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Yang Shi 88aa7cc688 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>
 		2018-06-07 17:34:34 -07:00
..
bpf bpf: implement bpf_get_current_cgroup_id() helper 2018-06-03 18:22:41 -07:00
cgroup - Introduce arithmetic overflow test helper functions (Rasmus) 2018-06-06 17:27:14 -07:00
configs KVM changes for 4.16 2018-02-10 13:16:35 -08:00
debug * Fix 2032 time access issues and new compiler warnings 2018-04-12 10:21:19 -07:00
events Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-06-06 18:39:49 -07:00
gcov License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
irq Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-04 19:59:22 -07:00
livepatch livepatch: Allow to call a custom callback when freeing shadow variables 2018-04-17 13:42:48 +02:00
locking Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-04 16:40:11 -07:00
power Power management updates for 4.18-rc1 2018-06-05 09:38:39 -07:00
printk Printk changes for 4.18 2018-06-06 16:04:55 -07:00
rcu rcu/x86: Provide early rcu_cpu_starting() callback 2018-05-22 16:12:26 -07:00
sched Power management updates for 4.18-rc1 2018-06-05 09:38:39 -07:00
time Power management updates for 4.18-rc1 2018-06-05 09:38:39 -07:00
trace powerpc updates for 4.18 2018-06-07 10:23:33 -07:00
.gitignore
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Kconfig.freezer
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Kconfig.hz
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Kconfig.locks
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Kconfig.preempt
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Makefile error-injection: Support fault injection framework 2018-01-12 17:33:38 -08:00
acct.c kernel/acct.c: fix the acct->needcheck check in check_free_space() 2018-01-04 16:45:09 -08:00
async.c kernel/async.c: revert "async: simplify lowest_in_progress()" 2018-02-06 18:32:44 -08:00
audit.c audit: use inline function to get audit context 2018-05-14 17:24:18 -04:00
audit.h audit: track the owner of the command mutex ourselves 2018-02-23 11:22:22 -05:00
audit_fsnotify.c
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audit_tree.c audit: track the owner of the command mutex ourselves 2018-02-23 11:22:22 -05:00
audit_watch.c audit: use inline function to get audit context 2018-05-14 17:24:18 -04:00
auditfilter.c audit: use existing session info function 2018-05-18 15:47:54 -04:00
auditsc.c audit: Fix wrong task in comparison of session ID 2018-05-21 14:27:43 -04:00
backtracetest.c
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bounds.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
capability.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
compat.c Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-04 20:27:54 -07:00
configs.c
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context_tracking.c
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cpu.c cpu/hotplug: Fix unused function warning 2018-03-15 20:34:40 +01:00
cpu_pm.c PM / CPU: replace raw_notifier with atomic_notifier 2017-07-31 13:09:49 +02:00
crash_core.c kexec: export PG_swapbacked to VMCOREINFO 2018-04-13 17:10:27 -07:00
crash_dump.c
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cred.c
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delayacct.c delayacct: Use raw_spinlocks 2018-04-27 14:34:51 +02:00
dma.c proc: introduce proc_create_single{,_data} 2018-05-16 07:23:35 +02:00
elfcore.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
exec_domain.c proc: introduce proc_create_single{,_data} 2018-05-16 07:23:35 +02:00
exit.c kernel: use kernel_wait4() instead of sys_wait4() 2018-04-02 20:14:51 +02:00
extable.c extable: Make init_kernel_text() global 2018-02-21 16:54:06 +01:00
fail_function.c error-injection: Fix to prohibit jump optimization 2018-03-12 16:16:00 +01:00
fork.c mm: introduce arg_lock to protect arg_start|end and env_start|end in mm_struct 2018-06-07 17:34:34 -07:00
freezer.c
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futex.c pids: introduce find_get_task_by_vpid() helper 2018-02-06 18:32:46 -08:00
futex_compat.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
groups.c kernel: make groups_sort calling a responsibility group_info allocators 2017-12-14 16:00:49 -08:00
hung_task.c
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irq_work.c irq/work: Improve the flag definitions 2018-01-08 19:43:15 +01:00
jump_label.c jump_label: Disable jump labels in __exit code 2018-03-20 08:57:17 +01:00
kallsyms.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk 2018-02-01 13:36:15 -08:00
kcmp.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kcov.c kcov: detect double association with a single task 2018-02-06 18:32:46 -08:00
kexec.c kexec: call do_kexec_load() in compat syscall directly 2018-04-02 20:15:01 +02:00
