Paul E. McKenney
24bbf2d6a7
srcu: Provide ordering for CPU not involved in grace period ...
Tree RCU guarantees that every online CPU has a memory barrier between
any given grace period and any of that CPU's RCU read-side sections that
must be ordered against that grace period. Since RCU doesn't always
know where read-side critical sections are, the actual implementation
guarantees order against prior and subsequent non-idle non-offline code,
whether in an RCU read-side critical section or not. As a result, there
does not need to be a memory barrier at the end of synchronize_rcu()
and friends because the ordering internal to the grace period has
ordered every CPU's post-grace-period execution against each CPU's
pre-grace-period execution, again for all non-idle online CPUs.
In contrast, SRCU can have non-idle online CPUs that are completely
uninvolved in a given SRCU grace period, for example, a CPU that
never runs any SRCU read-side critical sections and took no part in
the grace-period processing. It is in theory possible for a given
synchronize_srcu()'s wakeup to be delivered to a CPU that was completely
uninvolved in the prior SRCU grace period, which could mean that the
code following that synchronize_srcu() would end up being unordered with
respect to both the grace period and any pre-existing SRCU read-side
critical sections.
This commit therefore adds an smp_mb() to the end of __synchronize_srcu(),
which prevents this scenario from occurring.
Reported-by: Lance Roy <ldr709@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Lance Roy <ldr709@gmail.com>
Cc: <stable@vger.kernel.org> # 4.12.x
Signed-off-by: Twisted <36546624+TwistedPrime@users.noreply.github.com>
Signed-off-by: Sorayukii <sorayukii69@gmail.com>
2026-05-15 17:49:32 +07:00
treewide: Backport new vmalloc for large performance benefits
2026-05-15 17:48:25 +07:00
UPSTREAM: kdb: use correct pointer when 'btc' calls 'btt'
2022-02-21 16:30:05 +01:00
Merge branch 'android-4.9-q' of https://android.googlesource.com/kernel/common into lineage-20
2023-01-19 15:42:12 +01:00
Merge branch 'android-4.9-q' of https://android.googlesource.com/kernel/common into lineage-20
2023-01-19 15:42:12 +01:00
Merge remote-tracking branch 'common/android-4.9-q' into android12-4.9-sdm845
2022-07-18 14:05:31 +03:00
BACKPORT: rcu: Ports some of RCU's taken from k4.14
2026-05-15 17:49:30 +07:00
treewide: Backport new vmalloc for large performance benefits
2026-05-15 17:48:25 +07:00
Merge remote-tracking branch 'common/android-4.9-q' into android12-4.9-sdm845
2022-06-12 01:39:01 +03:00
srcu: Provide ordering for CPU not involved in grace period
2026-05-15 17:49:32 +07:00
sched,rcu: Make cond_resched() provide RCU quiescent state
2026-05-15 17:49:30 +07:00
BACKPORT: rcu: Ports some of RCU's taken from k4.14
2026-05-15 17:49:30 +07:00
Merge branch 'android-4.9-q' of https://android.googlesource.com/kernel/common into lineage-20
2023-01-19 15:42:12 +01:00
BACKPORT: Provide in-kernel headers to make extending kernel easier
2019-07-03 14:30:53 -04:00
acct: fix potential integer overflow in encode_comp_t()
2023-01-07 12:07:31 +01:00
kernel/async.c: revert "async: simplify lowest_in_progress()"
2018-02-17 13:21:18 +01:00
Merge branch 'android-4.9-q' of https://android.googlesource.com/kernel/common into lineage-18.1-caf-sdm845
2021-04-26 01:27:02 +03:00
audit: fix a net reference leak in audit_list_rules_send()
2021-04-07 12:05:41 +02:00
audit: CONFIG_CHANGE don't log internal bookkeeping as an event
2020-10-01 20:40:07 +02:00
audit: fix a net reference leak in audit_list_rules_send()
2021-04-07 12:05:41 +02:00
Merge android-4.9.204(72e8598) into msm-4.9
2020-01-06 18:13:26 +08:00
kbuild: fix kernel/bounds.c 'W=1' warning
2018-11-13 11:16:57 -08:00
ANDROID: cfi: Remove unused variable in ptr_to_check_fn
2019-03-06 18:27:16 +00:00
Merge remote-tracking branch 'common/android-4.9-q' into android12-4.9-sdm845
2022-07-18 14:05:31 +03:00
cgroup: pids: use atomic64_t for pids->limit
2019-12-21 10:42:02 +01:00
rcu: Migrate callbacks earlier in the CPU-offline timeline
2026-05-15 17:49:31 +07:00
Merge branch 'android-4.9-q' of https://android.googlesource.com/kernel/common into HEAD
2020-06-30 02:33:58 +03:00
Merge android-4.9.183 ( a80a7ab) into msm-4.9
