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d5d2c51f1e
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Sebastian Andrzej Siewior d5d2c51f1e kcov: replace local_irq_save() with a local_lock_t 
The kcov code mixes local_irq_save() and spin_lock() in
kcov_remote_{start|end}().  This creates a warning on PREEMPT_RT because
local_irq_save() disables interrupts and spin_lock_t is turned into a
sleeping lock which can not be acquired in a section with disabled
interrupts.

The kcov_remote_lock is used to synchronize the access to the hash-list
kcov_remote_map.  The local_irq_save() block protects access to the
per-CPU data kcov_percpu_data.

There is no compelling reason to change the lock type to raw_spin_lock_t
to make it work with local_irq_save().  Changing it would require to
move memory allocation (in kcov_remote_add()) and deallocation outside
of the locked section.

Adding an unlimited amount of entries to the hashlist will increase the
IRQ-off time during lookup.  It could be argued that this is debug code
and the latency does not matter.  There is however no need to do so and
it would allow to use this facility in an RT enabled build.

Using a local_lock_t instead of local_irq_save() has the befit of adding
a protection scope within the source which makes it obvious what is
protected.  On a !PREEMPT_RT && !LOCKDEP build the local_lock_irqsave()
maps directly to local_irq_save() so there is overhead at runtime.

Replace the local_irq_save() section with a local_lock_t.

