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About 40% of all csd_lock warnings observed in our fleet appear to
be due to sched_clock() going backward in time (usually only a little
bit), resulting in ts0 being larger than ts2.
When the local CPU is at fault, we should print out a message reflecting
that, rather than trying to get the remote CPU's stack trace.
Signed-off-by: Rik van Riel <riel@surriel.com>
Tested-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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Currently, the CSD-lock diagnostics in CONFIG_CSD_LOCK_WAIT_DEBUG=y
kernels are emitted at five-second intervals. Although this has proven
to be a good time interval for the first diagnostic, if the target CPU
keeps interrupts disabled for way longer than five seconds, the ratio
of useful new information to pointless repetition increases considerably.
Therefore, back off the time period for repeated reports of the same
incident, increasing linearly with the number of reports and logarithmicly
with the number of online CPUs.
[ paulmck: Apply Dan Carpenter feedback. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Imran Khan <imran.f.khan@oracle.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Leonardo Bras <leobras@redhat.com>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Reviewed-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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If a CSD-lock stall goes on long enough, it will cause an RCU CPU
stall warning. This additional warning provides much additional
console-log traffic and little additional information. Therefore,
provide a new csd_lock_is_stuck() function that returns true if there
is an ongoing CSD-lock stall. This function will be used by the RCU
CPU stall warnings to provide a one-line indication of the stall when
this function returns true.
[ neeraj.upadhyay: Apply Rik van Riel feedback. ]
[ neeraj.upadhyay: Apply kernel test robot feedback. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Imran Khan <imran.f.khan@oracle.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Leonardo Bras <leobras@redhat.com>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs fixes from Christian Brauner:
"VFS:
- Fix the name of file lease slab cache. When file leases were split
out of file locks the name of the file lock slab cache was used for
the file leases slab cache as well.
- Fix a type in take_fd() helper.
- Fix infinite directory iteration for stable offsets in tmpfs.
- When the icache is pruned all reclaimable inodes are marked with
I_FREEING and other processes that try to lookup such inodes will
block.
But some filesystems like ext4 can trigger lookups in their inode
evict callback causing deadlocks. Ext4 does such lookups if the
ea_inode feature is used whereby a separate inode may be used to
store xattrs.
Introduce I_LRU_ISOLATING which pins the inode while its pages are
reclaimed. This avoids inode deletion during inode_lru_isolate()
avoiding the deadlock and evict is made to wait until
I_LRU_ISOLATING is done.
netfs:
- Fault in smaller chunks for non-large folio mappings for
filesystems that haven't been converted to large folios yet.
- Fix the CONFIG_NETFS_DEBUG config option. The config option was
renamed a short while ago and that introduced two minor issues.
First, it depended on CONFIG_NETFS whereas it wants to depend on
CONFIG_NETFS_SUPPORT. The former doesn't exist, while the latter
does. Second, the documentation for the config option wasn't fixed
up.
- Revert the removal of the PG_private_2 writeback flag as ceph is
using it and fix how that flag is handled in netfs.
- Fix DIO reads on 9p. A program watching a file on a 9p mount
wouldn't see any changes in the size of the file being exported by
the server if the file was changed directly in the source
filesystem. Fix this by attempting to read the full size specified
when a DIO read is requested.
- Fix a NULL pointer dereference bug due to a data race where a
cachefiles cookies was retired even though it was still in use.
Check the cookie's n_accesses counter before discarding it.
nsfs:
- Fix ioctl declaration for NS_GET_MNTNS_ID from _IO() to _IOR() as
the kernel is writing to userspace.
pidfs:
- Prevent the creation of pidfds for kthreads until we have a
use-case for it and we know the semantics we want. It also confuses
userspace why they can get pidfds for kthreads.
