Jan Kara 4d4f11c356 rq-qos: fix missed wake-ups in rq_qos_throttle try two ... commit 11c7aa0ddea8611007768d3e6b58d45dc60a19e1 upstream. Commit 545fbd0775 ("rq-qos: fix missed wake-ups in rq_qos_throttle") tried to fix a problem that a process could be sleeping in rq_qos_wait() without anyone to wake it up. However the fix is not complete and the following can still happen: CPU1 (waiter1) CPU2 (waiter2) CPU3 (waker) rq_qos_wait() rq_qos_wait() acquire_inflight_cb() -> fails acquire_inflight_cb() -> fails completes IOs, inflight decreased prepare_to_wait_exclusive() prepare_to_wait_exclusive() has_sleeper = !wq_has_single_sleeper() -> true as there are two sleepers has_sleeper = !wq_has_single_sleeper() -> true io_schedule() io_schedule() Deadlock as now there's nobody to wakeup the two waiters. The logic automatically blocking when there are already sleepers is really subtle and the only way to make it work reliably is that we check whether there are some waiters in the queue when adding ourselves there. That way, we are guaranteed that at least the first process to enter the wait queue will recheck the waiting condition before going to sleep and thus guarantee forward progress. Fixes: 545fbd0775 ("rq-qos: fix missed wake-ups in rq_qos_throttle") CC: stable@vger.kernel.org Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20210607112613.25344-1-jack@suse.cz Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2021-07-19 08:53:16 +02:00
..
bpf	bpf: Fix up register-based shifts in interpreter to silence KUBSAN	2021-07-19 08:53:11 +02:00
cgroup	cgroup1: don't allow '\n' in renaming	2021-06-16 11:59:40 +02:00
configs	kvm_config: add CONFIG_VIRTIO_MENU	2018-10-24 20:55:56 -04:00
debug	kdb: Make memory allocations more robust	2021-03-04 10:26:10 +01:00
dma	swiotlb: fix "x86: Don't panic if can not alloc buffer for swiotlb"	2020-11-18 19:20:32 +01:00
events	perf: Fix data race between pin_count increment/decrement	2021-06-16 11:59:44 +02:00
gcov	gcov: re-fix clang-11+ support	2021-04-14 08:24:10 +02:00
irq	genirq/matrix: Prevent allocation counter corruption	2021-05-11 14:04:05 +02:00
livepatch	livepatch: Nullify obj->mod in klp_module_coming()'s error path	2019-08-19 13:03:37 +02:00
locking	lockding/lockdep: Avoid to find wrong lock dep path in check_irq_usage()	2021-07-14 16:53:15 +02:00
power	PM: EM: postpone creating the debugfs dir till fs_initcall	2021-03-30 14:35:28 +02:00
printk	printk: fix deadlock when kernel panic	2021-03-04 10:26:50 +01:00
rcu	rcu: Invoke rcu_spawn_core_kthreads() from rcu_spawn_gp_kthread()	2021-07-14 16:53:36 +02:00
sched	rq-qos: fix missed wake-ups in rq_qos_throttle try two	2021-07-19 08:53:16 +02:00
time	clocksource: Retry clock read if long delays detected	2021-07-14 16:53:18 +02:00
trace	tracepoint: Add tracepoint_probe_register_may_exist() for BPF tracing	2021-07-14 16:53:08 +02:00
.gitignore	kbuild: update config_data.gz only when the content of .config is changed	2021-05-11 14:04:16 +02:00
acct.c	acct_on(): don't mess with freeze protection	2019-04-04 21:04:13 -04:00
async.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441	2019-06-05 17:37:17 +02:00
audit_fsnotify.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157	2019-05-30 11:26:37 -07:00
audit_tree.c	fsnotify: switch send_to_group() and ->handle_event to const struct qstr *	2019-04-26 13:51:03 -04:00
audit_watch.c	audit: CONFIG_CHANGE don't log internal bookkeeping as an event	2020-10-01 13:17:32 +02:00
audit.c	audit: fix a net reference leak in audit_list_rules_send()	2020-06-22 09:30:59 +02:00
audit.h	audit: fix a net reference leak in audit_list_rules_send()	2020-06-22 09:30:59 +02:00
auditfilter.c	audit: fix a net reference leak in audit_list_rules_send()	2020-06-22 09:30:59 +02:00
auditsc.c	audit: enforce op for string fields	2019-05-28 17:46:43 -04:00
backtracetest.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441	2019-06-05 17:37:17 +02:00
bounds.c	kbuild: fix kernel/bounds.c 'W=1' warning	2018-10-31 08:54:14 -07:00
