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2009-08-18mm: revert "oom: move oom_adj value"KOSAKI Motohiro1-16/+3
The commit 2ff05b2b (oom: move oom_adj value) moveed the oom_adj value to the mm_struct. It was a very good first step for sanitize OOM. However Paul Menage reported the commit makes regression to his job scheduler. Current OOM logic can kill OOM_DISABLED process. Why? His program has the code of similar to the following. ... set_oom_adj(OOM_DISABLE); /* The job scheduler never killed by oom */ ... if (vfork() == 0) { set_oom_adj(0); /* Invoked child can be killed */ execve("foo-bar-cmd"); } .... vfork() parent and child are shared the same mm_struct. then above set_oom_adj(0) doesn't only change oom_adj for vfork() child, it's also change oom_adj for vfork() parent. Then, vfork() parent (job scheduler) lost OOM immune and it was killed. Actually, fork-setting-exec idiom is very frequently used in userland program. We must not break this assumption. Then, this patch revert commit 2ff05b2b and related commit. Reverted commit list --------------------- - commit 2ff05b2b4e (oom: move oom_adj value from task_struct to mm_struct) - commit 4d8b9135c3 (oom: avoid unnecessary mm locking and scanning for OOM_DISABLE) - commit 8123681022 (oom: only oom kill exiting tasks with attached memory) - commit 933b787b57 (mm: copy over oom_adj value at fork time) Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-08-10mm_for_maps: take ->cred_guard_mutex to fix the race with execOleg Nesterov1-11/+11
The problem is minor, but without ->cred_guard_mutex held we can race with exec() and get the new ->mm but check old creds. Now we do not need to re-check task->mm after ptrace_may_access(), it can't be changed to the new mm under us. Strictly speaking, this also fixes another very minor problem. Unless security check fails or the task exits mm_for_maps() should never return NULL, the caller should get either old or new ->mm. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-08-10mm_for_maps: shift down_read(mmap_sem) to the callerOleg Nesterov3-5/+5
mm_for_maps() takes ->mmap_sem after security checks, this looks strange and obfuscates the locking rules. Move this lock to its single caller, m_start(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-08-10mm_for_maps: simplify, use ptrace_may_access()Oleg Nesterov1-12/+11
It would be nice to kill __ptrace_may_access(). It requires task_lock(), but this lock is only needed to read mm->flags in the middle. Convert mm_for_maps() to use ptrace_may_access(), this also simplifies the code a little bit. Also, we do not need to take ->mmap_sem in advance. In fact I think mm_for_maps() should not play with ->mmap_sem at all, the caller should take this lock. With or without this patch, without ->cred_guard_mutex held we can race with exec() and get the new ->mm but check old creds. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-06-18proc: vmcore - use kzalloc in get_new_element()Cyrill Gorcunov1-6/+1
Instead of kmalloc+memset better use straight kzalloc Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-18procfs: remove sparse errors in proc_devtree.cMichal Simek1-5/+5
CHECK fs/proc/proc_devtree.c fs/proc/proc_devtree.c:197:14: warning: Using plain integer as NULL pointer fs/proc/proc_devtree.c:203:34: warning: Using plain integer as NULL pointer fs/proc/proc_devtree.c:210:14: warning: Using plain integer as NULL pointer fs/proc/proc_devtree.c:223:26: warning: Using plain integer as NULL pointer fs/proc/proc_devtree.c:226:14: warning: Using plain integer as NULL pointer Signed-off-by: Michal Simek <monstr@monstr.eu> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-18proc: export statistics for softirq to /procKeika Kobayashi3-0/+60
Export statistics for softirq in /proc/softirqs and /proc/stat. 1. /proc/softirqs Implement /proc/softirqs which shows the number of softirq for each CPU like /proc/interrupts. 2. /proc/stat Add the "softirq" line to /proc/stat. This line shows the number of softirq for all cpu. The first column is the total of all softirqs and each subsequent column is the total for particular softirq. [kosaki.motohiro@jp.fujitsu.com: remove redundant for_each_possible_cpu() loop] Signed-off-by: Keika Kobayashi <kobayashi.kk@ncos.nec.co.jp> Reviewed-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16oom: move oom_adj value from task_struct to mm_structDavid Rientjes1-3/+16
