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| author | Konstantin Khlebnikov <khlebnikov@yandex-team.ru> | 2019-07-11 20:59:53 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-07-31 07:24:54 +0200 |
| commit | cf30a361a65b9a50251eefd5945c6efd7099a7ec (patch) | |
| tree | e76bb6f60dc52e75a113c515316e66880b531b5f | |
| parent | ba56ef5fc677828fc5bf0d8d9ce393005046b924 (diff) | |
| download | linux-stable-cf30a361a65b9a50251eefd5945c6efd7099a7ec.tar.gz linux-stable-cf30a361a65b9a50251eefd5945c6efd7099a7ec.tar.bz2 linux-stable-cf30a361a65b9a50251eefd5945c6efd7099a7ec.zip | |
proc: use down_read_killable mmap_sem for /proc/pid/smaps_rollup
[ Upstream commit a26a97815548574213fd37f29b4b78ccc6d9ed20 ]
Do not remain stuck forever if something goes wrong. Using a killable
lock permits cleanup of stuck tasks and simplifies investigation.
Link: http://lkml.kernel.org/r/156007493429.3335.14666825072272692455.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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | fs/proc/task_mmu.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 01d4eb0e6bd1..4d9a8e72d91f 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -828,7 +828,10 @@ static int show_smaps_rollup(struct seq_file *m, void *v) memset(&mss, 0, sizeof(mss)); - down_read(&mm->mmap_sem); + ret = down_read_killable(&mm->mmap_sem); + if (ret) + goto out_put_mm; + hold_task_mempolicy(priv); for (vma = priv->mm->mmap; vma; vma = vma->vm_next) { @@ -845,8 +848,9 @@ static int show_smaps_rollup(struct seq_file *m, void *v) release_task_mempolicy(priv); up_read(&mm->mmap_sem); - mmput(mm); +out_put_mm: + mmput(mm); out_put_task: put_task_struct(priv->task); priv->task = NULL; |