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Steven Rostedt 858fa8a3b0 unwind: Add USED bit to only have one conditional on way back to user space 
On the way back to user space, the function unwind_reset_info() is called
unconditionally (but always inlined). It currently has two conditionals.
One that checks the unwind_mask which is set whenever a deferred trace is
called and is used to know that the mask needs to be cleared. The other
checks if the cache has been allocated, and if so, it resets the
nr_entries so that the unwinder knows it needs to do the work to get a new
user space stack trace again (it only does it once per entering the
kernel).

Use one of the bits in the unwind mask as a "USED" bit that gets set
whenever a trace is created. This will make it possible to only check the
unwind_mask in the unwind_reset_info() to know if it needs to do work or
not and eliminates a conditional that happens every time the task goes
back to user space.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Indu Bhagat <indu.bhagat@oracle.com>
Cc: "Jose E. Marchesi" <jemarch@gnu.org>
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Jens Remus <jremus@linux.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Sam James <sam@gentoo.org>
Link: https://lore.kernel.org/20250729182406.155422551@kernel.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-07-31 10:20:11 -04:00
..
bpf bpf: Specify access type of bpf_sysctl_get_name args 2025-06-23 21:50:44 -07:00
cgroup cgroup: A fix for v6.16-rc2 2025-06-18 14:25:50 -07:00
configs Kbuild updates for v6.16 2025-06-07 10:05:35 -07:00
debug TTY/Serial driver updates for 6.15-rc1 2025-04-02 18:17:33 -07:00
dma dma-mapping updates for Linux 6.16: 2025-05-27 20:09:06 -07:00
entry entry: Inline syscall_exit_to_user_mode() 2025-04-29 08:27:10 +02:00
events perf: Revert to requiring CAP_SYS_ADMIN for uprobes 2025-07-03 10:33:55 +02:00
futex futex: Verify under the lock if hash can be replaced 2025-06-11 17:24:09 +02:00
gcov kbuild: require gcc-8 and binutils-2.30 2025-04-30 21:53:35 +02:00
irq genirq/irq_sim: Initialize work context pointers properly 2025-06-13 15:36:35 +02:00
kcsan treewide, timers: Rename destroy_timer_on_stack() as timer_destroy_on_stack() 2025-05-08 19:49:33 +02:00
livepatch sched,livepatch: Untangle cond_resched() and live-patching 2025-05-14 13:16:24 +02:00
locking Generic: 2025-06-02 12:24:58 -07:00
module Kbuild updates for v6.16 2025-06-07 10:05:35 -07:00
power PM: Restrict swap use to later in the suspend sequence 2025-06-26 20:39:34 +02:00
printk printk changes for 6.15 2025-03-27 19:22:24 -07:00
rcu rcu: Return early if callback is not specified 2025-06-20 15:31:48 -04:00
sched sched/deadline: Fix dl_server runtime calculation formula 2025-07-04 10:35:56 +02:00
time posix-cpu-timers: fix race between handle_posix_cpu_timers() and posix_cpu_timer_del() 2025-06-13 10:55:49 -07:00
trace tracing: Fix filter logic error 2025-06-27 15:51:36 -04:00
unwind unwind: Add USED bit to only have one conditional on way back to user space 2025-07-31 10:20:11 -04:00
.gitignore
acct.c acct: block access to kernel internal filesystems 2025-02-12 12:24:16 +01:00
async.c async: Use a dedicated unbound workqueue with raised min_active 2024-02-09 11:13:59 -10:00
audit.c audit: record AUDIT_ANOM_* events regardless of presence of rules 2025-04-11 14:14:41 -04:00
audit.h audit: change context data from secid to lsm_prop 2024-10-11 14:34:16 -04:00
audit_fsnotify.c
audit_tree.c replace collect_mounts()/drop_collected_mounts() with a safer variant 2025-06-23 14:01:49 -04:00
audit_watch.c fs: add kern_path_locked_negative() 2025-04-15 11:32:34 +02:00
auditfilter.c audit: fix suffixed '/' filename matching 2024-12-05 19:22:38 -05:00
auditsc.c fs: dedup handling of struct filename init and refcounts bumps 2025-03-18 15:34:27 +01:00
backtracetest.c backtracetest: add MODULE_DESCRIPTION() 2024-06-24 22:24:55 -07:00