squashfs:
- Fix an unitialized value bug reported by KMSAN caused by a
corrupted symbolic link size read from disk. Check that the
symbolic link size is not larger than expected"
* tag 'vfs-6.11-rc4.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
Squashfs: sanity check symbolic link size
9p: Fix DIO read through netfs
vfs: Don't evict inode under the inode lru traversing context
netfs: Fix handling of USE_PGPRIV2 and WRITE_TO_CACHE flags
netfs, ceph: Revert "netfs: Remove deprecated use of PG_private_2 as a second writeback flag"
file: fix typo in take_fd() comment
pidfd: prevent creation of pidfds for kthreads
netfs: clean up after renaming FSCACHE_DEBUG config
libfs: fix infinite directory reads for offset dir
nsfs: fix ioctl declaration
fs/netfs/fscache_cookie: add missing "n_accesses" check
filelock: fix name of file_lease slab cache
netfs: Fault in smaller chunks for non-large folio mappings
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This commit uses the new rcu_tasks_torture_stats_print(),
rcu_tasks_trace_torture_stats_print(), and
rcu_tasks_rude_torture_stats_print() functions in order to provide
detailed diagnostics on grace-period, callback, and barrier state when
rcu_scale_writer() hangs.
[ paulmck: Apply kernel test robot feedback. ]
Signed-off-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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RCU keeps a count of the number of callbacks that the current
rcu_barrier() is waiting on, but there is currently no easy way to
work out which callback is stuck. One way to do this is to mark idle
RCU-barrier callbacks by making the ->next pointer point to the callback
itself, and this commit does just that.
Later commits will use this for debug output.
Signed-off-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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This commit adds a .stats function pointer to the rcu_scale_ops structure,
and if this is non-NULL, it is invoked after stack traces are dumped in
response to a rcu_scale_writer() stall.
Signed-off-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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This commit improves debuggability by dumping the stacks of
rcu_scale_writer() instances that have not completed in a reasonable
timeframe. These stacks are dumped remotely, but they will be accurate
in the thus-far common case where the stalled rcu_scale_writer() instances
are blocked.
[ paulmck: Apply kernel test robot feedback. ]
Signed-off-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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This whitespace-only commit fuses a few lines of code, taking advantage
of the newish 100-character-per-line limit to save a few lines of code.
Signed-off-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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process_durations() is not a hot path, but there is no good reason to
iterate over and over the data already in 'buf'.
Using a seq_buf saves some useless strcat() and the need of a temp buffer.
Data is written directly at the correct place.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Tested-by: "Paul E. McKenney" <paulmck@kernel.org>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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This commit adds the start time, in jiffies, of the most recently started
rcu_barrier_tasks*() operation to the diagnostic output used by rcuscale.
This information can be helpful in distinguishing a hung barrier operation
from a long series of barrier operations.
Signed-off-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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This commit adds rcu_tasks_torture_stats_print(),
rcu_tasks_trace_torture_stats_print(), and
rcu_tasks_rude_torture_stats_print() functions that provide detailed
diagnostics on grace-period, callback, and barrier state.
Signed-off-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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Each Tasks RCU flavor keeps a count of the number of callbacks that the
current rcu_barrier_tasks*() is waiting on, but there is currently no
easy way to work out which callback is stuck. One way to do this is to
mark idle RCU-barrier callbacks by making the ->next pointer point to
the callback itself, and this commit does just that.
Later commits will use this for debug output.
Signed-off-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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This commit provides a rcu_barrier_cb_is_done() function that returns
true if the *rcu_barrier*() callback passed in is done. This will be
used when printing grace-period debugging information.
Signed-off-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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The rtp->tasks_gp_seq grace-period sequence number is not a strict count,
but rather the usual RCU sequence number with the lower few bits tracking
per-grace-period state and the upper bits the count of grace periods
since boot, give or take the initial value. This commit therefore
adjusts this comment.
Signed-off-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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The current mapping of smp_processor_id() to a CPU processing Tasks-RCU
callbacks makes some assumptions about layout. This commit therefore
adds a WARN_ON() to check these assumptions.