The per-task oom_adj value is a characteristic of its mm more than the task itself since it's not possible to oom kill any thread that shares the mm. If a task were to be killed while attached to an mm that could not be freed because another thread were set to OOM_DISABLE, it would have needlessly been terminated since there is no potential for future memory freeing. This patch moves oomkilladj (now more appropriately named oom_adj) from struct task_struct to struct mm_struct. This requires task_lock() on a task to check its oom_adj value to protect against exec, but it's already necessary to take the lock when dereferencing the mm to find the total VM size for the badness heuristic. This fixes a livelock if the oom killer chooses a task and another thread sharing the same memory has an oom_adj value of OOM_DISABLE. This occurs because oom_kill_task() repeatedly returns 1 and refuses to kill the chosen task while select_bad_process() will repeatedly choose the same task during the next retry. Taking task_lock() in select_bad_process() to check for OOM_DISABLE and in oom_kill_task() to check for threads sharing the same memory will be removed in the next patch in this series where it will no longer be necessary. Writing to /proc/pid/oom_adj for a kthread will now return -EINVAL since these threads are immune from oom killing already. They simply report an oom_adj value of OOM_DISABLE. Cc: Nick Piggin <npiggin@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16mm: remove CONFIG_UNEVICTABLE_LRU config optionKOSAKI Motohiro2-6/+0
Currently, nobody wants to turn UNEVICTABLE_LRU off. Thus this configurability is unnecessary. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Andi Kleen <andi@firstfloor.org> Acked-by: Minchan Kim <minchan.kim@gmail.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Matt Mackall <mpm@selenic.com> Cc: Rik van Riel <riel@redhat.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16proc: export more page flags in /proc/kpageflagsWu Fengguang1-32/+120
Export all page flags faithfully in /proc/kpageflags. 11. KPF_MMAP (pseudo flag) memory mapped page 12. KPF_ANON (pseudo flag) memory mapped page (anonymous) 13. KPF_SWAPCACHE page is in swap cache 14. KPF_SWAPBACKED page is swap/RAM backed 15. KPF_COMPOUND_HEAD (*) 16. KPF_COMPOUND_TAIL (*) 17. KPF_HUGE hugeTLB pages 18. KPF_UNEVICTABLE page is in the unevictable LRU list 19. KPF_HWPOISON(TBD) hardware detected corruption 20. KPF_NOPAGE (pseudo flag) no page frame at the address 32-39. more obscure flags for kernel developers (*) For compound pages, exporting _both_ head/tail info enables users to tell where a compound page starts/ends, and its order. The accompanying page-types tool will handle the details like decoupling overloaded flags and hiding obscure flags to normal users. Thanks to KOSAKI and Andi for their valuable recommendations! Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Matt Mackall <mpm@selenic.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16proc: kpagecount/kpageflags code cleanupWu Fengguang1-6/+11
Move increments of pfn/out to bottom of the loop. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Andi Kleen <andi@firstfloor.org> Acked-by: Matt Mackall <mpm@selenic.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16mm: introduce PageHuge() for testing huge/gigantic pagesWu Fengguang1-0/+1
A series of patches to enhance the /proc/pagemap interface and to add a userspace executable which can be used to present the pagemap data. Export 10 more flags to end users (and more for kernel developers): 11. KPF_MMAP (pseudo flag) memory mapped page 12. KPF_ANON (pseudo flag) memory mapped page (anonymous) 13. KPF_SWAPCACHE page is in swap cache 14. KPF_SWAPBACKED page is swap/RAM backed 15. KPF_COMPOUND_HEAD (*) 16. KPF_COMPOUND_TAIL (*) 17. KPF_HUGE hugeTLB pages 18. KPF_UNEVICTABLE page is in the unevictable LRU list 19. KPF_HWPOISON hardware detected corruption 20. KPF_NOPAGE (pseudo flag) no page frame at the address (*) For compound pages, exporting _both_ head/tail info enables users to tell where a compound page starts/ends, and its order. a simple demo of the page-types tool # ./page-types -h page-types [options] -r|--raw Raw mode, for kernel developers -a|--addr addr-spec Walk a range of pages -b|--bits bits-spec Walk pages with specified bits -l|--list Show page details in ranges -L|--list-each Show page details one by one -N|--no-summary Don't show summay info -h|--help Show this usage message addr-spec: N one page at offset N (unit: pages) N+M pages range from N to N+M-1 N,M pages range from N to M-1 N, pages range from N to end ,M pages range from 0 to M bits-spec: bit1,bit2 (flags & (bit1|bit2)) != 0 bit1,bit2=bit1 (flags & (bit1|bit2)) == bit1 bit1,~bit2 (flags & (bit1|bit2)) == bit1 =bit1,bit2 flags == (bit1|bit2) bit-names: locked error referenced uptodate dirty lru active slab writeback reclaim buddy mmap anonymous swapcache swapbacked compound_head compound_tail huge unevictable hwpoison nopage reserved(r) mlocked(r) mappedtodisk(r) private(r) private_2(r) owner_private(r) arch(r) uncached(r) readahead(o) slob_free(o) slub_frozen(o) slub_debug(o) (r) raw mode bits (o) overloaded bits # ./page-types flags page-count MB symbolic-flags long-symbolic-flags 0x0000000000000000 487369 1903 _________________________________ 0x0000000000000014 5 0 __R_D____________________________ referenced,dirty 0x0000000000000020 1 0 _____l___________________________ lru 0x0000000000000024 34 0 __R__l___________________________ referenced,lru 0x0000000000000028 3838 14 ___U_l___________________________ uptodate,lru 