or more of the
atomic pools is not used.

Allocations for lowmem should also use GFP_KERNEL for the benefits of
reclaim, so use GFP_KERNEL | GFP_DMA and GFP_KERNEL | GFP_DMA32 for
lowmem allocations.

This also allows __dma_atomic_pool_init() to return a pointer to the pool
to make initialization cleaner.

Also switch over some node ids to the more appropriate NUMA_NO_NODE.

Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-04-25 13:17:02 +02:00
Linus Torvalds
ab51cac00e Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from David Miller:

 1) Fix memory leak in netfilter flowtable, from Roi Dayan.

 2) Ref-count leaks in netrom and tipc, from Xiyu Yang.

 3) Fix warning when mptcp socket is never accepted before close, from
    Florian Westphal.

 4) Missed locking in ovs_ct_exit(), from Tonghao Zhang.

 5) Fix large delays during PTP synchornization in cxgb4, from Rahul
    Lakkireddy.

 6) team_mode_get() can hang, from Taehee Yoo.

 7) Need to use kvzalloc() when allocating fw tracer in mlx5 driver,
    from Niklas Schnelle.

 8) Fix handling of bpf XADD on BTF memory, from Jann Horn.

 9) Fix BPF_STX/BPF_B encoding in x86 bpf jit, from Luke Nelson.

10) Missing queue memory release in iwlwifi pcie code, from Johannes
    Berg.

11) Fix NULL deref in macvlan device event, from Taehee Yoo.

12) Initialize lan87xx phy correctly, from Yuiko Oshino.

13) Fix looping between VRF and XFRM lookups, from David Ahern.

14) etf packet scheduler assumes all sockets are full sockets, which is
    not necessarily true. From Eric Dumazet.

15) Fix mptcp data_fin handling in RX path, from Paolo Abeni.

16) fib_select_default() needs to handle nexthop objects, from David
    Ahern.

17) Use GFP_ATOMIC under spinlock in mac80211_hwsim, from Wei Yongjun.

18) vxlan and geneve use wrong nlattr array, from Sabrina Dubroca.

19) Correct rx/tx stats in bcmgenet driver, from Doug Berger.

20) BPF_LDX zero-extension is encoded improperly in x86_32 bpf jit, fix
    from Luke Nelson.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (100 commits)
  selftests/bpf: Fix a couple of broken test_btf cases
  tools/runqslower: Ensure own vmlinux.h is picked up first
  bpf: Make bpf_link_fops static
  bpftool: Respect the -d option in struct_ops cmd
  selftests/bpf: Add test for freplace program with expected_attach_type
  bpf: Propagate expected_attach_type when verifying freplace programs
  bpf: Fix leak in LINK_UPDATE and enforce empty old_prog_fd
  bpf, x86_32: Fix logic error in BPF_LDX zero-extension
  bpf, x86_32: Fix clobbering of dst for BPF_JSET
  bpf, x86_32: Fix incorrect encoding in BPF_LDX zero-extension
  bpf: Fix reStructuredText markup
  net: systemport: suppress warnings on failed Rx SKB allocations
  net: bcmgenet: suppress warnings on failed Rx SKB allocations
  macsec: avoid to set wrong mtu
  mac80211: sta_info: Add lockdep condition for RCU list usage
  mac80211: populate debugfs only after cfg80211 init
  net: bcmgenet: correct per TX/RX ring statistics
  net: meth: remove spurious copyright text
  net: phy: bcm84881: clear settings on link down
  chcr: Fix CPU hard lockup
  ...
2020-04-24 19:17:30 -07:00
Zou Wei
6f302bfb22 bpf: Make bpf_link_fops static
Fix the following sparse warning:

kernel/bpf/syscall.c:2289:30: warning: symbol 'bpf_link_fops' was not declared. Should it be static?

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zou Wei <zou_wei@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/1587609160-117806-1-git-send-email-zou_wei@huawei.com
2020-04-24 17:42:44 -07:00