[ neeraj.upadhyay: Replace nr_cpu_ids with rcu_task_cpu_ids. ]
Signed-off-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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rcu_tasks_need_gpcb()
For kernels built with CONFIG_FORCE_NR_CPUS=y, the nr_cpu_ids is
defined as NR_CPUS instead of the number of possible cpus, this
will cause the following system panic:
smpboot: Allowing 4 CPUs, 0 hotplug CPUs
...
setup_percpu: NR_CPUS:512 nr_cpumask_bits:512 nr_cpu_ids:512 nr_node_ids:1
...
BUG: unable to handle page fault for address: ffffffff9911c8c8
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 0 PID: 15 Comm: rcu_tasks_trace Tainted: G W
6.6.21 #1 5dc7acf91a5e8e9ac9dcfc35bee0245691283ea6
RIP: 0010:rcu_tasks_need_gpcb+0x25d/0x2c0
RSP: 0018:ffffa371c00a3e60 EFLAGS: 00010082
CR2: ffffffff9911c8c8 CR3: 000000040fa20005 CR4: 00000000001706f0
Call Trace:
<TASK>
? __die+0x23/0x80
? page_fault_oops+0xa4/0x180
? exc_page_fault+0x152/0x180
? asm_exc_page_fault+0x26/0x40
? rcu_tasks_need_gpcb+0x25d/0x2c0
? __pfx_rcu_tasks_kthread+0x40/0x40
rcu_tasks_one_gp+0x69/0x180
rcu_tasks_kthread+0x94/0xc0
kthread+0xe8/0x140
? __pfx_kthread+0x40/0x40
ret_from_fork+0x34/0x80
? __pfx_kthread+0x40/0x40
ret_from_fork_asm+0x1b/0x80
</TASK>
Considering that there may be holes in the CPU numbers, use the
maximum possible cpu number, instead of nr_cpu_ids, for configuring
enqueue and dequeue limits.
[ neeraj.upadhyay: Fix htmldocs build error reported by Stephen Rothwell ]
Closes: https://lore.kernel.org/linux-input/CALMA0xaTSMN+p4xUXkzrtR5r6k7hgoswcaXx7baR_z9r5jjskw@mail.gmail.com/T/#u
Reported-by: Zhixu Liu <zhixu.liu@gmail.com>
Signed-off-by: Zqiang <qiang.zhang1211@gmail.com>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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The call_rcu_tasks_rude() and rcu_barrier_tasks_rude() APIs are currently
unused. This commit therefore removes their definitions and boot-time
self-tests.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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The call_rcu_tasks_rude() and rcu_barrier_tasks_rude() APIs are currently
unused. Furthermore, the idea is to get rid of RCU Tasks Rude entirely
once all architectures have their deep-idle and entry/exit code correctly
marked as inline or noinstr. As a step towards this goal, this commit
therefore removes these two functions from rcuscale testing.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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The call_rcu_tasks_rude() and rcu_barrier_tasks_rude() APIs are currently
unused. Furthermore, the idea is to get rid of RCU Tasks Rude entirely
once all architectures have their deep-idle and entry/exit code correctly
marked as inline or noinstr. As a first step towards this goal, this
commit therefore removes these two functions from rcutorture testing.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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This commit adds an stall_cpu_repeat kernel, which is also the
rcutorture.stall_cpu_repeat boot parameter, to test repeated CPU stalls.
Note that only the first stall will pay attention to the stall_cpu_irqsoff
module parameter. For the second and subsequent stalls, interrupts will
be enabled. This is helpful when testing the interaction between RCU
CPU stall warnings and CSD-lock stall warnings.
Reported-by: Rik van Riel <riel@surriel.com>
Signed-off-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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The two hrtimer_cpu_base_.*_expiry() functions are wrappers around the
locking functions and sparse complains about the missing counterpart.
Add sparse annotation to denote that this bevaviour is expected.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240812105326.2240000-3-bigeasy@linutronix.de
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timer_sync_wait_running() first releases two locks and then acquires
them again. This is unexpected and sparse complains about it.
Add sparse annotation for timer_sync_wait_running() to note that the
locking is expected.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240812105326.2240000-2-bigeasy@linutronix.de
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Commit 558abc7e3f89 ("perf: Fix event_function_call() locking") lost
IRQ disabling by mistake.