0x0001000000000028 48 0 ___U_l_______________________I___ uptodate,lru,readahead 0x000000000000002c 6478 25 __RU_l___________________________ referenced,uptodate,lru 0x000100000000002c 47 0 __RU_l_______________________I___ referenced,uptodate,lru,readahead 0x0000000000000040 8344 32 ______A__________________________ active 0x0000000000000060 1 0 _____lA__________________________ lru,active 0x0000000000000068 348 1 ___U_lA__________________________ uptodate,lru,active 0x0001000000000068 12 0 ___U_lA______________________I___ uptodate,lru,active,readahead 0x000000000000006c 988 3 __RU_lA__________________________ referenced,uptodate,lru,active 0x000100000000006c 48 0 __RU_lA______________________I___ referenced,uptodate,lru,active,readahead 0x0000000000004078 1 0 ___UDlA_______b__________________ uptodate,dirty,lru,active,swapbacked 0x000000000000407c 34 0 __RUDlA_______b__________________ referenced,uptodate,dirty,lru,active,swapbacked 0x0000000000000400 503 1 __________B______________________ buddy 0x0000000000000804 1 0 __R________M_____________________ referenced,mmap 0x0000000000000828 1029 4 ___U_l_____M_____________________ uptodate,lru,mmap 0x0001000000000828 43 0 ___U_l_____M_________________I___ uptodate,lru,mmap,readahead 0x000000000000082c 382 1 __RU_l_____M_____________________ referenced,uptodate,lru,mmap 0x000100000000082c 12 0 __RU_l_____M_________________I___ referenced,uptodate,lru,mmap,readahead 0x0000000000000868 192 0 ___U_lA____M_____________________ uptodate,lru,active,mmap 0x0001000000000868 12 0 ___U_lA____M_________________I___ uptodate,lru,active,mmap,readahead 0x000000000000086c 800 3 __RU_lA____M_____________________ referenced,uptodate,lru,active,mmap 0x000100000000086c 31 0 __RU_lA____M_________________I___ referenced,uptodate,lru,active,mmap,readahead 0x0000000000004878 2 0 ___UDlA____M__b__________________ uptodate,dirty,lru,active,mmap,swapbacked 0x0000000000001000 492 1 ____________a____________________ anonymous 0x0000000000005808 4 0 ___U_______Ma_b__________________ uptodate,mmap,anonymous,swapbacked 0x0000000000005868 2839 11 ___U_lA____Ma_b__________________ uptodate,lru,active,mmap,anonymous,swapbacked 0x000000000000586c 30 0 __RU_lA____Ma_b__________________ referenced,uptodate,lru,active,mmap,anonymous,swapbacked total 513968 2007 # ./page-types -r flags page-count MB symbolic-flags long-symbolic-flags 0x0000000000000000 468002 1828 _________________________________ 0x0000000100000000 19102 74 _____________________r___________ reserved 0x0000000000008000 41 0 _______________H_________________ compound_head 0x0000000000010000 188 0 ________________T________________ compound_tail 0x0000000000008014 1 0 __R_D__________H_________________ referenced,dirty,compound_head 0x0000000000010014 4 0 __R_D___________T________________ referenced,dirty,compound_tail 0x0000000000000020 1 0 _____l___________________________ lru 0x0000000800000024 34 0 __R__l__________________P________ referenced,lru,private 0x0000000000000028 3794 14 ___U_l___________________________ uptodate,lru 0x0001000000000028 46 0 ___U_l_______________________I___ uptodate,lru,readahead 0x0000000400000028 44 0 ___U_l_________________d_________ uptodate,lru,mappedtodisk 0x0001000400000028 2 0 ___U_l_________________d_____I___ uptodate,lru,mappedtodisk,readahead 0x000000000000002c 6434 25 __RU_l___________________________ referenced,uptodate,lru 0x000100000000002c 47 0 __RU_l_______________________I___ referenced,uptodate,lru,readahead 0x000000040000002c 14 0 __RU_l_________________d_________ referenced,uptodate,lru,mappedtodisk 0x000000080000002c 30 0 __RU_l__________________P________ referenced,uptodate,lru,private 0x0000000800000040 8124 31 ______A_________________P________ active,private 0x0000000000000040 219 0 ______A__________________________ active 0x0000000800000060 1 0 _____lA_________________P________ lru,active,private 0x0000000000000068 322 1 ___U_lA__________________________ uptodate,lru,active 0x0001000000000068 12 0 ___U_lA______________________I___ uptodate,lru,active,readahead 0x0000000400000068 13 0 ___U_lA________________d_________ uptodate,lru,active,mappedtodisk 0x0000000800000068 12 0 ___U_lA_________________P________ uptodate,lru,active,private 0x000000000000006c 977 3 __RU_lA__________________________ referenced,uptodate,lru,active 0x000100000000006c 48 0 __RU_lA______________________I___ referenced,uptodate,lru,active,readahead 0x000000040000006c 5 0 __RU_lA________________d_________ referenced,uptodate,lru,active,mappedtodisk 0x000000080000006c 3 0 __RU_lA_________________P________ referenced,uptodate,lru,active,private 0x0000000c0000006c 3 0 __RU_lA________________dP________ referenced,uptodate,lru,active,mappedtodisk,private 0x0000000c00000068 1 0 ___U_lA________________dP________ uptodate,lru,active,mappedtodisk,private 0x0000000000004078 1 0 ___UDlA_______b__________________ uptodate,dirty,lru,active,swapbacked 0x000000000000407c 34 0 __RUDlA_______b__________________ referenced,uptodate,dirty,lru,active,swapbacked 