The patch titled
Subject: proc: use down_read_killable mmap_sem for /proc/pid/maps
has been added to the -mm tree. Its filename is
proc-use-down_read_killable-mmap_sem-for-proc-pid-maps.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/proc-use-down_read_killable-mmap_sem-for-proc-pid-maps.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/proc-use-down_read_killable-mmap_sem-for-proc-pid-maps.patch
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The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
Subject: proc: use down_read_killable mmap_sem for /proc/pid/maps
Do not remain stuck forever if something goes wrong. Using a killable
lock permits cleanup of stuck tasks and simplifies investigation.
This function is also used for /proc/pid/smaps.
Link: http://lkml.kernel.org/r/156007493160.3335.14447544314127417266.stgit@buzz
Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
Reviewed-by: Roman Gushchin <guro@xxxxxx>
Reviewed-by: Cyrill Gorcunov <gorcunov@xxxxxxxxx>
Reviewed-by: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Michal Koutný <mkoutny@xxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/task_mmu.c | 6 +++++-
fs/proc/task_nommu.c | 6 +++++-
2 files changed, 10 insertions(+), 2 deletions(-)
--- a/fs/proc/task_mmu.c~proc-use-down_read_killable-mmap_sem-for-proc-pid-maps
+++ a/fs/proc/task_mmu.c
@@ -166,7 +166,11 @@ static void *m_start(struct seq_file *m,
if (!mm || !mmget_not_zero(mm))
return NULL;
- down_read(&mm->mmap_sem);
+ if (down_read_killable(&mm->mmap_sem)) {
+ mmput(mm);
+ return ERR_PTR(-EINTR);
+ }
+
hold_task_mempolicy(priv);
priv->tail_vma = get_gate_vma(mm);
--- a/fs/proc/task_nommu.c~proc-use-down_read_killable-mmap_sem-for-proc-pid-maps
+++ a/fs/proc/task_nommu.c
@@ -211,7 +211,11 @@ static void *m_start(struct seq_file *m,
if (!mm || !mmget_not_zero(mm))
return NULL;
- down_read(&mm->mmap_sem);
+ if (down_read_killable(&mm->mmap_sem)) {
+ mmput(mm);
+ return ERR_PTR(-EINTR);
+ }
+
/* start from the Nth VMA */
for (p = rb_first(&mm->mm_rb); p; p = rb_next(p))
if (n-- == 0)
_
Patches currently in -mm which might be from khlebnikov@xxxxxxxxxxxxxx are
proc-use-down_read_killable-mmap_sem-for-proc-pid-maps.patch
proc-use-down_read_killable-mmap_sem-for-proc-pid-smaps_rollup.patch
proc-use-down_read_killable-mmap_sem-for-proc-pid-pagemap.patch
proc-use-down_read_killable-mmap_sem-for-proc-pid-clear_refs.patch
proc-use-down_read_killable-mmap_sem-for-proc-pid-map_files.patch
mm-use-down_read_killable-for-locking-mmap_sem-in-access_remote_vm.patch