Fixes: 558abc7e3f89 ("perf: Fix event_function_call() locking")
Reported-by: Pengfei Xu <pengfei.xu@intel.com>
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Tested-by: Pengfei Xu <pengfei.xu@intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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consume_remote_task() and dispatch_to_local_dsq() use
move_task_to_local_dsq() to migrate the task to the target CPU. Currently,
move_task_to_local_dsq() expects the caller to lock both the source and
destination rq's. While this may save a few lock operations while the rq's
are not contended, under contention, the double locking can exacerbate the
situation significantly (refer to the linked message below).
Update the migration path so that double locking is not used.
move_task_to_local_dsq() now expects the caller to be locking the source rq,
drops it and then acquires the destination rq lock. Code is simpler this way
and, on a 2-way NUMA machine w/ Xeon Gold 6138, 'hackbench 100 thread 5000`
shows ~3% improvement with scx_simple.
Signed-off-by: Tejun Heo <tj@kernel.org>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20240806082716.GP37996@noisy.programming.kicks-ass.net
Acked-by: David Vernet <void@manifault.com>
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Add an interface for a user-defined workqueue lockdep map, which is
helpful when multiple workqueues are created for the same purpose. This
also helps avoid leaking lockdep maps on each workqueue creation.
v2:
- Add alloc_workqueue_lockdep_map (Tejun)
v3:
- Drop __WQ_USER_OWNED_LOCKDEP (Tejun)
- static inline alloc_ordered_workqueue_lockdep_map (Tejun)
Cc: Tejun Heo <tj@kernel.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Will help enable user-defined lockdep maps for workqueues.
Cc: Tejun Heo <tj@kernel.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Will help enable user-defined lockdep maps for workqueues.
Cc: Tejun Heo <tj@kernel.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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`__bpf_ops_sched_ext_ops` was missing the initialization of some struct
attributes. With
https://lore.kernel.org/all/20240722183049.2254692-4-martin.lau@linux.dev/
every single attributes need to be initialized programs (like scx_layered)
will fail to load.
05:26:48 [INFO] libbpf: struct_ops layered: member cgroup_init not found in kernel, skipping it as it's set to zero
05:26:48 [INFO] libbpf: struct_ops layered: member cgroup_exit not found in kernel, skipping it as it's set to zero
05:26:48 [INFO] libbpf: struct_ops layered: member cgroup_prep_move not found in kernel, skipping it as it's set to zero
05:26:48 [INFO] libbpf: struct_ops layered: member cgroup_move not found in kernel, skipping it as it's set to zero
05:26:48 [INFO] libbpf: struct_ops layered: member cgroup_cancel_move not found in kernel, skipping it as it's set to zero
05:26:48 [INFO] libbpf: struct_ops layered: member cgroup_set_weight not found in kernel, skipping it as it's set to zero
05:26:48 [WARN] libbpf: prog 'layered_dump': BPF program load failed: unknown error (-524)
05:26:48 [WARN] libbpf: prog 'layered_dump': -- BEGIN PROG LOAD LOG --
attach to unsupported member dump of struct sched_ext_ops
processed 0 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0
-- END PROG LOAD LOG --
05:26:48 [WARN] libbpf: prog 'layered_dump': failed to load: -524
05:26:48 [WARN] libbpf: failed to load object 'bpf_bpf'
05:26:48 [WARN] libbpf: failed to load BPF skeleton 'bpf_bpf': -524
Error: Failed to load BPF program
Signed-off-by: Manu Bretelle <chantr4@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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The regressing commit is new in 6.10. It assumed that anytime event->prog
is set bpf_overflow_handler() should be invoked to execute the attached bpf
program. This assumption is false for tracing events, and as a result the
regressing commit broke bpftrace by invoking the bpf handler with garbage
inputs on overflow.