kexec_core.c x86/mm, kexec: Allow kexec to be used with SME 2017-07-18 11:38:04 +02:00
kexec_file.c kernel/kexec_file.c: allow archs to set purgatory load address 2018-04-13 17:10:28 -07:00
kexec_internal.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kmod.c kmod: move #ifdef CONFIG_MODULES wrapper to Makefile 2017-09-08 18:26:51 -07:00
kprobes.c kprobes: Fix random address output of blacklist file 2018-04-25 10:27:56 -04:00
ksysfs.c
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kthread.c kthread: Allow kthread_park() on a parked kthread 2018-05-25 08:03:51 +02:00
latencytop.c
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memremap.c kernel/memremap: Remove stale devres_free() call 2018-03-06 10:58:54 -08:00
module-internal.h
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module.c - Introduce arithmetic overflow test helper functions (Rasmus) 2018-06-06 17:27:14 -07:00
module_signing.c
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notifier.c
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nsproxy.c
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padata.c padata: add SPDX identifier 2018-01-05 18:43:00 +11:00
panic.c taint: add taint for randstruct 2018-04-11 10:28:35 -07:00
params.c kernel/params.c: downgrade warning for unsafe parameters 2018-04-11 10:28:37 -07:00
pid.c xarray: add the xa_lock to the radix_tree_root 2018-04-11 10:28:39 -07:00
pid_namespace.c Merge branch 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2018-04-03 19:15:32 -07:00
profile.c
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ptrace.c pids: introduce find_get_task_by_vpid() helper 2018-02-06 18:32:46 -08:00
range.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
reboot.c kernel/reboot.c: add devm_register_reboot_notifier() 2017-11-17 16:10:04 -08:00
relay.c kernel/relay.c: limit kmalloc size to KMALLOC_MAX_SIZE 2018-02-21 15:35:43 -08:00
resource.c resource: switch to proc_create_seq_data 2018-05-16 07:24:30 +02:00
seccomp.c audit/stable-4.18 PR 20180605 2018-06-06 16:34:00 -07:00
signal.c Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2018-06-04 15:23:48 -07:00
smp.c smp/core: Use lockdep to assert IRQs are disabled/enabled 2017-11-08 11:13:50 +01:00
smpboot.c watchdog/core, powerpc: Lock cpus across reconfiguration 2017-10-04 10:53:54 +02:00
smpboot.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
softirq.c Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-04 19:59:22 -07:00
stacktrace.c
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stop_machine.c Linux 4.17-rc5 2018-05-15 08:10:50 +02:00
sys.c mm: introduce arg_lock to protect arg_start|end and env_start|end in mm_struct 2018-06-07 17:34:34 -07:00
sys_ni.c powerpc updates for 4.18 2018-06-07 10:23:33 -07:00
sysctl.c kernel/sysctl.c: add kdoc comments to do_proc_do{u}intvec_minmax_conv_param 2018-04-11 10:28:38 -07:00
sysctl_binary.c staging: irda: remove remaining remants of irda code removal 2018-04-16 11:26:49 +02:00
task_work.c locking/barriers: Convert users of lockless_dereference() to READ_ONCE() 2017-12-17 13:57:15 +01:00
taskstats.c pids: introduce find_get_task_by_vpid() helper 2018-02-06 18:32:46 -08:00
test_kprobes.c kprobes: Disable the jprobes test code 2017-10-20 11:02:54 +02:00
torture.c rcu: Rename cond_resched_rcu_qs() to cond_resched_tasks_rcu_qs() 2018-05-15 10:27:29 -07:00
tracepoint.c tracepoints: Fix the descriptions of tracepoint_probe_register{_prio} 2018-05-28 12:49:51 -04:00
tsacct.c
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ucount.c headers: untangle kmemleak.h from mm.h 2018-04-05 21:36:27 -07:00
uid16.c fs: add do_fchownat(), ksys_fchown() helpers and ksys_{,l}chown() wrappers 2018-04-02 20:15:59 +02:00
uid16.h kernel: provide ksys_*() wrappers for syscalls called by kernel/uid16.c 2018-04-02 20:15:30 +02:00
umh.c umh: introduce fork_usermode_blob() helper 2018-05-23 13:23:39 -04:00
up.c smp: Avoid using two cache lines for struct call_single_data 2017-08-29 15:14:38 +02:00
user-return-notifier.c
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user.c efivarfs: Limit the rate for non-root to read files 2018-02-22 10:21:02 -08:00
user_namespace.c fuse: Restrict allow_other to the superblock's namespace or a descendant 2018-03-20 17:11:44 +01:00
utsname.c uts: create "struct uts_namespace" from kmem_cache 2018-04-11 10:28:35 -07:00
utsname_sysctl.c
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watchdog.c Merge branch 'linus' into sched/core, to pick up fixes 2017-11-08 10:17:15 +01:00
watchdog_hld.c Merge branch 'linus' into core/urgent, to pick up dependent commits 2017-11-04 08:53:04 +01:00
workqueue.c - Introduce arithmetic overflow test helper functions (Rasmus) 2018-06-06 17:27:14 -07:00
workqueue_internal.h workqueue: Set worker->desc to workqueue name by default 2018-05-18 08:47:13 -07:00