bounds.c bounds: Use the right number of bits for power-of-two CONFIG_NR_CPUS 2024-04-29 08:29:29 -07:00
capability.c capability: Remove unused has_capability 2025-03-07 22:03:09 -06:00
cfi.c Modules changes for 6.15-rc1 2025-03-30 15:44:36 -07:00
compat.c
configs.c
context_tracking.c context_tracking: Make RCU watch ct_kernel_exit_state() warning 2025-03-04 18:44:29 -08:00
cpu.c perf: Remove too early and redundant CPU hotplug handling 2025-05-08 21:50:19 +02:00
cpu_pm.c
crash_core.c crash: Use note name macros 2025-02-10 16:56:58 -08:00
crash_dump_dm_crypt.c crash_dump: retrieve dm crypt keys in kdump kernel 2025-05-21 10:48:21 -07:00
crash_reserve.c crash: fix spelling mistake "crahskernel" -> "crashkernel" 2025-05-11 17:54:10 -07:00
cred.c cred: remove old {override,revert}_creds() helpers 2024-12-02 11:25:09 +01:00
delayacct.c delayacct: remove redundant code and adjust indentation 2025-05-27 19:40:33 -07:00
dma.c
elfcorehdr.c crash: remove dependency of FA_DUMP on CRASH_DUMP 2024-02-23 17:48:22 -08:00
exec_domain.c
exit.c - Avoid a crash on a heterogeneous machine where not all cores support the 2025-06-22 10:11:45 -07:00
exit.h
extable.c
fail_function.c
fork.c unwind_user/deferred: Add unwind_user_faultable() 2025-07-29 14:46:07 -04:00
freezer.c sched/fair: Fix external p->on_rq users 2024-10-14 09:14:35 +02:00
gen_kheaders.sh Revert "kheaders: Ignore silly-rename files" 2025-03-15 21:22:52 +09:00
groups.c
hung_task.c hung_task: show the blocker task if the task is hung on semaphore 2025-05-11 17:54:08 -07:00
iomem.c mm/memremap: Pass down MEMREMAP_* flags to arch_memremap_wb() 2025-02-21 15:05:38 +01:00
irq_work.c kasan: make kasan_record_aux_stack_noalloc() the default behaviour 2025-01-13 22:40:36 -08:00
jump_label.c jump_label: Use RCU in all users of __module_text_address(). 2025-03-10 11:54:46 +01:00
kallsyms.c kallsyms: Remove KALLSYMS_ABSOLUTE_PERCPU 2025-02-18 10:16:04 +01:00
kallsyms_internal.h kallsyms: get rid of code for absolute kallsyms 2024-07-20 16:33:21 +09:00
kallsyms_selftest.c kallsyms: Use kthread_run_on_cpu() 2025-01-02 22:12:12 +01:00
kallsyms_selftest.h
kcmp.c kcmp: improve performance adding an unlikely hint to task comparisons 2025-02-21 10:25:33 +01:00
Kconfig.freezer
Kconfig.hz kernel: Fix "select" wording on HZ_250 description 2025-02-21 09:20:30 +01:00
Kconfig.kexec crashdump: add CONFIG_KEYS dependency 2025-06-25 15:55:04 -07:00
Kconfig.locks
Kconfig.preempt sched: No PREEMPT_RT=y for all{yes,mod}config 2024-11-07 15:25:05 +01:00
kcov.c kcov: mark in_softirq_really() as __always_inline 2024-12-30 17:59:08 -08:00
kexec.c crash: add a new kexec flag for hotplug support 2024-04-23 14:59:01 +10:00
kexec_core.c PM: Restrict swap use to later in the suspend sequence 2025-06-26 20:39:34 +02:00
kexec_elf.c kexec: initialize ELF lowest address to ULONG_MAX 2025-03-16 22:30:47 -07:00
kexec_file.c - The 3 patch series "hung_task: extend blocking task stacktrace dump to 2025-05-31 19:12:53 -07:00
kexec_handover.c kho: initialize tail pages for higher order folios properly 2025-06-19 20:48:02 -07:00
kexec_internal.h kexec: add KHO support to kexec file loads 2025-05-12 23:50:40 -07:00
kheaders.c kheaders: Simplify attribute through __BIN_ATTR_SIMPLE_RO() 2024-12-24 09:46:49 +01:00
kprobes.c kprobes: Use RCU in all users of __module_text_address(). 2025-03-10 11:54:46 +01:00
ksyms_common.c
ksysfs.c kernel/ksysfs.c: simplify bin_attribute definition 2025-01-07 16:59:15 +01:00
kthread.c treewide, timers: Rename from_timer() to timer_container_of() 2025-06-08 09:07:37 +02:00
latencytop.c treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
Makefile unwind_user: Add user space unwinding API with frame pointer support 2025-07-29 14:46:07 -04:00
module_signature.c
notifier.c reboot: move reboot_notifier_list to kernel/reboot.c 2024-11-05 17:12:31 -08:00