Prior to the regression the overflow handlers formed a chain (of length 0,
1, or 2) and perf_event_set_bpf_handler() (the !tracing case) added
bpf_overflow_handler() to that chain, while perf_event_attach_bpf_prog()
(the tracing case) did not. Both set event->prog. The chain of overflow
handlers was replaced by a single overflow handler slot and a fixed call to
bpf_overflow_handler() when appropriate. This modifies the condition there
to check event->prog->type == BPF_PROG_TYPE_PERF_EVENT, restoring the
previous behavior and fixing bpftrace.
Signed-off-by: Kyle Huey <khuey@kylehuey.com>
Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Reported-by: Joe Damato <jdamato@fastly.com>
Closes: https://lore.kernel.org/lkml/ZpFfocvyF3KHaSzF@LQ3V64L9R2/
Fixes: f11f10bfa1ca ("perf/bpf: Call BPF handler directly, not through overflow machinery")
Cc: stable@vger.kernel.org
Tested-by: Joe Damato <jdamato@fastly.com> # bpftrace
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240813151727.28797-1-jdamato@fastly.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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commit 779dbc2e78d7 ("printk: Avoid non-panic CPUs writing
to ringbuffer") disabled non-panic CPUs to further write messages to
ringbuffer after panicked.
Since the commit, non-panicked CPU's are not allowed to write to
ring buffer after panicked and CPU backtrace which is triggered
after panicked to sample non-panicked CPUs' backtrace no longer
serves its function as it has nothing to print.
Fix the issue by allowing non-panicked CPUs to write into ringbuffer
while CPU backtrace is in flight.
Fixes: 779dbc2e78d7 ("printk: Avoid non-panic CPUs writing to ringbuffer")
Signed-off-by: Ryo Takakura <takakura@valinux.co.jp>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20240812072703.339690-1-takakura@valinux.co.jp
Signed-off-by: Petr Mladek <pmladek@suse.com>
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When the domain suffix is not supplied alloc_fwnode_name() unconditionally
adds a separator.
Fix the format strings to get rid of the stray '-' separator.
Fixes: 1e7c05292531 ("irqdomain: Allow giving name suffix for domain")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240812193101.1266625-3-andriy.shevchenko@linux.intel.com
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The code uses if (bus_token) and if (bus_token == DOMAIN_BUS_ANY).
Since bus_token is an enum, the latter is more robust against changes.
Convert all !bus_token checks to explicitely check for DOMAIN_BUS_ANY.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240812193101.1266625-2-andriy.shevchenko@linux.intel.com
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We want the compiler to see that fdput() on empty instance
is a no-op. The emptiness check is that file reference is NULL,
while fdput() is "fput() if FDPUT_FPUT is present in flags".
The reason why fdput() on empty instance is a no-op is something
compiler can't see - it's that we never generate instances with
NULL file reference combined with non-zero flags.
It's not that hard to deal with - the real primitives behind
fdget() et.al. are returning an unsigned long value, unpacked by (inlined)
__to_fd() into the current struct file * + int. The lower bits are
used to store flags, while the rest encodes the pointer. Linus suggested
that keeping this unsigned long around with the extractions done by inlined
accessors should generate a sane code and that turns out to be the case.
Namely, turning struct fd into a struct-wrapped unsinged long, with
fd_empty(f) => unlikely(f.word == 0)
fd_file(f) => (struct file *)(f.word & ~3)
fdput(f) => if (f.word & 1) fput(fd_file(f))
ends up with compiler doing the right thing. The cost is the patch
footprint, of course - we need to switch f.file to fd_file(f) all over
the tree, and it's not doable with simple search and replace; there are
false positives, etc.
Note that the sole member of that structure is an opaque
unsigned long - all accesses should be done via wrappers and I don't
want to use a name that would invite manual casts to file pointers,
etc. The value of that member is equal either to (unsigned long)p | flags,
p being an address of some struct file instance, or to 0 for an empty fd.
For now the new predicate (fd_empty(f)) has no users; all the
existing checks have form (!fd_file(f)). We will convert to fd_empty()
use later; here we only define it (and tell the compiler that it's
unlikely to return true).