0x0000000000000400 538 2 __________B______________________ buddy 0x0000000000000804 1 0 __R________M_____________________ referenced,mmap 0x0000000000000828 1029 4 ___U_l_____M_____________________ uptodate,lru,mmap 0x0001000000000828 43 0 ___U_l_____M_________________I___ uptodate,lru,mmap,readahead 0x000000000000082c 382 1 __RU_l_____M_____________________ referenced,uptodate,lru,mmap 0x000100000000082c 12 0 __RU_l_____M_________________I___ referenced,uptodate,lru,mmap,readahead 0x0000000000000868 192 0 ___U_lA____M_____________________ uptodate,lru,active,mmap 0x0001000000000868 12 0 ___U_lA____M_________________I___ uptodate,lru,active,mmap,readahead 0x000000000000086c 800 3 __RU_lA____M_____________________ referenced,uptodate,lru,active,mmap 0x000100000000086c 31 0 __RU_lA____M_________________I___ referenced,uptodate,lru,active,mmap,readahead 0x0000000000004878 2 0 ___UDlA____M__b__________________ uptodate,dirty,lru,active,mmap,swapbacked 0x0000000000001000 492 1 ____________a____________________ anonymous 0x0000000000005008 2 0 ___U________a_b__________________ uptodate,anonymous,swapbacked 0x0000000000005808 4 0 ___U_______Ma_b__________________ uptodate,mmap,anonymous,swapbacked 0x000000000000580c 1 0 __RU_______Ma_b__________________ referenced,uptodate,mmap,anonymous,swapbacked 0x0000000000005868 2839 11 ___U_lA____Ma_b__________________ uptodate,lru,active,mmap,anonymous,swapbacked 0x000000000000586c 29 0 __RU_lA____Ma_b__________________ referenced,uptodate,lru,active,mmap,anonymous,swapbacked total 513968 2007 # ./page-types --raw --list --no-summary --bits reserved offset count flags 0 15 _____________________r___________ 31 4 _____________________r___________ 159 97 _____________________r___________ 4096 2067 _____________________r___________ 6752 2390 _____________________r___________ 9355 3 _____________________r___________ 9728 14526 _____________________r___________ This patch: Introduce PageHuge(), which identifies huge/gigantic pages by their dedicated compound destructor functions. Also move prep_compound_gigantic_page() to hugetlb.c and make __free_pages_ok() non-static. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Matt Mackall <mpm@selenic.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11Move junk from proc_fs.h to fs/proc/internal.hAl Viro2-0/+26
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11Merge branch 'next' into for-linusJames Morris1-0/+6
2009-06-10Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tipLinus Torvalds1-12/+6
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: sched: fix typo in sched-rt-group.txt file ftrace: fix typo about map of kernel priority in ftrace.txt file. sched: properly define the sched_group::cpumask and sched_domain::span fields sched, timers: cleanup avenrun users sched, timers: move calc_load() to scheduler sched: Don't export sched_mc_power_savings on multi-socket single core system sched: emit thread info flags with stack trace sched: rt: document the risk of small values in the bandwidth settings sched: Replace first_cpu() with cpumask_first() in ILB nomination code sched: remove extra call overhead for schedule() sched: use group_first_cpu() instead of cpumask_first(sched_group_cpus()) wait: don't use __wake_up_common() sched: Nominate a power-efficient ilb in select_nohz_balancer() sched: Nominate idle load balancer from a semi-idle package. sched: remove redundant hierarchy walk in check_preempt_wakeup
2009-06-09Merge branch 'master' into nextJames Morris1-1/+1
2009-05-29procfs: make errno values consistent when open pident vs exit(2) race occursKOSAKI Motohiro1-1/+1
proc_pident_instantiate() has following call flow. proc_pident_lookup() proc_pident_instantiate() proc_pid_make_inode() And, proc_pident_lookup() has following error handling. const struct pid_entry *p, *last; error = ERR_PTR(-ENOENT); if (!task) goto out_no_task; Then, proc_pident_instantiate should return ENOENT too when racing against exit(2) occur. EINAL has two bad reason. - it implies caller is wrong. bad the race isn't caller's mistake. - man 2 open don't explain EINVAL. user often don't handle it. Note: Other proc_pid_make_inode() caller already use ENOENT properly. Acked-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-05-22Merge branch 'master' into nextJames Morris1-2/+1
Conflicts: fs/exec.c Removed IMA changes (the IMA checks are now performed via may_open()). Signed-off-by: James Morris <jmorris@namei.org>
2009-05-15sched, timers: cleanup avenrun usersThomas Gleixner1-12/+6
avenrun is an rough estimate so we don't have to worry about consistency of the three avenrun values. Remove the xtime lock dependency and provide a function to scale the values. Cleanup the users. [ Impact: cleanup ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org>
2009-05-11CRED: Guard the setprocattr security hook against ptraceDavid Howells1-0/+6