Link: https://lkml.kernel.org/r/20210923164741.1859522-6-bigeasy@linutronix.de
Link: https://lore.kernel.org/r/20210830172627.267989-6-bigeasy@linutronix.de
Reported-by: Clark Williams <williams@redhat.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Marco Elver <elver@google.com>
Tested-by: Marco Elver <elver@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-11-09 10:02:52 -08:00
..
bpf bpf: Fix potential race in tail call compatibility check 2021-10-26 12:37:28 -07:00
cgroup mm/page_alloc: detect allocation forbidden by cpuset and bail out early 2021-11-06 13:30:38 -07:00
configs drivers/char: remove /dev/kmem for good 2021-05-07 00:26:34 -07:00
debug kgdb patches for 5.15 2021-09-07 12:08:04 -07:00
dma memblock: use memblock_free for freeing virtual pointers 2021-11-06 13:30:41 -07:00
entry entry: rseq: Call rseq_handle_notify_resume() in tracehook_notify_resume() 2021-09-22 10:24:01 -04:00
events perf/core: fix userpage->time_enabled of inactive events 2021-10-01 13:57:54 +02:00
gcov Kconfig: Introduce ARCH_WANTS_NO_INSTR and CC_HAS_NO_PROFILE_FN_ATTR 2021-06-22 11:07:18 -07:00
irq irqchip fixes for 5.15, take #1 2021-09-24 14:11:04 +02:00
kcsan LKMM updates: 2021-09-02 13:00:15 -07:00
livepatch livepatch: Replace deprecated CPU-hotplug functions. 2021-08-19 12:00:24 +02:00
locking kallsyms: remove arch specific text and data check 2021-11-09 10:02:50 -08:00
power Merge branches 'pm-pci', 'pm-sleep', 'pm-domains' and 'powercap' 2021-08-30 19:25:42 +02:00
printk memblock: use memblock_free for freeing virtual pointers 2021-11-06 13:30:41 -07:00
rcu Updates for locking and atomics: 2021-08-30 14:26:36 -07:00
sched mm: move node_reclaim_distance to fix NUMA without SMP 2021-11-06 13:30:38 -07:00
time posix-cpu-timers: Prevent spuriously armed 0-value itimer 2021-09-23 11:53:51 +02:00
trace sections: move and rename core_kernel_data() to is_kernel_core_data() 2021-11-09 10:02:50 -08:00
.gitignore .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
acct.c kernel/acct.c: use dedicated helper to access rlimit values 2021-09-08 11:50:26 -07:00
async.c kernel/async.c: remove async_unregister_domain() 2021-05-07 00:26:33 -07:00
audit_fsnotify.c audit_alloc_mark(): don't open-code ERR_CAST() 2021-02-23 10:25:27 -05:00
audit_tree.c audit: move put_tree() to avoid trim_trees refcount underflow and UAF 2021-08-24 18:52:36 -04:00
audit_watch.c
audit.c lsm: separate security_task_getsecid() into subjective and objective variants 2021-03-22 15:23:32 -04:00
audit.h audit: add header protection to kernel/audit.h 2021-07-19 22:38:24 -04:00
auditfilter.c lsm: separate security_task_getsecid() into subjective and objective variants 2021-03-22 15:23:32 -04:00
auditsc.c audit: fix possible null-pointer dereference in audit_filter_rules 2021-10-18 18:27:47 -04:00
backtracetest.c
bounds.c
capability.c capability: handle idmapped mounts 2021-01-24 14:27:16 +01:00
cfi.c cfi: Use rcu_read_{un}lock_sched_notrace 2021-08-11 13:11:12 -07:00
compat.c arch: remove compat_alloc_user_space 2021-09-08 15:32:35 -07:00
configs.c
context_tracking.c
cpu_pm.c PM: cpu: Make notifier chain use a raw_spinlock_t 2021-08-16 18:55:32 +02:00
cpu.c cpu/hotplug: Add debug printks for hotplug callback failures 2021-08-10 18:31:32 +02:00
crash_core.c kdump: use vmlinux_build_id to simplify 2021-07-08 11:48:22 -07:00
crash_dump.c
cred.c ucounts: Move get_ucounts from cred_alloc_blank to key_change_session_keyring 2021-10-20 10:34:20 -05:00
delayacct.c delayacct: Add sysctl to enable at runtime 2021-05-12 11:43:25 +02:00
dma.c
exec_domain.c
exit.c io_uring: remove files pointer in cancellation functions 2021-08-23 13:10:37 -06:00
extable.c extable: use is_kernel_text() helper 2021-11-09 10:02:51 -08:00
fail_function.c fault-injection: handle EI_ETYPE_TRUE 2020-12-15 22:46:19 -08:00
fork.c kernel/fork.c: unshare(): use swap() to make code cleaner 2021-11-09 10:02:52 -08:00
freezer.c sched: Add get_current_state() 2021-06-18 11:43:08 +02:00
futex.c futex: Remove unused variable 'vpid' in futex_proxy_trylock_atomic() 2021-09-03 23:00:22 +02:00
gen_kheaders.sh kbuild: clean up ${quiet} checks in shell scripts 2021-05-27 04:01:50 +09:00
groups.c groups: simplify struct group_info allocation 2021-02-26 09:41:03 -08:00
hung_task.c Merge branch 'akpm' (patches from Andrew) 2021-07-02 12:08:10 -07:00
iomem.c
irq_work.c irq_work: Make irq_work_queue() NMI-safe again 2021-06-10 10:00:08 +02:00
jump_label.c jump_label: Fix jump_label_text_reserved() vs __init 2021-07-05 10:46:20 +02:00
kallsyms.c module: add printk formats to add module build ID to stacktraces 2021-07-08 11:48:22 -07:00
kcmp.c Merge branch 'exec-update-lock-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2020-12-15 19:36:48 -08:00
Kconfig.freezer
Kconfig.hz
Kconfig.locks locking/rwlock: Provide RT variant 2021-08-17 17:50:51 +02:00
Kconfig.preempt sched/core: Disable CONFIG_SCHED_CORE by default 2021-06-28 22:43:05 +02:00