This commit only deals with representation change; there will
be followups.
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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For any changes of struct fd representation we need to
turn existing accesses to fields into calls of wrappers.
Accesses to struct fd::flags are very few (3 in linux/file.h,
1 in net/socket.c, 3 in fs/overlayfs/file.c and 3 more in
explicit initializers).
Those can be dealt with in the commit converting to
new layout; accesses to struct fd::file are too many for that.
This commit converts (almost) all of f.file to
fd_file(f). It's not entirely mechanical ('file' is used as
a member name more than just in struct fd) and it does not
even attempt to distinguish the uses in pointer context from
those in boolean context; the latter will be eventually turned
into a separate helper (fd_empty()).
NOTE: mass conversion to fd_empty(), tempting as it
might be, is a bad idea; better do that piecewise in commit
that convert from fdget...() to CLASS(...).
[conflicts in fs/fhandle.c, kernel/bpf/syscall.c, mm/memcontrol.c
caught by git; fs/stat.c one got caught by git grep]
[fs/xattr.c conflict]
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Daniel Hodges reported a kernel verifier crash when playing with sched-ext.
Further investigation shows that the crash is due to invalid memory access
in stacksafe(). More specifically, it is the following code:
if (exact != NOT_EXACT &&
old->stack[spi].slot_type[i % BPF_REG_SIZE] !=
cur->stack[spi].slot_type[i % BPF_REG_SIZE])
return false;
The 'i' iterates old->allocated_stack.
If cur->allocated_stack < old->allocated_stack the out-of-bound
access will happen.
To fix the issue add 'i >= cur->allocated_stack' check such that if
the condition is true, stacksafe() should fail. Otherwise,
cur->stack[spi].slot_type[i % BPF_REG_SIZE] memory access is legal.
Fixes: 2793a8b015f7 ("bpf: exact states comparison for iterator convergence checks")
Cc: Eduard Zingerman <eddyz87@gmail.com>
Reported-by: Daniel Hodges <hodgesd@meta.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240812214847.213612-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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If a core is offline then enabling SMT should not online CPUs of
this core. By enabling SMT, what is intended is either changing the SMT
value from "off" to "on" or setting the SMT level (threads per core) from a
lower to higher value.
On PowerPC the ppc64_cpu utility can be used, among other things, to
perform the following functions:
ppc64_cpu --cores-on # Get the number of online cores
ppc64_cpu --cores-on=X # Put exactly X cores online
ppc64_cpu --offline-cores=X[,Y,...] # Put specified cores offline
ppc64_cpu --smt={on|off|value} # Enable, disable or change SMT level
If the user has decided to offline certain cores, enabling SMT should
not online CPUs in those cores. This patch fixes the issue and changes
the behaviour as described, by introducing an arch specific function
topology_is_core_online(). It is currently implemented only for PowerPC.
Fixes: 73c58e7e1412 ("powerpc: Add HOTPLUG_SMT support")
Reported-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Closes: https://groups.google.com/g/powerpc-utils-devel/c/wrwVzAAnRlI/m/5KJSoqP4BAAJ
Signed-off-by: Nysal Jan K.A <nysal@linux.ibm.com>
Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240731030126.956210-2-nysal@linux.ibm.com
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It's currently possible to create pidfds for kthreads but it is unclear
what that is supposed to mean. Until we have use-cases for it and we
figured out what behavior we want block the creation of pidfds for
kthreads.
Link: https://lore.kernel.org/r/20240731-gleis-mehreinnahmen-6bbadd128383@brauner
Fixes: 32fcb426ec00 ("pid: add pidfd_open()")
Cc: stable@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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SRCU keeps a count of the number of callbacks that the current
srcu_barrier() is waiting on, but there is currently no easy way to
work out which callback is stuck. One way to do this is to mark idle
SRCU-barrier callbacks by making the ->next pointer point to the callback
itself, and this commit does just that.
Later commits will use this for debug output.