Guard the setprocattr security hook against ptrace by taking the target task's cred_guard_mutex around it. The problem is that setprocattr() may otherwise note the lack of a debugger, and then perform an action on that basis whilst letting a debugger attach between the two points. Holding cred_guard_mutex across the test and the action prevents ptrace_attach() from doing that. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-05-09Convert obvious places to deactivate_locked_super()Al Viro1-2/+1
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-05-04proc: avoid information leaks to non-privileged processesJake Edge2-5/+13
By using the same test as is used for /proc/pid/maps and /proc/pid/smaps, only allow processes that can ptrace() a given process to see information that might be used to bypass address space layout randomization (ASLR). These include eip, esp, wchan, and start_stack in /proc/pid/stat as well as the non-symbolic output from /proc/pid/wchan. ASLR can be bypassed by sampling eip as shown by the proof-of-concept code at http://code.google.com/p/fuzzyaslr/ As part of a presentation (http://www.cr0.org/paper/to-jt-linux-alsr-leak.pdf) esp and wchan were also noted as possibly usable information leaks as well. The start_stack address also leaks potentially useful information. Cc: Stable Team <stable@kernel.org> Signed-off-by: Jake Edge <jake@lwn.net> Acked-by: Arjan van de Ven <arjan@linux.intel.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-05-02mm: fix Committed_AS underflow on large NR_CPUS environmentKOSAKI Motohiro1-1/+1
The Committed_AS field can underflow in certain situations: > # while true; do cat /proc/meminfo | grep _AS; sleep 1; done | uniq -c > 1 Committed_AS: 18446744073709323392 kB > 11 Committed_AS: 18446744073709455488 kB > 6 Committed_AS: 35136 kB > 5 Committed_AS: 18446744073709454400 kB > 7 Committed_AS: 35904 kB > 3 Committed_AS: 18446744073709453248 kB > 2 Committed_AS: 34752 kB > 9 Committed_AS: 18446744073709453248 kB > 8 Committed_AS: 34752 kB > 3 Committed_AS: 18446744073709320960 kB > 7 Committed_AS: 18446744073709454080 kB > 3 Committed_AS: 18446744073709320960 kB > 5 Committed_AS: 18446744073709454080 kB > 6 Committed_AS: 18446744073709320960 kB Because NR_CPUS can be greater than 1000 and meminfo_proc_show() does not check for underflow. But NR_CPUS proportional isn't good calculation. In general, possibility of lock contention is proportional to the number of online cpus, not theorical maximum cpus (NR_CPUS). The current kernel has generic percpu-counter stuff. using it is right way. it makes code simplify and percpu_counter_read_positive() don't make underflow issue. Reported-by: Dave Hansen <dave@linux.vnet.ibm.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Eric B Munson <ebmunson@us.ibm.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: <stable@kernel.org> [All kernel versions] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-05-02pagemap: require aligned-length, non-null reads of /proc/pid/pagemapVitaly Mayatskikh1-0/+4
The intention of commit aae8679b0ebcaa92f99c1c3cb0cd651594a43915 ("pagemap: fix bug in add_to_pagemap, require aligned-length reads of /proc/pid/pagemap") was to force reads of /proc/pid/pagemap to be a multiple of 8 bytes, but now it allows to read 0 bytes, which actually puts some data to user's buffer. According to POSIX, if count is zero, read() should return zero and has no other results. Signed-off-by: Vitaly Mayatskikh <v.mayatskih@gmail.com> Cc: Thomas Tuttle <ttuttle@google.com> Acked-by: Matt Mackall <mpm@selenic.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-23[S390] /proc/stat idle field for idle cpusMartin Schwidefsky1-0/+5
The cpu idle field in the output of /proc/stat is too small for cpus that have been idle for more than a tick. Add the architecture hook arch_idle_time that allows to add the not accounted idle time of a sleeping cpu without waking the cpu. The s390 implementation of arch_idle_time uses the already existing s390_idle_data per_cpu variable to find the sleep time of a neighboring idle cpu. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-04-16proc: mounts_poll() make consistent to mdstat_pollKOSAKI Motohiro1-2/+2
In recently sysfs_poll discussion, Neil Brown pointed out /proc/mounts also should be fixed. SUSv3 says "Regular files shall always poll TRUE for reading and writing". see http://www.opengroup.org/onlinepubs/009695399/functions/poll.html Then, mounts_poll()'s default should be "POLLIN | POLLRDNORM". it mean always readable. In addition, event trigger should use "POLLERR | POLLPRI" instead POLLERR. it makes consistent to mdstat_poll() and sysfs_poll(). and, select(2) can handle POLLPRI easily. Reported-by: Neil Brown <neilb@suse.de> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Ram Pai <linuxram@us.ibm.com> Cc: Miklos Szeredi <mszeredi@suse.cz> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-04-08nommu: fix typo vma->pg_off to vma->vm_pgoffNobuhiro Iwamatsu1-1/+1