2019-08-07 16:30:28 +08:00
memcg: account security cred as well to kmemcg
2020-01-12 11:24:13 +01:00
BACKPORT: delayacct: track delays from thrashing cache pages
2019-03-22 14:08:39 -07:00
Merge remote-tracking branch 'common/android-4.9-q' into android12-4.9-sdm845
2022-09-06 06:20:26 +03:00
extable: Make init_kernel_text() global
2021-06-06 18:42:18 +03:00
BACKPORT: rcu: Ports some of RCU's taken from k4.14
2026-05-15 17:49:30 +07:00
mm, futex: fix shared futex pgoff on shmem huge page
2021-07-11 12:46:40 +02:00
BACKPORT: kheaders: Do not regenerate archive if config is not changed
2019-07-03 14:31:16 -04:00
treewide: Backport new vmalloc for large performance benefits
2026-05-15 17:48:25 +07:00
Merge android-4.9.170 ( 1ef64da) into msm-4.9
2019-05-30 14:15:13 +08:00
jump_label: Disable jump labels in __exit code
2021-06-06 18:42:18 +03:00
kallsyms: strip the .cfi postfix from symbols with CONFIG_CFI_CLANG
2018-02-28 15:09:58 -08:00
locking/rwsem: for rwsem prio aware enhancement
2019-01-08 16:14:39 +08:00
This is the 4.9.117 stable release
2018-08-03 08:50:05 +02:00
treewide: Backport new vmalloc for large performance benefits
2026-05-15 17:48:25 +07:00
Merge remote-tracking branch 'common/android-4.9-q' into android12-4.9-sdm845
2022-07-18 14:05:31 +03:00
BACKPORT: kheaders: Move from proc to sysfs
2019-07-03 14:31:02 -04:00
usermodehelper: reset umask to default before executing user process
2020-10-14 09:48:14 +02:00
This is the 4.9.327 stable release
2022-09-05 14:02:59 +02:00
Merge branch 'android-4.9-q' of https://android.googlesource.com/kernel/common into lineage-18.1-caf-sdm845
2021-07-22 02:11:11 +03:00
Merge branch 'android-4.9-q' of https://android.googlesource.com/kernel/common into lineage-18.1-caf-sdm845
2021-04-26 01:27:02 +03:00
mm, devm_memremap_pages: kill mapping "System RAM" support
2019-01-13 10:03:51 +01:00
treewide: Backport new vmalloc for large performance benefits
2026-05-15 17:48:25 +07:00
x86/mm: split vmalloc_sync_all()
2020-04-02 17:20:26 +02:00
padata: purge get_cpu and reorder_via_wq from padata_do_serial
2020-05-27 16:41:53 +02:00
Merge android-4.9.197(e9766ef) into msm-4.9
2019-12-06 19:41:21 +08:00
UPSTREAM: locking/atomic, kref: Add KREF_INIT()
2021-01-05 16:00:48 +00:00
memcg: enable accounting for pids in nested pid namespaces
2021-09-22 11:43:08 +02:00
profiling: fix shift-out-of-bounds bugs
2021-09-26 13:36:18 +02:00
ptrace: Reimplement PTRACE_KILL by always sending SIGKILL
2022-06-14 16:52:28 +02:00
reboot: fix overflow parsing reboot cpu number
2020-11-18 18:26:32 +01:00
kernel/relay.c: fix memleak on destroy relay channel
2020-08-26 10:29:03 +02:00
Merge android-4.9.96 ( 320d53a) into msm-4.9
2018-05-11 05:38:48 -07:00
seccomp: Add missing return in non-void function
2021-03-03 17:44:43 +01:00
BACKPORT: rcu: Ports some of RCU's taken from k4.14
2026-05-15 17:49:30 +07:00
Merge remote-tracking branch 'common/android-4.9-q' into android12-4.9-sdm845
2022-06-12 01:39:01 +03:00
sched/walt: Fix the memory leak of idle task load pointers
2018-09-20 19:00:55 +05:30
Mark HI and TASKLET softirq synchronous
2018-08-15 18:14:42 +02:00
stop_machine: Use raw spinlocks
2018-08-03 07:55:24 +02:00
Merge remote-tracking branch 'common/android-4.9-q' into lineage-18.1-caf-sdm845
2021-10-19 16:05:50 +03:00
BACKPORT: signal: support CLONE_PIDFD with pidfd_send_signal
2019-09-03 13:44:59 -07:00
Revert "add toggle for disabling newly added USB devices"
2023-03-01 21:14:36 +02:00
net/ipv6/addrconf: IPv6 tethering enhancement
2018-03-15 11:36:45 -07:00
taskstats: fix data-race
2020-01-12 11:24:12 +01:00
tracepoint: Do not fail unregistering a probe due to memory failure
2021-03-03 17:44:38 +01:00
taskstats: Cleanup the use of task->exit_code
2022-02-23 11:56:40 +01:00
kernel: make groups_sort calling a responsibility group_info allocators
2018-01-10 09:29:52 +01:00
ANDROID: proc: Add /proc/uid directory
2018-04-03 11:15:30 -07:00
userns: move user access out of the mutex
2018-09-09 20:01:24 +02:00
sys: don't hold uts_sem while accessing userspace memory
2018-09-09 20:01:24 +02:00
rcu: Create RCU-specific workqueues with rescuers
2026-05-15 17:49:31 +07:00
UPSTREAM: psi: fix aggregation idle shut-off
2019-03-22 14:15:01 -07:00
24bbf2d6a7