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| author |   Konstantin Khlebnikov <khlebnikov@yandex-team.ru> | 2019-07-11 21:00:00 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2019-07-12 11:05:47 -0700 |
| commit | c46038017fbdcac627b670c9d4176f1d0c2f5fa3 (patch) | |
| tree | 5529fe8c15d395da61cba375ed13a35ff544ce34 /fs/proc | |
| parent | proc: use down_read_killable mmap_sem for /proc/pid/pagemap (diff) | |
| download | linux-dev-c46038017fbdcac627b670c9d4176f1d0c2f5fa3.tar.xz linux-dev-c46038017fbdcac627b670c9d4176f1d0c2f5fa3.zip | |
proc: use down_read_killable mmap_sem for /proc/pid/clear_refs
Do not remain stuck forever if something goes wrong. Using a killable
lock permits cleanup of stuck tasks and simplifies investigation.
Replace the only unkillable mmap_sem lock in clear_refs_write().
Link: http://lkml.kernel.org/r/156007493826.3335.5424884725467456239.stgit@buzz
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@gmail.com>
Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/proc')
| -rw-r--r-- | fs/proc/task_mmu.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 78bed6adc62d..7f84d1477b5b 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1140,7 +1140,10 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf, goto out_mm; } - down_read(&mm->mmap_sem); + if (down_read_killable(&mm->mmap_sem)) { + count = -EINTR; + goto out_mm; + } tlb_gather_mmu(&tlb, mm, 0, -1); if (type == CLEAR_REFS_SOFT_DIRTY) { for (vma = mm->mmap; vma; vma = vma->vm_next) { |