6260a4b0521a41189b2c2a8119096c1e21dbdf2c ("/proc/pid/maps: don't show pgoff of pure ANON VMAs" had a typo. fs/proc/task_nommu.c:138: error: 'struct vm_area_struct' has no member named 'pg_off' distcc[21484] ERROR: compile fs/proc/task_nommu.c on sprygo/32 failed Signed-off-by: Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07/proc/pid/maps: don't show pgoff of pure ANON VMAsKAMEZAWA Hiroyuki2-2/+6
Recently, it's argued that what proc/pid/maps shows is ugly when a 32bit binary runs on 64bit host. /proc/pid/maps outputs vma's pgoff member but vma->pgoff is of no use information is the vma is for ANON. With this patch, /proc/pid/maps shows just 0 if no file backing store. [akpm@linux-foundation.org: coding-style fixes] [kamezawa.hiroyu@jp.fujitsu.com: coding-style fixes] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mike Waychison <mikew@google.com> Reported-by: Ying Han <yinghan@google.com> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-03Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivialLinus Torvalds1-1/+1
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (28 commits) trivial: Update my email address trivial: NULL noise: drivers/mtd/tests/mtd_*test.c trivial: NULL noise: drivers/media/dvb/frontends/drx397xD_fw.h trivial: Fix misspelling of "Celsius". trivial: remove unused variable 'path' in alloc_file() trivial: fix a pdlfush -> pdflush typo in comment trivial: jbd header comment typo fix for JBD_PARANOID_IOFAIL trivial: wusb: Storage class should be before const qualifier trivial: drivers/char/bsr.c: Storage class should be before const qualifier trivial: h8300: Storage class should be before const qualifier trivial: fix where cgroup documentation is not correctly referred to trivial: Give the right path in Documentation example trivial: MTD: remove EOL from MODULE_DESCRIPTION trivial: Fix typo in bio_split()'s documentation trivial: PWM: fix of #endif comment trivial: fix typos/grammar errors in Kconfig texts trivial: Fix misspelling of firmware trivial: cgroups: documentation typo and spelling corrections trivial: Update contact info for Jochen Hein trivial: fix typo "resgister" -> "register" ...
2009-04-02Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6Linus Torvalds2-1/+3
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: Remove two unneeded exports and make two symbols static in fs/mpage.c Cleanup after commit 585d3bc06f4ca57f975a5a1f698f65a45ea66225 Trim includes of fdtable.h Don't crap into descriptor table in binfmt_som Trim includes in binfmt_elf Don't mess with descriptor table in load_elf_binary() Get rid of indirect include of fs_struct.h New helper - current_umask() check_unsafe_exec() doesn't care about signal handlers sharing New locking/refcounting for fs_struct Take fs_struct handling to new file (fs/fs_struct.c) Get rid of bumping fs_struct refcount in pivot_root(2) Kill unsharing fs_struct in __set_personality()
2009-04-02nommu: fix a number of issues with the per-MM VMA patchDavid Howells2-3/+3
Fix a number of issues with the per-MM VMA patch: (1) Make mmap_pages_allocated an atomic_long_t, just in case this is used on a NOMMU system with more than 2G pages. Makes no difference on a 32-bit system. (2) Report vma->vm_pgoff * PAGE_SIZE as a 64-bit value, not a 32-bit value, lest it overflow. (3) Move the allocation of the vm_area_struct slab back for fork.c. (4) Use KMEM_CACHE() for both vm_area_struct and vm_region slabs. (5) Use BUG_ON() rather than if () BUG(). (6) Make the default validate_nommu_regions() a static inline rather than a #define. (7) Make free_page_series()'s objection to pages with a refcount != 1 more informative. (8) Adjust the __put_nommu_region() banner comment to indicate that the semaphore must be held for writing. (9) Limit the number of warnings about munmaps of non-mmapped regions. Reported-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David Howells <dhowells@redhat.com> Cc: Greg Ungerer <gerg@snapgear.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01proc tty: remove struct tty_operations::read_procAlexey Dobriyan1-14/+4
struct tty_operations::proc_fops took it's place and there is one less create_proc_read_entry() user now! Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01proc tty: add struct tty_operations::proc_fopsAlexey Dobriyan1-7/+13
Used for gradual switch of TTY drivers from using ->read_proc which helps with gradual switch from ->read_proc for the whole tree. As side effect, fix possible race condition when ->data initialized after PDE is hooked into proc tree. ->proc_fops takes precedence over ->read_proc. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-31Get rid of indirect include of fs_struct.hAl Viro2-0/+2
Don't pull it in sched.h; very few files actually need it and those can include directly. sched.h itself only needs forward declaration of struct fs_struct; Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-03-31New locking/refcounting for fs_structAl Viro1-1/+1