capability.c	LSM: add SafeSetID module that gates setid calls	2019-01-25 11:22:43 -08:00
compat.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500	2019-06-19 17:09:55 +02:00
configs.c	kernel/configs: Replace GPL boilerplate code with SPDX identifier	2019-07-30 18:34:15 +02:00
context_tracking.c	treewide: Add SPDX license identifier for missed files	2019-05-21 10:50:45 +02:00
cpu_pm.c	kernel/cpu_pm: Fix uninitted local in cpu_pm	2020-06-22 09:31:22 +02:00
cpu.c	cpu/hotplug: Cure the cpusets trainwreck	2021-07-19 08:53:15 +02:00
crash_core.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 230	2019-06-19 17:09:06 +02:00
crash_dump.c	treewide: Add SPDX license identifier for missed files	2019-05-21 10:50:45 +02:00
cred.c	keys: Fix request_key() cache	2020-01-17 19:48:42 +01:00
delayacct.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 25	2019-05-21 11:52:39 +02:00
dma.c
exec_domain.c
exit.c	don't dump the threads that had been already exiting when zapped.	2020-11-18 19:20:31 +01:00
extable.c	extable: Add function to search only kernel exception table	2019-08-21 22:23:48 +10:00
fail_function.c	fail_function: Remove a redundant mutex unlock	2020-11-24 13:29:18 +01:00
fork.c	exec: Transform exec_update_mutex into a rw_semaphore	2021-01-09 13:44:55 +01:00
freezer.c	Revert "libata, freezer: avoid block device removal while system is frozen"	2019-10-06 09:11:37 -06:00
futex.c	mm, futex: fix shared futex pgoff on shmem huge page	2021-06-30 08:47:55 -04:00
gen_kheaders.sh	kbuild: add variables for compression tools	2020-09-03 11:27:10 +02:00
groups.c
hung_task.c	treewide: Add SPDX license identifier for missed files	2019-05-21 10:50:45 +02:00
iomem.c	mm/nvdimm: add is_ioremap_addr and use that to check ioremap address	2019-07-12 11:05:40 -07:00
irq_work.c	treewide: Add SPDX license identifier for missed files	2019-05-21 10:50:45 +02:00
jump_label.c	jump_label: Don't warn on __exit jump entries	2019-08-29 15:10:10 +01:00
kallsyms.c	kallsyms: Refactor kallsyms_show_value() to take cred	2020-07-16 08:16:44 +02:00
kcmp.c	exec: Transform exec_update_mutex into a rw_semaphore	2021-01-09 13:44:55 +01:00
Kconfig.freezer	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
Kconfig.hz	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
Kconfig.locks	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
Kconfig.preempt	sched/rt, Kconfig: Unbreak def/oldconfig with CONFIG_PREEMPT=y	2019-07-22 18:05:11 +02:00
kcov.c	kcov: convert kcov.refcount to refcount_t	2019-03-07 18:32:02 -08:00
kexec_core.c	kernel: kexec: remove the lock operation of system_transition_mutex	2021-02-03 23:25:56 +01:00
kexec_elf.c	kexec_elf: support 32 bit ELF files	2019-09-06 23:58:44 +02:00
kexec_file.c	kernel: kexec_file: fix error return code of kexec_calculate_store_digests()	2021-05-19 10:08:28 +02:00
kexec_internal.h
kexec.c	kexec_load: Disable at runtime if the kernel is locked down	2019-08-19 21:54:15 -07:00
kheaders.c	kheaders: Move from proc to sysfs	2019-05-24 20:16:01 +02:00
kmod.c	kmod: make request_module() return an error when autoloading is disabled	2020-04-17 10:50:22 +02:00
kprobes.c	tracing/kprobe: Fix to support kretprobe events on unloaded modules	2021-02-13 13:52:54 +01:00
ksysfs.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 170	2019-05-30 11:26:39 -07:00
kthread.c	kthread_worker: fix return value when kthread_mod_delayed_work() races with kthread_cancel_delayed_work_sync()	2021-07-14 16:53:19 +02:00
latencytop.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441	2019-06-05 17:37:17 +02:00
Makefile	kbuild: update config_data.gz only when the content of .config is changed	2021-05-11 14:04:16 +02:00
module_signature.c	module: harden ELF info handling	2021-04-07 14:47:38 +02:00
module_signing.c	module: harden ELF info handling	2021-04-07 14:47:38 +02:00
module-internal.h	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36	2019-05-24 17:27:11 +02:00
module.c	module: limit enabling module.sig_enforce	2021-06-30 08:47:42 -04:00
