Yang Shi 2f09e7ee6d mm: introduce arg_lock to protect arg_start|end and env_start|end in mm_struct ... mmap_sem is on the hot path of kernel, and it very contended, but it is abused too. It is used to protect arg_start|end and evn_start|end when reading /proc/$PID/cmdline and /proc/$PID/environ, but it doesn't make sense since those proc files just expect to read 4 values atomically and not related to VM, they could be set to arbitrary values by C/R. And, the mmap_sem contention may cause unexpected issue like below: INFO: task ps:14018 blocked for more than 120 seconds. Tainted: G E 4.9.79-009.ali3000.alios7.x86_64 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ps D 0 14018 1 0x00000004 Call Trace: schedule+0x36/0x80 rwsem_down_read_failed+0xf0/0x150 call_rwsem_down_read_failed+0x18/0x30 down_read+0x20/0x40 proc_pid_cmdline_read+0xd9/0x4e0 __vfs_read+0x37/0x150 vfs_read+0x96/0x130 SyS_read+0x55/0xc0 entry_SYSCALL_64_fastpath+0x1a/0xc5 Both Alexey Dobriyan and Michal Hocko suggested to use dedicated lock for them to mitigate the abuse of mmap_sem. So, introduce a new spinlock in mm_struct to protect the concurrent access to arg_start|end, env_start|end and others, as well as replace write map_sem to read to protect the race condition between prctl and sys_brk which might break check_data_rlimit(), and makes prctl more friendly to other VM operations. This patch just eliminates the abuse of mmap_sem, but it can't resolve the above hung task warning completely since the later access_remote_vm() call needs acquire mmap_sem. The mmap_sem scalability issue will be solved in the future. [yang.shi@linux.alibaba.com: add comment about mmap_sem and arg_lock] Link: http://lkml.kernel.org/r/1524077799-80690-1-git-send-email-yang.shi@linux.alibaba.com Link: http://lkml.kernel.org/r/1523730291-109696-1-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mateusz Guzik <mguzik@redhat.com> Cc: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2021-07-26 16:13:08 +08:00
..
bpf	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
cgroup	sched: /proc/cpuinfo in docker base on cpu quota	2020-07-16 14:59:05 +08:00
configs	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
debug	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
events	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
gcov	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
irq	irq: allow user manage irq affinity	2020-01-02 12:22:25 +08:00
livepatch	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
locking	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
power	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
printk	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
rcu	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
sched	backport wake affine upstream optimization	2021-03-17 17:00:12 +08:00
time	clocksource: add kernel.clocksource_unstable_cnt to track tsc unstable	2020-05-29 10:40:52 +08:00
tkernel	build: fix series of warnings	2020-06-04 18:43:47 +08:00
trace	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
.gitignore	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
Kconfig.freezer	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
Kconfig.hz	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
Kconfig.locks	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
Kconfig.preempt	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
Makefile	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
acct.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
async.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
audit.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
audit.h	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
audit_fsnotify.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
audit_tree.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
audit_watch.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
auditfilter.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
auditsc.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
backtracetest.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
bounds.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
capability.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
compat.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
configs.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
context_tracking.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
cpu.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
cpu_pm.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
crash_core.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
crash_dump.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
cred.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
delayacct.c	sched: add offline scheduler class	2020-03-02 22:03:09 +08:00
dma.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
elfcore.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
exec_domain.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
exit.c	sched: add offline scheduler class	2020-03-02 22:03:09 +08:00
extable.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
fork.c	mm: introduce arg_lock to protect arg_start|end and env_start|end in mm_struct	2021-07-26 16:13:08 +08:00
freezer.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
futex.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
futex_compat.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
groups.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
hung_task.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
irq_work.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
jump_label.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
kallsyms.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
kcmp.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
kcov.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
kexec.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
kexec_core.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
kexec_file.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
kexec_internal.h	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
kmod.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
kprobes.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
ksysfs.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
kthread.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
latencytop.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
memremap.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
module-internal.h	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
module.c	tkernel: add the kpatch kmod support	2020-01-02 12:15:37 +08:00
module_signing.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
notifier.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
nsproxy.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
padata.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
panic.c	kernel/panic: set crash_kexec_post_notifiers default to true	2020-01-02 12:17:31 +08:00
params.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
pid.c	vm:isolate max_map_count by pid namespace	2020-01-02 11:51:53 +08:00
pid_namespace.c	vm: add max_map_count isolate switch	2020-05-29 10:38:28 +08:00
profile.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
ptrace.c	tools: add ttools module to support ptrace protect	2020-01-02 15:12:03 +08:00
range.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
reboot.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
relay.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
resource.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
seccomp.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
signal.c	signal: add print_fatal_signals_src_dst sysctl to switch dump fatal signals from sender side	2020-01-02 11:44:57 +08:00
smp.c	smp: smp_call_function_many_async	2020-12-01 10:34:56 +08:00
smpboot.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
smpboot.h	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
softirq.c	softirq: enhance network latency	2020-10-16 11:55:22 +08:00
stacktrace.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
stop_machine.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
sys.c	mm: introduce arg_lock to protect arg_start|end and env_start|end in mm_struct	2021-07-26 16:13:08 +08:00
sys_ni.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
sysctl.c	net: rps using pvipi	2020-12-01 10:36:20 +08:00
sysctl_binary.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
task_work.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
taskstats.c	expose taskstats to all netspace	2020-01-02 12:00:26 +08:00
test_kprobes.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
torture.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
tracepoint.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
tsacct.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
ucount.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
uid16.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
umh.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
up.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
user-return-notifier.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
user.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
user_namespace.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
utsname.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
utsname_sysctl.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
watchdog.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
watchdog_hld.c	wathdog: add symbol info when panic by hard lockup	2020-01-02 11:50:31 +08:00
workqueue.c	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00
workqueue_internal.h	Init Repo base on 4.14.105 long term, and add base tlinux kernel interfaces	2020-01-02 10:51:04 +08:00