* all changes of current->fs are done under task_lock and write_lock of old fs->lock * refcount is not atomic anymore (same protection) * its decrements are done when removing reference from current; at the same time we decide whether to free it. * put_fs_struct() is gone * new field - ->in_exec. Set by check_unsafe_exec() if we are trying to do execve() and only subthreads share fs_struct. Cleared when finishing exec (success and failure alike). Makes CLONE_FS fail with -EAGAIN if set. * check_unsafe_exec() may fail with -EAGAIN if another execve() from subthread is in progress. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-03-31Revert "proc: revert /proc/uptime to ->read_proc hook"Alexey Dobriyan1-20/+18
This reverts commit 6c87df37dcb9c6c33923707fa5191e0a65874d60. proc files implemented through seq_file do pread(2) now. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
2009-03-31proc 2/2: remove struct proc_dir_entry::ownerAlexey Dobriyan2-17/+3
Setting ->owner as done currently (pde->owner = THIS_MODULE) is racy as correctly noted at bug #12454. Someone can lookup entry with NULL ->owner, thus not pinning enything, and release it later resulting in module refcount underflow. We can keep ->owner and supply it at registration time like ->proc_fops and ->data. But this leaves ->owner as easy-manipulative field (just one C assignment) and somebody will forget to unpin previous/pin current module when switching ->owner. ->proc_fops is declared as "const" which should give some thoughts. ->read_proc/->write_proc were just fixed to not require ->owner for protection. rmmod'ed directories will be empty and return "." and ".." -- no harm. And directories with tricky enough readdir and lookup shouldn't be modular. We definitely don't want such modular code. Removing ->owner will also make PDE smaller. So, let's nuke it. Kudos to Jeff Layton for reminding about this, let's say, oversight. http://bugzilla.kernel.org/show_bug.cgi?id=12454 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
2009-03-31proc 1/2: do PDE usecounting even for ->read_proc, ->write_procAlexey Dobriyan3-11/+40
struct proc_dir_entry::owner is going to be removed. Now it's only necessary to protect PDEs which are using ->read_proc, ->write_proc hooks. However, ->owner assignments are racy and make it very easy for someone to switch ->owner on live PDE (as some subsystems do) without fixing refcounts and so on. http://bugzilla.kernel.org/show_bug.cgi?id=12454 So, ->owner is on death row. Proxy file operations exist already (proc_file_operations), just bump usecount when necessary. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
2009-03-31proc: fix sparse warnings in pagemap_read()Milind Arun Choudhary1-4/+4
fs/proc/task_mmu.c:696:12: warning: cast removes address space of expression fs/proc/task_mmu.c:696:9: warning: incorrect type in assignment (different address spaces) fs/proc/task_mmu.c:696:9: expected unsigned long long [noderef] [usertype] <asn:1>*out fs/proc/task_mmu.c:696:9: got unsigned long long [usertype] *<noident> fs/proc/task_mmu.c:697:12: warning: cast removes address space of expression fs/proc/task_mmu.c:697:9: warning: incorrect type in assignment (different address spaces) fs/proc/task_mmu.c:697:9: expected unsigned long long [noderef] [usertype] <asn:1>*end fs/proc/task_mmu.c:697:9: got unsigned long long [usertype] *<noident> fs/proc/task_mmu.c:723:12: warning: cast removes address space of expression fs/proc/task_mmu.c:723:26: error: subtraction of different types can't work (different address spaces) fs/proc/task_mmu.c:725:24: error: subtraction of different types can't work (different address spaces) Signed-off-by: Milind Arun Choudhary <milindchoudhary@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
2009-03-31proc: move fs/proc/inode-alloc.txt comment into a source fileRandy Dunlap2-14/+15
so that people will realize that it exists and can update it as needed. Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
2009-03-30trivial: fix typo "kernal" -> "kernel"Uwe Kleine-Koenig1-1/+1
Signed-off-by: Uwe Kleine-Koenig <Uwe.Kleine-Koenig@digi.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-03-28fix setuid sometimes wouldn'tHugh Dickins1-34/+16
check_unsafe_exec() also notes whether the fs_struct is being shared by more threads than will get killed by the exec, and if so sets LSM_UNSAFE_SHARE to make bprm_set_creds() careful about euid. But /proc/<pid>/cwd and /proc/<pid>/root lookups make transient use of get_fs_struct(), which also raises that sharing count. This might occasionally cause a setuid program not to change euid, in the same way as happened with files->count (check_unsafe_exec also looks at sighand->count, but /proc doesn't raise that one). We'd prefer exec not to unshare fs_struct: so fix this in procfs, replacing get_fs_struct() by get_fs_path(), which does path_get while still holding task_lock, instead of raising fs->count. Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: stable@kernel.org ___ fs/proc/base.c | 50 +++++++++++++++-------------------------------- 1 file changed, 16 insertions(+), 34 deletions(-) Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-27vfs: simple_set_mnt() should return voidSukadev Bhattiprolu1-1/+2