notifier.c	kernel/notifier.c: intercept duplicate registrations to avoid infinite loops	2020-10-01 13:17:23 +02:00
nsproxy.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441	2019-06-05 17:37:17 +02:00
padata.c	padata: add separate cpuhp node for CPUHP_PADATA_DEAD	2020-06-17 16:40:22 +02:00
panic.c	panic: ensure preemption is disabled during panic()	2019-10-07 15:47:19 -07:00
params.c	lockdown: Lock down module params that specify hardware parameters (eg. ioport)	2019-08-19 21:54:16 -07:00
pid_namespace.c	proc/sysctl: add shared variables for range check	2019-07-18 17:08:07 -07:00
pid.c	kernel/pid.c: convert struct pid count to refcount_t	2019-07-16 19:23:24 -07:00
profile.c	treewide: Add SPDX license identifier for missed files	2019-05-21 10:50:45 +02:00
ptrace.c	ptrace: make ptrace() fail if the tracee changed its pid unexpectedly	2021-05-26 12:05:15 +02:00
range.c
reboot.c	reboot: fix overflow parsing reboot cpu number	2020-11-18 19:20:30 +01:00
relay.c	kernel/relay.c: fix memleak on destroy relay channel	2020-08-26 10:40:51 +02:00
resource.c	/dev/mem: Revoke mappings when a driver claims the region	2020-06-24 17:50:35 +02:00
rseq.c	signal: Remove task parameter from force_sig	2019-05-27 09:36:28 -05:00
seccomp.c	seccomp: Add missing return in non-void function	2021-03-04 10:26:45 +01:00
signal.c	ptrace: fix task_join_group_stop() for the case when current is traced	2020-11-10 12:37:24 +01:00
smp.c	smp: Fix smp_call_function_single_async prototype	2021-05-14 09:44:33 +02:00
smpboot.c	kthread: Extract KTHREAD_IS_PER_CPU	2021-02-07 15:35:49 +01:00
smpboot.h
softirq.c	Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2019-07-08 11:01:13 -07:00
stackleak.c	stackleak: Mark stackleak_track_stack() as notrace	2018-12-05 19:31:44 -08:00
stacktrace.c	stacktrace: Don't skip first entry on noncurrent tasks	2019-11-04 21:19:25 +01:00
stop_machine.c	stop_machine: Avoid potential race behaviour	2019-10-17 12:47:12 +02:00
sys_ni.c	arch: handle arches who do not yet define clone3	2019-06-21 01:54:53 +02:00
sys.c	kernel/sys.c: avoid copying possible padding bytes in copy_to_user	2020-10-01 13:17:23 +02:00
sysctl_binary.c	kernel/sysctl: add panic_print into sysctl	2019-01-04 13:13:47 -08:00
sysctl-test.c	kernel/sysctl-test: Add null pointer test for sysctl.c:proc_dointvec()	2020-10-01 13:17:10 +02:00
sysctl.c	sysctl.c: fix underflow value setting risk in vm_table	2021-03-17 17:03:45 +01:00
task_work.c
taskstats.c	taskstats: fix data-race	2020-01-09 10:19:54 +01:00
test_kprobes.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 25	2019-05-21 11:52:39 +02:00
torture.c	torture: Remove exporting of internal functions	2019-08-01 14:30:22 -07:00
tracepoint.c	tracepoint: Add tracepoint_probe_register_may_exist() for BPF tracing	2021-07-14 16:53:08 +02:00
tsacct.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157	2019-05-30 11:26:37 -07:00
ucount.c	proc/sysctl: add shared variables for range check	2019-07-18 17:08:07 -07:00
uid16.c
uid16.h
umh.c	usermodehelper: reset umask to default before executing user process	2020-10-14 10:32:58 +02:00
up.c	smp: Fix smp_call_function_single_async prototype	2021-05-14 09:44:33 +02:00
user_namespace.c	Keyrings namespacing	2019-07-08 19:36:47 -07:00
user-return-notifier.c	treewide: Add SPDX license identifier for missed files	2019-05-21 10:50:45 +02:00
user.c	Keyrings namespacing	2019-07-08 19:36:47 -07:00
utsname_sysctl.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441	2019-06-05 17:37:17 +02:00
utsname.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441	2019-06-05 17:37:17 +02:00
watchdog_hld.c	kernel/watchdog_hld.c: hard lockup message should end with a newline	2019-04-19 09:46:05 -07:00
watchdog.c	watchdog/softlockup: Enforce that timestamp is valid on boot	2020-02-24 08:36:52 +01:00
workqueue_internal.h	sched/core, workqueues: Distangle worker accounting from rq lock	2019-04-16 16:55:15 +02:00
workqueue.c	wq: handle VM suspension in stall detection	2021-06-16 11:59:35 +02:00