Signed-off-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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SRCU maintains the ->srcu_n_exp_nodelay and ->reschedule_count values
to guide heuristics governing auto-expediting of normal SRCU grace
periods and grace-period-state-machine delays. This commit adds KCSAN
ASSERT_EXCLUSIVE_WRITER() calls to check for concurrent updates to
these fields.
Signed-off-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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Using a higher value for the initial gp sequence counters allows for
wrapping to occur faster. It can help with surfacing any issues that may
be happening as a result of the wrap around.
Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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It was discovered that isolated CPUs could sometimes be disturbed by
kworkers processing kfree_rcu() works causing higher than expected
latency. It is because the RCU core uses "system_wq" which doesn't have
the WQ_UNBOUND flag to handle all its work items. Fix this violation of
latency limits by using "system_unbound_wq" in the RCU core instead.
This will ensure that those work items will not be run on CPUs marked
as isolated.
Beside the WQ_UNBOUND flag, the other major difference between system_wq
and system_unbound_wq is their max_active count. The system_unbound_wq
has a max_active of WQ_MAX_ACTIVE (512) while system_wq's max_active
is WQ_DFL_ACTIVE (256) which is half of WQ_MAX_ACTIVE.
Reported-by: Vratislav Bendel <vbendel@redhat.com>
Closes: https://issues.redhat.com/browse/RHEL-50220
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Tested-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull time keeping fixes from Thomas Gleixner:
- Fix a couple of issues in the NTP code where user supplied values are
neither sanity checked nor clamped to the operating range. This
results in integer overflows and eventualy NTP getting out of sync.
According to the history the sanity checks had been removed in favor
of clamping the values, but the clamping never worked correctly under
all circumstances. The NTP people asked to not bring the sanity
checks back as it might break existing applications.
Make the clamping work correctly and add it where it's missing
- If adjtimex() sets the clock it has to trigger the hrtimer subsystem
so it can adjust and if the clock was set into the future expire
timers if needed. The caller should provide a bitmask to tell
hrtimers which clocks have been adjusted.
adjtimex() uses not the proper constant and uses CLOCK_REALTIME
instead, which is 0. So hrtimers adjusts only the clocks, but does
not check for expired timers, which might make them expire really
late. Use the proper bitmask constant instead.
* tag 'timers-urgent-2024-08-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timekeeping: Fix bogus clock_was_set() invocation in do_adjtimex()
ntp: Safeguard against time_constant overflow
ntp: Clamp maxerror and esterror to operating range
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq fixes from Thomas Gleixner:
"Three small fixes for interrupt core and drivers:
- The interrupt core fails to honor caller supplied affinity hints
for non-managed interrupts and uses the system default affinity on
startup instead. Set the missing flag in the descriptor to tell the
core to use the provided affinity.
- Fix a shift out of bounds error in the Xilinx driver
- Handle switching to level trigger correctly in the RISCV APLIC
driver. It failed to retrigger the interrupt which causes it to
become stale"
* tag 'irq-urgent-2024-08-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip/riscv-aplic: Retrigger MSI interrupt on source configuration
irqchip/xilinx: Fix shift out of bounds
genirq/irqdesc: Honor caller provided affinity in alloc_desc()
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Add the __counted_by compiler attribute to the flexible array member
records to improve access bounds-checking via CONFIG_UBSAN_BOUNDS and
CONFIG_FORTIFY_SOURCE.
Increment nr_records before adding a new pointer to the records array.
Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Reviewed-by: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Reviewed-by: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, and the 'dynticks' prefix can be dropped without losing any
meaning.
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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ct_nmi_nesting_cpu()
The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, and the 'dynticks' prefix can be dropped without losing any
meaning.
Suggested-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, and the 'dynticks' prefix can be dropped without losing any
meaning.
Suggested-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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into .nmi_nesting
The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, and the 'dynticks' prefix can be dropped without losing any
meaning.
[ neeraj.upadhyay: Fix htmldocs build error reported by Stephen Rothwell ]
Suggested-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, and the 'dynticks' prefix can be dropped without losing any
meaning.
Suggested-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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