simple_set_mnt() is defined as returning 'int' but always returns 0. Callers assume simple_set_mnt() never fails and don't properly cleanup if it were to _ever_ fail. For instance, get_sb_single() and get_sb_nodev() should: up_write(sb->s_unmount); deactivate_super(sb); if simple_set_mnt() fails. Since simple_set_mnt() never fails, would be cleaner if it did not return anything. [akpm@linux-foundation.org: fix build] Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-03-27constify dentry_operations: procfsAl Viro3-6/+6
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-03-17Avoid 64-bit "switch()" statements on 32-bit architecturesLinus Torvalds1-1/+1
Commit ee6f779b9e0851e2f7da292a9f58e0095edf615a ("filp->f_pos not correctly updated in proc_task_readdir") changed the proc code to use filp->f_pos directly, rather than through a temporary variable. In the process, that caused the operations to be done on the full 64 bits, even though the offset is never that big. That's all fine and dandy per se, but for some unfathomable reason gcc generates absolutely horrid code when using 64-bit values in switch() statements. To the point of actually calling out to gcc helper functions like __cmpdi2 rather than just doing the trivial comparisons directly the way gcc does for normal compares. At which point we get link failures, because we really don't want to support that kind of crazy code. Fix this by just casting the f_pos value to "unsigned long", which is plenty big enough for /proc, and avoids the gcc code generation issue. Reported-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Zhang Le <r0bertz@gentoo.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-16filp->f_pos not correctly updated in proc_task_readdirZhang Le1-9/+7
filp->f_pos only get updated at the end of the function. Thus d_off of those dirents who are in the middle will be 0, and this will cause a problem in glibc's readdir implementation, specifically endless loop. Because when overflow occurs, f_pos will be set to next dirent to read, however it will be 0, unless the next one is the last one. So it will start over again and again. There is a sample program in man 2 gendents. This is the output of the program running on a multithread program's task dir before this patch is applied: $ ./a.out /proc/3807/task --------------- nread=128 --------------- i-node# file type d_reclen d_off d_name 506442 directory 16 1 . 506441 directory 16 0 .. 506443 directory 16 0 3807 506444 directory 16 0 3809 506445 directory 16 0 3812 506446 directory 16 0 3861 506447 directory 16 0 3862 506448 directory 16 8 3863 This is the output after this patch is applied $ ./a.out /proc/3807/task --------------- nread=128 --------------- i-node# file type d_reclen d_off d_name 506442 directory 16 1 . 506441 directory 16 2 .. 506443 directory 16 3 3807 506444 directory 16 4 3809 506445 directory 16 5 3812 506446 directory 16 6 3861 506447 directory 16 7 3862 506448 directory 16 8 3863 Signed-off-by: Zhang Le <r0bertz@gentoo.org> Acked-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-11proc: fix kflags to uflags copying in /proc/kpageflagsWu Fengguang1-1/+1
Fix kpf_copy_bit(src,dst) to be kpf_copy_bit(dst,src) to match the actual call patterns, e.g. kpf_copy_bit(kflags, KPF_LOCKED, PG_locked). This misplacement of src/dst only affected reporting of PG_writeback, PG_reclaim and PG_buddy. For others kflags==uflags so not affected. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-24proc: fix PG_locked reporting in /proc/kpageflagsHelge Bahmann1-1/+1
Expr always evaluates to zero. Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
2009-02-23proc: proc_get_inode should de_put when inode already initializedKrzysztof Sachanowicz1-1/+3
de_get is called before every proc_get_inode, but corresponding de_put is called only when dropping last reference to an inode. This might cause something like remove_proc_entry: /proc/stats busy, count=14496 to be printed to the syslog. The fix is to call de_put in case of an already initialized inode in proc_get_inode. Signed-off-by: Krzysztof Sachanowicz <analyzer1@gmail.com> Tested-by: Marcin Pilipczuk <marcin.pilipczuk@gmail.com> Acked-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-09Merge git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-2.6-nommuLinus Torvalds4-74/+125
* git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-2.6-nommu: NOMMU: Support XIP on initramfs NOMMU: Teach kobjsize() about VMA regions. FLAT: Don't attempt to expand the userspace stack to fill the space allocated FDPIC: Don't attempt to expand the userspace stack to fill the space allocated NOMMU: Improve procfs output using per-MM VMAs NOMMU: Make mmap allocation page trimming behaviour configurable. NOMMU: Make VMAs per MM as for MMU-mode linux NOMMU: Delete askedalloc and realalloc variables NOMMU: Rename ARM's struct vm_region NOMMU: Fix cleanup handling in ramfs_nommu_get_umapped_area()