kcov.c kcov: replace local_irq_save() with a local_lock_t 2021-11-09 10:02:52 -08:00
kexec_core.c Merge branch 'rework/printk_safe-removal' into for-linus 2021-08-30 16:36:10 +02:00
kexec_elf.c
kexec_file.c memblock: add MEMBLOCK_DRIVER_MANAGED to mimic IORESOURCE_SYSRAM_DRIVER_MANAGED 2021-11-06 13:30:42 -07:00
kexec_internal.h kexec: move machine_kexec_post_load() to public interface 2021-02-22 12:33:26 +00:00
kexec.c kexec: avoid compat_alloc_user_space 2021-09-08 15:32:34 -07:00
kheaders.c
kmod.c modules: add CONFIG_MODPROBE_PATH 2021-05-07 00:26:33 -07:00
kprobes.c Locking fixes: 2021-07-11 11:06:09 -07:00
ksysfs.c
kthread.c Merge branch 'akpm' (patches from Andrew) 2021-06-29 17:29:11 -07:00
latencytop.c
Makefile kbuild: update config_data.gz only when the content of .config is changed 2021-05-02 00:43:35 +09:00
module_signature.c module: harden ELF info handling 2021-01-19 10:24:45 +01:00
module_signing.c module: harden ELF info handling 2021-01-19 10:24:45 +01:00
module-internal.h
module.c module: fix clang CFI with MODULE_UNLOAD=n 2021-09-28 12:56:26 +02:00
notifier.c notifier: Remove atomic_notifier_call_chain_robust() 2021-08-16 18:55:32 +02:00
nsproxy.c memcg: enable accounting for new namesapces and struct nsproxy 2021-09-03 09:58:12 -07:00
padata.c padata: Remove repeated verbose license text 2021-08-27 16:30:18 +08:00
panic.c Merge branch 'rework/printk_safe-removal' into for-linus 2021-08-30 16:36:10 +02:00
params.c params: lift param_set_uint_minmax to common code 2021-08-16 14:42:22 +02:00
pid_namespace.c memcg: enable accounting for new namesapces and struct nsproxy 2021-09-03 09:58:12 -07:00
pid.c kernel/pid.c: implement additional checks upon pidfd_create() parameters 2021-08-10 12:53:07 +02:00
profile.c profiling: fix shift-out-of-bounds bugs 2021-09-08 11:50:26 -07:00
ptrace.c sched: Change task_struct::state 2021-06-18 11:43:09 +02:00
range.c
reboot.c reboot: Add hardware protection power-off 2021-06-21 13:08:36 +01:00
regset.c
relay.c relay: allow the use of const callback structs 2020-12-15 22:46:18 -08:00
resource_kunit.c
resource.c kernel/resource: fix return code check in __request_free_mem_region 2021-05-14 19:41:32 -07:00
rseq.c KVM: rseq: Update rseq when processing NOTIFY_RESUME on xfer to KVM guest 2021-09-22 10:24:01 -04:00
scftorture.c scftorture: Avoid NULL pointer exception on early exit 2021-07-27 11:39:30 -07:00
scs.c
seccomp.c Merge branch 'exit-cleanups-for-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2021-09-01 14:52:05 -07:00
signal.c Merge branch 'ucount-fixes-for-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2021-10-21 17:27:17 -10:00
smp.c smp: Fix all kernel-doc warnings 2021-08-11 14:47:16 +02:00
smpboot.c smpboot: Replace deprecated CPU-hotplug functions. 2021-08-10 14:57:42 +02:00
smpboot.h
softirq.c genirq: Change force_irqthreads to a static key 2021-08-10 22:50:07 +02:00
stackleak.c
stacktrace.c stacktrace: move filter_irq_stacks() to kernel/stacktrace.c 2021-11-06 13:30:43 -07:00
static_call.c static_call: Fix static_call_text_reserved() vs __init 2021-07-05 10:46:33 +02:00
stop_machine.c stop_machine: Add caller debug info to queue_stop_cpus_work 2021-03-23 16:01:58 +01:00
sys_ni.c compat: remove some compat entry points 2021-09-08 15:32:35 -07:00
sys.c Merge branch 'akpm' (patches from Andrew) 2021-09-08 12:55:35 -07:00
sysctl-test.c kernel/sysctl-test: Remove some casts which are no-longer required 2021-06-23 16:41:24 -06:00
sysctl.c Merge branch 'akpm' (patches from Andrew) 2021-09-03 10:08:28 -07:00
task_work.c kasan: record task_work_add() call stack 2021-04-30 11:20:42 -07:00
taskstats.c
test_kprobes.c
torture.c torture: Replace deprecated CPU-hotplug functions. 2021-08-10 10:48:07 -07:00
tracepoint.c tracepoint: Fix kerneldoc comments 2021-08-16 11:39:51 -04:00
tsacct.c mm/mmap.c: fix a data race of mm->total_vm 2021-11-06 13:30:35 -07:00
ucount.c ucounts: Fix signal ucount refcounting 2021-10-18 16:02:30 -05:00
uid16.c
uid16.h
umh.c kernel/umh.c: fix some spelling mistakes 2021-05-07 00:26:34 -07:00
up.c A set of locking related fixes and updates: 2021-05-09 13:07:03 -07:00
user_namespace.c memcg: enable accounting for new namesapces and struct nsproxy 2021-09-03 09:58:12 -07:00
user-return-notifier.c
user.c fs/epoll: use a per-cpu counter for user's watches count 2021-09-08 11:50:27 -07:00
usermode_driver.c Merge branch 'work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2021-07-03 11:41:14 -07:00
utsname_sysctl.c
utsname.c
watch_queue.c watch_queue: rectify kernel-doc for init_watch() 2021-01-26 11:16:34 +00:00
watchdog_hld.c
watchdog.c kernel: watchdog: modify the explanation related to watchdog thread 2021-06-29 10:53:46 -07:00
workqueue_internal.h workqueue: Assign a color to barrier work items 2021-08-17 07:49:10 -10:00
workqueue.c workqueue, kasan: avoid alloc_pages() when recording stack 2021-11-06 13:30:33 -07:00