nsproxy.c kernel/nsproxy: remove unnecessary guards 2025-05-09 13:13:54 +02:00
padata.c padata: do not leak refcount in reorder_work 2025-05-19 13:44:16 +08:00
panic.c - The 3 patch series "hung_task: extend blocking task stacktrace dump to 2025-05-31 19:12:53 -07:00
params.c module: ensure that kobject_put() is safe for module type kobjects 2025-05-07 20:24:59 +02:00
pid.c pidfs: detect refcount bugs 2025-05-06 13:59:00 +02:00
pid_namespace.c pid: Do not set pid_max in new pid namespaces 2025-03-06 10:18:36 +01:00
pid_sysctl.h treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
profile.c profiling: remove profile=sleep support 2024-08-04 13:36:28 -07:00
ptrace.c ptrace: introduce PTRACE_SET_SYSCALL_INFO request 2025-05-11 17:48:15 -07:00
range.c
reboot.c - The 7 patch series "powerpc/crash: use generic crashkernel 2025-04-01 10:06:52 -07:00
regset.c regset: use kvzalloc() for regset_get_alloc() 2024-04-25 21:07:03 -07:00
relay.c relay: remove unused relay_late_setup_files 2025-05-11 17:54:09 -07:00
resource.c resource: replace open coded variant of DEFINE_RES() 2025-03-21 22:10:05 -07:00
resource_kunit.c resource, kunit: fix user-after-free in resource_test_region_intersects() 2024-10-09 12:47:19 -07:00
rseq.c rseq: Fix segfault on registration when rseq_cs is non-zero 2025-03-06 22:26:49 +01:00
scftorture.c scftorture: Handle NULL argument passed to scf_add_to_free_list(). 2024-11-14 16:09:51 -08:00
scs.c
seccomp.c seccomp: avoid the lock trip seccomp_filter_release in common case 2025-02-24 11:17:10 -08:00
signal.c signal: Move signal ctl tables into signal.c 2025-04-09 13:32:16 +02:00
smp.c CSD-lock pull request for v6.14 2025-01-28 11:34:03 -08:00
smpboot.c
smpboot.h
softirq.c lockdep: Fix wait context check on softirq for PREEMPT_RT 2025-03-25 10:46:44 +01:00
stackleak.c treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
stacktrace.c
static_call.c
static_call_inline.c Modules changes for 6.15-rc1 2025-03-30 15:44:36 -07:00
stop_machine.c sched/core: Fix migrate_swap() vs. hotplug 2025-07-01 15:02:03 +02:00
sys.c futex: Add basic infrastructure for local task local hash 2025-05-03 12:02:07 +02:00
sys_ni.c Probes updates for v6.11: 2024-07-18 12:19:20 -07:00
sysctl-test.c sysctl: move u8 register test to lib/test_sysctl.c 2025-04-14 14:13:41 +02:00
sysctl.c sparc: mv sparc sysctls into their own file under arch/sparc/kernel 2025-04-09 13:32:16 +02:00
task_work.c kasan: make kasan_record_aux_stack_noalloc() the default behaviour 2025-01-13 22:40:36 -08:00
taskstats.c fdget(), more trivial conversions 2024-11-03 01:28:06 -05:00
torture.c torture: Add get_torture_init_jiffies() for test-start time 2025-02-05 07:14:24 -08:00
tracepoint.c tracepoint: Print the function symbol when tracepoint_debug is set 2025-03-21 15:30:10 -04:00
tsacct.c tsacct: replace strncpy() with strscpy() 2024-07-12 16:39:53 -07:00
ucount.c ucount: use rcuref_t for reference counting 2025-03-16 22:30:50 -07:00
uid16.c
uid16.h
umh.c treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
up.c
user-return-notifier.c
user.c uidgid: make sure we fit into one cacheline 2024-09-12 12:16:09 +02:00
user_namespace.c uidgid: add map_id_range_up() 2025-02-12 12:12:27 +01:00
usermode_driver.c
utsname.c
utsname_sysctl.c treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
vhost_task.c vhost_task: fix vhost_task_create() documentation 2025-04-18 10:08:11 -04:00
vmcore_info.c crash: export PAGE_UNACCEPTED_MAPCOUNT_VALUE to vmcoreinfo 2025-05-11 17:54:04 -07:00
watch_queue.c vfs-6.15-rc1.pipe 2025-03-24 09:52:37 -07:00
watchdog.c kernel/watchdog: add /sys/kernel/{hard,soft}lockup_count 2025-05-21 10:48:22 -07:00
watchdog_buddy.c
watchdog_perf.c - The 7 patch series "powerpc/crash: use generic crashkernel 2025-04-01 10:06:52 -07:00
workqueue.c workqueue: Initialize wq_isolated_cpumask in workqueue_init_early() 2025-06-17 08:58:29 -10:00
workqueue_internal.h